Sample records for atr-ftir spectroscopy detects

  1. Rapid detection of gelatin in dental materials using attenuated total reflection fourier transform infrared spectroscopy (ATR-FTIR) (United States)

    Irfanita, N.; Jaswir, I.; Mirghani, M. E. S.; Sukmasari, S.; Ardini, Y. D.; Lestari, W.


    The presence of gelatin is not limited to food products but has also been found in pharmaceuticals. Most dental materials available in Malaysia are imported from other countries and might contain gelatin which is a protein derived either from porcine, bovine or other animal sources. Authentication of gelatin is crucial due to religious and health concerns. Therefore, this study aimed to detect gelatin in dental materials using ATR-FTIR. Forty two samples of dental material were purchased from dental suppliers and detection was done using ATR-FTIR. The spectrum from each sample was compared against standard bovine and porcine gelatin. Experimental dental paste containing bovine and porcine gelatin at concentrations of 5, 10, 15 and 20% were also prepared for quantification analysis. The results showed that gelatin was present in nine out of forty two samples of dental materials but the species of origin was not confirmed. Meanwhile, in the experimental bovine and porcine dental paste, it was seen that as the concentration increased, the intensity of the absorption of Amide group also increased. Thus, ATR-FTIR can be utilized as a reliable tool to detect gelatin in dental materials and other pharmaceuticals.

  2. Preliminary Discrimination of Butter Adulteration by ATR-FTIR Spectroscopy

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    Lucian Cuibus


    Full Text Available The Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR  was applied for the discrimination of butter samples adulterated with solid fraction of palm oil. For FTIR fingerprinting of butter samples, with or without controlled additions of palm oil as adulterant was firstly obtained, using a Shimatsu Prestige 21 Spectrophotometer, including a horizontal diamond ATR accessory with reflection in the MIR region (3873-690 cm-1.The spiked butter samples including 0 level and seven increasing concentrations of palm fats, up to 50% were fingerprinted and the calibration curve was obtained (n=19. In parallel, the validation was realized using different set of spiked butter samples ranging 1-44.4 % of palm fat (n=7. Finally, an independent set of commercial samples was analized (n=14.Partial least squares (PLS model was used for statistical data processing in accordance with standard method. The value of the correlation coefficient (R2= 0.977 between actual and predicted values was statistically significant (p<0.001, considering the superposition of  "actual vs predicted” curves. This combined FTIR-PLS evaluation revealed that 3 out of  samples of butter were suspected of adulteration with palm oil, presented values 14 ranging 4-12%.In conclusion, ATR-FTIR methodology may offer an rapid evaluation of  butter samples authenticity. The low value for detection limit (3%palm oil in butter and the low limit of quantification (9.8% palm oil in butter confirms that ATR-FTIR spectroscopy  is a sensitive method to identify the adulteration of butter with  palm oil.   

  3. Detection and quantification of soymilk in cow-buffalo milk using Attenuated Total Reflectance Fourier Transform Infrared spectroscopy (ATR-FTIR). (United States)

    Jaiswal, Pranita; Jha, Shyam Narayan; Borah, Anjan; Gautam, Anuj; Grewal, Manpreet Kaur; Jindal, Gaurav


    Milk consumption is steadily increasing, especially in India and China, due to rising income. To bridge the gap between supply and demand, unscrupulous milk vendors add milk-like products from vegetable sources (soymilk) to milk without declaration. A rapid detection technique is required to enforce the safety norms of food regulatory authorities. Fourier Transform Infrared (FTIR) spectroscopy has demonstrated potential as a rapid quality monitoring method and was therefore explored for detection of soymilk in milk. In the present work, spectra of milk, soymilk (SM), and milk adulterated with known quantity of SM were acquired in the wave number range of 4000-500cm(-1) using Attenuated Total Reflectance (ATR)-FTIR. The acquired spectra revealed differences amongst milk, SM and adulterated milk (AM) samples in the wave number range of 1680-1058cm(-1). This region encompasses the absorption frequency of amide-I, amide-II, amide-III, beta-sheet protein, α-tocopherol and Soybean Kunitz Trypsin Inhibitor. Principal component analysis (PCA) showed clustering of samples based on SM concentration at 5% level of significance and thus SM could be detected in milk using ATR-FTIR. The SM was best predicted in the range of 1472-1241cm(-1) using multiple linear regression with coefficient of determination (R(2)) of 0.99 and 0.92 for calibration and validation, respectively. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. ATR-FTIR spectroscopy and chemometrics: An interesting tool to discriminate and characterize counterfeit medicines. (United States)

    Custers, D; Cauwenbergh, T; Bothy, J L; Courselle, P; De Beer, J O; Apers, S; Deconinck, E


    Counterfeit medicines pose a huge threat to public health worldwide. High amounts of counterfeit pharmaceuticals enter the European market and therefore detection of these products is essential. Attenuated Total Reflection Fourier-Transform infrared spectroscopy (ATR-FTIR) might be useful for the screening of counterfeit medicines since it is easy to use and little sample preparation is required. Furthermore, this approach might be helpful to customs to obtain a first evaluation of suspected samples. This study proposes a combination of ATR-FTIR and chemometrics to discriminate and classify counterfeit medicines. A sample set, containing 209 samples in total, was analyzed using ATR-FTIR and the obtained spectra were used as fingerprints in the chemometric data-analysis which included Principal Component Analysis (PCA), k-Nearest Neighbours (k-NN), Classification and Regression Trees (CART) and Soft Independent Modelling of Class Analogy (SIMCA). First it was verified whether the mentioned techniques are capable to distinguish samples containing different active pharmaceutical ingredients (APIs). PCA showed a clear tendency of discrimination based on the API present; k-NN, CART and SIMCA were capable to create suitable prediction models based on the presence of different APIs. However k-NN performs the least while SIMCA performs the best. Secondly, it was tested whether these three models could be expanded to discriminate between genuine and counterfeit samples as well. k-NN was not able to make the desired discrimination and therefore it was not useful. CART performed better but also this model was less suited. SIMCA, on the other hand, resulted in a model with a 100% correct discrimination between genuine and counterfeit drugs. This study shows that chemometric analysis of ATR-FTIR fingerprints is a valuable tool to discriminate genuine from counterfeit samples and to classify counterfeit medicines. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Hydroxyl accessibility in wood by deuterium exchange and ATR-FTIR spectroscopy

    DEFF Research Database (Denmark)

    Tarmian, Asghar; Burgert, Ingo; Thybring, Emil Engelund


    The accessibility of wood hydroxyls to water is commonly studied by infrared spectroscopy after deuteration where water-interacting hydroxyls have their H exchanged for D. In this study, the hydroxyl accessibility is determined with ATR-FTIR spectroscopy after deuteration of specimens with liquid D...

  6. Cutaneous approach towards clinical and pathophysiological aspects of hyperglycemia by ATR FTIR spectroscopy (United States)

    Eikje, Natalja Skrebova; Sota, Takayuki; Aizawa, Katsuo


    Attempts were made to non-invasively detect glucose-specific spectral signals in the skin by ATR-FTIR spectroscopy. In vivo spectra were collected from the inner wrists of healthy, prediabetes and diabetes subjects in the 750-4000 cm -1 region, with a closer assessment of the glucose-related region between 1000 and 1180 cm -1. Spectra in vivo showed glucose-specific peaks at 1030, 1080, 1118 and 1151 cm -1, as a variety of glucose solutions are found in vitro. Based on the differences of intensities at 1030 and 1118 cm -1 two spectral patterns were seen: I 1118 > I 1030 for a diabetes and I 1030> I 1118 for non-diabetes subjects. The peak at 1030 cm -1 was used to assess glucose concentrations in the skin due to its good correlation with glucose concentrations in vitro. Calculated mean values of the peak at 1030 cm -1 showed evidence of correlation with blood glucose levels when grouped as = 200 mg/dL, though there was no constant correlation between them when compared before/after OGTT or at the fasting/postprandial states. Absorbances at 1030 cm -1 were not only increased in a dose-dependent manner in a diabetes patient, but were also generally higher than in non-diabetes subjects at 30 min OGTT assessment. Also we could monitor absorbances at 1030 cm -1 and determine their changes in the skin tissue at different times of OGTT. We assume that our approach to in vivo measurement and monitoring of glucose concentrations at 1030 cm -1 may be one of the indicators to assess glucose activity level and its changes in the skin tissue, and has further implications in the study of clinical and pathophysiological aspects of hyperglycemia in diabetes and non-diabetes subjects by ATR-FTIR spectroscopy.

  7. Analysis of European honeybee (Apis mellifera) wings using ATR-FTIR and Raman spectroscopy: A pilot study

    Czech Academy of Sciences Publication Activity Database

    Machovič, Vladimír; Lapčák, L.; Havelcová, Martina; Borecká, Lenka; Novotná, M.; Novotná, M.; Javůrková, I.; Langrová, I.; Hájková, Š.; Brožová, A.; Titěra, D.


    Roč. 48, č. 1 (2017), s. 22-29 ISSN 1211-3174 Institutional support: RVO:67985891 Keywords : honeybee wings * ATR-FTIR * Raman spectroscopy * protein * lipid * chitin Subject RIV: CB - Analytical Chemistry, Separation OBOR OECD: Analytical chemistry

  8. Fast quantitative determination of microbial rhamnolipids from cultivation broths by ATR-FTIR Spectroscopy

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    Hausmann Rudolf


    Full Text Available Abstract Background Vibrational spectroscopic techniques are becoming increasingly important and popular because they have the potential to provide rapid and convenient solutions to routine analytical problems. Using these techniques, a variety of substances can be characterized, identified and also quantified rapidly. Results The rapid ATR-FTIR (Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy in time technique has been applied, which is suitable to quantify the concentrations of microbial rhamnolipids in a typical cultivation process. While the usually applied HPLC analysis requires an extensive and time consuming multi step extraction protocol for sample preparation, the ATR-FTIR-method allows the quantification of the rhamnolipids within 20 minutes. Accuracies between 0.5 g/l – 2.1 g/l for the different analytes were determined by cross validation of the calibration set. Even better accuracies between 0.28 g/l – 0.59 g/l were found for independent test samples of an arbitrarily selected cultivation. Conclusion ATR-FTIR was found to be suitable for the rapid analysis of rhamnolipids in a biotechnological process with good reproducibility in sample determination and sufficient accuracy. An improvement in accuracy through continuous expansion and validation of the reference spectra set seems very likely.

  9. Analysis of European Honeybee (Apis Mellifera Wings Using ATR-FTIR and Raman Spectroscopy: A Pilot Study

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    Machovič V.


    Full Text Available The infrared (ATR-FTIR and Raman spectroscopy was used for the structural characterization of honeybee wings. Protein, chitin, and lipid characteristic spectral features were detected using both methods. The protein secondary structure was predominantly composed of the β-sheet molecular conformation with β-turns or coil contributions. The vibration modes of the side-chain aromatic amino acid residues (tyrosine, phenylalanine, tryptophan occurred in the wing spectra. The results of discriminant analysis showed that the infrared spectroscopy of the wing in combination with a multivariate analysis seemed promising for a resolution of the chemical structure of the wings based on lipid, proteins, and chitin content.

  10. In vivo interstitial glucose characterization and monitoring in the skin by ATR-FTIR spectroscopy (United States)

    Skrebova Eikje, Natalja


    Successful development of real-time non-invasive glucose monitoring would represent a major advancement not only in the treatment and management of patients with diabetes mellitus and carbohydrate metabolism disorders, but also for understanding in those biochemical, metabolic and (patho-)physiological processes of glucose at the molecular level in vivo. Here, ATR-FTIR spectroscopy technique has been challenged not only for in vivo measurement of interstitial glucose levels, but also for their non-invasive molecular qualitative and quantitative comparative characterization in the skin tissue. The results, based on calculated mean values of determined 5 glucose-specific peaks in the glucose-related 1000-1160 cm-1 region, showed intra- and inter-subject differences in interstitial glucose activity levels with their changes at different times and doses of OGTT, while raising questions about the relationships between interstitial and blood glucose levels. In conclusion, the introduction of ATR-FTIR spectroscopy technique has opened up an access to the interstitial fluid space in the skin tissue for interstitial glucose characterization and monitoring in vivo. Though interstitial versus blood glucose monitoring has different characteristics, it can be argued that accurate and precise measurements of interstitial glucose levels may be more important clinically.

  11. ATR-FTIR Spectroscopy in the Undergraduate Chemistry Laboratory: Part II--A Physical Chemistry Laboratory Experiment on Surface Adsorption (United States)

    Schuttlefield, Jennifer D.; Larsen, Sarah C.; Grassian, Vicki H.


    Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy is a useful technique for measuring the infrared spectra of solids and liquids as well as probing adsorption on particle surfaces. The use of FTIR-ATR spectroscopy in organic and inorganic chemistry laboratory courses as well as in undergraduate research was presented…

  12. Characterization of poly(L-lactide/Propylene glycol) based polyurethane films using ATR-FTIR spectroscopy (United States)

    Manap, Siti Munirah; Ahmad, Azizan; Anuar, Farah Hannan


    A polyurethane films consisting of PLLA, PPG and PLLA-PPG were prepared using solution casting method. Three types of polyurethane were prepared: PPLA:PMDI, PPG:PMDI and PLLA-PPG:PMDI in the presence of polymeric diphenylmethane diisocyanate (PMDI) as the coupling agent and catalyst, Sn(Oct)2. The aim of this research was to improve the physicals properties of PLLA and PPG homopolymers through copolymerization between the two polymers. The homopolymers and polyurethane films were characterized using ATR-FTIR spectroscopy. Chemical reaction between PLLA, PPG and PMDI before and after the reaction were confirmed by observing the shifting of wavenumber for the carbonyl and ether group. Other than that, the additional band for N-H after the reaction indicated that the reaction was successful.

  13. ATR-FTIR Spectroscopy Highlights the Problem of Distinguishing Between Exophiala dermatitidis and E. phaeomuriformis Using MALDI-TOF MS

    NARCIS (Netherlands)

    Ergin, C.; Gok, Y.; Baygu, Y.; Gumral, R.; Ozhak-Baysan, B.; Dogen, A.; Ogunc, D.; Ilkit, M.; Seyedmousavi, S.


    The present study compared two chemical-based methods, namely, matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS) and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, to understand the misidentification of Exophiala

  14. In-column ATR-FTIR spectroscopy to monitor affinity chromatography purification of monoclonal antibodies (United States)

    Boulet-Audet, Maxime; Kazarian, Sergei G.; Byrne, Bernadette


    In recent years many monoclonal antibodies (mAb) have entered the biotherapeutics market, offering new treatments for chronic and life-threatening diseases. Protein A resin captures monoclonal antibody (mAb) effectively, but the binding capacity decays over repeated purification cycles. On an industrial scale, replacing fouled Protein A affinity chromatography resin accounts for a large proportion of the raw material cost. Cleaning-in-place (CIP) procedures were developed to extend Protein A resin lifespan, but chromatograms cannot reliably quantify any remaining contaminants over repeated cycles. To study resin fouling in situ, we coupled affinity chromatography and Fourier transform infrared (FTIR) spectroscopy for the first time, by embedding an attenuated total reflection (ATR) sensor inside a micro-scale column while measuring the UV 280 nm and conductivity. Our approach quantified the in-column protein concentration in the resin bed and determined protein conformation. Our results show that Protein A ligand leached during CIP. We also found that host cell proteins bound to the Protein A resin even more strongly than mAbs and that typical CIP conditions do not remove all fouling contaminants. The insights derived from in-column ATR-FTIR spectroscopic monitoring could contribute to mAb purification quality assurance as well as guide the development of more effective CIP conditions to optimise resin lifespan.

  15. Rapid detection of NBOME's and other NPS on blotter papers by direct ATR-FTIR spectrometry. (United States)

    Coelho Neto, José


    Blotter paper is among the most common forms of consumption of new psychotropic substances (NPS), formerly referred as designer drugs. In many cases, users are misled to believe they are taking LSD when, in fact, they are taking newer and less known drugs like the NBOMEs or other substituted phenethylamines. We report our findings in quick testing of blotter papers for illicit substances like NBOMEs and other NPS by taking ATR-FTIR spectra directly from blotters seized on the streets, without any sample preparation. Both sides (front and back) of each blotter were tested. Collected data were analyzed by single- and multi-component spectral matching and submitted to chemometric discriminant analysis. Our results showed that, on 66.7% of the cases analyzed, seized blotters contained one or more types of NBOMEs, confirming the growing presence of this novel substances on the market. Matching IR signals were detected on both or just one side of the blotters and showed variable strength. Although no quantitative analysis was made, detection of these substances by the proposed approach serves as indication of variable and possibly higher dosages per blotter when compared to LSD, which showed to be below the detection limit of the applied method. Blotters containing a mescaline-like compound, later confirmed by GC-MS and LC-MS to be MAL (methallylescaline), a substance very similar to mescaline, were detected among the samples tested. Validity of direct ATR-FTIR testing was confirmed by checking the obtained results against independent GC-MS or LC-MS results for the same cases/samples. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  16. ATR-FTIR Spectroscopy on intact dried leaves of sage (Salvia officinalis L. – chemotaxonomic discrimination and essential oil composition

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    Gudi, Gennadi


    Full Text Available Sage (Salvia officinalis L. is cultivated worldwide for its aromatic leaves which are used as herbal spice and for phytopharmaceutical applications. Fast analytical strategies for essential oil analysis, performed directly on plant material would reduce the delay between sampling and analytical results. This would enhance product quality by improving technical control of cultivation. The attenuated total reflectance Fourier transform infrared (ATR-FTIR spectroscopy method described here provides a reliable calibration model for quantification of essential oil components (EOC and its main constituents (e.g. -thujone and -thujone directly on dried, intact leaves of sage. Except for drying no further sample preparation is required for ATR-FTIR and the measurement time of less than 5 min per sample contrasts with the most common alternative of hydro-distillation followed by GC analysis which can take several hours per sample.

  17. Improving precursor adsorption characteristics in ATR-FTIR spectroscopy with a ZrO{sub 2} nanoparticle coating

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jaeseo [Korea Research Institute of Standards and Science, Center for Vacuum Technology (Korea, Republic of); Mun, Jihun [University of Science and Technology, Department of Advanced Device Technology (Korea, Republic of); Shin, Jae-Soo; Kim, Jongho; Park, Hee Jung [Daejeon University, Department of Advanced Materials Engineering (Korea, Republic of); Kang, Sang-Woo, E-mail: [Korea Research Institute of Standards and Science, Center for Vacuum Technology (Korea, Republic of)


    Nanoparticles were applied to a crystal surface to increase its precursor adsorption efficiency in an attenuated total reflection Fourier transform infrared (ATR-FTIR) spectrometer. Nanoparticles with varying dispersion stabilities were employed and the resulting precursor adsorption characteristics were assessed. The size of the nanoparticles was <100 nm (TEM). In order to vary the dispersion stability, ZrO{sub 2} nanoparticles were dispersed in aqueous solutions of different pH. The ZrO{sub 2} dispersion solutions were analyzed using scanning electron microscopy (SEM) while particle distribution measurements were analyzed using electrophoretic light scattering (ELS) and dynamic light scattering (DLS) techniques. ZrO{sub 2} nanoparticles dispersed in solutions of pH 3 and 11 exhibited the most stable zeta potentials (≥+30 or ≤−30 mV); these observations were confirmed by SEM analysis and particle distribution measurements. Hexamethyldisilazane (HMDS) was used as a precursor for ATR-FTIR spectroscopy. Consequently, when ZrO{sub 2} nanoparticle solutions with the best dispersion stabilities (pH 3 and 11) were applied to the adsorption crystal surface, the measurement efficiency of ATR-FTIR spectroscopy improved by ∼200 and 300%, respectively.

  18. Determination of surface concentrations of individual molecule-layers used in nanoscale biosensors by in situ ATR-FTIR spectroscopy

    KAUST Repository

    Punzet, Manuel


    For the development of nanowire sensors for chemical and medical detection purposes, the optimal functionalization of the surface is a mandatory component. Quantitative ATR-FTIR spectroscopy was used in situ to investigate the step-by-step layer formation of typical functionalization protocols and to determine the respective molecule surface concentrations. BSA, anti-TNF-α and anti-PSA antibodies were bound via 3-(trimethoxy)butylsilyl aldehyde linkers to silicon-oxide surfaces in order to investigate surface functionalization of nanowires. Maximum determined surface concentrations were 7.17 × 10 -13 mol cm -2 for BSA, 1.7 × 10 -13 mol cm -2 for anti-TNF-α antibody, 6.1 × 10 -13 mol cm -2 for anti-PSA antibody, 3.88 × 10 -13 mol cm -2 for TNF-α and 7.0 × 10 -13 mol cm -2 for PSA. Furthermore we performed antibody-antigen binding experiments and determined the specific binding ratios. The maximum possible ratio of 2 was obtained at bulk concentrations of the antigen in the μg ml -1 range for TNF-α and PSA. © 2012 The Royal Society of Chemistry.

  19. The application of ATR-FTIR spectroscopy and multivariate data analysis to study drug crystallisation in the stratum corneum. (United States)

    Goh, Choon Fu; Craig, Duncan Q M; Hadgraft, Jonathan; Lane, Majella E


    Drug permeation through the intercellular lipids, which pack around and between corneocytes, may be enhanced by increasing the thermodynamic activity of the active in a formulation. However, this may also result in unwanted drug crystallisation on and in the skin. In this work, we explore the combination of ATR-FTIR spectroscopy and multivariate data analysis to study drug crystallisation in the skin. Ex vivo permeation studies of saturated solutions of diclofenac sodium (DF Na) in two vehicles, propylene glycol (PG) and dimethyl sulphoxide (DMSO), were carried out in porcine ear skin. Tape stripping and ATR-FTIR spectroscopy were conducted simultaneously to collect spectral data as a function of skin depth. Multivariate data analysis was applied to visualise and categorise the spectral data in the region of interest (1700-1500cm-1) containing the carboxylate (COO-) asymmetric stretching vibrations of DF Na. Spectral data showed the redshifts of the COO- asymmetric stretching vibrations for DF Na in the solution compared with solid drug. Similar shifts were evident following application of saturated solutions of DF Na to porcine skin samples. Multivariate data analysis categorised the spectral data based on the spectral differences and drug crystallisation was found to be confined to the upper layers of the skin. This proof-of-concept study highlights the utility of ATR-FTIR spectroscopy in combination with multivariate data analysis as a simple and rapid approach in the investigation of drug deposition in the skin. The approach described here will be extended to the study of other actives for topical application to the skin. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Analytical characterization of polymers used in conservation and restoration by ATR-FTIR spectroscopy. (United States)

    Chércoles Asensio, Ruth; San Andrés Moya, Margarita; de la Roja, José Manuel; Gómez, Marisa


    In the last few decades many new polymers have been synthesized that are now being used in cultural heritage conservation. The physical and chemical properties and the long-term behaviors of these new polymers are determined by the chemical composition of the starting materials used in their synthesis along with the nature of the substances added to facilitate their production. The practical applications of these polymers depend on their composition and form (foam, film, sheets, pressure-sensitive adhesives, heat-seal adhesives, etc.). Some materials are used in restoration works and others for the exhibition, storage and transport of works of art. In all cases, it is absolutely necessary to know their compositions. Furthermore, many different materials that are manufactured for other objectives are also used for conservation and restoration. The technical information about the materials provided by the manufacturer is usually incomplete, so it is necessary to analytically characterize such materials. FTIR spectrometry is widely used for polymer identification, and, more recently, ATR-FTIR has been shown to give excellent results. This paper reports the ATR-FTIR analysis of samples of polymeric materials used in the conservation of artworks. These samples were examined directly in the solid material without sample preparation.

  1. Raman and ATR FTIR spectroscopy in reactive crystallization: Simultaneous monitoring of solute concentration and polymorphic state of the crystals (United States)

    Qu, Haiyan; Alatalo, Hannu; Hatakka, Henry; Kohonen, Jarno; Louhi-Kultanen, Marjatta; Reinikainen, Satu-Pia; Kallas, Juha


    Batch-reactive crystallization of the two polymorphs of L-glutamic acid was studied using in-line Raman and ATR FTIR spectroscopy. It was observed that the barrier to the nucleation of the stable β-form was higher, and thus the occurrence of β-form nucleation requires a higher supersaturation level. The local supersaturation level inside the reactive crystallizer is significantly affected by the feeding manner of the reactant. When the reactant was fed to a poorly mixed zone, such as the surface of the liquid, a high local supersaturation level was generated near the feeding point. This high local supersaturation level drastically increased with the increase in the concentrations of the reactants. As a consequence, the fraction of the β-form increased with the increase in reactants concentrations. On the other hand, feeding the reactant to a well-mixed zone near the impeller can avoid the occurrence of high local supersaturation, and therefore the dependence of the polymorphic composition of the final product on the concentration of the reactants can be reduced. The information obtained from the spectroscopy leads to improved understanding of the precipitation process and offers great potential for process optimization and control of crystalline quality.

  2. Perfluoroalkylated Substance Effects in Xenopus laevis A6 Kidney Epithelial Cells Determined by ATR-FTIR Spectroscopy and Chemometric Analysis (United States)


    The effects of four perfluoroalkylated substances (PFASs), namely, perfluorobutanesulfonate (PFBS), perfluorooctanoic acid (PFOA), perfluorooctanesulfonate (PFOS), and perfluorononanoic acid (PFNA) were assessed in Xenopus laevis A6 kidney epithelial cells by attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy and chemometric analysis. Principal component analysis–linear discriminant analysis (PCA-LDA) was used to visualize wavenumber-related alterations and ANOVA-simultaneous component analysis (ASCA) allowed data processing considering the underlying experimental design. Both analyses evidenced a higher impact of low-dose PFAS-treatments (10–9 M) on A6 cells forming monolayers, while there was a larger influence of high-dose PFAS-treatments (10–5 M) on A6 cells differentiated into dome structures. The observed dose–response PFAS-induced effects were to some extent related to their cytotoxicity: the EC50-values of most influential PFAS-treatments increased (PFOS < PFNA < PFOA ≪ PFBS), and higher-doses of these chemicals induced a larger impact. Major spectral alterations were mainly attributed to DNA/RNA, secondary protein structure, lipids, and fatty acids. Finally, PFOS and PFOA caused a decrease in A6 cell numbers compared to controls, whereas PFBS and PFNA did not significantly change cell population levels. Overall, this work highlights the ability of PFASs to alter A6 cells, whether forming monolayers or differentiated into dome structures, and the potential of PFOS and PFOA to induce cell death. PMID:27078751

  3. Bacterial and abiotic decay in waterlogged archaeological Picea abies (L.) Karst studied by confocal Raman imaging and ATR-FTIR spectroscopy

    DEFF Research Database (Denmark)

    Pedersen, Nanna Bjerregaard; Gierlinger, Notburga; Thygesen, Lisbeth Garbrecht


    Waterlogged archaeological Norway spruce [Picea abies (L.) Karst] poles were studied by means of confocal Raman imaging (CRI) and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) analysis to determine lignin and polysaccharide composition and distribution in the cell...... wall. The waterlogged archaeological wood (WAW) was submerged under anoxic conditions for approximately 400 years and solely decayed by erosion bacteria (EB). CRI showed that decayed tracheids contain a residual material (RM) with heterogeneous lignin distribution; within the same tracheid RM often...

  4. Sorption of phosphate onto mesoporous γ-alumina studied with in-situ ATR-FTIR spectroscopy

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    Zheng Ting-Ting


    Full Text Available Abstract Background Due to the extensive use of phosphates in industry, agriculture and households, the phosphate - γ-alumina interactions are important for understanding its detrimental contribution to eutrophication in lakes and rivers. In situ Fourier transform infrared (FTIR spectroscopy can provide more detailed information on the adsorbate-adsorbent interaction and the formation of hydrogen bonds. Results In situ ATR-FTIR spectroscopy was used to identify phosphate complexes adsorbed within the three-dimensional network of mesoporous γ-alumina at pH 4.1 and 9.0. The integrated intensity between 850 cm-1 and 1250 cm-1 was used as a relative measure of the amount of adsorbed phosphate. The integrated intensity proved to be about 3 times higher at pH 4.1 as compared with the corresponding intensity at pH 9.0. The adsorption of phosphate at the two pH conditions could be well described by the Langmuir adsorption isotherm at low concentrations and the empirical Freundlich adsorption isotherm for the whole concentration range, viz. 5 – 2000 μM. Conclusions From the band shape of infrared spectra at pH 4.1 and pH 9.0, it was proposed that the symmetry of the inner-sphere surface complex formed between phosphate and γ-alumina was C1 at the lower pH value, whilst the higher value (9.0 implied a surface complex with C2v or C1 symmetry. The difference in adsorbed amount of phosphate at the two pH values was ascribed to the reduced fraction of ≡ AlOH2+ surface sites and the increased fraction of ≡ AlO- sites upon increasing pH from 4 to 9.

  5. Qualitative and quantitative assessment of water sorption in natural fibres using ATR-FTIR spectroscopy. (United States)

    Célino, Amandine; Gonçalves, Olivier; Jacquemin, Frédéric; Fréour, Sylvain


    In the field of composite materials, natural fibres appear to be a viable replacement for glass fibres. However, in humid conditions, strong hydrophilic behaviour of such materials can lead to their structural modification. Then, understanding moisture sorption mechanisms in these materials is an important issue for their efficient use. In this work, the water sorption on three natural fibres (flax, hemp and sisal) was studied using Fourier transformed infrared spectroscopy. The spectral information allowed both qualitative and quantitative analyses of the moisture absorption mechanisms. The main chemical functions involved in the water sorption phenomenon were identified. The absolute water content of the fibres was also determined by using a partial least square regression (PLS-R) approach. Moreover, typical sorption isotherm curves described by Park model were fitted as well as water diffusion kinetics. These last applications confirmed the validity of the FTIR spectra based predictive models. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Quality Control of Valerianae Radix by Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) Spectroscopy. (United States)

    Nikzad-Langerodi, Ramin; Arth, Katharina; Klatte-Asselmeyer, Valerie; Bressler, Sabine; Saukel, Johannes; Reznicek, Gottfried; Dobeš, Christoph


    (Acetoxy-)valerenic acid and total essential oil content are important quality attributes of pharmacy grade valerian root (Valerianae radix). Traditional analysis of these quantities is time-consuming and necessitates (harmful) solvents. Here we investigated an application of attenuated total reflection Fourier transform infrared spectroscopy for extractionless analysis of these quality attributes on a representative sample comprising 260 wild-crafted individuals covering the Central European taxonomic diversity of the Valeriana officinalis L. s. l. species aggregate with its three major ploidy cytotypes (i.e., di-, tetra- and octoploid). Calibration models were built by orthogonal partial least squares regression for quantitative analysis of (acetoxy-)valerenic acid and total essential oil content. For the latter, we propose a simplistic protocol involving apolar extraction followed by gas chromatography as a reference method for multivariate calibration in order to handle the analysis of samples taken from individual plants. We found good predictive ability of chemometric models for quantification of valerenic acid, acetoxyvalerenic acid, total sesquiterpenoid acid, and essential oil content with a root mean squared error of cross-validation of 0.064, 0.043, and 0.09 and root mean squared error of prediction of 0.066, 0.057, and 0.09 (% content), respectively. Orthogonal partial least squares discriminant analysis revealed good discriminability between the most productive phenotype (i.e., the octoploid cytotype) in terms of sesquiterpenoid acids, and the less productive ones (i.e., di- and tetraploid). All in all, our results demonstrate the application of attenuated total reflection Fourier transform infrared spectroscopy for rapid, extractionless estimation of the most important quality attributes of valerian root and minimally invasive identification of the most productive phenotype in terms of sesquiterpenoid acids. Georg Thieme Verlag KG Stuttgart · New

  7. Discrimination of Solanaceae taxa and quantification of scopolamine and hyoscyamine by ATR-FTIR spectroscopy. (United States)

    Naumann, Annette; Kurtze, Lukas; Krähmer, Andrea; Hagels, Hansjoerg; Schulz, Hartwig


    Plant species of the Solanaceae family (nightshades) contain pharmacologically active anticholinergic tropane alkaloids, e.g., scopolamine and hyoscyamine. Tropane alkaloids are of special interest, either as active principles or as starting materials for semisynthetic production of other substances. For genetic evaluation, domestication, cultivation, harvest and post-harvest treatments, quantification of the individual active principles is necessary to monitor industrial processes and the resulting finished products. Up to now, frequently applied methods for quantification are based on high performance liquid chromatography and gas chromatography optionally combined with mass spectrometry. However, alternative analytical methods have the potential to replace the established standard methods partly. In this context, attenuated total reflection-Fourier transform infrared spectroscopy enabled chemotaxonomical classification of the Solanaceae Atropa belladonna, Datura stramonium, Hyoscyamus niger, Solanum dulcamara, and Duboisia in combination with cluster analysis. Also discrimination of genotypes within species was achieved to some extent. The most characteristic scopolamine bands could be identified in attenuated total reflection-Fourier transform infrared spectra of Solanaceae leaves, which allow a fast characterisation of plants with high scopolamine content. Applying a partial least square algorithm, very good calibration statistics were obtained for the prediction of the scopolamine content (residual prediction deviation = 7.67), and moderate prediction quality could be achieved for the hyoscyamine content (residual prediction deviation = 2.48). Georg Thieme Verlag KG Stuttgart · New York.

  8. Determination of trans Fat in Selected Fast Food Products and Hydrogenated Fats of India Using Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) Spectroscopy. (United States)

    Khan, Mohd Umar; Hassan, Mohammad Fahimul; Rauf, Abdul


    This paper reports the application of a simple and rapid method for the determination of trans fatty acid (TFA) content in some of the selected Indian fast food products and hydrogenated fats using Fourier transform infrared (FTIR) spectroscopy in conjunction with second derivative procedure. FTIR spectroscopy has been successfully applied to trans measurement using the absorbance bands at or near 966 cm-1 in the FTIR spectra. It was found from the analysis that TFA content of fast food product was ranging from 1.57% to 3.83% of the total fat while for hydrogenated fats, comparatively large quantity of TFA was detected in the range of 3.31% to 4.73%. Since GC-FID is most widely used method for the determination of fatty acid (FA) composition, this method was used for the sake of comparison. Value of regression coefficient was found very close to one (0.99503) with standard deviation of 0.10247 showing a good agreement between GC-FID and proposed ATR-FTIR method.

  9. Characterization of microRNA-125b expression in MCF7 breast cancer cells by ATR-FTIR spectroscopy. (United States)

    Ozek, Nihal Simsek; Tuna, Serkan; Erson-Bensan, A Elif; Severcan, Feride


    MicroRNAs (miRNAs), are ~22 nucleotides long, non-coding RNAs that control gene expression post-transcriptionally by binding to their target mRNA's 3'UTRs (untranslated regions). Due to their roles in various important regulatory processes and pathways, miRNAs have been implicated in disease mechanisms such as tumorigenesis when their expression is deregulated. To date, a significant number of miRNAs and their target messenger RNAs (mRNAs) have been identified and verified. It is generally accepted that miRNAs can potentially bind to many mRNAs, which brings the requirement of validation of these interactions. While understanding that such individual interactions is crucial to delineate the role of a specific miRNA, we took a holistic approach and analyzed global changes in the cell due to expression of a miRNA in a model cell line system. Our model consisted of MCF7 cells stably transfected with miR-125b (MCF7-125b) and empty vector (MCF7-EV). MiR-125b is one of the known down-regulated miRNAs in breast cancers. In this study we examined the global structural changes in MCF7 cells lacking and expressing miR-125b by Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) Spectroscopy and investigated the dynamic changes by more sensitive spin-labelling Electron Spin Resonance (ESR) spectroscopy. Our results revealed less RNA, protein, lipid, and glycogen content in MCF7-125b compared to MCF7-EV cells. Membrane fluidity and proliferation rate were shown to be lower in MCF7-125b cells. Based on these changes, MCF7-125b and MCF7-EV cells were discriminated successfully by cluster analysis. Here, we provide a novel means to understand the global effects of miRNAs in cells. Potential applications of this approach are not only limited to research purposes. Such a strategy is also promising to pioneer the development of future diagnostic tools for deregulated miRNA expression in patient samples.

  10. Prediction of peroxide value in omega-3 rich microalgae oil by ATR-FTIR spectroscopy combined with chemometrics. (United States)

    Cebi, Nur; Yilmaz, Mustafa Tahsin; Sagdic, Osman; Yuce, Hande; Yelboga, Emrah


    Our work explored, for the first time, monitoring peroxide value (PV) of omega-3 rich algae oil using ATR-FTIR spectroscopic technique. The PV of the developed method was compared by that obtained by standard method of Association of Official Analytical Chemists (AOAC). In this study, peak area integration (PAI), Partial Least Squares Regression (PLSR), and Principal Component Regression (PCR) were used as the calibration techniques. PV obtained by the AOAC method and by FTIR-ATR technique were well correlated considering the peak area related to trans double bonds and chemometrics techniques of PLSR and PCR. Calibration model was established using the band with a peak point at 966cm-1 (990-940cm-1) related to CH out of plane deformation vibration of trans double bond. Algae oil oxidation could be successfully quantified using PAI, PLSR and PCR techniques. Additionally, hierarchical cluster analysis was performed and significant discrimination was observed coherently with oxidation process. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Estimation of the age of human bloodstains under the simulated indoor and outdoor crime scene conditions by ATR-FTIR spectroscopy. (United States)

    Lin, Hancheng; Zhang, Yinming; Wang, Qi; Li, Bing; Huang, Ping; Wang, Zhenyuan


    Estimation of the age of human bloodstains is of great importance in forensic practices, but it is a challenging task because of the lack of a well-accepted, reliable, and established method. Here, the attenuated total reflection (ATR)-Fourier transform infrared (FTIR) technique combined with advanced chemometric methods was utilized to determine the age of indoor and outdoor bloodstains up to 107 days. The bloodstain storage conditions mimicked crime scene scenarios as closely as possible. Two partial least squares regression models-indoor and outdoor models with 7-85 days-exhibited good performance for external validation, with low values of predictive root mean squared error (5.83 and 4.77) and high R(2) values (0.94 and 0.96) and residual predictive deviation (4.08 and 5.14), respectively. Two partial least squares-discriminant analysis classification models were built and demonstrated excellent distinction between fresh (age ≤1 d) and older (age >1 d) bloodstains, which is highly valuable for forensic investigations. These findings demonstrate that ATR-FTIR spectroscopy coupled with advanced chemometric methods can be employed as a rapid and non-destructive tool for age estimation of bloodstains in real-world forensic investigation.

  12. ATR-FTIR spectroscopy study of the influence of pH and contact time on the adhesion of Shewanella putrefaciens bacterial cells to the surface of hematite. (United States)

    Elzinga, Evert J; Huang, Jen-How; Chorover, Jon; Kretzschmar, Ruben


    Attachment of live cells of Shewanella putrefaciens strain CN-32 to the surface of hematite (α-Fe(2)O(3)) was studied with in situ ATR-FTIR spectroscopy at variable pH (4.5-7.7) and contact times up to 24 h. The IR spectra indicate that phosphate based functional groups on the cell wall play an important role in mediating adhesion through formation of inner-sphere coordinative bonds to hematite surface sites. The inner-sphere attachment mode of microbial P groups varies with pH, involving either a change in protonation or in coordination to hematite surface sites as pH is modified. At all pH values, spectra collected during the early stages of adhesion show intense IR bands associated with reactive P-groups, suggestive of preferential coordination of P-moieties at the hematite surface. Spectra collected after longer sorption times show distinct frequencies from cell wall protein and carboxyl groups, indicating that bacterial adhesion occurring over longer time scales is to a lesser degree associated with preferential attachment of P-based bacterial functional groups to the hematite surface. The results of this study demonstrate that pH and reaction time influence cell-mineral interactions, implying that these parameters play an important role in determining cell mobility and biofilm formation in aqueous geochemical environments.

  13. Effects of metal ions on entero-soluble poly(methacrylic acid-methyl methacrylate) coating: a combined analysis by ATR-FTIR spectroscopy and computational approaches. (United States)

    Cilurzo, Francesco; Gennari, Chiara G M; Selmin, Francesca; Vistoli, Giulio


    Poly(methacrylic acid-methyl methacrylate)s (HPMMs) are pH-dependent polymers which ionize and form salts (PMMs) in neutral conditions. Despite their wide use in tablet coating, the interactions of PMMs with electrolytes present in biorelevant media and luminal fluids have been scantly investigated. The data generated in the current work provide the basic information on the effect of bivalent cations, namely, Ca2+, Zn2+ and Mn2+, on the HPMMs' solubility and, consequently, on the performances (disintegration and drug dissolution) of acetaminophen gastroresistant tablets when exposed to fluid containing such salts. The interactions between polymers and metal ions were analyzed by ATR-FTIR spectroscopy and in silico combining molecular dynamics simulations to explore the conformational profiles of several oligomers with different M(w), taken as model of the polymers, with ab initio and semiempirical calculations in the gas phase. The computational results agree with the experimental data in terms of spatial disposition of the bications with respect to PMMs (Ca2+ and Mn2+ as bidentate form and Zn2+ as monodentate ligand) and interaction strength (Zn2+ > Mn(2+) > Ca2+). The tablet disintegration and dissolution rate of acetaminophen were strongly affected by the interactions of the dissolving copolymer with the metal ions which led to coating insolubilization. These preliminary results underline that the ingestion of metal ions at high concentrations could affect the drug liberation from gastroresistant dosage forms.

  14. Efficacy of metformin in human single hair fibre by ATR-FTIR spectroscopy coupled with statistical analysis. (United States)

    Sundaramoorthi, Kamatchi; Sethu, Gunasekaran; Ethirajulu, Sailatha; Raja Marthandam, Pavithra


    Diabetes mellitus is chronic metabolic disorder, resulting from insulin deficiency, characterized by hyperglycemia altered metabolism of carbohydrates, proteins and lipids and an increased risk of vascular complications. There are different classes of anti-diabetic drugs in allopathic system of medicine. Metformin (dimethyl biguanide) is a blood glucose lowering agent used in the treatment of non-insulin dependent diabetes mellitus. Almost in all diseases the blood serves as the primary metabolic transport system in the body. Its composition is the preferred indicator with respect to the pathophysiological condition of the patient. Instead of analyzing blood to diagnose diabetes, hair could be used to detect diabetes using FTIR-ATR technique. The most important components of hair are fibrous proteins (keratins), melanins, glycogen, and lipids. Hair follicles are located 3-4mm below the surface of the skin and are surrounded by rich blood capillary system. In the present study, ten diabetic subjects were considered to evaluate the efficacy of metformin hydrochloride for the treatment of diabetes mellitus using FTIR-ATR spectroscopy. The spectra of diabetic hair fibre samples have been recorded in the mid infrared region of 4000-450cm -1 . The hair samples of the diabetic subjects before medication were taken as pre-treatment samples. The hair samples of diabetic subjects referred to medication with metformin for a period of three month were taken as post-treatment sample. Some remarkable spectral differences were elucidated between pre- and post-treatment hair fibre samples. A comparative study on the FTIR-ATR hair spectra of patients (pre- and post-treatment) along with the healthy subjects has been made. The absorption values of some of the specific bands of biomolecules present in the hair samples viz., protein, lipids and glucose for both the pre- and post-treatment subjects are noted. It was observed that, these biomarkers are significantly different between

  15. Degradation patterns of natural and synthetic textiles on a soil surface during summer and winter seasons studied using ATR-FTIR spectroscopy (United States)

    Ueland, Maiken; Howes, Johanna M.; Forbes, Shari L.; Stuart, Barbara H.


    obtained using ATR-FTIR spectroscopy, and has provided insight into textile degradation processes relevant to a soil environment.

  16. Rapid Quantification of Methamphetamine: Using Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR) and Chemometrics (United States)

    Hughes, Juanita; Ayoko, Godwin; Collett, Simon; Golding, Gary


    In Australia and increasingly worldwide, methamphetamine is one of the most commonly seized drugs analysed by forensic chemists. The current well-established GC/MS methods used to identify and quantify methamphetamine are lengthy, expensive processes, but often rapid analysis is requested by undercover police leading to an interest in developing this new analytical technique. Ninety six illicit drug seizures containing methamphetamine (0.1%–78.6%) were analysed using Fourier Transform Infrared Spectroscopy with an Attenuated Total Reflectance attachment and Chemometrics. Two Partial Least Squares models were developed, one using the principal Infrared Spectroscopy peaks of methamphetamine and the other a Hierarchical Partial Least Squares model. Both of these models were refined to choose the variables that were most closely associated with the methamphetamine % vector. Both of the models were excellent, with the principal peaks in the Partial Least Squares model having Root Mean Square Error of Prediction 3.8, R2 0.9779 and lower limit of quantification 7% methamphetamine. The Hierarchical Partial Least Squares model had lower limit of quantification 0.3% methamphetamine, Root Mean Square Error of Prediction 5.2 and R2 0.9637. Such models offer rapid and effective methods for screening illicit drug samples to determine the percentage of methamphetamine they contain. PMID:23936058

  17. Is it possible to find presence of lactose in pharmaceuticals? - Preliminary studies by ATR-FTIR spectroscopy and chemometrics (United States)

    Banas, A.; Banas, K.; Kalaiselvi, S. M. P.; Pawlicki, B.; Kwiatek, W. M.; Breese, M. B. H.


    Lactose and saccharose have the same molecular formula; however, the arrangement of their atoms is different. A major difference between lactose and saccharose with regard to digestion and processing is that it is not uncommon for individuals to be lactose intolerant (around two thirds of the population has a limited ability to digest lactose after infancy), but it is rather unlikely to be saccharose intolerant. The pharmaceutical industry uses lactose and saccharose as inactive ingredients of drugs to help form tablets because of their excellent compressibility properties. Some patients with severe lactose intolerance may experience symptoms of many allergic reactions after taking medicine that contains this substance. People who are specifically "allergic" to lactose (not just lactose intolerant) should not use tablets containing this ingredient. Fourier Transform Infrared (FTIR) spectroscopy has a unique chemical fingerprinting capability and plays a significant important role in the identification and characterization of analyzed samples and hence has been widely used in pharmaceutical science. However, a typical FTIR spectrum collected from tablets contains a myriad of valuable information hidden in a family of tiny peaks. Powerful multivariate spectral data processing can transform FTIR spectroscopy into an ideal tool for high volume, rapid screening and characterization of even minor tablet components. In this paper a method for distinction between FTIR spectra collected for tablets with or without lactose is presented. The results seem to indicate that the success of identifying one component in FTIR spectra collected for pharmaceutical composition (that is tablet) is largely dependent on the choice of the chemometric technique applied.

  18. Measuring Heterogeneous Reaction Rates with ATR-FTIR Spectroscopy to Evaluate Chemical Fates in an Atmospheric Environment: A Physical Chemistry and Environmental Chemistry Laboratory Experiment (United States)

    Roberts, Jason E.; Zeng, Guang; Maron, Marta K.; Mach, Mindy; Dwebi, Iman; Liu, Yong


    This paper reports an undergraduate laboratory experiment to measure heterogeneous liquid/gas reaction kinetics (ozone-oleic acid and ozone-phenothrin) using a flow reactor coupled to an attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectrometer. The experiment is specially designed for an upper-level undergraduate Physical…

  19. Application of ATR-FTIR Spectroscopy to Compare the Cell Materials of Wood Decay Fungi with Wood Mould Fungi

    Directory of Open Access Journals (Sweden)

    Barun Shankar Gupta


    Full Text Available Wood fungi create vast damage among standing trees and all types of wood materials. The objectives of this study are to (a characterize the cell materials of two major wood decay fungi (Basidiomycota, namely, Trametes versicolor and Postia placenta, and (b compare the cell materials of decay fungi with four wood mould fungi (Ascomycota, namely, Aureobasidium pullulans, Alternaria alternata, Cladosporium cladosporioides, and Ulocladium atrum. Fourier transform infrared (FTIR spectroscopy is used to characterize the microbial cellular materials. The results showed that the IR bands for the fatty acid at ∼2900 cm−1 were different for the two-decay-fungi genre. Postia placenta shows more absorbance peaks at the fatty acid region. Band ratio indices for amide I and amide II from protein amino acids were higher for the mould fungi (Ascomycota than the decay fungi (Basidiomycota. Similarly, the band ratio index calculated for the protein end methyl group was found to be higher for the mould fungi than the decay fungi. Mould fungi along with the decay fungi demonstrated a positive correlation (R2=0.75 between amide I and amide II indices. The three-component multivariate, principal component analysis showed a strong correlation of amide and protein band indices.

  20. A rapid ATR-FTIR spectroscopic method for detection of sibutramine adulteration in tea and coffee based on hierarchical cluster and principal component analyses. (United States)

    Cebi, Nur; Yilmaz, Mustafa Tahsin; Sagdic, Osman


    Sibutramine may be illicitly included in herbal slimming foods and supplements marketed as "100% natural" to enhance weight loss. Considering public health and legal regulations, there is an urgent need for effective, rapid and reliable techniques to detect sibutramine in dietetic herbal foods, teas and dietary supplements. This research comprehensively explored, for the first time, detection of sibutramine in green tea, green coffee and mixed herbal tea using ATR-FTIR spectroscopic technique combined with chemometrics. Hierarchical cluster analysis and PCA principle component analysis techniques were employed in spectral range (2746-2656cm -1 ) for classification and discrimination through Euclidian distance and Ward's algorithm. Unadulterated and adulterated samples were classified and discriminated with respect to their sibutramine contents with perfect accuracy without any false prediction. The results suggest that existence of the active substance could be successfully determined at the levels in the range of 0.375-12mg in totally 1.75g of green tea, green coffee and mixed herbal tea by using FTIR-ATR technique combined with chemometrics. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Revisiting the Brønsted acid catalysed hydrolysis kinetics of polymeric carbohydrates in ionic liquids by in situ ATR-FTIR spectroscopy

    DEFF Research Database (Denmark)

    Kunov-Kruse, Andreas Jonas; Riisager, Anders; Shunmugavel, Saravanamurugan


    A new versatile method to measure rates and determine activation energies for the Brønsted acid catalysed hydrolysis of cellulose and cellobiose (and other polymeric carbohydrates) in ionic liquids is demonstrated by following the C–O stretching band of the glycoside bond with in situ ATR......-FTIR. An activation energy in excellent agreement with the literature was determined for cellulose hydrolysis, whereas a distinctly lower activation energy was determined for cellobiose hydrolysis. The methodology also allowed to independently determine activation energies for the formation of 5-hydroxymethylfurfural...

  2. Combining Mass Spectrometry and ATR-FTIR Spectroscopy to Study Phase, Diffusion and Composition of Secondary Organic Aerosol from the Ozonolysis of α-pinene (United States)

    Perraud, V. M.; Finlayson-Pitts, B. J.; Waring-Kidd, C.


    Secondary organic aerosol (SOA) is ubiquitous in the atmosphere and composes a large fraction of the total aerosol budget. Recent reports from field measurements and laboratory studies show that some SOA particles are better represented by a semi-solid low viscosity tar-like material rather than a ideal liquid often assumed in regional and global models. Characterizing the phase of SOA is crucial to understanding how particles interact with trace gases and how it ultimately impacts their growth and evolution in the atmosphere. We report here laboratory studies carried out in the unique UCI large-volume, slow-flow, aerosol flow reactor. Particles from the ozonolysis of a-pinene were formed at various relative humidities (RH from < 3% to 90%) and collected onto a custom ATR-FTIR impactor. The observed impaction pattern provided insights into changes in phase/viscosity of the SOA as a function of relative humidity. In addition, attenuated total reflectance FTIR and mass spectrometry measurements provided information on simultaneous changes on composition. Application of ATR-FTIR combined with PTR-MS provided additional data on the volatility of the SOA at room temperature and diffusion coefficients of two key components pinonaldehyde and acetic acid present in the SOA. Implication for modeling the growth and ultimately the lifetime of SOA in the atmosphere will be discussed.

  3. Quantitative assessment of copper proteinates used as animal feed additives using ATR-FTIR spectroscopy and powder X-ray diffraction (PXRD) analysis. (United States)

    Cantwell, Caoimhe A; Byrne, Laurann A; Connolly, Cathal D; Hynes, Michael J; McArdle, Patrick; Murphy, Richard A


    The aim of the present work was to establish a reliable analytical method to determine the degree of complexation in commercial metal proteinates used as feed additives in the solid state. Two complementary techniques were developed. Firstly, a quantitative attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopic method investigated modifications in vibrational absorption bands of the ligand on complex formation. Secondly, a powder X-ray diffraction (PXRD) method to quantify the amount of crystalline material in the proteinate product was developed. These methods were developed in tandem and cross-validated with each other. Multivariate analysis (MVA) was used to develop validated calibration and prediction models. The FTIR and PXRD calibrations showed excellent linearity (R2 > 0.99). The diagnostic model parameters showed that the FTIR and PXRD methods were robust with a root mean square error of calibration RMSEC ≤3.39% and a root mean square error of prediction RMSEP ≤7.17% respectively. Comparative statistics show excellent agreement between the MVA packages assessed and between the FTIR and PXRD methods. The methods can be used to determine the degree of complexation in complexes of both protein hydrolysates and pure amino acids.

  4. Conservation of Moroccan manuscript papers aged 150, 200 and 800 years. Analysis by infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD), and scanning electron microscopy energy dispersive spectrometry (SEM-EDS). (United States)

    Hajji, Latifa; Boukir, Abdellatif; Assouik, Jamal; Lakhiari, Hamid; Kerbal, Abdelali; Doumenq, Pierre; Mille, Gilbert; De Carvalho, Maria Luisa


    The preservation of manuscripts and archive materials is a serious problem for librarians and restorers. Paper manuscript is subjected to numerous degradation factors affecting their conservation state. This research represents an attempt to evaluate the conservation restoration process applied in Moroccan libraries, especially the alkaline treatment for strengthening weakened paper. In this study, we focused on six samples of degraded and restored paper taken from three different Moroccan manuscripts aged 150, 200 and 800 years. In addition, the Japanese paper used in restoration has been characterized. A modern paper was also analyzed as reference. A three-step analytical methodology based on infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD) and scanning electron microscopy coupled to energy dispersive spectrometry (SEM-EDS) analysis was developed before and after restoration in order to determine the effect of the consolidation treatment on the paper structure. The results obtained by XRD and ATR-FTIR disclosed the presence of barium sulfate (BaSO4) in all restored paper manuscripts. The presence of calcium carbonate (CaCO3) in all considered samples was confirmed by FTIR spectroscopy. The application of de-acidification treatment causes significant changes connected with the increase of intensity mostly in the region 1426 cm(-1), assigned to the asymmetric and symmetric CO stretching mode of calcite, indicating the effectiveness of de-acidification procedure proved by the rise of the alkaline reserve content allowing the long term preservation of paper. Observations performed by SEM magnify the typical paper morphology and the structure of fibbers, highlighting the effect of the restoration process, manifested by the reduction of impurities. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Use of ATR-FTIR spectroscopy coupled with chemometrics for the authentication of avocado oil in ternary mixtures with sunflower and soybean oils. (United States)

    Jiménez-Sotelo, Paola; Hernández-Martínez, Maylet; Osorio-Revilla, Guillermo; Meza-Márquez, Ofelia Gabriela; García-Ochoa, Felipe; Gallardo-Velázquez, Tzayhrí


    Avocado oil is a high-value and nutraceutical oil whose authentication is very important since the addition of low-cost oils could lower its beneficial properties. Mid-FTIR spectroscopy combined with chemometrics was used to detect and quantify adulteration of avocado oil with sunflower and soybean oils in a ternary mixture. Thirty-seven laboratory-prepared adulterated samples and 20 pure avocado oil samples were evaluated. The adulterated oil amount ranged from 2% to 50% (w/w) in avocado oil. A soft independent modelling class analogy (SIMCA) model was developed to discriminate between pure and adulterated samples. The model showed recognition and rejection rate of 100% and proper classification in external validation. A partial least square (PLS) algorithm was used to estimate the percentage of adulteration. The PLS model showed values of R(2) > 0.9961, standard errors of calibration (SEC) in the range of 0.3963-0.7881, standard errors of prediction (SEP estimated) between 0.6483 and 0.9707, and good prediction performances in external validation. The results showed that mid-FTIR spectroscopy could be an accurate and reliable technique for qualitative and quantitative analysis of avocado oil in ternary mixtures.

  6. In vitro evaluation of ionizing radiation effects in bone tissue by FTIR spectroscopy and dynamic mechanical analysis; Avaliacao in vitro dos efeitos da radiacao ionizante em tecido osseo bovino por espectroscoia ATR-FTIR e analise dinamica-mecanica

    Energy Technology Data Exchange (ETDEWEB)

    Veloso, Marcelo Noronha


    Ionizing radiation from gamma radiation sources or X-ray generators is frequently used in Medical Science, such as radiodiagnostic exams, radiotherapy, and sterilization of haloenxerts. Ionizing radiation is capable of breaking polypeptidic chains and causing the release of free radicals by radiolysis.of water. It interacts also with organic material at the molecular level, and it may change its mechanical properties. In the specific case of bone tissue, studies report that ionizing radiation induces changes in collagen molecules and reduces the density of intermolecular crosslinks. The aim of this study was to verify the changes promoted by different doses of ionizing radiation in bone tissue using Fourier Transform Infrared Spectroscopy (FTIR) and dynamic mechanical analysis (DMA). Samples of bovine bone were irradiated using Cobalt-60 with five different doses: 0.01 kGy, 0.1 kGy, 1 kGy, 15 kGy and 75 kGy. To study the effects of ionizing irradiation on the chemical structure of the bone, the sub-bands of amide I, the crystallinity index and relation of organic and inorganic materials, were studied. The mechanical changes were evaluated using the elastic modulus and the damping value. To verify whether the chemical changes and the mechanical characteristics of the bone were correlated, the relation between the analysis made with spectroscopic data and the mechanical analysis data was studied. It was possible to evaluate the effects of different doses of ionizing radiation in bone tissue. With ATR-FTIR spectroscopy, it was possible to observe changes in the organic components and in the hydroxyapatite crystals organization. Changes were also observed in the elastic modulus and in the damping value. High correlation with statistical significance was observed among (amide III + collagen)/{sub v1,v3}, PO{sub 4}{sup 3-} and the delta tangent, and among 1/FHWM and the elastic modulus. (author)

  7. Investigation on Crude and High-Temperature Heated Coffee Oil by ATR-FTIR Spectroscopy along with Antioxidant and Antimicrobial Properties.

    Directory of Open Access Journals (Sweden)

    Diana Nicoleta Raba

    Full Text Available The coffee oil has a promising potential to be used in food industry, but an efficient use, especially in products that required high-temperature heating, depends on its chemical composition and the changes induced by processing. Since there is little information on this topic, the aim of our study was to investigate the crude green and roasted coffee oil (GCO, RCO and heated (HGCO, HRCO for 1 h at 200°C, by Fourier Transform Infrared (FTIR spectroscopy and in terms of antioxidant and antimicrobial properties. The results of FTIR spectroscopy revealed that no statistically significant differences (one-way ANOVA, p>0.05 in the oxidative status of GCO and RCO were found. The coffee oils heating induced significant spectral changes in the regions 3100-3600 cm(-1, 2800-3050 cm(-1 and 1680-1780 cm(-1 proved by the differences in the absorbance ratios A 3009 cm(-1/A 2922 cm(-1, A 3009 cm(-1/A 2853 cm(-1, A 3009 cm(-1/A 1744 cm(-1, A 1744 cm(-1/A 2922 cm(-1. These alterations were related to the reduction of the unsaturation degree due to primary and secondary oxidation processes of the lipid fraction. The radical scavenging ability of oils investigated by 2,2-diphenyl-1-picrylhydrazyl (DPPH assay revealed that the IC50 value of GCO was significantly lower than of RCO (p0.05. Also, HGCO and HRCO showed significantly different inhibitory potential related to the control (p<0.05. The heating induced statistically significant decreases in the effectiveness of coffee oils against the tested bacteria. GCO proved to be the most effective among investigated coffee oils against the tested bacteria.

  8. ATR FTIR Mapping of Leather Fiber Panels (United States)

    Tondi, G.; Grünewald, T.; Petutschnigg, A.; Schnabel, T.


    Leather fiber panels are very promising materials for many applications, not only for the easy availability of the constituents but also for their outstanding fi re-retardant properties. These innovative composite panels can be an excellent material for building insulation, and in recent times, the interest of industries in this composite board has considerably arisen. For this reason the discrimination of the components in the leather fiber panels is becoming fundamental in order to ensure their homogeneous properties. A method to characterize the surface of these materials is then required. An ATR FTIR mapping system for the leather fiber panels has been performed with a Perkin-Elmer microscope coupled with a Frontier FTIR spectrometer. The system has successfully allowed transforming the optical image to a chemical one. This technique can be considered as a right tool for routine controls of the surface quality, especially when the leather shavings cannot be optically distinguished.

  9. In-situ ATR-FTIR for characterization of thin biorelated polymer films

    Energy Technology Data Exchange (ETDEWEB)

    Müller, M., E-mail: [Leibniz Institute of Polymer Research Dresden (IPF Dresden), Hohe Straße 6, 01069 Dresden (Germany); Technical University of Dresden (TUD), Department of Chemistry and Food Chemistry, 01062 Dresden (Germany); Torger, B. [Leibniz Institute of Polymer Research Dresden (IPF Dresden), Hohe Straße 6, 01069 Dresden (Germany); Technical University of Dresden (TUD), Department of Chemistry and Food Chemistry, 01062 Dresden (Germany); Bittrich, E. [Leibniz Institute of Polymer Research Dresden (IPF Dresden), Hohe Straße 6, 01069 Dresden (Germany); Kaul, E.; Ionov, L. [Leibniz Institute of Polymer Research Dresden (IPF Dresden), Hohe Straße 6, 01069 Dresden (Germany); Technical University of Dresden (TUD), Department of Chemistry and Food Chemistry, 01062 Dresden (Germany); Uhlmann, P. [Leibniz Institute of Polymer Research Dresden (IPF Dresden), Hohe Straße 6, 01069 Dresden (Germany); Stamm, M. [Leibniz Institute of Polymer Research Dresden (IPF Dresden), Hohe Straße 6, 01069 Dresden (Germany); Technical University of Dresden (TUD), Department of Chemistry and Food Chemistry, 01062 Dresden (Germany)


    We present and review in-situ-attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopic data from thin biorelated polymer films useful for the modification and functionalization of polymer and inorganic materials and discuss their applications related to life sciences. A special ATR mirror attachment operated by the single-beam-sample-reference (SBSR) concept and housing a homebuilt thermostatable flow cell was used, which allows for appropriate background compensation and signal to noise ratio. ATR-FTIR data on the reactive deposition of dopamine on inorganic model surfaces are shown. Information on the structure and deposition pathway for such bioinspired melanin-like films is provided. ATR-FTIR data on thermosensitive polymer brushes of poly(N-isopropylacrylamide) (PNIPAAM) is then presented. The thermotropic hydration and hydrogen bonding behavior of PNIPAAM brush films is described. Finally, ATR-FTIR data on biorelated polyelectrolyte multilayers (PEM) are given together with details on PEM growth and detection. Applications of these latter films for biopassivation/activation and local drug delivery are addressed.

  10. Simultaneous ATR-FTIR Based Determination of Malaria Parasitemia, Glucose and Urea in Whole Blood Dried onto a Glass Slide. (United States)

    Roy, Supti; Perez-Guaita, David; Andrew, Dean W; Richards, Jack S; McNaughton, Don; Heraud, Philip; Wood, Bayden R


    New diagnostic tools that can detect malaria parasites in conjunction with other diagnostic parameters are urgently required. In this study, Attenuated Total Reflection Fourier transform infrared (ATR-FTIR) spectroscopy in combination with Partial Least Square Discriminant Analysis (PLS-DA) and Partial Least Square Regression (PLS-R) have been applied as a point-of-care test for identifying malaria parasites, blood glucose, and urea levels in whole blood samples from thick blood films on glass slides. The specificity for the PLS-DA was found to be 98% for parasitemia levels >0.5%, but a rather low sensitivity of 70% was achieved because of the small number of negative samples in the model. In PLS-R the Root Mean Square Error of Cross Validation (RMSECV) for parasite concentration (0-5%) was 0.58%. Similarly, for glucose (0-400 mg/dL) and urea (0-250 mg/dL) spiked samples, relative RMSECVs were 16% and 17%, respectively. The method reported here is the first example of multianalyte/disease diagnosis using ATR-FTIR spectroscopy, which in this case, enabled the simultaneous quantification of glucose and urea analytes along with malaria parasitemia quantification using one spectrum obtained from a single drop of blood on a glass microscope slide.

  11. Assessing and calibrating the ATR-FTIR approach as a carbonate rock characterization tool (United States)

    Henry, Delano G.; Watson, Jonathan S.; John, Cédric M.


    ATR-FTIR (attenuated total reflectance Fourier transform infrared) spectroscopy can be used as a rapid and economical tool for qualitative identification of carbonates, calcium sulphates, oxides and silicates, as well as quantitatively estimating the concentration of minerals. Over 200 powdered samples with known concentrations of two, three, four and five phase mixtures were made, then a suite of calibration curves were derived that can be used to quantify the minerals. The calibration curves in this study have an R2 that range from 0.93-0.99, a RMSE (root mean square error) of 1-5 wt.% and a maximum error of 3-10 wt.%. The calibration curves were used on 35 geological samples that have previously been studied using XRD (X-ray diffraction). The identification of the minerals using ATR-FTIR is comparable with XRD and the quantitative results have a RMSD (root mean square deviation) of 14% and 12% for calcite and dolomite respectively when compared to XRD results. ATR-FTIR is a rapid technique (identification and quantification takes < 5 min) that involves virtually no cost if the machine is available. It is a common tool in most analytical laboratories, but it also has the potential to be deployed on a rig for real-time data acquisition of the mineralogy of cores and rock chips at the surface as there is no need for special sample preparation, rapid data collection and easy analysis.

  12. Predicting the physical properties of tablets from ATR-FTIR spectra using partial least squares regression. (United States)

    Taylor, Michael; Elhissi, Abdelbary M A


    The formulation of a new tablet is a time-consuming activity involving the preparation and testing of many different formulations with the aim of identifying one with the desired properties. In complex formulations it may not be clear which excipient is responsible for eliciting a particular property. To investigate partial least squares (PLS) regression analysis of ATR-FTIR spectra of tablets as a predictive and investigative tool in the formulation of novel tablet formulations. Magnesium stearate, lactose, acetylsalicylic acid and Ac-Di-Sol. ATR-FTIR spectra of a simple aspirin tablet formulation with varying amounts of the lubricant magnesium stearate were obtained. PLS models were built using the spectral data as the multivariate variable and various physical properties of the tablets as the univariate variables. PLS models that allowed good predications to be made for samples not included in the training set were obtained for tablet hardness and disintegration time. It was clear from PLS model regression coefficients that magnesium stearate was responsible for the variation in the tablets' physical properties. PLS regression in combination with ATR-FTIR spectroscopy has been shown to be a useful approach for the prediction of the physical properties of tablets.

  13. In Situ ATR-FTIR Study on the Selective Photo-oxidation of Cyclohexane over Anatase TiO2

    NARCIS (Netherlands)

    Almeida, A.; Moulijn, J.A.; Mul, Guido


    Anatase-catalyzed photo-oxidation of cyclohexane was analyzed by in situ ATR-FTIR spectroscopy. A set of seven UV-LEDs (375 nm), with a photon flux of 9 × 10-9 Einstein·cm-2·s-1 (at the catalyst surface) was used to initiate the photoreaction. Surface-adsorbed cyclohexanone and water are the primary

  14. Stability of indomethacin with relevance to the release from amorphous solid dispersions studied with ATR-FTIR spectroscopic imaging. (United States)

    Ewing, Andrew V; Clarke, Graham S; Kazarian, Sergei G


    This work presents the use of attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy and spectroscopic imaging to study the stability and dissolution behaviour of amorphous solid dispersions (ASDs). ASDs are employed to improve the bioavailability of drugs which are poorly soluble in aqueous solutions. Selecting the appropriate polymeric excipients for use in pharmaceutical tablets is crucial to control drug stability and subsequent release. In this study, indomethacin was used as a model poorly-aqueous soluble drug since the amorphous-form has improved dissolution properties over its crystalline forms. ASDs of indomethacin/polyethylene glycol (PEG) and indomethacin/hydroxypropyl methylcellulose (HPMC) in a 1:3 wt ratio were compared. Firstly, ATR-FTIR spectroscopy was employed to monitor the stability of indomethacin in the ASDs over 96 h. While the indomethacin/HPMC ASD showed the ability to maintain the amorphous indomethacin form for longer periods of time, ATR-FTIR spectra revealed that indomethacin in the drug/PEG ASD crystallised to the stable γ-form, via the α-form. Secondly, ATR-FTIR spectroscopic imaging was used to study the dissolution of ASD tablets in a phosphate buffer (pH 7.5). Crystallisation of amorphous indomethacin was characterised in the spectra collected during the dissolution of the indomethacin/PEG ASD which consequently hindered release into the surrounding solution. In contrast, release of amorphous indomethacin was more effective from HPMC. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Classification of Edible Oils Based on ATR-FTIR Spectral Information During a Long Heating Treatment. (United States)

    Mahboubifar, Marjan; Hemmateenejad, Bahram; Yousefinejad, Saeed


    Identification of oil type and its QC are important concerns in food control laboratories. Classifying edible oils that have not been used (i.e., unheated) with the aid of vibrational spectroscopy has previously been reported. However, the classification of used (i.e., heat-treated) oils needs special attention. The effect of long heating times on the classification of four kinds of edible oils (canola, corn, frying, and sunflower) based on attenuated total reflectance (ATR)-FTIR spectra was surveyed. The sampling was done on the oils during a 36 h heating process (at 170°C). The ATR-FTIR spectra of the samples were collected in the range of 4000-550 cm-1. Interval extended canonical variates analysis (ECVA), as a variable selection and classification tool, was used to determine the best intervals during the heating procedure for classification. Principal component analysis discriminate analysis, partial least-squares discriminate analysis, and ECVA were performed on the selected intervals and on the total heating time. The effect of autoscaling and mean-centering, as data preprocessing methods, was also investigated. The ECVA method resulted in the best performances for classification, with a 94% cross-validated nonerror rate (one misclassification) for the heating process times of 24-27 and 33-36 h.

  16. Structural transformation of synthetic hydroxyapatite under simulated in vivo conditions studied with ATR-FTIR spectroscopic imaging (United States)

    Sroka-Bartnicka, Anna; Borkowski, Leszek; Ginalska, Grazyna; Ślósarczyk, Anna; Kazarian, Sergei G.


    Hydroxyapatite and carbonate-substituted hydroxyapatite are widely used in bone tissue engineering and regenerative medicine. Both apatite materials were embedded into recently developed ceramic/polymer composites, subjected to Simulated Body Fluid (SBF) for 30 days and characterized using ATR-FTIR spectroscopic imaging to assess their behaviour and structures. The specific aim was to detect the transition phases between both types of hydroxyapatite during the test and to analyze the surface modification caused by SBF. ATR-FTIR spectroscopic imaging was successfully applied to characterise changes in the hydroxyapatite lattice due to the elastic properties of the scaffolds. It was observed that SBF treatment caused a replacement of phosphates in the lattice of non-substituted hydroxyapatite by carbonate ions. A detailed study excluded the formation of pure A type carbonate apatite. In turn, CO32- content in synthetic carbonate-substituted hydroxyapatite decreased. The usefulness of ATR-FTIR spectroscopic imaging studies in the evaluation of elastic and porous β-glucan hydroxyapatite composites has been demonstrated.

  17. Comparison of ATR-FTIR spectra of porcine vaginal and buccal mucosa with ear skin and penetration analysis of drug and vehicle components into pig ear. (United States)

    Schwarz, Julia C; Pagitsch, Elisabeth; Valenta, Claudia


    In the present study, porcine buccal and vaginal mucosae were successfully characterised by ATR-FTIR for the first time and compared to porcine ear skin. By analysing typical bands of the spectra, the structure of proteins and the lipid matrix were elucidated. According to the body site, differences in membrane permeability were detected when analysing the CH2-stretching and -scissoring vibrations. The results indicated a higher permeability for porcine vaginal and buccal tissue compared to skin. Furthermore, the influence of a lecithin-based microemulsion on the barrier properties of the above mentioned tissues was investigated by ATR-FTIR; the results revealed structural changes in all tissues. In addition, the ATR-FTIR technique was employed to semi-quantitatively analyse compounds directly on skin. To this end, tape stripping experiments were performed with a deuterated liposomal drug delivery system containing the model drug flufenamic acid. While the amount of penetrated deuterated liposomes was determined directly on skin samples by ATR-FTIR, the drug amount was analysed by HPLC after extraction of the tape strips since higher sensitivity was achieved in this fashion. Thus, it was possible to monitor the skin penetration of drug and vehicle simultaneously. Interestingly, the results indicated an independent drug penetration after release from the liposomal carrier system. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. ATR-FTIR spectroscopic characterization of coexisting carbonate surface complexes on hematite (United States)

    Bargar, J.R.; Kubicki, J.D.; Reitmeyer, R.; Davis, J.A.


    The speciation of carbonate adsorbed to hematite in air-equilibrated aqueous solutions has been studied using ATR-FTIR spectroscopy. Samples were measured over a range of pH conditions, at 0.1 M NaCl and at low ionic strength, and in H2O and D2O solutions to permit a multispecies analysis of the data. Second-derivative analyses and fits to the spectra indicate the presence of two major and two minor surface-bound carbonate species. The two major complexes coexist at near-neutral pH and low ionic strength. One of these two complexes is relatively sensitive to ionic strength, being displaced at 0.1 M NaCl, whereas the other is not. Comparison of experimental to DFT/MO-calculated frequencies suggest these two major species to be (a) a monodentate binuclear inner-sphere carbonate surface complex, and (b) a fully or partially solvated carbonate (CO32-) species that is symmetry broken and appears to reside in the structured vicinal water layers at the hematite-water interface, retained by hydrogen bonding and/or other forces. Minor carbonate complexes include diffuse layer CO32- and an unidentified inner-sphere species. Both of the dominant species observed here are likely to be significant controls of the surface charge and sorptive properties of Fe-oxides. Copyright ?? 2005 Elsevier Ltd.

  19. Differentiation and identification of fungi by ATR-FTIR method in a leather collection relating back to Seljuk period

    Directory of Open Access Journals (Sweden)

    Mohsen Mohammadi Achachluei


    Full Text Available Introduction: Biodegradation is one of the main degrading factors of leather artifacts. Determination of fungi and other microorganisms has vital importance for conservation of valuable objects made from organic materials. Usual classic techniques for identification of pathogens and fungi have some difficulties, but FTIR spectroscopy has been introduced as useful technique for characterization and determination of microorganisms. Materials and methods: In this study, historic leathers were related to the Seljuk period. The leathers were sampled in laboratory and fungi were cultivated in SDA medium. Genuses of fungi were identified according to macroscopic, microscopic and morphologic characteristics. Microorganisms were analyzed by ATR-FTIR spectrometer and differences of spectral properties were assessed. Spectral properties were assessed according to form and absorption region of peaks. Cluster analysis was used for evaluation of different regions and areas on the measured spectra.Results: Results showed the presence of Penicillium sp. (9 samples, 33.3%, Aspergillus sp. (5 samples, 18.5%, Cladosporium sp. (4 samples, 14.8%, Rhizoctonia sp. (2 samples, 7.4%, Trichophyton sp. (1 sample, 3.7% and also one sample of yeast (3.7%. Two species of fungi remained unidentified (7.4% and there was not any growth in 3 samples (11.1%. Spectral properties indicated to structural differences between microorganisms (fungi, yeast, bacteria. It showed characteristics of fungi genus and species in some cases.Discussion and conclusion: Active fungi induce decomposition, hydrolysis and decay of leather and its vegetable tannins. The decay leads to aesthetic change and health problems. Therefore, it is necessary to remove of fungi and appropriate treatment of leather artifacts. Application of ATR-FTIR spectroscopy had good results for identification of fungi, yeast and bacteria. Assessments showed the potential of ATR-FTIR spectroscopy for easy and rapid

  20. Cocaine profiling: Implementation of a predictive model by ATR-FTIR coupled with chemometrics in forensic chemistry. (United States)

    Materazzi, Stefano; Gregori, Adolfo; Ripani, Luigi; Apriceno, Azzurra; Risoluti, Roberta


    In this study, a strategy based on Infrared Spectroscopy with Fourier Transformed and Attenuated Total Reflectance associated with chemometrics (ATR-FTIR) is proposed to identify the chemical "fingerprint" of cocaine samples. To this end, standard mixtures of cocaine and cuttings at differents ratio were investigated in order to develop a multivariate classification model to simultaneously predict the composition of the samples and to obtain a profile of adulteration of cocaine seizures. In addition, the application of a Partial Least Squares (PLS) and Principal Component Regression (PCR) calibration approaches were found to be a useful tool to predict the content of cocaine, caffeine, procaine, lidocaine and phenacetin in drug seizures. The achieved results on real confiscated samples, in cooperation with the Italian Scientific Investigation Department (Carabinieri-RIS) of Rome, allow to consider ATR-FTIR followed to chemometrics as a promising forensic tool in such situations involving profile comparisons and supporting forensic investigations. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Comparison of pharmaceutical formulations: ATR-FTIR spectroscopic imaging to study drug-carrier interactions. (United States)

    Ewing, Andrew V; Biggart, Gordon D; Hale, Carwyn R; Clarke, Graham S; Kazarian, Sergei G


    Attenuated total reflection (ATR) Fourier transform infrared (FTIR) spectroscopic imaging has been used in combination with UV detection to study the release of a model poorly water-soluble drug, indomethacin, when formulated with selected drug carriers. Firstly, formulations of indomethacin and nicotinamide in varying weight ratios were studied since novel tablet dosage forms containing multi-drugs are of industrial interest. The in situ spectroscopic imaging measurements of the dissolving tablets showed that as the loading of indomethacin was increased, the rate of drug release changed from one that expressed first-order drug release to one which showed zero-order drug release. Two drug release mechanisms have been identified from the recorded spectroscopic images and UV dissolution profiles. To further validate these mechanisms, specific formulations containing the model drug and two other excipients, urea and mannitol, were studied. The formulations with urea showed similar first-order release, indicative of the drug-carrier interactions. Whereas, the indomethacin/mannitol formulations showed a zero-order release curve explained by disintegration of the tablet. ATR-FTIR spectroscopic imaging provided highly chemically specific information as well as the spatial distribution of the components during the dissolution process which has demonstrated the potential of this combined analytical setup to determine the mechanisms of drug release. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. The use of ATR-FTIR imaging to study coated oil capsules

    NARCIS (Netherlands)

    Heussen, P.C.M.; Dalen, van G.; Nootenboom, P.; Smit, I.; Duynhoven, van J.P.M.


    Fourier transform infrared (FTIR) spectroscopic imaging using a large Internal Reflection Element (IRE), also called Attenuated Total Reflection (ATR) crystal, can be used for the identification and localisation of chemical compounds in solid food products. In this study ATR-FTIR imaging, by means

  3. Rapid classification and quantification of cocaine in seized powders with ATR-FTIR and chemometrics. (United States)

    Eliaerts, Joy; Dardenne, Pierre; Meert, Natalie; Van Durme, Filip; Samyn, Nele; Janssens, Koen; De Wael, Karolien


    Traditionally, fast screening for the presence of cocaine in unknown powders is performed by means of colour tests. The major drawbacks of these tests are subjective colour evaluation depending on the operator ('50 shades of blue') and a lack of selectivity. An alternative fast screening technique is Fourier Transform InfraRed (FTIR) spectrometry. This technique provides spectra that are difficult to interpret without specialized expertise and shows a lack of sensitivity for the detection of cocaine in mixtures. To overcome these limitations, a portable FTIR spectrometer using Attenuated Total Reflectance (ATR) sampling was combined with a multivariate technique, called Support Vector Machines (SVM). Representative street drug powders (n = 482), seized during the period January 2013 to July 2015, and reference powders (n = 33) were used to build and validate a classification model (n = 515) and a quantification model (n = 378). Both models were compared with the conventional chromatographic techniques. The SVM classification model showed a high sensitivity, specificity, and efficiency (99%). The SVM quantification model determined cocaine content with a root mean squared error of prediction (RMSEP) of 6% calculated over a wide working range from 4 to 99 w%. In conclusion, the developed models resulted in a clear output (cocaine detected or cocaine not detected) and a reliable estimation of the cocaine content in a wide variety of mixtures. The ATR-FTIR technique combined with SVM is a straightforward, user-friendly, and fast approach for routine classification and quantification of cocaine in seized powders. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  4. Formation of carboxy- and amide-terminated alkyl monolayers on silicon(111) investigated by ATR-FTIR, XPS, and X-ray scattering: Construction of photoswitchable surfaces

    DEFF Research Database (Denmark)

    Rück-Braun, Karola; Petersen, Michael Åxman; Michalik, Fabian


    zigzag-like substitution pattern for the ester- and carboxy-terminated monolayer. Hydrolysis of the remaining H-Si(111) bonds at the surface furnished HO-Si(111) groups according to XPS and attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) studies. The amide-terminated alkyl...... acid end-group. X-ray photoelectron spectroscopy (XPS) and grazing incidence X-ray diffraction (GIXD) indicate a surface coverage of about 50% of the initially H-terminated sites. In agreement, GIXD implies a rectangular unit mesh of 6.65 and 7.68 Å side lengths, containing two molecules in a regular...

  5. Surface characterization of poly(L-lactic acid)-methoxy poly(ethylene glycol) diblock copolymers by static and dynamic contact angle measurements, FTIR, and ATR-FTIR. (United States)

    Mert, O; Doganci, E; Erbil, H Y; Demir, A S


    The surface composition and surface free energy properties of two types of amphiphilic and semicrystalline diblock copolymers consisting of poly(L-lactic acid) coupled to (methoxy poly(ethylene glycol) (PLLA-MePEG) having differing block lengths of PEG were investigated by using static and dynamic contact angle measurements, transmission Fourier infrared spectroscopy (FTIR), and attenuated total reflection spectroscopy (ATR-FTIR) and compared with results obtained from PLLA and MePEG homopolymers. The contact angle results were evaluated by using the van Oss-Good method (acid-base method), and it was determined that the Lewis base surface tension coefficient (gamma-) of the copolymers increased with an increase of the PEG molar content at the copolymer surface. This result is in good agreement with the transmission FTIR and ATR-FTIR results but not proportional to them, indicating that the surfaces of the copolymers are highly mobile and that the molecular rearrangement takes place upon contact with a polar liquid drop. The dynamic contact angle measurements showed that the strong acid-base interaction between the oxygen atoms in the copolymer backbone of the relatively more hydrophilic PEG segments with the Lewis acidic groups of the polar and hydrogen-bonding water molecules enabled the surface molecules to restructure (conformational change) at the contact area, so that the PEG segments moved upward, whereas the apolar methyl pendant groups of PLLA segments buried downward.

  6. Investigation of aged Asian dust particles by the combined use of quantitative ED-EPMA and ATR-FTIR imaging

    Directory of Open Access Journals (Sweden)

    Y.-C. Song


    Full Text Available In our previous works, it was demonstrated that the combined use of quantitative energy-dispersive electron probe X-ray microanalysis (ED-EPMA, which is also known as low-Z particle EPMA, and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR imaging has great potential for a detailed characterization of individual aerosol particles. In this study, extensively chemically modified (aged individual Asian dust particles collected during an Asian dust storm event on 11 November 2002 in Korea were characterized by the combined use of low-Z particle EPMA and ATR-FTIR imaging. Overall, 109 individual particles were classified into four particle types based on their morphology, elemental concentrations, and molecular species and/or functional groups of individual particles available from the two analytical techniques: Ca-containing (38%, NaNO3-containing (30%, silicate (22%, and miscellaneous particles (10%. Among the 41 Ca-containing particles, 10, 8, and 14 particles contained nitrate, sulfate, and both, respectively, whereas only two particles contained unreacted CaCO3. Airborne amorphous calcium carbonate (ACC particles were observed in this Asian dust sample for the first time, where their IR peaks for the insufficient symmetric environment of CO32− ions of ACC were clearly differentiated from those of crystalline CaCO3. This paper also reports the first inland field observation of CaCl2 particles probably converted from CaCO3 through the reaction with HCl(g. HCl(g was likely released from the reaction of sea salt with NOx/HNO3, as all 33 particles of marine origin contained NaNO3 (no genuine sea salt particle was encountered. Some silicate particles with minor amounts of calcium were observed to be mixed with nitrate, sulfate, and water. Among 24 silicate particles, 10 particles are mixed with water, the presence of which could facilitate atmospheric heterogeneous reactions of silicate particles including swelling

  7. Mebendazole crystal forms in tablet formulations. An ATR-FTIR/chemometrics approach to polymorph assignment. (United States)

    Calvo, Natalia L; Kaufman, Teodoro S; Maggio, Rubén M


    Structural polymorphism of active pharmaceutical ingredients (API) is a relevant concern for the modern pharmaceutical industry, since different polymorphic forms may display dissimilar properties, critically affecting the performance of the corresponding drug products. Mebendazole (MEB) is a widely used broad spectrum anthelmintic drug of the benzimidazole class, which exhibits structural polymorphism (Forms A-C). Form C, which displays the best pharmaceutical profile, is the recommended one for clinical use. The polymorphs of MEB were prepared and characterized by spectroscopic, calorimetric and microscopic means. The polymorphs were employed to develop a suitable chemometrics-assisted sample display model based on the first two principal components of their ATR-FTIR spectra in the 4000-600 cm(-1) region. The model was internally and externally validated employing the leave-one-out procedure and an external validation set, respectively. Its suitability for revealing the polymorphic identity of MEB in tablets was successfully assessed analyzing commercial tablets under different physical forms (whole, powdered, dried, sieved and aged). It was concluded that the ATR-FTIR/PCA (principal component analysis) association is a fast, efficient and non-destructive technique for assigning the solid-state forms of MEB in its drug products, with minimum sample pre-treatment. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Colloidal carriers of isotretinoin for topical acne treatment: skin uptake, ATR-FTIR and in vitro cytotoxicity studies. (United States)

    Gürbüz, Aslı; Özhan, Gül; Güngör, Sevgi; Erdal, M Sedef


    Acne vulgaris is the chronical, multifactorial and complex disease of the pilosebaceous unit in the skin. The main goal of the topical therapy in acne is to target the drug to epidermal and deep dermal regions by minimizing systemic absorption . Isotretinoin, a retinoic acid derivative, is the most effective drug in acne pathogenesis. Because systemic treatment may cause many side effects, topical isotretinoin treatment is an option in the management of acne. However, due to its high lipophilic character, isotretinoin tends to accumulate in the upper stratum corneum, thus its penetration into the lower layers is limited, which restricts the efficiency of topical treatment. Microemulsions are fluid, isotropic, colloidal drug carriers that have been widely studied as drug delivery systems. The percutaneous transport of active agents can be enhanced by microemulsions when compared with their conventional formulations. The purpose of this study was to evaluate microemulsions as alternative topical carriers for isotretinoin with an objective to improve its skin uptake. After in vitro permeation studies, the dermal penetration of isotretinoin from microemulsions was investigated by tape stripping procedure. Confocal laser scanning microscopy provided insight about the localization of the drug in the skin. The interaction between the microemulsion components and stratum corneum lipids is studied by ATR-FTIR spectroscopy. The relative safety of the microemulsions was assessed in mouse embryonic fibroblasts using MTT viability test. The results indicate that microemulsion-based novel colloidal carriers have a potential for enhanced skin delivery and localization of isotretinoin.

  9. Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) in the discrimination of normal and oral cancer blood plasma (United States)

    Pachaiappan, Rekha; Prakasarao, Aruna; Singaravelu, Ganesan


    Oral cancer is the most frequent type of cancer that occurs with 75000 to 80000 new cases reported every year in India. The carcinogens from tobacco and related products are the main cause for the oral cancer. ATR-FTIR method is label free, fast and cost-effective diagnostic method would allow for rapid diagnostic results in earlier stages by the minimal chemical changes occur in the biological metabolites available in the blood plasma. The present study reports the use of ATR-FTIR data with advanced statistical model (LDA-ANN) in the diagnosis of oral cancer from normal with better accuracy. The infrared spectra were acquired on ATR-FTIR Jasco spectrophotometer at 4 cm-1 resolution, 30 scans, in the 1800-900 cm-1 spectral range. Each sample had 5 spectra recorded from each blood plasma sample. The spectral data were routed through the multilayer perception of artificial neural network to evaluate for the statistical efficacy. Among the spectral data it was found that amide II (1486 cm-1) and lipid (1526 cm-1) affords about 90 % in the discrimination between groups using LDA. These preliminary results indicate that ATR-FTIR is useful to differentiate normal subject from oral cancer patients using blood plasma.

  10. An ATR-FTIR study of sulphate sorption on magnetite; rate of adsorption, surface speciation, and effect of calcium ions. (United States)

    Roonasi, Payman; Holmgren, Allan


    The adsorption of sulphate on magnetite was studied in-situ using ATR-FTIR spectroscopy. Synthetic magnetite particles were deposited on a ZnSe internal reflection element and the spectra of sulphate adsorbed at pH 4-8.5 were recorded. Two different ionic strengths were used viz. 0.01 M and 0.1 M NaCl. The spectra of adsorbed sulphate on magnetite coated ZnSe were compared with the spectra of sulphate solutions at the same pH values and in contact with uncoated ZnSe. The spectrum of adsorbed sulphate at pH 4 showed three maxima at 979, 1044, and 1115 cm(-1) indicating a monodentate adsorption in which the T(d) symmetry of SO(4)(2-) is lowered to C(3v). At pH 6.5, sulphate adsorbed as an outer-sphere complex with two weak bands appearing at 1102 and 980 cm(-1). Moreover, spectra of the adsorbed sulphate at pH 4 were recorded as a function of time and sulphate concentration. The equilibrium absorbance at different concentrations fitted a Langmuir type adsorption isotherm. The Langmuir affinity constant K at pH 4 was determined from the slope and intercept of the Langmuir plot to be K=1.2344x10(4) M(-1) and the Gibbs free energy of adsorption DeltaG(ads)(0) was estimated from this value to be -33.3 kJ/mol. Kinetic analysis indicated that adsorption at pH 4 is fast, whilst the desorption kinetic at the same pH is very slow. In addition, the effect of Ca ions on sulphate adsorption was also studied. It was shown that Ca ions increased the sulphate adsorption on magnetite at pH 8.5.

  11. Tungstate (VI) sorption on hematite: An in situ ATR-FTIR probe on the mechanism. (United States)

    Rakshit, Sudipta; Sallman, Bryan; Davantés, Athénais; Lefèvre, Grégory


    Owing to the suspected toxicity and carcinogenicity of tungstate (VI) oxyanions [i.e. mono tungstate and several polytungstate, generally represented by W (VI)], the environmental fate of W (VI) has been widely studied. Sorption is regarded as a major mechanism by which W (VI) species are retained in the solid/water interface. Iron (hydr)oxides have been considered important environmental sinks for W (VI) species. Here we report sorption mechanisms of W (VI) on a common iron oxide mineral-hematite under environmentally relevant solution properties using in situ attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopic probes. Initial W (VI) loadings varied from 10 to 200 μM at fixed pH values ranged from 4.6 to 8.1. For pH envelop (pHs = 4.6, 5.0, 5.5, 6.0, 6.5, 7.5, and 8.1) experiments, fixed W (VI) concentrations (i.e. 10 & 200 μM) were used to understand the effects of pH. The results indicated that at acidic pH values (pH hematite surface and the strength of the interaction increases with decreasing pH. In addition, initial W (VI) concentration affected the sorption mechanisms of W (VI) on hematite. Our study will aid the molecular level understanding of W (VI) retention on iron oxide surfaces. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. In situ ATR-FTIR study of the early stages of fly ash geopolymer gel formation. (United States)

    Rees, Catherine A; Provis, John L; Lukey, Grant C; van Deventer, Jannie S J


    The kinetics of geopolymer formation are monitored using a novel in situ attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopic technique. Reaction rates are determined from the intensity variation of the bands related to the geopolymer gel network and the unreacted fly ash particles. Comparison with deuterated geopolymer samples provides critical information regarding peak assignments. An initial induction (lag) period is observed to occur for hydroxide-activated geopolymers, followed by gel evolution according to an approximately linear reaction profile. The length of the lag period is reduced by increasing the concentration of NaOH. An increase in the rate of network formation also occurs with increasing NaOH concentration up to a maximum point, beyond which an increased NaOH concentration leads to a reduced rate of network formation. This trend is attributed to the competing effects of increased alkalinity and stronger ion pairing with an increase in NaOH concentration. In situ analysis also shows that the rate of fly ash dissolution is similar for all moderate- to high-alkali geopolymer slurries, which is attributed to the very highly water-deficient nature of these systems and is contrary to predictions from classical glass dissolution chemistry. This provides for the first time detailed kinetic information describing fly ash geopolymer formation kinetics.

  13. ATR-FTIR sensor development for continuous on-line monitoring of chlorinated aliphatic hydrocarbons in a fixed-bed bioreactor. (United States)

    Acha, V; Meurens, M; Naveau, H; Agathos, S N


    This article describes the continuous on-line monitoring of a dechlorination process by a novel attenuated total reflection-Fourier transform infrared (ATR-FTIR) sensor. This optical sensor was developed to measure noninvasively part-per-million (ppm) concentrations of trichloroethylene (TCE), tetrachloroethylene (PCE), and carbon tetrachloride (CT) in the aqueous effluent of a fixed-bed dechlorinating bioreactor, without any prior sample preparation. The sensor was based on an ATR internal reflection element (IRE) coated with an extracting hydrophobic polymer, which prevented water molecules from interacting with the infrared (IR) radiation. The selective diffusion of chlorinated compound molecules from aqueous solution into the polymer made possible their detection by the IR beam. With the exclusion of water the detection limits were lowered, and measurements in the low ppm level became possible. The best extracting polymer was polyisobutylene (PIB) in the form of a 5.8-microm thick film, which afforded a detection limit of 2, 3, and 2. 5 mg/L (ppm) for TCE, PCE, and CT, respectively. Values of the enrichment factors between the polymer coating and the water matrix of these chloro-organics were determined experimentally and were compared individually with predictions obtained from the slopes of absorbance/concentration curves for the three analytes. Before coupling the ATR-FTIR sensor to the dechlorinating bioreactor, preliminary spectra of the chlorinated compounds were acquired on a laboratory scale configuration in stop-flow and flow-through closed-loop modes. In this way, it was possible to study the behavior and direct response of the optical sensor to any arbitrary concentration change of the analytes. Subsequently, the bioreactor was monitored with the infrared sensor coupled permanently to it. The sensor tracked the progression of the analytes' spectra over time without perturbing the dechlorinating process. To calibrate the ATR-FTIR sensor, a total of 13

  14. Fourier Transform Infrared Radiation Spectroscopy Applied for Wood Rot Decay and Mould Fungi Growth Detection

    Directory of Open Access Journals (Sweden)

    Bjørn Petter Jelle


    Full Text Available Material characterization may be carried out by the attenuated total reflectance (ATR Fourier transform infrared (FTIR radiation spectroscopical technique, which represents a powerful experimental tool. The ATR technique may be applied on both solid state materials, liquids, and gases with none or only minor sample preparations, also including materials which are nontransparent to IR radiation. This facilitation is made possible by pressing the sample directly onto various crystals, for example, diamond, with high refractive indices, in a special reflectance setup. Thus ATR saves time and enables the study of materials in a pristine condition, that is, the comprehensive sample preparation by pressing thin KBr pellets in traditional FTIR transmittance spectroscopy is hence avoided. Materials and their ageing processes, both ageing by natural and accelerated climate exposure, decomposition and formation of chemical bonds and products, may be studied in an ATR-FTIR analysis. In this work, the ATR-FTIR technique is utilized to detect wood rot decay and mould fungi growth on various building material substrates. An experimental challenge and aim is to be able to detect the wood rot decay and mould fungi growth at early stages when it is barely visible to the naked eye. Another goal is to be able to distinguish between various species of fungi and wood rot.

  15. Detection of aflatoxin M1 in milk using spectroscopy and multivariate analyses. (United States)

    Jaiswal, Pranita; Jha, Shyam Narayan; Kaur, Jaspreet; Borah, Anjan; Ramya, H G


    Aflatoxin M1 (AFM1), a potentially carcinogenic compound, is found in milk obtained from animals that consume contaminated feed. Spectra of bovine milk, spiked with AFM1 (0, 0.02, 0.04, 0.06, 0.08 and 0.1μg/l) were acquired using attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectrometer. Spectra revealed significant differences among pure and AFM1 spiked samples in spectral regions 1800-650cm(-1) and 3689-3499cm(-1), which may be attributed to complex chemical structure of AFM1. Principal component analysis (PCA) showed clear clustering of samples (p⩽0.05). The models could successfully classify (>86%) and detect even 0.02μg/l AFM1 in milk (p⩽0.05) using SIMCA. AFM1 was best predicted in wavenumber range of 1800-650cm(-1) with coefficient of determination (R(2)) of 0.99 and 0.98, for calibration and validation, respectively, using partial least square (PLS) regression. The study indicated feasibility of ATR-FTIR spectroscopy and chemometrics in rapid detection and quantification of AFM1 in milk. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Evaluation of low trans fat edible oils by attenuated total reflection-Fourier transform infrared spectroscopy and gas chromatography: a comparison of analytical approaches. (United States)

    Tyburczy, Cynthia; Mossoba, Magdi M; Fardin-Kia, Ali Reza; Rader, Jeanne I


    Current interest by the food industry in exploring reformulation options that lower the content of trans fat in edible fats and oils requires methods to accurately measure low levels of trans fat. In the present study, the quantitation of trans fat in 25 edible fat and oil samples was evaluated using two current analytical approaches, attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), and gas chromatography with flame ionization detection (GC-FID) according to Official Methods of the American Oil Chemists' Society. Significant differences between the ATR-FTIR and reference GC-FID quantitations were found for samples with a trans fat content fat. These discrepancies could be explained, in part, by the presence of certain oil constituents (e.g., vitamins, carotenoids, high levels of saturated fat) that produced absorbance bands at or near 966 cm(-1) in the ATR-FTIR spectra, a region that was previously identified as being characteristic of isolated trans double bonds. Results demonstrate that the natural content of such oil constituents could result in significant overestimations of trans fat when ATR-FTIR is used to analyze edible fats and oils with a trans fat content fat.

  17. Reprocessability of PHB in extrusion: ATR-FTIR, tensile tests and thermal studies

    Directory of Open Access Journals (Sweden)

    Leonardo Fábio Rivas

    Full Text Available Abstract Mechanical recycling of biodegradable plastics has to be encouraged, since the consumption of energy and raw materials can be reduced towards a sustainable development in plastics materials. In this study, the evolution of thermal and mechanical properties, as well as structural changes of poly(hydroxybutyrate (PHB up to three extrusion cycles were investigated. Results indicated a significant reduction in mechanical properties already at the second extrusion cycle, with a reduction above 50% in the third cycle. An increase in the crystallinity index was observed due to chemicrystallization process during degradation by chain scission. On the other hand, significant changes in the chemical structure or in thermal stability of PHB cannot be detected by Fourier transform infrared spectroscopy (FTIR and thermogravimetric analyses (TGA, respectively.

  18. Fast and calibration free determination of first order reaction kinetics in API synthesis using in-situ ATR-FTIR. (United States)

    Rehbein, Moritz C; Husmann, Sascha; Lechner, Christian; Kunick, Conrad; Scholl, Stephan


    In early stages of drug development only sparse amounts of the key substances are available, which is problematic for the determination of important process data like reaction kinetics. Therefore, it is important to perform experiments as economically as possible, especially in regards to limiting compounds. Here we demonstrate the use of a temperature step experiment enabling the determination of complete reaction kinetics in a single non-isothermal experiment. In contrast to the traditionally used HPLC, the method takes advantage of the high measuring rate and the low amount of labor involved in using in-situ ATR-FTIR to determine time-dependent concentration-equivalent data. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. ATR-FTIR as a potential tool for controlling high quality vinegar categories

    DEFF Research Database (Denmark)

    Ríos-Reina, Rocío; Callejón, Raquel M.; Oliver-Pozo, Celia


    Characterization of wine vinegars qualified with a Protected Designation of Origin (PDO) is crucial to certify their quality and authenticity. Spectroscopic techniques as Fourier transform mid infrared spectroscopy (FTIR) with Attenuated Total Reflectance (ATR) has been applied to investigate its...

  20. Characterization of postmortem biochemical changes in rabbit plasma using ATR-FTIR combined with chemometrics: A preliminary study (United States)

    Zhang, Ji; Li, Bing; Wang, Qi; Li, Chengzhi; Zhang, Yinming; Lin, Hancheng; Wang, Zhenyuan


    Postmortem interval (PMI) determination is one of the most challenging tasks in forensic medicine due to a lack of accurate and reliable methods. It is especially difficult for late PMI determination. Although many attempts with various types of body fluids based on chemical methods have been made to solve this problem, few investigations are focused on blood samples. In this study, we employed an attenuated total reflection (ATR)-Fourier transform infrared (FTIR) technique coupled with principle component analysis (PCA) to monitor biochemical changes in rabbit plasma with increasing PMI. Partial least square (PLS) model was used based on the spectral data for PMI prediction in an independent sample set. Our results revealed that postmortem chemical changes in compositions of the plasma were time-dependent, and various components including proteins, lipids and nucleic acids contributed to the discrimination of the samples at different time points. A satisfactory prediction within 48 h postmortem was performed by the combined PLS model with a good fitting between actual and predicted PMI of 0.984 and with an error of ± 1.92 h. In consideration of the simplicity and portability of ATR-FTIR, our preliminary study provides an experimental and theoretical basis for application of this technique in forensic practice.

  1. Effects of Near Infrared Radiation on DNA. DLS and ATR-FTIR Study. (United States)

    Szymborska-Małek, Katarzyna; Komorowska, Małgorzata; Gąsior-Głogowska, Marlena


    We presume that the primary effect of Near Infrared (NIR) radiation on aqueous solutions of biological molecules concerns modification of hydrogen bonded structures mainly the global and the hydration shell water molecules. Since water has a significant influence on the DNA structure, we expect that the thermal stability of DNA could be modified by NIR radiation. The herring sperm DNA was exposed to NIR radiation (700-1100nm) for 5, 10, and 20min periods. The temperature dependent infrared measurements were done for the thin films formed on the diamond ATR crystal from evaporated DNA solutions exposed and unexposed to NIR radiation. For the NIR-treated samples (at room temperature) the B form was better conserved than in the control sample independently of the irradiation period. Above 50°C a considerable increase in the A form was only observed for 10min NIR exposed samples. The hydrodynamic radius, (Rh), studied by the dynamic light scattering, showed drastic decrease with the increasing irradiation time. Principal components analysis (PCA) allowed to detect the spectral features correlated with the NIR effect and thermal stability of the DNA films. Obtained results strongly support the idea that the photoionization of water by NIR radiation in presence of DNA molecules is the main factor influencing on its physicochemical properties. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Effects of Near Infrared Radiation on DNA. DLS and ATR-FTIR Study (United States)

    Szymborska-Małek, Katarzyna; Komorowska, Małgorzata; Gąsior-Głogowska, Marlena


    We presume that the primary effect of Near Infrared (NIR) radiation on aqueous solutions of biological molecules concerns modification of hydrogen bonded structures mainly the global and the hydration shell water molecules. Since water has a significant influence on the DNA structure, we expect that the thermal stability of DNA could be modified by NIR radiation. The herring sperm DNA was exposed to NIR radiation (700-1100 nm) for 5, 10, and 20 min periods. The temperature dependent infrared measurements were done for the thin films formed on the diamond ATR crystal from evaporated DNA solutions exposed and unexposed to NIR radiation. For the NIR-treated samples (at room temperature) the B form was better conserved than in the control sample independently of the irradiation period. Above 50 °C a considerable increase in the A form was only observed for 10 min NIR exposed samples. The hydrodynamic radius, (Rh), studied by the dynamic light scattering, showed drastic decrease with the increasing irradiation time. Principal components analysis (PCA) allowed to detect the spectral features correlated with the NIR effect and thermal stability of the DNA films. Obtained results strongly support the idea that the photoionization of water by NIR radiation in presence of DNA molecules is the main factor influencing on its physicochemical properties.

  3. Kinetic and Conformational Insights of Protein Adsorption onto Montmorillonite Revealed Using in Situ ATR-FTIR/2D-COS. (United States)

    Schmidt, Michael P; Martínez, Carmen Enid


    Protein adsorption onto clay minerals is a process with wide-ranging impacts on the environmental cycling of nutrients and contaminants. This process is influenced by kinetic and conformational factors that are often challenging to probe in situ. This study represents an in situ attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopic investigation of the adsorption of a model protein (bovine serum albumin (BSA)) onto a clay mineral (montmorillonite) at four concentrations (1.50, 3.75, 7.50, and 15.0 μM) under environmentally relevant conditions. At all concentrations probed, FTIR spectra show that BSA readily adsorbs onto montmorillonite. Adsorption kinetics follow an Elovich model, suggesting that primary limitations on adsorption rates are surface-related heterogeneous energetic restrictions associated with protein rearrangement and lateral protein-protein interaction. BSA adsorption onto montmorillonite fits the Langmuir model, yielding K = 5.97 × 10(5) M(-1). Deconvolution and curve fitting of the amide I band at the end of the adsorption process (∼120 min) shows a large extent of BSA unfolding upon adsorption at 1.50 μM, with extended chains and turns increasing at the expense of α-helices. At higher concentrations/surface coverages, BSA unfolding is less pronounced and a more compact structure is assumed. Two-dimensional correlation spectroscopic (2D-COS) analysis reveals three different pathways corresponding to adsorbed conformations. At 1.50 μM, adsorption increases extended chains, followed by a loss in α-helices and a subsequent increase in turns. At 3.75 μM, extended chains decrease and then aggregated strands increase and side chains decrease, followed by a decrease in turns. With 7.50 and 15.0 μM BSA, the loss of side-chain vibrations is followed by an increase in aggregated strands and a subsequent decrease in turns and extended chains. Overall, the BSA concentration and resultant surface coverage have a profound

  4. Combined use of quantitative ED-EPMA, Raman microspectrometry, and ATR-FTIR imaging techniques for the analysis of individual particles. (United States)

    Jung, Hae-Jin; Eom, Hyo-Jin; Kang, Hyun-Woo; Moreau, Myriam; Sobanska, Sophie; Ro, Chul-Un


    In this work, quantitative energy-dispersive electron probe X-ray microanalysis (ED-EPMA) (called low-Z particle EPMA), Raman microspectrometry (RMS), and attenuated total reflectance Fourier transform infrared spectroscopic (ATR-FTIR) imaging were applied in combination for the analysis of the same individual airborne particles for the first time. After examining individual particles of micrometer size by low-Z particle EPMA, consecutive examinations by RMS and ATR-FTIR imaging of the same individual particles were then performed. The relocation of the same particles on Al or Ag foils was successfully carried out among the three standalone instruments for several standard samples and an indoor airborne particle sample, resulting in the successful acquisition of quality spectral data from the three single-particle analytical techniques. The combined application of the three techniques to several different standard particles confirmed that those techniques provided consistent and complementary chemical composition information on the same individual particles. Further, it was clearly demonstrated that the three different types of spectral and imaging data from the same individual particles in an indoor aerosol sample provided richer information on physicochemical characteristics of the particle ensemble than that obtainable by the combined use of two single-particle analytical techniques.

  5. Ablation of burned skin with ultra-short pulses laser to promote healing: evaluation by optical coherence tomography, histology, {mu}ATR-FTIR and Nonlinear Microscopy; Ablacao de pele queimada com laser de pulsos ultra-curtos para promocao da cicatrizacao: avaliacao por tomografia por coerencia optica, histologia, {mu}ATR-FTIR e microscopia nao-linear

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Moises Oliveira dos


    Burns cause changes in the anatomical structure of the skin associated with trauma. The severity of the burn injury is divided into first, second and third-degree burns. The third-degree burns have been a major focus of research in search of more conservative treatments and faster results in repair for a functional and cosmetically acceptable. The conventional treatment is the use of topical natural or synthetic skin graft. An alternative therapy is the laser ablation process for burned tissue necrosis removal due to the no mechanical contact, fast application and access to difficult areas. The purpose of this study is to evaluate the feasibility of using high intensity femtosecond lasers as an adjunct treatment of burned patients. For this study, 65 Wistar rats were divided into groups of five animals: healthy skin, burned skin, two types of treatment (surgical debridement or femtosecond laser ablation) and four different times in the healing process monitoring. Three regions of the back of the animals were exposed to steam source causing third-degree burn. On the third day after the burn, one of the regions was ablated with high intensity ultrashort laser pulses ({lambda} = 785 nm, 90 fs, 2 kHz and 10 {mu}J/ pulse), the other received surgical debridement, and the last was considered the burn control. The regions were analyzed by optical coherence tomography (OCT), histology, attenuated total reflectance infrared spectroscopy using Fourier transform ({mu}-ATR-FTIR), two-photon excitation fluorescence microscopy (TPEFM) and second harmonic generation technique (SHG) on days 3, 5, 7 and 14 pos-treatments. The results showed that with the laser irradiation conditions used it was possible to remove debris from third degree burn. The techniques used to characterize the tissue allowed to verify that all treatments promoted wound healing. On the fourteenth day, the regeneration curve showed that the attenuation coefficient of laser ablated tissue converges to the values

  6. Interaction of Zn(II) with hematite nanoparticles and microparticles: Part 2. ATR-FTIR and EXAFS study of the aqueous Zn(II)/oxalate/hematite ternary system. (United States)

    Ha, Juyoung; Trainor, Thomas P; Farges, François; Brown, Gordon E


    Sorption of Zn(II) to hematite nanoparticles (HN) (av diam=10.5 nm) and microparticles (HM) (av diam=550 nm) was studied in the presence of oxalate anions (Ox2-(aq)) in aqueous solutions as a function of total Zn(II)(aq) to total Ox2-(aq) concentration ratio (R=[Zn(II)(aq)]tot/[Ox2-(aq)]tot) at pH 5.5. Zn(II) uptake is similar in extent for both the Zn(II)/Ox/HN and Zn(II)/Ox/HM ternary systems and the Zn(II)/HN binary system at [Zn(II)(aq)](tot)system than for the Zn(II)/Ox/HM ternary and the Zn(II)/HN and Zn(II)/HM binary systems at [Zn(II)(aq)]tot>4 mM. In contrast, Zn(II) uptake for the Zn(II)/HM binary system is a factor of 2 greater than that for the Zn(II)/Ox/HM and Zn(II)/Ox/HN ternary systems and the Zn(II)/HN binary system at [Zn(II)(aq)]totternary system at both R values examined (0.16 and 0.68), attenuated total reflectance Fourier transform infrared (ATR-FTIR) results are consistent with the presence of inner-sphere oxalate complexes and outer-sphere ZnOx(aq) complexes, and/or type A ternary complexes. In addition, extended X-ray absorption fine structure (EXAFS) spectroscopic results suggest that type A ternary surface complexes (i.e., >O2-Zn-Ox) are present. In the Zn(II)/Ox/HN ternary system at R=0.15, ATR-FTIR results indicate the presence of inner-sphere oxalate and outer-sphere ZnOx(aq) complexes; the EXAFS results provide no evidence for inner-sphere Zn(II) complexes or type A ternary complexes. In contrast, ATR-FTIR results for the Zn/Ox/HN sample with R = 0.68 are consistent with a ZnOx(s)-like surface precipitate and possibly type B ternary surface complexes (i.e., >O2-Ox-Zn). EXAFS results are also consistent with the presence of ZnOx(s)-like precipitates. We ascribe the observed increase of Zn(II)(aq) uptake in the Zn(II)/Ox/HN ternary system at [Zn(II)(aq)]tot>or=4 mM relative to the Zn(II)/Ox/HM ternary system to formation of a ZnOx(s)-like precipitate at the hematite nanoparticle/water interface.

  7. Assessment of historical polymers using attenuated total reflectance-Fourier transform infra-red spectroscopy with principal component analysis

    National Research Council Canada - National Science Library

    Mitchell, Gemma; France, Fenella; Nordon, Alison; Tang, Pik Leung; Gibson, Lorraine T


    Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy with a diamond ATR crystal was used to examine 41 historical polymer fragments and a selection of polyurethane fragments subjected to accelerated ageing...

  8. Rapid detection of melamine adulteration in dairy milk by SB-ATR-Fourier transform infrared spectroscopy. (United States)

    Jawaid, Sana; Talpur, Farah N; Sherazi, S T H; Nizamani, Shafi M; Khaskheli, Abid A


    Melamine is a nitrogenous chemical substance used principally as a starting material for the manufacture of synthetic resins. Due to its very high proportion of nitrogen melamine has been added illegitimately to foods and feeds to increase the measured protein content, which determines the value of the product. These issues prompted private as well as governmental laboratories to develop methods for the analysis of melamine in a wide variety of food products and ingredients. Owing to this fact present study is aimed to use single bounce attenuated total reflectance (SB-ATR) Fourier transform infrared spectroscopy (FTIR) method as an effective rapid tool for the detection and quantification of melamine in milk (liquid and powder). Partial least-squares (PLS) models were established for correlating spectral data to melamine concentration with R(2)>0.99, and RMSEC 0.370. Linear calibration curves were obtained over the calibration range of 25-0.0625%. The LOD and LOQ of the method was 0.00025% (2.5 ppm) and 0.0015% (15 ppm) respectively. Proposed SB-ATR-FTIR method requires little or no sample preparation with an assay time of 1-2 min. Copyright © 2013. Published by Elsevier Ltd.

  9. Differentiation and identification of fungi by ATR-FTIR method in a leather collection relating back to Seljuk period


    Mohsen Mohammadi Achachluei; Hosseyn Ahmadi; Alireza Koochakzaei


    Introduction: Biodegradation is one of the main degrading factors of leather artifacts. Determination of fungi and other microorganisms has vital importance for conservation of valuable objects made from organic materials. Usual classic techniques for identification of pathogens and fungi have some difficulties, but FTIR spectroscopy has been introduced as useful technique for characterization and determination of microorganisms. Materials and methods: In this study, historic leathers were re...

  10. In-Situ ATR-FTIR and Surface Complexation Modeling Study of the Adsorption of Dimethylarsenic Acid and p-Arsanilic Acid on Iron Oxides (United States)

    Goldberg, S. R.; Al-Abadleh, H.; Mitchell, W.


    Arsenic is an element that exists naturally in many rocks and minerals around the world, accumulates in petroleum, shale, and coal deposits as a result of biogeochemical processes, and is found in fly ash from fuel combustion. Arsenic compounds in their organic and inorganic forms pose both health and environmental risks. The environmental fate of arsenic compounds is controlled to a large extent by their surface interactions with inorganic and organic surfaces. We report results from applying the triple layer surface complexation model to adsorption isotherm and pH-envelope experimental data of dimethylarsenic acid, DMA, and p-arsanilic acid, p-AsA on the iron oxides, hematite and goethite. Ligand exchange reactions were based on the interpretation of ATR-FTIR spectra of DMA and p-AsA surface complexes. Surface coverage of the organoarsenicals was quantified in-situ from the spectral component at 840 cm-1. The best model fit to the DMA adsorption data was obtained using an outer-sphere complex, whereas for p-AsA, best model fit was obtained using two monodentate inner-sphere surface complexes. The significance of the results is discussed in relation to improving modeling tools used by environmental regulators. Accurate predictive modeling tools are needed for effective design of arsenic removal technologies using iron oxide minerals.

  11. In situ ATR-FTIR and surface complexation modeling studies on the adsorption of dimethylarsinic acid and p-arsanilic acid on iron-(oxyhydr)oxides. (United States)

    Mitchell, William; Goldberg, Sabine; Al-Abadleh, Hind A


    Arsenic is an element that exists naturally in many rocks and minerals around the world. It also accumulates in petroleum, shale, oil sands, and coal deposits as a result of biogeochemical processes, and it has been found in fly ash from the combustion of solid biofuels. Arsenic compounds in their organic and inorganic forms pose both a health and an environmental risk, and continue to be a challenge to the energy industry. The environmental fate and removal technologies of arsenic compounds are controlled to a large extent by their surface interactions with inorganic and organic adsorbents. We report thermodynamic binding constants, K(binding), from applying the triple-layer surface complexation model to adsorption isotherm and pH envelope data for dimethylarsinic acid (DMA) and p-arsanilic acid (p-AsA) on hematite and goethite. Ligand exchange reactions were constructed based on the interpretation of ATR-FTIR spectra of DMA and p-AsA surface complexes. Surface coverage of adsorbates was quantified in situ from the spectral component at 840 cm(-1). The best fit to the DMA adsorption data was obtained using outer-sphere complex formation, whereas for p-AsA, the best fit was obtained using two monodentate inner-sphere surface complexes. The significance of the results is discussed in relation to improving modeling tools used by environmental regulators and the energy sector for optimum control of arsenic content in fuels. Copyright © 2011 Elsevier Inc. All rights reserved.

  12. Glyphosate complexation to aluminium(III). An equilibrium and structural study in solution using potentiometry, multinuclear NMR, ATR-FTIR, ESI-MS and DFT calculations. (United States)

    Purgel, Mihály; Takács, Zoltán; Jonsson, Caroline M; Nagy, Lajos; Andersson, Ingegärd; Bányai, István; Pápai, Imre; Persson, Per; Sjöberg, Staffan; Tóth, Imre


    The stoichiometries and stability constants of a series of Al(3+)-N-phosponomethyl glycine (PMG/H(3)L) complexes have been determined in acidic aqueous solution using a combination of precise potentiometric titration data, quantitative (27)Al and (31)P NMR spectra, ATR-FTIR spectrum and ESI-MS measurements (0.6M NaCl, 25 degrees C). Besides the mononuclear AlH(2)L(2+), Al(H(2)L)(HL), Al(HL)(2)(-) and Al(HL)L(2-), dimeric Al(2)(HL)L(+) and trinuclear Al(3)H(5)L(4)(2+) complexes have been postulated. (1)H and (31)P NMR data show that different isomers co-exist in solution and the isomerization reactions are slow on the (31)P NMR time scale. The geometries of monomeric and dimeric complexes likely double hydroxo bridged and double phosphonate bridged isomers have been optimized using DFT ab initio calculations starting from rational structural proposals. Energy calculations using the PCM solvation method also support the co-existence of isomers in solutions.

  13. Kinetic Parameters during Bis-GMA and TEGDMA Monomer Polymerization by ATR-FTIR: The Influence of Photoinitiator and Light Curing Source

    Directory of Open Access Journals (Sweden)

    Aline B. Denis


    Full Text Available This study aimed to analyze the kinetic parameters of two monomers using attenuated total reflectance Fourier transform infrared (ATR-FTIR: 2,2-bis-[4-(2-hydroxy-3-methacryloxypropyl-1-oxy-phenyl] propane (Bis-GMA and triethylene glycol dimethacrylate (TEGDMA. The following were calculated to evaluate the kinetic parameters: maximum conversion rate (Rpmax, time at the maximum polymerization rate (tmax, conversion at Rpmax, and total conversion recorded at the maximum conversion point after 300 s. Camphorquinone (CQ and phenyl propanedione (PPD were used in this study as photoinitiators, whereas N,N-dimethyl-p-toluidine (DMPT amine was used as a coinitiator. LED apparatus and halogen lamp were used in turn to evaluate the effect that light source had on the monomer kinetics. The mass concentration ratio for the three resin preparations was 0.7 : 0.3 for Bis-GMA and TEGDMA: R1 (CQ + DMPT, R2 (PPD + DMPT, and R3 (PPD + CQ + DMPT. The PPD association with the CQ photoinitiator altered the polymerization kinetics compared to a resin containing only the CQ photoinitiator. The light sources exhibited no significant differences for tmax of R1 and R3. Resins containing only the PPD initiator exhibited a higher tmax than those containing only CQ. However, the Rpmax decreased for resins containing the PPD photoinitiator.

  14. Synthesis, physicochemical and spectroscopic characterization of copper(II)-polysaccharide pullulan complexes by UV-vis, ATR-FTIR, and EPR. (United States)

    Mitić, Zarko; Cakić, Milorad; Nikolić, Goran M; Nikolić, Ružica; Nikolić, Goran S; Pavlović, Radmila; Santaniello, Enzo


    Bioactive copper(II) complexes with polysaccharides, like pullulan and dextran, are important in both veterinary and human medicine for the treatment of hypochromic microcitary anemia and hypocupremia. In aqueous alkaline solutions, Cu(II) ion forms complexes with the exopolysaccharide pullulan and its reduced low-molecular derivative. The metal content and the solution composition depend on pH, temperature, and time of the reaction. The complexing process begins in a weak alkali solution (pH >7) and involves OH groups of pullulan monomer (glucopyranose) units. Complexes of Cu(II) ion with reduced low-molecular pullulan (RLMP, M(w) 6000 g mol(-1)) were synthesized in water solutions, at the boiling temperature and at different pH values ranging from 7.5 to 12. The Cu(II) complex formation with RLMP was analyzed by UV-vis spectrophotometry and other physicochemical methods. Spectroscopic characterizations (ATR-FTIR, FT-IRIS, and EPR) and spectra-structure correlation of Cu(II)-RLMP complexes were also carried out. Copyright © 2010 Elsevier Ltd. All rights reserved.

  15. Plasma-treated polyethylene film: A smart material applied for Salmonella Typhimurium detection

    Energy Technology Data Exchange (ETDEWEB)

    Peng-Ubol, Triranat [Department of Chemistry, Faculty of Science, Mahidol University, Rama 6 Rd, Phayathai, Bangkok 10400 (Thailand); Phinyocheep, Pranee, E-mail: [Department of Chemistry, Faculty of Science, Mahidol University, Rama 6 Rd, Phayathai, Bangkok 10400 (Thailand); Daniel, Philippe [Laboratoire de Physique de l' Etat Condense (LPEC-UMR CNRS 6087), Universite du Maine, Avenue Olivier Messiaen, 72085, Le Mans Cedex 9 (France); Panbangred, Watanalai [Department of Biotechnology and Mahidol University-Osaka University Collaborative Research Center for Bioscience and Biotechnology (MU-OU: CRC), Faculty of Science, Mahidol University, Rama 6 Rd, Phayathai, Bangkok 10400 (Thailand); Pilard, Jean-Francois [Unite de Chimie Organique Moleculaire et Macromoleculaire (UCO2M-UMR CNRS 6011), Universite du Maine, Avenue Olivier Messiaen, 72085 Le Mans Cedex 9 (France); Thouand, Gerald; Durand-Thouand, Marie-Jose [Genie des Procedes Environnement et Agroalimentaire (GEPEA UMR CNRS 6144), Departement Genie Biologique, IUT de la Roche/Yon, Universite de Nantes, 18 Bd G. Defferre, 85035 La Roche sur Yon (France)


    Salmonella is a major cause of foodborne illness worldwide and is not allowed to be present in any food in all countries. The purpose of this study is to develop a simple alternative method for the detection of Salmonella based on functionalized polyethylene (PE) surfaces. Salmonella Typhimurium was used as a model bacterium. PE film was treated using dielectric plasma in order to alter the wettability of the PE surface and consequently introduce functionality on the surface. The PE film characterized by ATR-FTIR spectroscopy revealed the presence of C=O stretching of ketones, aldehydes and carboxylic acids. The antibodies against O or H antigens of Salmonella and S. Typhimurium were then respectively immobilized on the PE surface after activation of the carboxylic group using NHS/EDC followed by protein A. The evidences from ATR-FTIR, scanning electron microscopy and optical microscopy showed the presence of S. Typhimurium attached to the plasma treated PE surfaces via the two types of anti-Salmonella antibody. The plasma treated PE film developed is simple and allows efficient association of bacterial cells on the treated surfaces without the necessity of time-consuming centrifugation and washing steps for isolation of the cells. This material is considered to be a smart material applicable for S. Typhimurium detection. Highlights: Black-Right-Pointing-Pointer We developed a functionalized polyethylene film for bacterial detection. Black-Right-Pointing-Pointer We modified the surface of polyethylene film by plasma treatment. Black-Right-Pointing-Pointer ATR-FTIR spectroscopy was used to analyze the functionality on the PE surface. Black-Right-Pointing-Pointer We introduced Salmonella Typhimurium on the modified PE film. Black-Right-Pointing-Pointer SEM revealed the presence of S. Typhimurium on the plasma treated PE film.

  16. Photoacoustic spectroscopy for chemical detection (United States)

    Holthoff, Ellen L.; Pellegrino, Paul M.


    The Global War on Terror has made rapid detection and identification of chemical and biological agents a priority for Military and Homeland Defense applications. Reliable real-time detection of these threats is complicated by our enemy's use of a diverse range of materials. Therefore, an adaptable platform is necessary. Photoacoustic spectroscopy (PAS) is a useful monitoring technique that is well suited for trace detection of gaseous media. This method routinely exhibits detection limits at the parts-per-billion (ppb) or sub-ppb range. The versatility of PAS also allows for the investigation of solid and liquid analytes. Current research utilizes quantum cascade lasers (QCLs) in combination with an air-coupled solid-phase photoacoustic cell design for the detection of condensed phase material films deposited on a surface. Furthermore, variation of the QCL pulse repetition rate allows for identification and molecular discrimination of analytes based solely on photoacoustic spectra collected at different film depths.

  17. In situ probing of surface hydrides on hydrogenated amorphous silicon using attenuated total reflection infrared spectroscopy

    CERN Document Server

    Kessels, W M M; Sanden, M C M; Aydil, E S


    An in situ method based on attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) is presented for detecting surface silicon hydrides on plasma deposited hydrogenated amorphous silicon (a-Si:H) films and for determining their surface concentrations. Surface silicon hydrides are desorbed by exposing the a-Si:H films to low energy ions from a low density Ar plasma and by comparing the infrared spectrum before and after this low energy ion bombardment, the absorptions by surface hydrides can sensitively be separated from absorptions by bulk hydrides incorporated into the film. An experimental comparison with other methods that utilize isotope exchange of the surface hydrogen with deuterium showed good agreement and the advantages and disadvantages of the different methods are discussed. Furthermore, the determination of the composition of the surface hydrogen bondings on the basis of the literature data on hydrogenated crystalline silicon surfaces is presented, and quantification of the h...

  18. An Infrared Spectroscopy Study Of Pb(II) And Siderophore Sorption To Montmorillonite (United States)

    Maurice, P. A.; Hunter, E. L.; Quicksall, A. N.; Haack, E.; Johnston, C. T.


    Aerobic microorganisms exude low molecular weight organic ligands known as siderophores in order to acquire nutrient Fe. Because siderophores can also bind other metals such as Pb, Zn, and Cd, they may affect metal sorption, fate, and transport. This study combined batch sorption experiments, thermodynamic modeling, X-ray diffraction (XRD), and spectroscopic analysis, to investigate Pb(II) and desferrioxamine B (DFOB) sorption to montmorillonite, alone and in combination, at pH 3-9, ~22 C, and in 0.1 M NaCl. Samples at pH 3, 5.5, and 7.5 were analyzed by XRD and Fourier-Transform Infrared Spectroscopy (FTIR) and samples at pH5.5 were analyzed by in-situ Attenuated Total Reflection Infrared Spectroscopy (ATR-FTIR). DFOB does not bind Pb substantially at pH 3, and sorption results showed that the ligand only minimally affects Pb sorption at this pH. However, combination of batch sorption experiments with XRD, FTIR, and ATR-FTIR analysis suggested that Pb(II)/DFOB (co)absorption in the interlayer is likely an important sorption mechanism at pH 5.5 and 7.5 under both air-dried and aqueous conditions. The precise structure of the sorption complex(es) could not be determined by these methods. Some adsorption of Pb(II)/DFOB to the external clay surface is also possible. In the absence of DFOB, a Pb-carbonate complex or precipitate (perhaps hydrocerrusite) was detected by FTIR. Overall, results showed that a microbial siderophore may affect Pb sorption to montmorillonite, that (co)absorption in the interlayer region can be important, and that sorption effects can vary substantially depending upon solution conditions.

  19. Explosive detection using infrared laser spectroscopy (United States)

    Hildenbrand, J.; Herbst, J.; Wöllenstein, J.; Lambrecht, A.


    Stand-off and extractive explosive detection methods for short distances are investigated using mid-infrared laser spectroscopy. A quantum cascade laser (QCL) system for TATP-detection by open path absorption spectroscopy in the gas phase was developed. In laboratory measurements a detection limit of 5 ppm*m was achieved. For explosives with lower vapor pressure an extractive hollow fiber based measurement system was investigated. By thermal desorption gaseous TATP or TNT is introduced into a heated fiber. The small sample volume and a fast gas exchange rate enable fast detection. TNT and TATP detection levels below 100 ng are feasible even in samples with a realistic contaminant background.

  20. Olive fruit growth and ripening as seen by vibrational spectroscopy. (United States)

    López-Sánchez, Macarena; Ayora-Cañada, María José; Molina-Díaz, Antonio


    The aim of this work was to examine the potential of ATR-FTIR and Raman spectroscopies to evaluate changes happening during the development and maturation of olive fruit. To do this, the spectra of the different parts of the olive (skin, flesh and stone) have been measured at different stages of development. The evolution of different spectral bands has been related to the content of olive constituents like triglycerides, water, carotenoids and phenolic compounds. Oil accumulation can be followed using both FTIR and Raman spectroscopy. The increase in bands at 1746 cm(-1) (ATR-FTIR) and 1440 cm(-1) (Raman) correlates well with the oil content in the fruit determined using the standard Soxhlet extraction method. In the case of overripe olives ATR-FTIR does not provide a representative spectrum of the olive flesh due to the accumulation of water on the surface of the ATR crystal. The increase of the content in carotenoids and phenolic compounds during olive growing and their decrease during the ripening phase can be successfully monitored by means of the Raman bands at 1525 and 1605 cm(-1), respectively.

  1. Detecting changes during pregnancy with Raman spectroscopy (United States)

    Vargis, Elizabeth; Robertson, Kesha; Al-Hendy, Ayman; Reese, Jeff; Mahadevan-Jansen, Anita


    Preterm labor is the second leading cause of neonatal mortality and leads to a myriad of complications like delayed development and cerebral palsy. Currently, there is no way to accurately predict preterm labor, making its prevention and treatment virtually impossible. While there are some at-risk patients, over half of all preterm births do not fall into any high-risk category. This study seeks to predict and prevent preterm labor by using Raman spectroscopy to detect changes in the cervix during pregnancy. Since Raman spectroscopy has been used to detect cancers in vivo in organs like the cervix and skin, it follows that spectra will change over the course of pregnancy. Previous studies have shown that fluorescence decreased during pregnancy and increased during post-partum exams to pre-pregnancy levels. We believe significant changes will occur in the Raman spectra obtained during the course of pregnancy. In this study, Raman spectra from the cervix of pregnant mice and women will be acquired. Specific changes that occur due to cervical softening or changes in hormonal levels will be observed to understand the likelihood that a female mouse or a woman will enter labor.

  2. Análise exploratória aplicada a espectros de reflexão total atenuada no infravermelho com transformada de Fourier (ATR-FTIR de blendas de biodiesel/diesel

    Directory of Open Access Journals (Sweden)

    Carla Felippi Chiella Ruschel


    Full Text Available In this study, hierarchical cluster analysis (HCA and principal component analysis (PCA were used to classify blends produced from diesel S500 and different kinds of biodiesel produced by the TDSP methodology. The different kinds of biodiesel studied in this work were produced from three raw materials: soybean oil, waste cooking oil and hydrogenated vegetable oil. Methylic and ethylic routes were employed for the production of biodiesel. HCA and PCA were performed on the data from attenuated total reflectance Fourier transform infrared spectroscopy, showing the separation of the blends into groups according to biodiesel content present in the blends and to the kind of biodiesel used to form the mixtures.

  3. Characterisation of Pb-induced changes and prediction of Pb exposure in microalgae using infrared spectroscopy. (United States)

    Dao, Ly; Beardall, John; Heraud, Philip


    Macromolecular changes in Chlorella sp. FleB1 and Scenedesmus acutus YaA6 exposed to Pb were characterised by Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy. Spectra were collected in the mid-infrared spectral region and a chemometric approach was used to analyse the spectra. Principal Component Analysis showed that under Pb treatment, carbohydrates and lipids increased while proteins and phosphorylated molecules decreased in both the isolates. These conclusions were corroborated by conventional measurements of photosynthesis and neutral lipids. In the two strains, Pb inhibited photosynthesis, which directly affects the synthesis of polysaccharides and other macromolecules. Neutral lipids as measured by Nile Red were increased in lead-treated samples. Modelling of spectral data against Pb exposure levels allowed Pb-exposed samples to be readily discriminated from unexposed controls and the level of Pb exposure could be predicted with good accuracy in independent validation testing. This study demonstrates the utility of the spectroscopic approach as a rapid, inexpensive, non-destructive method to understand changes in cellular composition induced by Pb and allowing detection and quantification of Pb levels in metal-contaminated cells in a "snapshot". Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Detection of biologically active diterpenoic acids by Raman Spectroscopy

    DEFF Research Database (Denmark)

    Talian, Ivan; Orinak, Andrej; Efremov, Evtim V.


    Three poorly detectable, biologically active diterpenoic acids, kaurenoic, abietic, and gibberellic acid, were studied by using different modes of Raman spectroscopy. Because of their structural similarities, in the absence of strongly polarizable groups, conventional Raman spectroscopy is not su......Three poorly detectable, biologically active diterpenoic acids, kaurenoic, abietic, and gibberellic acid, were studied by using different modes of Raman spectroscopy. Because of their structural similarities, in the absence of strongly polarizable groups, conventional Raman spectroscopy......, and these 'fingerprints' would be suitable for the unambiguous identification of these diterpenoic acids....

  5. Raman spectroscopy of human saliva for acute myocardial infarction detection (United States)

    Chen, Maowen; Chen, Yuanxiang; Wu, Shanshan; Huang, Wei; Lin, Jinyong; Weng, Guo-Xing; Chen, Rong


    Raman spectroscopy is a rapidly non-invasive technique with great potential for biomedical research. The aim of this study was to evaluate the feasibility of using Raman spectroscopy of human saliva for acute myocardial infarction (AMI) detection. Raman spectroscopy measurements were performed on two groups of saliva samples: one group from patients (n=30) with confirmed AMI and the other group from healthy controls (n=31). The diagnostic performance for differentiating AMI saliva from normal saliva was evaluated by multivariate statistical analysis. The combination of principal component analysis (PCA) and linear discriminate analysis (LDA) of the measured Raman spectra separated the spectral features of the two groups into two distinct clusters with little overlaps, rendering the sensitivity of 80.0% and specificity of 80.6%. The results from this exploratory study demonstrated that Raman spectroscopy of human saliva can serve as a potentially clinical tool for rapid AMI detection and screening.

  6. Detection of Nitric Oxide by Electron Paramagnetic Resonance Spectroscopy


    Hogg, Neil


    Electron paramagnetic resonance (EPR) spectroscopy has been used in a number of ways to study nitric oxide chemistry and biology. As an intrinsically stable and relatively unreactive diatomic free radical, the challenges for detecting this species by EPR are somewhat different than those for transient radical species. This review gives a basic introduction to EPR spectroscopy and discusses its uses to assess and quantify nitric oxide formation in biological systems.

  7. In situ infrared spectroscopy study of the surface reactions during the atomic layer deposition of TiO2 on GaAs (100) surfaces (United States)

    Ye, Liwang; Kropp, Jaron A.; Gougousi, Theodosia


    The surface reactions during the atomic layer deposition (ALD) of TiO2 on chemical oxide and hydrogen fluoride etched GaAs (100) surfaces at 100 and 200 °C have been studied by in situ attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. Tetrakis (dimethylamino) titanium (TDMAT) and H2O were used as precursors. The adsorption of TDMAT on both GaAs surfaces at 200 °C was self-limiting, while significant contribution from physisorption was confirmed at 100 °C. In addition to the basic ligand substitution mechanism, the presence of parallel/competing reaction pathways was confirmed through the detection of Ti metallacycles and methylmethyleneimine [CH3Ndbnd CH2] (MMI). Isotope exchange experiments using D2O and H218O were used to confirm the presence of MMI. This product was produced at each H2O exposure step and partially removed during the subsequent TDMAT exposure leading to its accumulation in the growing film.

  8. IR spectroscopy together with multivariate data analysis as a process analytical tool for in-line monitoring of crystallization process and solid-state analysis of crystalline product

    DEFF Research Database (Denmark)

    Pöllänen, Kati; Häkkinen, Antti; Reinikainen, Satu-Pia


    Fourier transform infra red (ATR-FTIR) spectroscopy provides valuable information on process, which can be utilized for more controlled crystallization processes. Diffuse reflectance Fourier transform infra red (DRIFT-IR) is applied for polymorphic characterization of crystalline product using X......Crystalline product should exist in optimal polymorphic form. Robust and reliable method for polymorph characterization is of great importance. In this work, infra red (IR) spectroscopy is applied for monitoring of crystallization process in situ. The results show that attenuated total reflection...

  9. Moisture detection in composites by terahertz spectroscopy (United States)

    Malinowski, Paweł; Pałka, Norbert; Opoka, Szymon; Wandowski, Tomasz; Ostachowicz, Wiesław


    The application of Glass Fibre Reinforced Polymers (GFRP) in many branches of industry has been increasing steadily. Many research works focus on damage identification for structures made out of such materials. However, not only delaminations, cracks or other damage can have a negative influence of GFRP parts performance. Previous research proved that fluid absorption influences the mechanical performance of composites. GFRP parts can be contaminated by moisture or release agent during manufacturing, while fuel, hydraulic fluid and moisture ingression into the composite can be the in-service treats. In the reported research authors focus on moisture detection. There are numerous sources of moisture such as post manufacturing NDT inspection with ultrasonics coupled by water or exposition to moisture during transportation and in service. An NDT tool used for the research is a terahertz (THz) spectrometer. The device uses an electromagnetic radiation in the terahertz range (0.1-3 THz) and allows for reflection and transmission measurements. The spectrometer is equipped with moving table that allows for XY scanning of large objects such as GFRP panels. In the conducted research refractive indices were experimentally extracted from the materials of interest (water and GFRP). Time signals as well as C-scans were analysed for samples with moisture contamination. In order to be sure that the observed effects are related to moisture contamination reference measurements were conducted. The obtained results showed that the THz NDT technique can detect moisture hidden under a GFRP with multiple layers.

  10. Preliminary Discrimination of Cheese Adulteration by FT-IR Spectroscopy

    Directory of Open Access Journals (Sweden)

    Lucian Cuibus


    Full Text Available The present work describes a preliminary study to compare some traditional Romanian cheeses and adulterated cheeses using Attenuated Total Reflectance-Fourier transform infrared spectroscopy (ATR-FTIR. For PLS model calibration (6 concentration levels and validation (5 concentration levels sets were prepared from commercial Dalia Cheese from different manufacturers by spiking it with palm oil at concentrations ranging 2-50 % and 5-40 %, respectively. Fifteen Dalia Cheese were evaluated as external set. The spectra of each sample, after homogenization, were acquired in triplicate using a FTIR Shimatsu Prestige 21 Spectrophotometer, with a horizontal diamond ATR accessory in the MIR region 4000-600 cm-1. Statistical methods as PLS were applied using MVC1 routines written for Matlab R2010a. As first step the optimal condition for PLS model were obtained using cross-validation on the Calibration set. Spectral region in 3873-652 cm-1, and 3 PLS-factors were stated as the best conditions and showed an R2 value of 0.9338 and a relative error in the calibration of 17.2%. Then validation set was evaluated, obtaining good recovery rates (108% and acceptable dispersion of the data (20%. The curve of actual vs. predicted values shows slope near to 1 and origin close to 0, with an R2 of 0.9695. When the external sample set was evaluated, samples F19, F21, F22 and F24, showed detectable levels of palm fats. The results proved that FTIR-PLS is a reliable non-destructive technique for a rapid quantification the level of adulteration in cheese.  The spectroscopic methods could assist the quality control authority, traders and the producers to discriminate the adulterated cheeses with palm oil.

  11. Detection of Counterfeit Tequila by Fluorescence Spectroscopy

    Directory of Open Access Journals (Sweden)

    José Manuel de la Rosa Vázquez


    Full Text Available An ultraviolet (UV light induced fluorescence study to discriminate fake tequila from genuine ones is presented. A portable homemade system based on four light emitting diodes (LEDs from 255 to 405 nm and a miniature spectrometer was used. It has been shown that unlike fake and silver tequila, which produce weak fluorescence signal, genuine mixed, rested, and aged tequilas show high fluorescence emission in the range from 400 to 750 nm. The fluorescence intensity grows with aging in 100% agave tequila. Such fluorescence differences can even be observed with naked eyes. The presented results demonstrate that the fluorescence measurement could be a good method to detect counterfeit tequila.

  12. Intracavity Faraday modulation spectroscopy (INFAMOS): A tool for radical detection (United States)

    Gianella, Michele; Pinto, Tomas H. P.; Wu, Xia; Ritchie, Grant A. D.


    We present the intra-cavity Faraday modulation spectroscopy technique, whereby optical feedback cavity-enhanced spectroscopy is coupled with Faraday modulation spectroscopy to greatly enhance the interaction path length of a laser beam with a paramagnetic sample in a magnetic field. We describe a first prototype based upon a cw quantum cascade laser targeting a selection of fundamental rovibrational R-branch transitions of nitric oxide (1890 cm-1), consisting of a linear cavity (finesse F =6300 ) and a water-cooled solenoid. We demonstrate a minimum detectable Verdet constant of Vmin=4.7 ×10-14 rad cm-1 G-1 H z-1/2 (at SNR = 1), corresponding to a single-pass rotation angle of 1.6 ×10-10 rad Hz-1/2 and a limit of detection of 0.21 ppbv Hz-1/2 NO.

  13. Detection and identification of explosive particles in fingerprints using attenuated total reflection-Fourier transform infrared spectromicroscopy. (United States)

    Mou, Yongyan; Rabalais, J Wayne


    The application of attenuated total reflection (ATR)-Fourier transform infrared (FTIR) spectromicroscopy for detection of explosive particles in fingerprints is described. The combined functions of ATR-FTIR spectromicroscopy are visual searching of particles in fingerprints and measuring the FTIR spectra of the particles. These functions make it possible to directly identify whether a suspect has handled explosives from the fingerprints alone. Particles in explosive contaminated fingerprints are either ingredients of the explosives, finger residues, or other foreign materials. These cannot normally be discriminated by their morphology alone. ATR-FTIR spectra can provide both particle morphology and composition. Fingerprints analyzed by ATR-FTIR can be used for further analysis and identification because of its non-destructive character. Fingerprints contaminated with three different types of explosives, or potential explosives, have been analyzed herein. An infrared spectral library was searched in order to identify the explosive residues. The acquired spectra are compared to those of finger residue alone, in order to differentiate such residue from explosive residue.

  14. Detection and Classification of Measurement Errors in Bioimpedance Spectroscopy


    David Ayllón; Roberto Gil-Pita; Fernando Seoane


    Bioimpedance spectroscopy (BIS) measurement errors may be caused by parasitic stray capacitance, impedance mismatch, cross-talking or their very likely combination. An accurate detection and identification is of extreme importance for further analysis because in some cases and for some applications, certain measurement artifacts can be corrected, minimized or even avoided. In this paper we present a robust method to detect the presence of measurement artifacts and identify what kind of measur...

  15. In vivo detection of dysplastic tissue by Raman spectroscopy

    NARCIS (Netherlands)

    Schut, TCB; Witjes, MJH; Sterenborg, HJCM; Speelman, OC; Roodenburg, JLN; Marple, ET; Bruining, HA; Puppels, GJ


    The detection of dysplasia and early cancer is important because of the improved survival rates associated with early treatment of cancer. Raman spectroscopy is sensitive to the changes in molecular composition and molecular conformation that occur in tissue during carcinogenesis, and recent

  16. Supercontinuum based mid-IR imaging spectroscopy for cancer detection

    DEFF Research Database (Denmark)

    Bang, Ole; Møller, Uffe Visbech; Kubat, Irnis


    The mid-infrared (IR) spectral region is of significant technical and scientific interest because most molecules display fundamental vibrational absorptions in this region, leaving distinct spectral fingerprints. To date, the limitations of mid-IR light sources, such as thermal emitters, low...... cancer detection with mid-IR imaging spectroscopy....

  17. Infrared spectroscopy as a screening technique for colitis (United States)

    Titus, Jitto; Ghimire, Hemendra; Viennois, Emilie; Merlin, Didier; Perera, A. G. Unil


    There remains a great need for diagnosis of inflammatory bowel disease (IBD), for which the current technique, colonoscopy, is not cost-effective and presents a non-negligible risk for complications. Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy is a new screening technique to evaluate colitis. Comparing infrared spectra of sera to study the differences between them can prove challenging due to the complexity of its biological constituents giving rise to a plethora of vibrational modes. Overcoming these inherent infrared spectral analysis difficulties involving highly overlapping absorbance peaks and the analysis of the data by curve fitting to improve the resolution is discussed. The proposed technique uses colitic and normal wild type mice dried serum to obtain ATR/FTIR spectra to effectively differentiate colitic mice from normal mice. Using this method, Amide I group frequency (specifically, alpha helix to beta sheet ratio of the protein secondary structure) was identified as disease associated spectral signature in addition to the previously reported glucose and mannose signatures in sera of chronic and acute mice models of colitis. Hence, this technique will be able to identify changes in the sera due to various diseases.

  18. Raman spectroscopy for cancer detection and characterization in metastasis models (United States)

    Koga, Shigehiro; Oshima, Yusuke; Sato, Mitsunori; Ishimaru, Kei; Yoshida, Motohira; Yamamoto, Yuji; Matsuno, Yusuke; Watanabe, Yuji


    Raman spectroscopy provides a wealth of diagnostic information to the surgeon with in situ cancer detection and label-free histopathology in clinical practice. Raman spectroscopy is a developing optical technique which can analyze biological tissues with light scattering. The difference in frequencies between the incident light and the scattering light are called Raman shifts, which correspond to the vibrational energy of the molecular bonds. Raman spectrum gives information about the molecular structure and composition in biological specimens. We had been previously reported that Raman spectroscopy could distinguish various histological types of human lung cancer cells from normal cells in vitro. However, to identify and detect cancer diagnostic biomarkers in vivo on Raman spectroscopy is still challenging, because malignancy can be characterized not only by the cancer cells but also by the environmental factors including immune cells, stroma cells, secretion vesicles and extracellular matrix. Here we investigate morphological and molecular dynamics in both cancer cells and their environment in xenograft models and spontaneous metastasis models using Raman spectroscopy combined with fluorescence microscopy and photoluminescence imaging. We are also constructing a custom-designed Raman spectral imaging system for both in vitro and in vivo assay of tumor tissues to reveal the metastasis process and to evaluate therapeutic effects of anti-cancer drugs and their drug delivery toward the clinical application of the technique.

  19. Optical detection and spectroscopy of single metal nanoparticles (United States)

    Berciaud, S.; Lasne, D.; Blab, G. A.; Tamarat, Ph.; Cognet, L.; Lounis, B.


    Photothermal Heterodyne Imaging (PHI) is a highly sensitive optical detection method of individual absorptive nano-objects. It can be applied to absorption spectroscopy measurements Surface Plasmon Resonance spectra of individual gold nanoparticules with diameters down to 5nm were recorded. Intrinsic size effects which result in a broadening of the Resonance are unambiguously observed and analyzed within the frame of Mie theory. Preliminary results obtained with silver nanoparticles are also presented.

  20. Optical fiber fluorescence spectroscopy for detecting AFM1 in milk (United States)

    Mignani, A. G.; Cucci, C.; Ciaccheri, L.; Dall'Asta, C.; Galaverna, G.; Dossena, A.; Marchelli, R.


    Fluorescence spectroscopy carried out by means of optical fibers was used for the rapid screening of M1 aflatoxin in milk, enabling the detection of concentrations up to the legal limit, which is 50 ppt. A compact fluorometric device equipped with a LED source, a miniaturized spectrometer, and optical fibers for illumination/detection of the measuring micro-cell was tested for measuring threshold values of AFM1 in pre-treated milk samples. Multivariate processing of the spectral data made it possible to obtain a preliminary screening at the earlier stages of the industrial process, as well as to discard contaminated milk stocks before their inclusion in the production chain.

  1. Attenuated total reflectance Fourier-transform infrared spectroscopy of carboxylic acids adsorbed onto mineral surfaces (United States)

    Kubicki, J. D.; Schroeter, L. M.; Itoh, M. J.; Nguyen, B. N.; Apitz, S. E.


    A suite of naturally-occurring carboxylic acids (acetic, oxalic, citric, benzoic, salicylic and phthalic) and their corresponding sodium salts were adsorbed onto a set of common mineral substrates (quartz, albite, illite, kaolinite and montmorillonite) in batch slurry experiments. Solution pH's of approximately 3 and 6 were used to examine the effects of pH on sorption mechanisms. Attenuated total reflectance Fourier-transform infrared (ATR FTIR) spectroscopy was employed to obtain vibrational frequencies of the organic ligands on the mineral surfaces and in solution. UV/visible spectroscopy on supernatant solutions was also employed to confirm that adsorption from solution had taken place for benzoic, salicylic and phthalic acids. Molecular orbital calculations were used to model possible surface complexes and interpret the experimental spectra. In general, the tectosilicates, quartz and albite feldspar, did not chemisorb (i.e., strong, inner-sphere adsorption) the carboxylate anions in sufficient amounts to produce infrared spectra of the organics after rinsing in distilled water. The clays (illite, kaolinite and montmorillonite) each exhibited similar ATR FTIR spectra. However, the illite sample used in this study reacted to form strong surface and aqueous complexes with salicylic acid before being treated to remove free Fe-hydroxides. Chemisorption of carboxylic acids onto clays is shown to be limited without the presence of Fe-hydroxides within the clay matrix.

  2. An infrared spectroscopy method to detect ammonia in gastric juice. (United States)

    Giovannozzi, Andrea M; Pennecchi, Francesca; Muller, Paul; Balma Tivola, Paolo; Roncari, Silvia; Rossi, Andrea M


    Ammonia in gastric juice is considered a potential biomarker for Helicobacter pylori infection and as a factor contributing to gastric mucosal injury. High ammonia concentrations are also found in patients with chronic renal failure, peptic ulcer disease, and chronic gastritis. Rapid and specific methods for ammonia detection are urgently required by the medical community. Here we present a method to detect ammonia directly in gastric juice based on Fourier transform infrared spectroscopy. The ammonia dissolved in biological liquid samples as ammonium ion was released in air as a gas by the shifting of the pH equilibrium of the ammonium/ammonia reaction and was detected in line by a Fourier transform infrared spectroscopy system equipped with a gas cell for the quantification. The method developed provided high sensitivity and selectivity in ammonia detection both in pure standard solutions and in a simulated gastric juice matrix over the range of diagnostic concentrations tested. Preliminary analyses were also performed on real gastric juice samples from patients with gastric mucosal injury and with symptoms of H. pylori infection, and the results were in agreement with the clinicopathology information. The whole analysis, performed in less than 10 min, can be directly applied on the sample without extraction procedures and it ensures high specificity of detection because of the ammonia fingerprint absorption bands in the infrared spectrum. This method could be easily used with endoscopy instrumentation to provide information in real time and would enable the endoscopist to improve and integrate gastroscopic examinations.

  3. Detection of hazelnut oil adulteration using FT-IR spectroscopy. (United States)

    Ozen, Banu F; Mauer, Lisa J


    Fourier transform infrared spectroscopy (FT-IR) was used to detect the adulteration of hazelnut oil with different types of oils and to detect the adulteration of extra-virgin olive oil with hazelnut oil. Spectra of hazelnut oil, seven other types of oils, extra-virgin olive oil, and the adulterated oils were collected with a FT-IR equipped with a ZnSe-ATR accessory and a MCTA detector. Discriminant analysis and partial least-squares analysis were used to analyze the data. Classification of hazelnut oil, olive oil, and the other types of oils was achieved successfully with FT-IR. The detection level for sunflower oil adulteration of hazelnut oil was 2%, and the correlation coefficient for the PLS model was 0.99. Adulteration of virgin olive oil with hazelnut oil could be detected only at levels of 25% and higher.

  4. Detection of early caries by laser-induced breakdown spectroscopy (United States)

    Sasazawa, Shuhei; Kakino, Satoko; Matsuura, Yuji


    To improve sensitivity of dental caries detection by laser-induced breakdown spectroscopy (LIBS) analysis, it is proposed to utilize emission peaks in the ultraviolet. We newly focused on zinc whose emission peaks exist in ultraviolet because zinc exists at high concentration in the outer layer of enamel. It was shown that by using ratios between heights of an emission peak of Zn and that of Ca, the detection sensitivity and stability are largely improved. It was also shown that early caries are differentiated from healthy part by properly setting a threshold in the detected ratios. The proposed caries detection system can be applied to dental laser systems such as ones based on Er:YAG-lasers. When ablating early caries part by laser light, the system notices the dentist that the ablation of caries part is finished. We also show the intensity of emission peaks of zinc decreased with ablation with Er:YAG laser light.

  5. Discrimination of fennel chemotypes applying IR and Raman spectroscopy – discovery of a new -asarone chemotype

    Directory of Open Access Journals (Sweden)

    Krähmer, Andrea


    Full Text Available Various vibrational spectroscopy methods have been applied to classify different fennel chemotypes according to their individual profile of volatile substances. Intact fennel fruits of different chemotypes could be successfully discriminated by Attenuated Total Reflectance Fourier transform Infrared (ATR-FTIR and Near Infrared (NIR spectroscopy. Solvent extracts (CCl4 of the considered fennel fruits showed characteristic fingerprints with marker bands related to the individual volatile components (trans-anethole, fenchone, estragole, piperitenone oxide, -asarone, limonene for ATR-FTIR and FT-Raman spectroscopy. Especially C=C and C=O absorption bands contribute to the different spectral profiles. Based on hierarchical cluster analysis, the considered fennel accessions were classified according to gas chromatographic (GC and vibrational spectroscopic data. Furthermore, even a discrimination of “sweet” and “bitter” fennel fruits, both belonging to the trans-anethole chemotype, could be successfully performed. All vibrational spectroscopical techniques used in this study are rapid and easy to apply. Hence, they allow different fennel chemotypes to be reliably distinguished and can also be used for on-site measurement in free nature.

  6. Quantitative determination of competitive molecular adsorption on gold nanoparticles using attenuated total reflectance-Fourier transform infrared spectroscopy. (United States)

    Tsai, De-Hao; Davila-Morris, Melissa; DelRio, Frank W; Guha, Suvajyoti; Zachariah, Michael R; Hackley, Vincent A


    Surface-sensitive quantitative studies of competitive molecular adsorption on nanoparticles were conducted using a modified attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy method. Adsorption isotherms for thiolated poly(ethylene glycol) (SH-PEG) on gold nanoparticles (AuNPs) as a function of molecular mass (1, 5, and 20 kDa) were characterized. We find that surface density of SH-PEG on AuNPs is inversely proportional to the molecular mass (M(m)). Equilibrium binding constants for SH-PEG, obtained using the Langmuir adsorption model, show the binding affinity for SH-PEG is proportional to M(m). Simultaneous competitive adsorption between mercaptopropionic acid (MPA) and 5 kDa SH-PEG (SH-PEG5K) was investigated, and we find that MPA concentration is the dominant factor influencing the surface density of both SH-PEG5K and MPA, whereas the concentration of SH-PEG5K affects only SH-PEG5K surface density. Electrospray differential mobility analysis (ES-DMA) was employed as an orthogonal characterization technique. ES-DMA results are consistent with the results obtained by ATR-FTIR, confirming our conclusions about the adsorption process in this system. Ligand displacement competitive adsorption, where the displacing molecular species is added after completion of the ligand surface binding, was also interrogated by ATR-FTIR. Results indicate that for SH-PEG increasing M(m) yields greater stability on AuNPs when measured against displacement by bovine serum albumin (BSA) as a model serum protein. In addition, the binding affinity of BSA to AuNPs is inhibited for SH-PEG conjugated AuNPs, an effect that is enhanced at higher SH-PEG M(m) values.

  7. Cavity ring-down Faraday rotation spectroscopy for oxygen detection (United States)

    Westberg, Jonas; Wysocki, Gerard


    A combination of the path length enhancement provided by cavity ring-down spectroscopy together with the selectivity and noise suppression capabilities of Faraday rotation spectroscopy is utilized for highly sensitive detection of oxygen at 762.3 nm. The system achieves a noise-equivalent rotation angle of 1.3 × 10-9 rad/√Hz, and a trace O2 detection limit of 160 ppb for 100 s of averaging. The technique relies on measurements of the losses in two orthogonal polarization directions simultaneously, whereby an absolute assessment of the magnetically induced polarization rotation can be retrieved, analogous to the absolute absorption measurement provided by stand-alone cavity ring-down spectroscopy. The differential nature of the technique described here eliminates the need for off-resonance decay measurements and thereby allows for efficient shot-to-shot fluctuation suppression. This is especially advantageous when operating the system under measurement conditions that severely affect the non-absorber related losses, such as particulate matter contamination typically present in combustion or open-path applications.

  8. Detection of propofol concentrations in blood by Raman spectroscopy (United States)

    Wróbel, M. S.; Gnyba, M.; UrniaŻ, R.; Myllylä, T. S.; Jedrzejewska-Szczerska, M.


    In this paper we present a proof-of-concept of a Raman spectroscopy-based approach for measuring the content of propofol, a common anesthesia drug, in whole human blood, and plasma, which is intended for use during clinical procedures. This method utilizes the Raman spectroscopy as a chemically-sensitive method for qualitative detection of the presence of a drug and a quantitative determination of its concentration. A number of samples from different patients with added various concentrations of propofol IV solution were measured. This is most equivalent to a real in-vivo situation. Subsequent analysis of a set of spectra was carried out to extract qualitative and quantitative information. We conclude, that the changes in the spectra of blood with propofol, overlap with the most prominent lines of the propofol solution, especially at spectral regions: 1450 cm-1, 1250- 1260 cm-1, 1050 cm-1, 875-910 cm-1, 640 cm-1. Later, we have introduced a quantitative analysis program based on correlation matrix closest fit, and a LOO cross-validation. We have achieved 36.67% and 60% model precision when considering full spectra, or specified bands, respectively. These results prove the possibility of using Raman spectroscopy for quantitative detection of propofol concentrations in whole human blood.

  9. Single-electron detection and spectroscopy via relativistic cyclotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Asner, David M.; Bradley, Rich; De Viveiros Souza Filho, Luiz A.; Doe, Peter J.; Fernandes, Justin L.; Fertl, M.; Finn, Erin C.; Formaggio, Joseph; Furse, Daniel L.; Jones, Anthony M.; Kofron, Jared N.; LaRoque, Benjamin; Leber, Michelle; MCBride, Lisa; Miller, M. L.; Mohanmurthy, Prajwal T.; Monreal, Ben; Oblath, Noah S.; Robertson, R. G. H.; Rosenberg, Leslie; Rybka, Gray; Rysewyk, Devyn M.; Sternberg, Michael G.; Tedeschi, Jonathan R.; Thummler, Thomas; VanDevender, Brent A.; Woods, N. L.


    It has been understood since 1897 that accelerating charges should emit electromagnetic radiation. Cyclotron radiation, the particular form of radiation emitted by an electron orbiting in a magnetic field, was first derived in 1904. Despite the simplicity of this concept, and the enormous utility of electron spectroscopy in nuclear and particle physics, single-electron cyclotron radiation has never been observed directly. Here we demonstrate single-electron detection in a novel radiofrequency spectrometer. We observe the cyclotron radiation emitted by individual electrons that are produced with mildly-relativistic energies by a gaseous radioactive source and are magnetically trapped. The relativistic shift in the cyclotron frequency permits a precise electron energy measurement. Precise beta electron spectroscopy from gaseous radiation sources is a key technique in modern efforts to measure the neutrino mass via the tritium decay endpoint, and this work is a proof-of-concept for future neutrino mass experiments using this technique.

  10. Laser-induced fluorescence spectroscopy in tissue local necrosis detection (United States)

    Cip, Ondrej; Buchta, Zdenek; Lesundak, Adam; Randula, Antonin; Mikel, Bretislav; Lazar, Josef; Veverkova, Lenka


    The recent effort leads to reliable imaging techniques which can help to a surgeon during operations. The fluorescence spectroscopy was selected as very useful online in vivo imaging method to organics and biological materials analysis. The presented work scopes to a laser induced fluorescence spectroscopy technique to detect tissue local necrosis in small intestine surgery. In first experiments, we tested tissue auto-fluorescence technique but a signal-to-noise ratio didn't express significant results. Then we applied a contrast dye - IndoCyanine Green (ICG) which absorbs and emits wavelengths in the near IR. We arranged the pilot experimental setup based on highly coherent extended cavity diode laser (ECDL) used for stimulating of some critical areas of the small intestine tissue with injected ICG dye. We demonstrated the distribution of the ICG exciter with the first file of shots of small intestine tissue of a rabbit that was captured by high sensitivity fluorescent cam.

  11. Diamond-coated ATR prism for infrared absorption spectroscopy of surface-modified diamond nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Remes, Z., E-mail: [Institute of Physics of the ASCR, v.v.i., Cukrovarnicka 10, Praha 6 (Czech Republic); Kozak, H.; Rezek, B.; Ukraintsev, E.; Babchenko, O.; Kromka, A. [Institute of Physics of the ASCR, v.v.i., Cukrovarnicka 10, Praha 6 (Czech Republic); Girard, H.A.; Arnault, J.-C.; Bergonzo, P. [CEA, LIST, Diamond Sensors Laboratory, F-91191 Gif-sur-Yvette (France)


    Linear antenna microwave chemical vapor deposition process was used to homogeneously coat a 7 cm long silicon prism by 85 nm thin nanocrystalline diamond (NCD) layer. To show the advantages of the NCD-coated prism for attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) of nanoparticles, we apply diamond nanoparticles (DNPs) of 5 nm nominal size with various surface modifications by a drop-casting of their methanol dispersions. ATR-FTIR spectra of as-received, air-annealed, plasma-oxidized, and plasma-hydrogenated DNPs were measured in the 4000–1500 cm{sup −1} spectral range. The spectra show high spectral resolution, high sensitivity to specific DNP surface moieties, and repeatability. The NCD coating provides mechanical protection against scratching and chemical stability of the surface. Moreover, unlike on bare Si surface, NCD hydrophilic properties enable optically homogeneous coverage by DNPs with some aggregation on submicron scale as evidenced by scanning electron microscopy and atomic force microscopy. Compared to transmission FTIR regime with KBr pellets, direct and uniform deposition of DNPs on NCD-ATR prism significantly simplifies and speeds up the analysis (from days to minutes). We discuss prospects for in situ monitoring of surface modifications and molecular grafting.

  12. Characterization of ionizing radiation effects on bone using Fourier Transform Infrared Spectroscopy and multivariate analysis of spectra

    Energy Technology Data Exchange (ETDEWEB)

    Castro, Pedro Arthur Augusto de; Dias, Derly Augusto; Zezell, Denise Maria, E-mail: [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)


    Ionizing radiation has been used as an important treatment and diagnostic method for several diseases. Optical techniques provides an efficient clinical diagnostic to support an accurate evaluation of the interaction of radiation with molecules. Fourier-transform infrared spectroscopy coupled with attenuated total reflectance (ATR-FTIR) is a label-free and nondestructive optical technique that can recognize functional groups in biological samples. In this work, 30 fragments of bone were collected from bovine femur diaphysis. Samples were cut and polished until 1 cm x 1 cm x 1 mm, which were then stored properly in the refrigerated environment. Samples irradiation was performed with a Cobalt-60 Gammacell Irradiator source at doses of 0.1 kGy, 1 kGy, whereas the fragments exposed to dose of 15 kGy was irradiated in a multipurpose irradiator of Cobalt-60. Spectral data was submitted to principal component analysis followed by linear discriminant analysis. Multivariate analysis was performed with Principal component analysis(PCA) followed by Linear Discriminant Analysis(LDA) using MATLAB R2015a software (The Mathworks Inc., Natick, MA, USA). We demonstrated the feasibility of using ATR-FTIR spectroscopy associated with PCA-LDA multivariate technique to evaluate the molecular changes in bone matrix caused by different doses: 0.1 kGy, 1 kGy and 15 kGy. These alterations between the groups are mainly reported in phosphate region. Our results open up new possibilities for protein monitoring relating to dose responses. (author)

  13. Infrared Spectroscopy as a Tool to Study the Antioxidant Activity of Polyphenolic Compounds in Isolated Rat Enterocytes (United States)

    Barraza-Garza, Guillermo; Castillo-Michel, Hiram; de la Rosa, Laura A.; Martinez-Martinez, Alejandro; Pérez-León, Jorge A.; Cotte, Marine; Alvarez-Parrilla, Emilio


    The protective effect of different polyphenols, catechin (Cat), quercetin (Qc) (flavonoids), gallic acid (GA), caffeic acid (CfA), chlorogenic acid (ChA) (phenolic acids), and capsaicin (Cap), against H2O2-induced oxidative stress was evaluated in rat enterocytes using Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) Spectroscopy and Fourier Transform Infrared Microspectroscopy (FTIRM), and results were compared to standard lipid peroxidation techniques: conjugated dienes (CD) and Thiobarbituric Acid Reactive Substances (TBARS). Analysis of ATR-FTIR and FTIRM spectral data allowed the simultaneous evaluation of the effects of H2O2 and polyphenols on lipid and protein oxidation. All polyphenols showed a protective effect against H2O2-induced oxidative stress in enterocytes, when administered before or after H2O2. Cat and capsaicin showed the highest protective effect, while phenolic acids had weaker effects and Qc presented a mild prooxidative effect (IR spectral profile of biomolecules between control and H2O2-treated cells) according to FTIR analyses. These results demonstrated the viability to use infrared spectroscopy to evaluate the oxidant and antioxidant effect of molecules in cell systems assays. PMID:27213031

  14. Infrared Spectroscopy as a Tool to Study the Antioxidant Activity of Polyphenolic Compounds in Isolated Rat Enterocytes

    Directory of Open Access Journals (Sweden)

    Guillermo Barraza-Garza


    Full Text Available The protective effect of different polyphenols, catechin (Cat, quercetin (Qc (flavonoids, gallic acid (GA, caffeic acid (CfA, chlorogenic acid (ChA (phenolic acids, and capsaicin (Cap, against H2O2-induced oxidative stress was evaluated in rat enterocytes using Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR Spectroscopy and Fourier Transform Infrared Microspectroscopy (FTIRM, and results were compared to standard lipid peroxidation techniques: conjugated dienes (CD and Thiobarbituric Acid Reactive Substances (TBARS. Analysis of ATR-FTIR and FTIRM spectral data allowed the simultaneous evaluation of the effects of H2O2 and polyphenols on lipid and protein oxidation. All polyphenols showed a protective effect against H2O2-induced oxidative stress in enterocytes, when administered before or after H2O2. Cat and capsaicin showed the highest protective effect, while phenolic acids had weaker effects and Qc presented a mild prooxidative effect (IR spectral profile of biomolecules between control and H2O2-treated cells according to FTIR analyses. These results demonstrated the viability to use infrared spectroscopy to evaluate the oxidant and antioxidant effect of molecules in cell systems assays.

  15. Valence-to-core-detected X-ray absorption spectroscopy

    DEFF Research Database (Denmark)

    Hall, Eleanor R.; Pollock, Christopher J.; Bendix, Jesper


    X-ray absorption spectroscopy (XAS) can provide detailed insight into the electronic and geometric structures of transition-metal active sites in metalloproteins and chemical catalysts. However, standard XAS spectra inherently represent an average contribution from the entire coordination...... environment with limited ligand selectivity. To address this limitation, we have investigated the enhancement of XAS features using valence-to-core (VtC)-detected XAS, whereby XAS spectra are measured by monitoring fluorescence from valence-to-core X-ray emission (VtC XES) events. VtC emission corresponds...... to transitions from filled ligand orbitals to the metal 1s core hole, with distinct energetic shifts for ligands of differing ionization potentials. VtC-detected XAS data were obtained from multiple valence emission features for a series of well-characterized Mn model compounds; taken together, these data...

  16. Line-scanning Raman imaging spectroscopy for detection of fingerprints. (United States)

    Deng, Sunan; Liu, Le; Liu, Zhiyi; Shen, Zhiyuan; Li, Guohua; He, Yonghong


    Fingerprints are the best form of personal identification for criminal investigation purposes. We present a line-scanning Raman imaging system and use it to detect fingerprints composed of β-carotene and fish oil on different substrates. Although the line-scanning Raman system has been used to map the distribution of materials such as polystyrene spheres and minerals within geological samples, this is the first time to our knowledge that the method is used in imaging fingerprints. Two Raman peaks of β-carotene (501.2, 510.3 nm) are detected and the results demonstrate that both peaks can generate excellent images with little difference between them. The system operates at a spectra resolution of about 0.4 nm and can detect β-carotene signals in petroleum ether solution with the limit of detection of 3.4×10(-9) mol/L. The results show that the line-scanning Raman imaging spectroscopy we have built has a high accuracy and can be used in the detection of latent fingerprints in the future.

  17. An automatic detection software for differential reflection spectroscopy (United States)

    Yuksel, Seniha Esen; Dubroca, Thierry; Hummel, Rolf E.; Gader, Paul D.


    Recent terrorist attacks have sprung a need for a large scale explosive detector. Our group has developed differential reflection spectroscopy which can detect explosive residue on surfaces such as parcel, cargo and luggage. In short, broad band ultra-violet and visible light is shone onto a material (such as a parcel) moving on a conveyor belt. Upon reflection off the surface, the light intensity is recorded with a spectrograph (spectrometer in combination with a CCD camera). This reflected light intensity is then subtracted and normalized with the next data point collected, resulting in differential reflection spectra in the 200-500 nm range. Explosives show spectral finger-prints at specific wavelengths, for example, the spectrum of 2,4,6, trinitrotoluene (TNT) shows an absorption edge at 420 nm. Additionally, we have developed an automated software which detects the characteristic features of explosives. One of the biggest challenges for the algorithm is to reach a practical limit of detection. In this study, we introduce our automatic detection software which is a combination of principal component analysis and support vector machines. Finally we present the sensitivity and selectivity response of our algorithm as a function of the amount of explosive detected on a given surface.

  18. Over-hydration detection in brain by magnetic induction spectroscopy (United States)

    González, César A.; Pérez, María; Hevia, Nidiyare; Arámbula, Fernándo; Flores, Omar; Aguilar, Eliot; Hinojosa, Ivonne; Joskowicz, Leo; Rubinsky, Boris


    Detection and continuous monitoring of edema in the brain in early stages is useful for assessment of medical condition and treatment. We have proposed a solution in which the bulk measurements of the tissue electrical properties to detect edema or in general accumulation of fluids are made through measurement of the magnetic induction phase shift between applied and measured currents at different frequencies (Magnetic Induction Spectroscopy; MIS). Magnetic Resonant Imaging (MRI) has been characterized because its capability to detect different levels of brain tissue hydration by differences in diffusion-weighted (DW) sequences and it's involve apparent diffusion coefficient (ADC). The objective of this study was to explore the viability to use measurements of the bulk tissue electrical properties to detect edema or in general accumulation of fluids by MIS. We have induced a transitory and generalized tissue over-hydration condition in ten volunteers ingesting 1.5 to 2 liters of water in ten minutes. Basal and over-hydration conditions were monitored by MIS and MRI. Changes in the inductive phase shift at certain frequencies were consistent with changes in the brain tissue hydration level observed by DW-ADC. The results suggest that MIS has the potential to detect pathologies associated to changes in the content of fluids in brain tissue such as edema and hematomas.

  19. Detection of Ionic liquid using terahertz time-domain spectroscopy (United States)

    Wang, Cuicui; Zhao, Xiaojing; Liu, Shangjian; Zuo, Jian; Zhang, Cunlin


    Terahertz (THz, THz+1012Hz) spectroscopy is a far-infrared analytical technology with spectral bands locating between microware and infrared ranges. Being of excellent transmission, non-destruction and high discrimination, this technology has been applied in various fields such as physics, chemistry, nondestructive detection, communication, biomedicine public security. Terahertz spectrum is corresponding with vibration and rotation of liquid molecules, which is suitable to identify and study the liquid molecular dynamics. It is as a powerful spectral detection technology, terahertz time-domain spectroscopy is widely used in solution detection. can enable us to extract the material parameters or dielectric spectrum that show material micro-structure and dynamics by measuring amplitude and phase from coherent terahertz pulses. Ionic liquid exists in most biological tissues, and it is very important for life. It has recently been suggested that near-fired terahertz ionic contrast microscopy can be employed to image subtle changes in ionic concentrations arising from neuronal activity. In this paper, we detected Ionic liquid with different concentrations at room temperature by THz-TDS technique in the range of 0.2-1.5 THz. The liquid cell with a thickness of 0.2mm is made of quartz. The absorption coefficient, refractive index and dielectric function of solutions can be extracted based on THz-TDS. We use an expanded model for fitting the dielectric function based on a combination of a Debye relation for the anions and cations. We find A linear increase of the real and imaginary part of the dielectric function compared with pure water with increasing ion concentrations. A good agreement between the model and the experimental results is obtained. By means of dielectric relaxation process, it was found that the characteristic time of molecular movement and the information related to the liquid molecular structure and movement was obtained.

  20. TATP and TNT detection by mid-infrared transmission spectroscopy (United States)

    Herbst, Johannes; Hildenbrand, Jürgen; Wöllenstein, Jürgen; Lambrecht, Armin


    Sensitive and fast detection of explosives remains a challenge in many threat scenarios. Fraunhofer IPM works on two different detection methods using mid-infrared absorption spectroscopy in combination with quantum cascade lasers (QCL). 1. stand-off detection for a spatial distance of several meters and 2. contactless extractive sampling for short distance applications. The extractive method is based on a hollow fiber that works as gas cell and optical waveguide for the QCL light. The samples are membranes contaminated with the explosives and real background. The low vapor pressure of TNT requires a thermal desorbtion to introduce gaseous TNT and TATP into the heated fiber. The advantage of the hollow fiber setup is the resulting small sample volume. This enables a fast gas exchange rate and fast detection in the second range. The presented measurement setup achieves a detection limit of around 58 ng TNT and 26 ng TATP for 1 m hollow fiber. TATP - an explosive with a very high vapor pressure in comparison to TNT or other explosives - shows potential for an adequate concentration in gas phase under normal ambient conditions and thus the possibility of an explosive detection using open path absorption of TATP at 8 μm wavelength. In order to lower the cross sensitivities or interferents with substances with an absorption in the wavelength range of the TATP absorption the probe volume is checked synchronously by a second QCL emitting beside the target absorption wavelength. In laboratory measurements a detection limit of 5 ppm*m TATP are achieved.

  1. Study of gas detection based on integrated cavity output spectroscopy (United States)

    Pei, Shixin; Cui, Fenping; Su, Jing; Xu, Linhua; Sun, Tingting


    A trace gases detection system based on integrated cavity output spectroscopy (ICOS) was developed, where a NIR tunable diode laser (TDL) was used as light source, an optical cavity composed by two plan-concave mirrors with reflection near 99.7% was used as the absorption cell. Trace water vapour (H2O), carbon dioxide (CO2), methane (CH4), carbon monoxide (CO) and mixture of CO2 and CO were tested by ICOS based on the characteristics absorption. The wavelength calibration, cavity transmission characteristics, quantitative measurement ability and sensitivity of the TDL-ICOS were also studied, and a evaluated minimum detectable sensitivity of 1.15 × 10-7 cm-1 was obtained when the system was used to CH4 detection. The experiment results show that TDL-ICOS is expected to be a reliable and promising system for the detection of trace gases since it has some advantages such as real-time monitoring, simple device, easy operation, high sensitivity, good stability and quantitative ability.

  2. Detection of Water Content in Rapeseed Leaves Using Terahertz Spectroscopy

    Directory of Open Access Journals (Sweden)

    Pengcheng Nie


    Full Text Available The terahertz (THz spectra of rapeseed leaves with different water content (WC were investigated. The transmission and absorption spectra in the range of 0.3–2 THz were measured by using THz time-domain spectroscopy. The mean transmittance and absorption coefficients were applied to analyze the change regulation of WC. In addition, the Savitzky-Golay method was performed to preprocess the spectra. Then, the partial least squares (PLS, kernel PLS (KPLS, and Boosting-PLS were conducted to establish models for predicting WC based on the processed transmission and absorption spectra. Reliable results were obtained by these three methods. KPLS generated the best prediction accuracy of WC. The prediction coefficient correlation (Rval and root mean square error (RMSEP of KPLS based on transmission were Rval = 0.8508, RMSEP = 0.1015, and that based on absorption were Rval = 0.8574, RMSEP = 0.1009. Results demonstrated that THz spectroscopy combined with modeling methods provided an efficient and feasible technique for detecting plant physiological information.

  3. Early detection of precancer using Polarized Light Scattering Spectroscopy (United States)

    Gurjar, Rajan; Backman, Vadim; Itzkan, Irving; Dasari, Ramachandra; Perelman, Lev; Feld, Michael; Badizadegan, Kamran


    We have developed a light scattering technique to detect early pre-cancerous changes in the tissues which, line the epithelial surfaces of the body. The majority of cancers are epithelial in nature. We use light reflection spectroscopy to observe the earliest sign, the enlargement of the index of the cells which, line this layer. Our method is based on the feature that single scattering in the backward direction retains the polarization of the light incident on nucleus in the epithelial layer whereas multiple scattering destroys the polarization. Collecting the backscattering spectral intensities of both polarizations, and taking their difference, we extract the single scattering component. The signals are analyzed to extract the nuclear density, size and the relative refractive index. The experimental results will be presented to illustrate the physical basis of the technique, and its biological application.

  4. Single Molecule Spectral Diffusion in a Solid Detected Via Fluorescence Spectroscopy (United States)


    NO. NO ACCESSION NO. 11. TITLE (Include Security Classification) Single Molecule Spectral Diffusion In A Solid Detected Via Fluorescence Spectroscopy...and identify by block number) FIELD jGROUP SUB-GROUP_ Single molecule spectroscopy Precision detection Spectral diffusion, Pentacene in p-terphenyl 19... Single Molecule Spectral Diffusion ’n A Solid Detected Via Fluorescence Spectroscopy hy W. P. Ambrose, T. Basche, and W. E. Moerner

  5. Noninvasive skin fluorescence spectroscopy for detection of abnormal glucose tolerance

    Directory of Open Access Journals (Sweden)

    Edward L. Hull, PhD


    Full Text Available The ENGINE study evaluated noninvasive skin fluorescence spectroscopy (SFS for detection of abnormal glucose tolerance (AGT. The AGT detection performance of SFS was compared to fasting plasma glucose (FPG and hemoglobin A1C (A1C. The study was a head-to-head comparison of SFS to FPG and A1C in an at-risk population of 507 subjects, with no prior diagnosis of diabetes, each of whom received a 75 g, two-hour oral glucose tolerance test (OGTT. Subjects were measured by SFS on multiple days in fasting and non-fasting states. SFS data were acquired and analyzed with the SCOUT DS® device (VeraLight, Albuquerque, NM, USA. Disease truth was AGT, defined as OGTT ≥ 7.8 mmol/L. Sensitivity, false positive rate (FPR, ROC area, and equal error rate (EER for detection of AGT were computed. The reproducibility of SFS and FPG was assessed. The AGT sensitivity of SFS at the device's recommended screening threshold of 50 was 75.2%, higher than that of FPG (thresholds of 5.6 mmol/L or 6.1 mmol/L and A1C (thresholds of 5.7% or 6.0%. The SFS FPR was 42.1%, comparable to an A1C threshold of 5.7% (FPR = 43.5%. The EERs of SFS, FPG and A1C were similar, as were the partial ROC areas for FPRs of 20–50%. The reproducibility of SFS was 7.7% versus 8.1% for FPG. SFS had similar AGT detection performance to FPG and A1C and is a viable alternative to screening individuals for AGT.

  6. Nanoscale investigation of the interaction of colistin with model phospholipid membranes by Langmuir technique, and combined infrared and force spectroscopies. (United States)

    Freudenthal, Oona; Quilès, Fabienne; Francius, Grégory; Wojszko, Kamila; Gorczyca, Marcelina; Korchowiec, Beata; Rogalska, Ewa


    Colistin (Polymyxin E), an antimicrobial peptide, is increasingly put forward as salvage for severe multidrug-resistant infections. Unfortunately, colistin is potentially toxic to mammalian cells. A better understanding of the interaction with specific components of the cell membranes may be helpful in controlling the factors that may enhance toxicity. Here, we report a physico-chemical study of model phospholipid (PL) mono- and bilayers exposed to colistin at different concentrations by Langmuir technique, atomic force microscopy (AFM) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). The effect of colistin on chosen PL monolayers was examined. Insights into the topographical and elastic changes in the PL bilayers within time after peptide injection are presented via AFM imaging and force spectra. Finally, changes in the PL bilayers' ATR-FTIR spectra as a function of time within three bilayer compositions, and the influence of colistin on their spectral fingerprint are examined together with the time-evolution of the Amide II and νCO band integrated intensity ratios. Our study reveals a great importance in the role of the PL composition as well as the peptide concentration on the action of colistin on PL model membranes. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Infrared spectroscopy of secondary organic aerosol precursors and investigation of the hygroscopicity of SOA formed from the OH reaction with guaiacol and syringol. (United States)

    Ahmad, Waed; Coeur, Cecile; Tomas, Alexandre; Fagniez, Thomas; Brubach, Jean-Blaise; Cuisset, Arnaud


    Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) synchrotron analyses supplemented by density functional theory (DFT) anharmonic calculations have been undertaken to study the fundamental vibrational signatures of guaiacol and syringol, two methoxyphenol compounds found at the highest concentrations in fresh wood smoke and precursors of secondary organic aerosols (SOA) affecting the radiative balance and chemistry of the atmosphere. Nitroderivatives of these two compounds have also been studied experimentally for nitroguaiacol and theoretically for nitrosyringol. All the active fundamental vibrational bands have been assigned and compared to available gas phase measurements, providing a vibrational database of the main precursors for the analysis of SOA produced by atmospheric oxidation of methoxyphenols. In addition, the SOA formed in an atmospheric simulation chamber from the OH reaction with guaiacol and syringol were analyzed using the ATR-FTIR synchrotron spectroscopy and their hygroscopic properties were also investigated. The vibrational study confirms that nitroguaiacol and nitrosyringol are the main oxidation products of methoxyphenols by OH and are key intermediates in SOA production. The hydration experiments highlight the hydrophilic and hydrophobic characters of nitrosyringol and nitroguaiacol, respectively.

  8. Ultrasensitive Laser Spectroscopy in Solids: Statistical Fine Structure and Single-Molecule Detection (United States)


    the measurement. Keywords: Statistical fine structure, Atomic properties, Single molecule detection, Molecule properties, Laser spectroscopy of solids, Instrumentation, Pentacene in p-terphenyl, Organic compounds, Near field.

  9. Detection and Classification of Measurement Errors in Bioimpedance Spectroscopy.

    Directory of Open Access Journals (Sweden)

    David Ayllón

    Full Text Available Bioimpedance spectroscopy (BIS measurement errors may be caused by parasitic stray capacitance, impedance mismatch, cross-talking or their very likely combination. An accurate detection and identification is of extreme importance for further analysis because in some cases and for some applications, certain measurement artifacts can be corrected, minimized or even avoided. In this paper we present a robust method to detect the presence of measurement artifacts and identify what kind of measurement error is present in BIS measurements. The method is based on supervised machine learning and uses a novel set of generalist features for measurement characterization in different immittance planes. Experimental validation has been carried out using a database of complex spectra BIS measurements obtained from different BIS applications and containing six different types of errors, as well as error-free measurements. The method obtained a low classification error (0.33% and has shown good generalization. Since both the features and the classification schema are relatively simple, the implementation of this pre-processing task in the current hardware of bioimpedance spectrometers is possible.

  10. Detection and Classification of Measurement Errors in Bioimpedance Spectroscopy. (United States)

    Ayllón, David; Gil-Pita, Roberto; Seoane, Fernando


    Bioimpedance spectroscopy (BIS) measurement errors may be caused by parasitic stray capacitance, impedance mismatch, cross-talking or their very likely combination. An accurate detection and identification is of extreme importance for further analysis because in some cases and for some applications, certain measurement artifacts can be corrected, minimized or even avoided. In this paper we present a robust method to detect the presence of measurement artifacts and identify what kind of measurement error is present in BIS measurements. The method is based on supervised machine learning and uses a novel set of generalist features for measurement characterization in different immittance planes. Experimental validation has been carried out using a database of complex spectra BIS measurements obtained from different BIS applications and containing six different types of errors, as well as error-free measurements. The method obtained a low classification error (0.33%) and has shown good generalization. Since both the features and the classification schema are relatively simple, the implementation of this pre-processing task in the current hardware of bioimpedance spectrometers is possible.

  11. Multiphoton Ionization Detection in Collinear Laser Spectroscopy of Isolde Beams

    CERN Multimedia


    The experiments using the multiphoton ionization technique have been continued in the beginning of 1990 with stable beam tests on the modified apparatus and with another radioactive beam time on Yb. Higher laser power and an increased vacuum in the ionization region (see figure) yielded a further gain in sensitivity, mainly due to the better suppression of the background ions produced in rest gas collisions. For even Yb isotopes we have now reached a detection efficiency of $\\epsilon$~=~1~x~10$^{-5}$ ions per incoming atom at a background count rate of 30~ions from a beam of 5~x~10$^9$. This sensitivity was high enough for spectroscopy on $^{157}$Yb, where the typical ISOLDE yield of 5~x~10$^7$Yb ions is covered by an isobaric contamination of more than 10$^{10}$ ions. Measurements have also been performed on $^{175}$Yb. These give the first precise value for the magnetic moment of this isotope, $\\mu$~=~0.766(8)$ mu _{N} $, which agrees rather well with the magnetic moment of the isotone $^{177}$Hf. The isoto...

  12. Application of micro-attenuated total reflectance Fourier transform infrared spectroscopy to ink examination in signatures written with ballpoint pen on questioned documents. (United States)

    Nam, Yun Sik; Park, Jin Sook; Lee, Yeonhee; Lee, Kang-Bong


    Questioned documents examined in a forensic laboratory sometimes contain signatures written with ballpoint pen inks; these signatures were examined to assess the feasibility of micro-attenuated total reflectance (ATR) Fourier transform infrared (FTIR) spectroscopy as a forensic tool. Micro-ATR FTIR spectra for signatures written with 63 ballpoint pens available commercially in Korea were obtained and used to construct an FTIR spectral database. A library-searching program was utilized to identify the manufacturer, blend, and model of each black ballpoint pen ink based upon their FTIR peak intensities, positions, and patterns in the spectral database. This FTIR technique was also successfully used in determining the sequence of homogeneous line intersections from the crossing lines of two ballpoint pen signatures. We have demonstrated with a set of sample documents that micro-ATR FTIR is a viable nondestructive analytical method that can be used to identify the origin of the ballpoint pen ink used to mark signatures. © 2014 American Academy of Forensic Sciences.

  13. Characterization of beta-lactoglobulin fibrillar assembly using atomic force microscopy, polyacrylamide gel electrophoresis, and in situ fourier transform infrared spectroscopy. (United States)

    Oboroceanu, Daniela; Wang, Lizhe; Brodkorb, André; Magner, Edmond; Auty, Mark A E


    The aggregation process of beta-lactoglobulin (beta-lg) from 0 min to 20 h was studied using atomic force microscopy (AFM), scanning transmission electron microscopy (STEM), sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and in situ attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). Fibril assembly was monitored in real time using AFM up to 20 h. From 0 to 85 min, beta-lg monomers deformed and expanded with some aggregation. After 85 min, fibrillar structures were formed, exceeding 10 mum in length. Fibrillar structures were confirmed by STEM. Secondary structural changes occurring during fibril formation were monitored by ATR-FTIR at 80 degrees C and indicated a decrease in alpha-helix content and an increase in beta-sheet content. SDS-PAGE indicated that fibrils were composed of polypeptides and not intact monomers. In this study, beta-lg and whey protein isolate (WPI)-derived fibrils, including some double helices, in water were observed by AFM under ambient conditions and in their native aqueous environment.

  14. Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy on Intact Dried Leaves of Sage (Salvia officinalis L.): Accelerated Chemotaxonomic Discrimination and Analysis of Essential Oil Composition. (United States)

    Gudi, Gennadi; Krähmer, Andrea; Krüger, Hans; Schulz, Hartwig


    Sage (Salvia officinalis L.) is cultivated worldwide for its aromatic leaves, which are used as herbal spice, and for phytopharmaceutical applications. Fast analytical strategies for essential oil analysis, performed directly on plant material, would reduce the delay between sampling and analytical results. This would enhance product quality by improving technical control of cultivation. The attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) method described here provides a reliable calibration model for quantification of essential oil components [EOCs; R(2) = 0.96; root-mean-square error of cross-validation (RMSECV) = 0.249 mL 100 g(-1) of dry matter (DM); and range = 1.115-5.280 mL 100 g(-1) of DM] and main constituents [e.g., α-thujone/β-thujone; R(2) = 0.97/0.86; RMSECV = 0.0581/0.0856 mL 100 g(-1) of DM; and range = 0.010-1.252/0.005-0.893 mL 100 g(-1) of DM] directly on dried intact leaves of sage. Except for drying, no further sample preparation is required for ATR-FTIR, and the measurement time of less than 5 min per sample contrasts with the most common alternative of hydrodistillation followed by gas chromatography analysis, which can take several hours per sample.

  15. A Catalytic Path for Electrolyte Reduction in Lithium-Ion Cells Revealed by in Situ Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy

    KAUST Repository

    Shi, Feifei


    © 2015 American Chemical Society. Although controlling the interfacial chemistry of electrodes in Li-ion batteries (LIBs) is crucial for maintaining the reversibility, electrolyte decomposition has not been fully understood. In this study, electrolyte decomposition on model electrode surfaces (Au and Sn) was investigated by in situ attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy. Simultaneously obtained ATR-FTIR spectra and cyclic voltammetry measurements show that lithium ethylene dicarbonate and lithium propionate form on the Au electrode at 0.6 V, whereas diethyl 2,5-dioxahexane dicarboxylate and lithium propionate form on the Sn electrode surface at 1.25 V. A noncatalytic reduction path on the Au surface and a catalytic reduction path on the Sn surface are introduced to explain the surface dependence of the overpotential and product selectivity. This represents a new concept for explaining electrolyte reactions on the anode of LIBs. The present investigation shows that catalysis plays a dominant role in the electrolyte decomposition process and has important implications in electrode surface modification and electrolyte recipe selection, which are critical factors for enhancing the efficiency, durability, and reliability of LIBs.

  16. Surface modification of polyacrylonitrile fiber for immobilization of antibodies and detection of analyte

    Energy Technology Data Exchange (ETDEWEB)

    Jain, Swati, E-mail: [Center for Biomedical Engineering, Indian Institute of Technology, New Delhi, 110016 (India); Chattopadhyay, Sruti, E-mail: [Center for Biomedical Engineering, Indian Institute of Technology, New Delhi, 110016 (India); Jackeray, Richa, E-mail: [Center for Biomedical Engineering, Indian Institute of Technology, New Delhi, 110016 (India); Singh, Harpal, E-mail: [Center for Biomedical Engineering, Indian Institute of Technology, New Delhi, 110016 (India)


    Pendent nitrile groups of multifilamentous polyacrylonitrile (PAN) fibers were reduced to amino groups using lithium aluminum hydride for different time of reduction and amine content was estimated by performing acid-base titrations. Attenuated total reflection-fourier transform infrared spectroscopy (ATR-FTIR) and Differential Scanning Calorimetry (DSC) were used for the characterization of the generated amino groups and thermal properties of the reduced fibers, respectively. The surface morphology of the fibers after reduction and immobilization was characterized using Scanning Electron Microscope (SEM). The newly formed amino groups of the fibers were activated by using glutaraldehyde for the covalent linking of Goat anti-Rabbit IgG-HRP (GAR-HRP) antibody enzyme conjugate. Modified PAN fibers were evaluated as a matrix for sandwich ELISA by using Goat anti-Rabbit antibody (GAR-IgG), Rabbit anti-Goat (RAG-IgG) as analyte and enzyme conjugate GAR-HRP. The fibers reduced for 24 h were able to detect the analyte RAG-IgG at a concentration as low as 3.75 ng mL{sup -1} with 12% skimmed milk as blocking reagent for the optimized concentration of primary antibody GAR-IgG 3 {mu}g mL{sup -1} and peroxidase conjugate GAR-HRP dilution of 8000 fold. The sensitivity, specificity and reproducibility of the developed immunoassay was further established with antibodies present in human blood using Rabbit anti-Human (RAH-IgG) antibody and the corresponding HRP enzyme conjugate. As low as 0.1 {mu}L of human blood was sufficient to perform the assay with the modified fibers.

  17. Detection of Molecular Oxygen at Low Concentrations Using Quartz Enhanced Photoacoustic Spectroscopy


    Andreas Pohlkötter; Michael Köhring; Ulrike Willer; Wolfgang Schade


    Molecular oxygen is detected at low concentrations using photoacoustic spectroscopy despite its unfavorable photoacoustic properties. The system consists of a seed laser diode, a tapered amplifier and a quartz tuning fork based spectrophone, thus employing quartz enhanced photoacoustic spectroscopy (QEPAS). With this system a detection limit of 13 ppm is reached with a compact and long term stable setup. Further improvement of the detection limit is possible by adding suitable gases to the sa...

  18. [Comparison of quasi-continuous and continuous tunable diode laser absorption spectroscopy for gas detection]. (United States)

    Du, Zhen-Hui; Gao, Dong-Yu; Qi, Ru-Bin; Xu, Xiao-Bin; Jiao, Meng


    The theoretical analysis of the direct absorption spectroscopy, the continuous modulation spectroscopy and the quasi-continuous modulation spectroscopy was shown and the corresponding experiments were carried out in order to choose the adequate scheme of the laser modulation spectroscopy to satisfy different requirements of the detection. CO2 gas with different concentrations was detected under the same experimental conditions by using the three different modulation techniques with the same laser. Technical characteristics, signal features and detection limits were compared respectively. Results showed that the detection limit of the quasi-continuous modulation spectroscopy was approaching to that of the continuous modulation spectroscopy. However the linear distortion of the detection signal was obvious, because of the effects of laser energy intermittent and parasitic amplitude modulation on the line shape. Therefore the quasi-continuous modulation spectroscopy is not suitable for the pressure and flow measurements, which closely depend on the line shape. This work has provided reference for selections of the laser modulation spectroscopy.

  19. Micro-Raman spectroscopy for meat type detection (United States)

    De Biasio, M.; Stampfer, P.; Leitner, R.; Huck, C. W.; Wiedemair, V.; Balthasar, D.


    The recent horse meat scandal in Europe increased the demand for optical sensors that can identify meat type. Micro-Raman spectroscopy is a promising technique for the discrimination of meat types. Here, we present micro-Raman measurements of chicken, pork, turkey, mutton, beef and horse meat test samples. The data was analyzed with different combinations of data normalization and classification approaches. Our results show that Raman spectroscopy can discriminate between different meat types. Red and white meat are easily discriminated, however a sophisticated chemometric model is required to discriminate species within these groups.

  20. In vitro evaluation of ionizing radiation effects in bone tissue by FTIR spectroscopy (United States)

    Zezell, Denise Maria; Veloso, Marcelo Noronha; Dias, Derly Augusto; Politano, Rodolfo; Benetti, Carolina


    We verified the changes promoted by ionizing radiation in bone tissue using FTIR. Samples of bovine bone were irradiated using Cobalt-60 with 0.01kGy, 0.1kGy, 1kGy, 15kGy and 75kGy. The effects of ionizing irradiation on chemical structure of bone, were studied considering the sub-bands of amide I, the crystallinity index and relation of organic and inorganic materials. ATR-FTIR spectroscopy showed changes in organic components and in hydroxyapatite crystals organization. High correlation with statistical significance was observed between (amideIII+collagen)/ ν1,ν3PO4, crystallinity and mechanical properties of the samples.

  1. Time domain PD-detection vs. dielectric spectroscopy

    DEFF Research Database (Denmark)

    Holbøll, Joachim T.; Edin, Hans; Gäfvert, Uno


    A theoretically developed relationship between partial discharges and the response from a system for dielectric spectroscopy was experimentally confirmed. The losses caused by the discharges were highest at test voltages with low frequencies. At 0.1 Hz, tanδ tip-up at discharge inception was very...

  2. Avaliação da eficiência das técnicas ESI-MS e ATR/FTIR na determinação de adulteração de BX com querosene e óleo residual


    Itânia Pinheiro Soares; Renato Monteiro de Oliveira Russo; Ravi Govinda Dardot Prates; Rodinei Augusti; Isabel Cristina Pereira Fortes; Vânya Márcia Duarte Pasa


    Direct infusion electrospray ionization mass spectrometry in the negative ion mode, ESI(-)-MS and Fourier transform infrared spectroscopy (FTIR) were used together with partial least squares (PLS) as a tool to determine B3 adulteration (B3 - mixture of 3% v/v of biodiesel in diesel) with kerosene and residual oil.

  3. Avaliação da eficiência das técnicas ESI-MS e ATR/FTIR na determinação de adulteração de BX com querosene e óleo residual

    Directory of Open Access Journals (Sweden)

    Itânia Pinheiro Soares


    Full Text Available Direct infusion electrospray ionization mass spectrometry in the negative ion mode, ESI(--MS and Fourier transform infrared spectroscopy (FTIR were used together with partial least squares (PLS as a tool to determine B3 adulteration (B3 - mixture of 3% v/v of biodiesel in diesel with kerosene and residual oil.

  4. Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hellman, Hal


    This booklet discusses spectroscopy, the study of absorption of radiation by matter, including X-ray, gamma-ray, microwave, mass spectroscopy, as well as others. Spectroscopy has produced more fundamental information to the study of the detailed structure of matter than any other tools.

  5. Spectroscopy

    CERN Document Server

    Walker, S


    The three volumes of Spectroscopy constitute the one comprehensive text available on the principles, practice and applications of spectroscopy. By giving full accounts of those spectroscopic techniques only recently introduced into student courses - such as Mössbauer spectroscopy and photoelectron spectroscopy - in addition to those techniques long recognised as being essential in chemistry teaching - sucha as e.s.r. and infrared spectroscopy - the book caters for the complete requirements of undergraduate students and at the same time provides a sound introduction to special topics for graduate students.

  6. Ultraviolet resonance Raman spectroscopy for the detection of cocaine in oral fluid (United States)

    D'Elia, Valentina; Montalvo, Gemma; Ruiz, Carmen García; Ermolenkov, Vladimir V.; Ahmed, Yasmine; Lednev, Igor K.


    Detecting and quantifying cocaine in oral fluid is of significant importance for practical forensics. Up to date, mainly destructive methods or biochemical tests have been used, while spectroscopic methods were only applied to pretreated samples. In this work, the possibility of using resonance Raman spectroscopy to detect cocaine in oral fluid without pretreating samples was tested. It was found that ultraviolet resonance Raman spectroscopy with 239-nm excitation allows for the detection of cocaine in oral fluid at 10 μg/mL level. Further method development will be needed for reaching the practically useful levels of cocaine detection.

  7. Linearity of Air-Biased Coherent Detection for Terahertz Time-Domain Spectroscopy

    DEFF Research Database (Denmark)

    Wang, Tianwu; Iwaszczuk, Krzysztof; Wrisberg, Emil Astrup


    The performance of air-biased coherent detection (ABCD) in a broadband two-color laser-induced air plasma system for terahertz time-domain spectroscopy (THz-TDS) has been investigated. Fundamental parameters of the ABCD detection, including signal-to-noise ratio (SNR), dynamic range (DR), and lin......The performance of air-biased coherent detection (ABCD) in a broadband two-color laser-induced air plasma system for terahertz time-domain spectroscopy (THz-TDS) has been investigated. Fundamental parameters of the ABCD detection, including signal-to-noise ratio (SNR), dynamic range (DR...

  8. Rapid-scan Fourier-transform coherent anti-Stokes Raman scattering spectroscopy with heterodyne detection. (United States)

    Hiramatsu, Kotaro; Luo, Yizhi; Ideguchi, Takuro; Goda, Keisuke


    High-speed Raman spectroscopy has become increasingly important for analyzing chemical dynamics in real time. To address the need, rapid-scan Fourier-transform coherent anti-Stokes Raman scattering (FT-CARS) spectroscopy has been developed to realize broadband CARS measurements at a scan rate of more than 20,000 scans/s. However, the detection sensitivity of FT-CARS spectroscopy is inherently low due to the limited number of photons detected during each scan. In this Letter, we show our experimental demonstration of enhanced sensitivity in rapid-scan FT-CARS spectroscopy by heterodyne detection. Specifically, we implemented heterodyne detection by superposing the CARS electric field with an external local oscillator (LO) for their interference. The CARS signal was amplified by simply increasing the power of the LO without the need for increasing the incident power onto the sample. Consequently, we achieved enhancement in signal intensity and the signal-to-noise ratio by factors of 39 and 5, respectively, compared to FT-CARS spectroscopy with homodyne detection. The sensitivity-improved rapid-scan FT-CARS spectroscopy is expected to enable the sensitive real-time observation of chemical dynamics in a broad range of settings, such as combustion engines and live biological cells.

  9. [Study of automatic marine oil spills detection using imaging spectroscopy]. (United States)

    Liu, De-Lian; Han, Liang; Zhang, Jian-Qi


    To reduce artificial auxiliary works in oil spills detection process, an automatic oil spill detection method based on adaptive matched filter is presented. Firstly, the characteristics of reflectance spectral signature of C-H bond in oil spill are analyzed. And an oil spill spectral signature extraction model is designed by using the spectral feature of C-H bond. It is then used to obtain the reference spectral signature for the following oil spill detection step. Secondly, the characteristics of reflectance spectral signature of sea water, clouds, and oil spill are compared. The bands which have large difference in reflectance spectral signatures of the sea water, clouds, and oil spill are selected. By using these bands, the sea water pixels are segmented. And the background parameters are then calculated. Finally, the classical adaptive matched filter from target detection algorithms is improved and introduced for oil spill detection. The proposed method is applied to the real airborne visible infrared imaging spectrometer (AVIRIS) hyperspectral image captured during the deepwater horizon oil spill in the Gulf of Mexico for oil spill detection. The results show that the proposed method has, high efficiency, does not need artificial auxiliary work, and can be used for automatic detection of marine oil spill.

  10. Detection of Molecular Oxygen at Low Concentrations Using Quartz Enhanced Photoacoustic Spectroscopy

    Directory of Open Access Journals (Sweden)

    Andreas Pohlkötter


    Full Text Available Molecular oxygen is detected at low concentrations using photoacoustic spectroscopy despite its unfavorable photoacoustic properties. The system consists of a seed laser diode, a tapered amplifier and a quartz tuning fork based spectrophone, thus employing quartz enhanced photoacoustic spectroscopy (QEPAS. With this system a detection limit of 13 ppm is reached with a compact and long term stable setup. Further improvement of the detection limit is possible by adding suitable gases to the sample gas that promote the radiationless de-excitation of the oxygen molecules.

  11. Detection of molecular oxygen at low concentrations using quartz enhanced photoacoustic spectroscopy. (United States)

    Pohlkötter, Andreas; Köhring, Michael; Willer, Ulrike; Schade, Wolfgang


    Molecular oxygen is detected at low concentrations using photoacoustic spectroscopy despite its unfavorable photoacoustic properties. The system consists of a seed laser diode, a tapered amplifier and a quartz tuning fork based spectrophone, thus employing quartz enhanced photoacoustic spectroscopy (QEPAS). With this system a detection limit of 13 ppm is reached with a compact and long term stable setup. Further improvement of the detection limit is possible by adding suitable gases to the sample gas that promote the radiationless de-excitation of the oxygen molecules.

  12. Atmospheric greenhouse gases detection by optical similitude absorption spectroscopy


    Anselmo, Christophe


    This thesis concerns the theoretical and experimental development of a new methodology for greenhouse gases detection based on the optical absorption. The problem relies on the unambiguous retrieval of a gas concentration from differential absorption measurements, in which the spectral width of the light source is wider than one or several absorption lines of the considered target gas given that the detection is not spectrally resolved. This problem could lead to the development of a robust r...

  13. Raman spectroscopy for detection of stretched DNAs on superhydrophobic surfaces

    KAUST Repository

    Marini, Monica


    A novel approach for the study of low concentrated DNAs (60 pM) using microRaman spectroscopy is reported. A superhydrophobic substrate with array of microPillars is fabricated over which the sample was drop casted. The substrate concentrates the molecules in a very small area with higher molecular density, enabling to carry out the microRaman measurements. Two different DNAs (single strand and double strand) were used to investigate through Raman technique. A spectral Raman difference was found to distinguish the ssDNA and dsDNAs. The approach can be of interest for a wide variety of applications ranging from biological materials interactions characterization to the biomedical field. © 2014 Elsevier B.V. All rights reserved.

  14. Communication: atomic force detection of single-molecule nonlinear optical vibrational spectroscopy. (United States)

    Saurabh, Prasoon; Mukamel, Shaul


    Atomic Force Microscopy (AFM) allows for a highly sensitive detection of spectroscopic signals. This has been first demonstrated for NMR of a single molecule and recently extended to stimulated Raman in the optical regime. We theoretically investigate the use of optical forces to detect time and frequency domain nonlinear optical signals. We show that, with proper phase matching, the AFM-detected signals closely resemble coherent heterodyne-detected signals. Applications are made to AFM-detected and heterodyne-detected vibrational resonances in Coherent Anti-Stokes Raman Spectroscopy (χ((3))) and sum or difference frequency generation (χ((2))).

  15. Sensor data fusion for spectroscopy-based detection of explosives (United States)

    Shah, Pratik V.; Singh, Abhijeet; Agarwal, Sanjeev; Sedigh, Sahra; Ford, Alan; Waterbury, Robert


    In-situ trace detection of explosive compounds such as RDX, TNT, and ammonium nitrate, is an important problem for the detection of IEDs and IED precursors. Spectroscopic techniques such as LIBS and Raman have shown promise for the detection of residues of explosive compounds on surfaces from standoff distances. Individually, both LIBS and Raman techniques suffer from various limitations, e.g., their robustness and reliability suffers due to variations in peak strengths and locations. However, the orthogonal nature of the spectral and compositional information provided by these techniques makes them suitable candidates for the use of sensor fusion to improve the overall detection performance. In this paper, we utilize peak energies in a region by fitting Lorentzian or Gaussian peaks around the location of interest. The ratios of peak energies are used for discrimination, in order to normalize the effect of changes in overall signal strength. Two data fusion techniques are discussed in this paper. Multi-spot fusion is performed on a set of independent samples from the same region based on the maximum likelihood formulation. Furthermore, the results from LIBS and Raman sensors are fused using linear discriminators. Improved detection performance with significantly reduced false alarm rates is reported using fusion techniques on data collected for sponsor demonstration at Fort Leonard Wood.

  16. The Rapid Detection of Single Bacterial Cells by Deep UV Micro Raman Spectroscopy. (United States)


    developed for the purpose of rapid bacterial detection. Techniques include mass spectroscopy and its various combinations with chromatography and pyrolysis...Methods: Chromatography and Mass Spectroscopy", Plenum Press, N.Y. 1990. 6. P.J.H. Jackman in "Methods in Microbiology", Vol. 19, eds., R.R., Colwell and R...4847198 issued July 11, 1989. 5. "Ultraviolet Resonance Raman Spectra of Bacteria, Bacterial Spores, Protoplasts and Calcium Dipicolinate", R

  17. Cervical cancer detection based on serum sample Raman spectroscopy. (United States)

    González-Solís, José Luis; Martínez-Espinosa, Juan Carlos; Torres-González, Luis Adolfo; Aguilar-Lemarroy, Adriana; Jave-Suárez, Luis Felipe; Palomares-Anda, Pascual


    The use of Raman spectroscopy to analyze the biochemical composition of serum samples and hence distinguish between normal and cervical cancer serum samples was investigated. The serum samples were obtained from 19 patients who were clinically diagnosed with cervical cancer, 3 precancer, and 20 healthy volunteer controls. The imprint was put under an Olympus microscope, and around points were chosen for Raman measurement.All spectra were collected at a Horiba Jobin-Yvon LabRAM HR800 Raman Spectrometer with a laser of 830-nm wavelength and 17-mW power irradiation. Raw spectra were processed by carrying out baseline correction, smoothing, and normalization to remove noise, florescence, and shot noise and then analyzed using principal component analysis (PCA). The control serum spectrum showed the presence of higher amounts of carotenoids indicated by peaks at 1,002, 1,160, and 1,523 cm(-1)and intense peaks associated with protein components at 754, 853, 938, 1,002, 1,300-1,345, 1,447, 1,523, 1,550, 1,620, and 1,654 cm(-1). The Raman bands assigned to glutathione (446, 828, and 1,404 cm(-1)) and tryptophan (509, 1,208, 1,556, 1,603, and 1,620 cm(-1)) in cervical cancer were higher than those of control samples, suggesting that their presence may also play a role in cervical cancer. Furthermore, weak bands in the control samples attributed to tryptophan (545, 760, and 1,174 cm(-1)) and amide III (1,234-1,290 cm(-1)) seem to disappear and decrease in the cervical cancer samples, respectively. It is shown that the serum samples from patients with cervical cancer and from the control group can be discriminated with high sensitivity and specificity when the multivariate statistical methods of PCA is applied to Raman spectra. PCA allowed us to define the wavelength differences between the spectral bands of the control and cervical cancer groups by confirming that the main molecular differences among the control and cervical cancer samples were glutathione, tryptophan,

  18. Nondestructive detection of infested chestnuts based on NIR spectroscopy (United States)

    Insect feeding is a significant postharvest problem for processors of Chestnuts (Castanea sativa, Miller). In most cases, damage from insects is 'hidden', i.e. not visually detectable on the fruit surface. Consequently, traditional sorting techniques, including manual sorting, are generally inadequa...

  19. Mental fatigue detection based on the functional near infrared spectroscopy (United States)

    Zhang, Zhen; Xu, Fenggang; Yang, Hanjun; Jiang, Jin; Cao, Yong; Jiao, Xuejun


    Mental fatigue can be induced by long time mental work, mental fatigue caused worse performance and accidents. As a non-invasive technique, functional near-infrared spectroscopy (fNIRS) can measure blood oxygen activity in the cerebral cortex which reflect the cognitive function of brain indirectly. Aiming at investigating whether fNIRS can measure the mental fatigue and study the spatial pattern of hemodynamic response for mental fatigue, we used three sessions of verbal 2-back working memory task for a total of 120 minutes to induce mental fatigue, 15 healthy subjects were recruited and 30 channels including prefrontal cortex (PFC) and motor cortex (MC) were measured by fNIRS. The mean oxyhemoglobin feature for 20s was extracted as well as subjective fatigue level and performance. The results showed significant increase of subjected fatigue level as well as significant decrease performance from session one to three task. With the increased level of fatigue, oxyhemoglobin in PFC increase significantly and the spatial pattern of hemodynamic response in the all 30 channels varied with task duration as well. These findings indicated the potential of fNIRS measured hemodynamic as a mental fatigue indicator.

  20. Spectroscopy

    DEFF Research Database (Denmark)

    Berg, Rolf W.

    This introductory booklet covers the basics of molecular spectroscopy, infrared and Raman methods, instrumental considerations, symmetry analysis of molecules, group theory and selection rules, as well as assignments of fundamental vibrational modes in molecules.......This introductory booklet covers the basics of molecular spectroscopy, infrared and Raman methods, instrumental considerations, symmetry analysis of molecules, group theory and selection rules, as well as assignments of fundamental vibrational modes in molecules....

  1. Noninvasive Detection of Inflammatory Changes in White Adipose Tissue by Label-Free Raman Spectroscopy. (United States)

    Haka, Abigail S; Sue, Erika; Zhang, Chi; Bhardwaj, Priya; Sterling, Joshua; Carpenter, Cassidy; Leonard, Madeline; Manzoor, Maryem; Walker, Jeanne; Aleman, Jose O; Gareau, Daniel; Holt, Peter R; Breslow, Jan L; Zhou, Xi Kathy; Giri, Dilip; Morrow, Monica; Iyengar, Neil; Barman, Ishan; Hudis, Clifford A; Dannenberg, Andrew J


    White adipose tissue inflammation (WATi) has been linked to the pathogenesis of obesity-related diseases, including type 2 diabetes, cardiovascular disease, and cancer. In addition to the obese, a substantial number of normal and overweight individuals harbor WATi, putting them at increased risk for disease. We report the first technique that has the potential to detect WATi noninvasively. Here, we used Raman spectroscopy to detect WATi with excellent accuracy in both murine and human tissues. This is a potentially significant advance over current histopathological techniques for the detection of WATi, which rely on tissue excision and, therefore, are not practical for assessing disease risk in the absence of other identifying factors. Importantly, we show that noninvasive Raman spectroscopy can diagnose WATi in mice. Taken together, these results demonstrate the potential of Raman spectroscopy to provide objective risk assessment for future cardiometabolic complications in both normal weight and overweight/obese individuals.

  2. Fluorescence correlation spectroscopy: Ultrasensitive detection in clear and turbid media (United States)

    Tahari, Abdel Kader

    In this work, I describe the development of a simple, inexpensive, and powerful alternative technique to detect and analyze, without enrichment, extremely low concentrations of cells, bacteria, viruses, and protein aggregates in turbid fluids for clinical and biotechnological applications. The anticipated applications of this technique are many. They range from the determination of the somatic cell count in milk for the dairy industry, to the enumeration and characterization of microorganisms in environmental microbiology and the food industry, and to the fast and ultrasensitive detection of protein aggregates for the diagnosis of Alzheimer's and other neurodegenerative diseases in clinical medicine. A prototype instrument has been built and allowed the detection and quantification of particles down to a few per milliliter in short scanning times. It consists of a small microscope that has a horizontal geometry and a mechanical instrument that holds a cylindrical cuvette (1 cm in diameter) with two motors that provide a rotational and a slower vertical inversion motions. The illumination focus is centered about 200 mum from the wall of the cuvette inside the sample. The total volume that is explored is large (˜1ml/min for bright particles). The data is analyzed with a correlation filter program based on particle passage pattern recognition. I will also describe further work on improving the sensitivity of the technique, expanding it for multiple-species discrimination and enumeration, and testing the prototype device in actual clinical and biotechnological applications. The main clinical application of this project seeks to establish conditions and use this new technique to quantify and size-analyze oligomeric complexes of the Alzheimer's disease beta-peptide in cerebrospinal fluid and other body fluids as a molecular biomarker for persons at risk of Alzheimer's disease dementia. The technology could potentially be extended to the diagnosis and therapeutic

  3. Optical spectroscopy for the detection of ischemic tissue injury (United States)

    Demos, Stavros [Livermore, CA; Fitzgerald, Jason [Sacramento, CA; Troppmann, Christoph [Sacramento, CA; Michalopoulou, Andromachi [Athens, GR


    An optical method and apparatus is utilized to quantify ischemic tissue and/or organ injury. Such a method and apparatus is non-invasive, non-traumatic, portable, and can make measurements in a matter of seconds. Moreover, such a method and apparatus can be realized through optical fiber probes, making it possible to take measurements of target organs deep within a patient's body. Such a technology provides a means of detecting and quantifying tissue injury in its early stages, before it is clinically apparent and before irreversible damage has occurred.

  4. Wavelength-stabilization-based photoacoustic spectroscopy for methane detection (United States)

    Wang, Qiang; Wang, Zhen; Ren, Wei


    A compact and portable photoacoustic gas sensor was developed for sensitive methane (CH4) detection at 1.6 µm using a software-based wavelength stabilization scheme. A transmission-type photoacoustic cell was connected in series with a reference gas cell to measure the photoacoustic signal and the reference gas absorption for wavelength stabilization simultaneously. The central wavelength of the diode laser was locked to the target CH4 line with a fluctuation of less than 10.6 MHz using a digital proportional-integral-derivative controller. The CH4 sensor was designed to be insensitive to the incoherent external acoustic noise by the cumulative average of the demodulated photoacoustic signal by a digital lock-in amplifier. With an incident laser power of 6 mW, our CH4 sensor achieved a minimum detection limit of 11.5 ppm at 10 s response time and an excellent linearity (R 2  =  0.9999) in the concentration range of 400-6300 ppm.

  5. Detection of explosives based on surface-enhanced Raman spectroscopy. (United States)

    Wackerbarth, Hainer; Salb, Christian; Gundrum, Lars; Niederkrüger, Matthias; Christou, Konstantin; Beushausen, Volker; Viöl, Wolfgang


    In this study we present a device based on surface-enhanced Raman scattering (SERS) for the detection of airborne explosives. The explosives are resublimated on a cooled nanostructured gold substrate. The explosives trinitrotoluene (TNT) and triacetone triperoxide (TATP) are used. The SERS spectrum of the explosives is analyzed. Thus, TNT is deposited from an acetonitrile solution on the gold substrate. In the case of TATP, first the bulk TATP Raman spectrum was recorded and compared with the SERS spectrum, generated by deposition out of the gas phase. The frequencies of the SERS spectrum are hardly shifted compared to the spectrum of bulk TATP. The influence of the nanostructured gold substrate temperature on the signals of TATP was studied. A decrease in temperature up to 200 K increased the intensities of the TATP bands in the SERS spectrum; below 200 K, the TATP fingerprint disappeared.

  6. Laser Calorimetry Spectroscopy for ppm-level Dissolved Gas Detection and Analysis (United States)

    K. S., Nagapriya; Sinha, Shashank; Prashanth, R.; Poonacha, Samhitha; Chaudhry, Gunaranjan; Bhattacharya, Anandaroop; Choudhury, Niloy; Mahalik, Saroj; Maity, Sandip


    In this paper we report a newly developed technique - laser calorimetry spectroscopy (LCS), which is a combination of laser absorption spectroscopy and calorimetry - for the detection of gases dissolved in liquids. The technique involves determination of concentration of a dissolved gas by irradiating the liquid with light of a wavelength where the gas absorbs, and measuring the temperature change caused by the absorbance. Conventionally, detection of dissolved gases with sufficient sensitivity and specificity was done by first extracting the gases from the liquid and then analyzing the gases using techniques such as gas chromatography. Using LCS, we have been able to detect ppm levels of dissolved gases without extracting them from the liquid. In this paper, we show the detection of dissolved acetylene in transformer oil in the mid infrared (MIR) wavelength (3021 nm) region.

  7. Nanogap dielectric spectroscopy for aptamer-based protein detection. (United States)

    Mannoor, Manu Sebastian; James, Teena; Ivanov, Dentcho V; Beadling, Les; Braunlin, William


    Among the various label-free methods for monitoring biomolecular interactions, capacitive sensors stand out due to their simple instrumentation and compatibility with multiplex formats. However, electrode polarization due to ion gradient formation and noise from solution conductance limited early dielectric spectroscopic measurements to high frequencies only, which in turn limited their sensitivity to biomolecular interactions, as the applied excitation signals were too fast for the charged macromolecules to respond. To minimize electrode polarization effects, capacitive sensors with 20 nm electrode separation were fabricated using silicon dioxide sacrificial layer techniques. The nanoscale separation of the capacitive electrodes in the sensor results in an enhanced overlapping of electrical double layers, and apparently a more ordered "ice-like" water structure. Such effects in turn reduce low frequency contributions from bulk sample resistance and from electrode polarization, and thus markedly enhance sensitivity toward biomolecular interactions. Using these nanogap capacitive sensors, highly sensitive, label-free aptamer-based detection of protein molecules is achieved. Copyright 2010 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  8. Large Scale Plasmonic nanoCones array For Spectroscopy Detection

    KAUST Repository

    Das, Gobind


    Advanced optical materials or interfaces are gaining attention for diagnostic applications. However, the achievement of large device interface as well as facile surface functionalization largely impairs their wide use. The present work is aimed to address different innovative aspects related to the fabrication of large area 3D plasmonic arrays, their direct and easy functionalization with capture elements and their spectroscopic verifications through enhanced Raman and enhanced fluorescence techniques. In detail we have investigated the effect of Au-based nanoCones array, fabricated by means of direct nanoimprint technique over large area (mm2), on protein capturing and on the enhancement in optical signal. A selective functionalization of gold surfaces was proposed by using a peptide (AuPi3) previously selected by phage display. In this regard, two different sequences, labeled with fluorescein and biotin, were chemisorbed on metallic surfaces. The presence of Au nanoCones array consents an enhancement in electric field on the apex of cone, enabling the detection of molecules. We have witnessed around 12-fold increase in fluorescence intensity and SERS enhancement factor around 1.75 ×105 with respect to the flat gold surface. Furthermore, a sharp decrease in fluorescence lifetime over nanoCones confirms the increase in radiative emission (i.e. an increase in photonics density at the apex of cones).

  9. Precise and Rapid Detection of Optical Activity for Accumulative Femtosecond Spectroscopy

    Directory of Open Access Journals (Sweden)

    Nuernberger P.


    Full Text Available We present a fast and sensitive polarimeter combining common-path optical heterodyne interferometry and accumulative spectroscopy to detect rotatory power. The sensitivity of rotatory detection is determined to be 0.10 milli-degrees for a measurement time of only one second and an interaction length of 250 μm. Its suitability for femtosecond studies is demonstrated in a non-resonant two-photon photodissociation experiment.

  10. Optimization of metabolite detection by quantum mechanics simulations in magnetic resonance spectroscopy


    Gambarota, Giulio


    International audience; Magnetic resonance spectroscopy (MRS) is a well established modality for investigating tissue metabolism in vivo. In recent years, many efforts by the scientific community have been directed towards the improvement of metabolite detection and quantitation.Quantum mechanics simulations allow for investigations of the MR signal behaviour of metabolites; thus, they provide an essential tool in the optimization of metabolite detection.In this review, we will examine quantu...

  11. Standoff Detection of Explosives at 1 m using Laser Induced Breakdown Spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Junjuri, R.; Myakalwar, A.K.; Gundawar, M.K.


    Roč. 67, č. 6 (2017), s. 623-630 ISSN 0011-748X Institutional support: RVO:67985882 Keywords : Laser induced breakdown spectroscopy * Multivariate analysis * Principal component analysis * Explosive detection Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 0.500, year: 2016

  12. Ultra-Broadband Dielectric THz Spectroscopy with Air-Biased-Coherent-Detection

    DEFF Research Database (Denmark)

    D'Angelo, Francesco; Bonn, Mischa; Turchinovich, Dmitry


    We present results on ultra-broadband THz-TDS on silicon using air biased coherent detection (ABCD) technique. We find that the positioning of the sample in the spectrometer, leading to the spatial shift of THz focus, is crucial for accurate spectroscopy results....

  13. Detection of pit fragments in fresh cherries using near infrared spectroscopy (United States)

    NIR spectroscopy in the wavelength region from 900nm to 2600nm was evaluated as the basis for a rapid, non-destructive method for the detection of pits and pit fragments in fresh cherries. Partial Least Squares discriminant analysis (PLS-DA) following various spectral pretreatments was applied to sp...

  14. Fluid Properties Measurements Using Wavelength Modulation Spectroscopy with First Harmonic Detection (United States)

    Chen, Shin-Juh (Inventor); Silver, Joel A. (Inventor)


    An apparatus and method for monitoring gas velocity, temperature, and pressure in combustion systems and flow devices, in particular at inlets and isolators of scramjet engines. The invention employs wavelength modulation spectroscopy with first harmonic detection and without the need to scan the full absorption spectra.

  15. Targeted and Untargeted Detection of Skim Milk Powder Adulteration by Near-Infrared Spectroscopy

    NARCIS (Netherlands)

    Capuano, Edoardo; Boerrigter-Eenling, Rita; Koot, Alex; Ruth, van S.M.


    In the present study, near-infrared spectroscopy (NIRS) was explored as a fast and reliable screening method for the detection of adulteration of skim milk powder (SMP). Sixty genuine SMP were adulterated with acid whey (1–25 % w/w), starch (2 and 5 %) and maltodextrin (2 and 5 %) for a total of

  16. Non-destructive detection of flawed hazelnut kernels and lipid oxidation assessment using NIR spectroscopy

    NARCIS (Netherlands)

    Pannico, A.; Schouten, R.E.; Basile, B.; Woltering, E.J.; Cirillo, C.


    Microbial contamination, seed browning, bad taste and lipid oxidation are primary causes of quality deterioration in stored hazelnuts, affecting their marketability. The feasibility of NIR spectroscopy to detect flawed kernels and estimate lipid oxidation in in-shell and shelled hazelnuts was

  17. Detection of Potential Induced Degradation in c-Si PV Panels Using Electrical Impedance Spectroscopy

    DEFF Research Database (Denmark)

    Oprea, Matei-lon; Spataru, Sergiu; Sera, Dezso

    This work, for the first time, investigates an Impedance Spectroscopy (IS) based method for detecting potential-induced degradation (PID) in crystalline silicon photovoltaic (c-Si PV) panels. The method has been experimentally tested on a set of panels that were confirmed to be affected by PID...

  18. Early stage detection of β→α transition in Sn by Mössbauer spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Skwarek, Agata, E-mail: [Institute of Electron Technology Cracow Division, Zabłocie 39, 30-701 Kraków (Poland); Zachariasz, Piotr [Institute of Electron Technology Cracow Division, Zabłocie 39, 30-701 Kraków (Poland); Żukrowski, Jan [AGH University of Science and Technology, Academic Center for Materials and Nanotechnology, A. Mickiewicza 30, 30-059 Kraków (Poland); Synkiewicz, Beata; Witek, Krzysztof [Institute of Electron Technology Cracow Division, Zabłocie 39, 30-701 Kraków (Poland)


    Mössbauer spectroscopy was used for the early stage detection of the β→α transition (tin pest) in Sn matrix. The results were compared with the data from X-ray diffraction and a variance in the sensitivity for both methods has been proven. Mössbauer spectroscopy is more responsive method than XRD to tin pest finding and with possible detection level of even 1.8%. Furthermore, in reference sample, suspected to be pure α-Sn, large content of white tin (β-Sn), even after 6 years of exposure at sub-zero temperature, has been identified. 48% of α-Sn phase but also 52% of non-transferred β-Sn has been still detectable. - Highlights: • β→α transition (tin pest) could completely disintegrate Sn-rich material. • Early stage detection of β→α transition still exhibits substantial difficulties. • Mössbauer spectroscopy is very sensitive method in detection of β→α transition in Sn matrix. • Different values of Mössbauer-Lamb factors for β and α-Sn allow to detect tin pest at the level of 1.8%.

  19. Application of fluorescence spectroscopy and imaging in the detection of a photosensitizer in photodynamic therapy (United States)

    Zang, Lixin; Zhao, Huimin; Zhang, Zhiguo; Cao, Wenwu


    Photodynamic therapy (PDT) is currently an advanced optical technology in medical applications. However, the application of PDT is limited by the detection of photosensitizers. This work focuses on the application of fluorescence spectroscopy and imaging in the detection of an effective photosenzitizer, hematoporphyrin monomethyl ether (HMME). Optical properties of HMME were measured and analyzed based on its absorption and fluorescence spectra. The production mechanism of its fluorescence emission was analyzed. The detection device for HMME based on fluorescence spectroscopy was designed. Ratiometric method was applied to eliminate the influence of intensity change of excitation sources, fluctuates of excitation sources and photo detectors, and background emissions. The detection limit of this device is 6 μg/L, and it was successfully applied to the diagnosis of the metabolism of HMME in the esophageal cancer cells. To overcome the limitation of the point measurement using fluorescence spectroscopy, a two-dimensional (2D) fluorescence imaging system was established. The algorithm of the 2D fluorescence imaging system is deduced according to the fluorescence ratiometric method using bandpass filters. The method of multiple pixel point addition (MPPA) was used to eliminate fluctuates of signals. Using the method of MPPA, SNR was improved by about 30 times. The detection limit of this imaging system is 1.9 μg/L. Our systems can be used in the detection of porphyrins to improve the PDT effect.

  20. Characterization of extracellular vesicles by IR spectroscopy: Fast and simple classification based on amide and CH stretching vibrations. (United States)

    Mihály, Judith; Deák, Róbert; Szigyártó, Imola Csilla; Bóta, Attila; Beke-Somfai, Tamás; Varga, Zoltán


    Extracellular vesicles isolated by differential centrifugation from Jurkat T-cell line were investigated by attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR). Amide and CH stretching band intensity ratios calculated from IR bands, characteristic of protein and lipid components, proved to be distinctive for the different extracellular vesicle subpopulations. This proposed 'spectroscopic protein-to-lipid ratio', combined with the outlined spectrum-analysis protocol is valid also for low sample concentrations (0.15-0.05mg/ml total protein content) and can carry information about the presence of other non-vesicular formations such as aggregated proteins, lipoproteins and immune complexes. Detailed analysis of IR data reveals compositional changes of extracellular vesicles subpopulations: second derivative spectra suggest changes in protein composition from parent cell towards exosomes favoring proteins with β-turns and unordered motifs at the expense of intermolecular β-sheet structures. The IR-based protein-to-lipid assessment protocol was tested also for red blood cell derived microvesicles for which similar values were obtained. The potential applicability of this technique for fast and efficient characterization of vesicular components is high as the investigated samples require no further preparations and all the different molecular species can be determined in the same sample. The results indicate that ATR-FTIR measurements provide a simple and reproducible method for the screening of extracellular vesicle preparations. It is hoped that this sophisticated technique will have further impact in extracellular vesicle research. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Novel Concept of Frequency-Combs Interferometric Spectroscopy in the Mid-IR for Significantly Enhanced Detection of Explosives (United States)


    continuous-wave photonic THz source tunable from 1 to 4.5 THz for nonlinear molecular spectroscopy " International Symposium on Photoelectronic... spectroscopy in the mid-ir for significantly enhanced detection of explosives" . For technical questions, please contact Dr. Vodopyanov at vodopyanov... spectroscopy in the mid- IR for significantly enhanced detection of explosives Sb. GRANT NUMBER N0001 4-14-1 -0447 Sc. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Sd

  2. Detection of metanil yellow contamination in turmeric using FT-Raman and FT-IR spectroscopy (United States)

    Dhakal, Sagar; Chao, Kuanglin; Qin, Jianwei; Kim, Moon; Schmidt, Walter; Chan, Dian


    Turmeric is well known for its medicinal value and is often used in Asian cuisine. Economically motivated contamination of turmeric by chemicals such as metanil yellow has been repeatedly reported. Although traditional technologies can detect such contaminants in food, high operational costs and operational complexities have limited their use to the laboratory. This study used Fourier Transform Raman Spectroscopy (FT-Raman) and Fourier Transform - Infrared Spectroscopy (FT-IR) to identify metanil yellow contamination in turmeric powder. Mixtures of metanil yellow in turmeric were prepared at concentrations of 30%, 25%, 20%, 15%, 10%, 5%, 1% and 0.01% (w/w). The FT-Raman and FT-IR spectral signal of pure turmeric powder, pure metanil yellow powder and the 8 sample mixtures were obtained and analyzed independently to identify metanil yellow contamination in turmeric. The results show that FT-Raman spectroscopy and FT-IR spectroscopy can detect metanil yellow mixed with turmeric at concentrations as low as 1% and 5%, respectively, and may be useful for non-destructive detection of adulterated turmeric powder.

  3. [Quartz-enhanced photoacoustic spectroscopy trace gas detection system based on the Fabry-Perot demodulation]. (United States)

    Lin, Cheng; Zhu, Yong; Wei, Wei; Zhang, Jie; Tian, Li; Xu, Zu-Wen


    An all-optical quartz-enhanced photoacoustic spectroscopy system, based on the F-P demodulation, for trace gas detection in the open environment was proposed. In quartz-enhanced photoacoustic spectroscopy (QEPAS), an optical fiber Fabry-Perot method was used to replace the conventional electronic demodulation method. The photoacoustic signal was obtained by demodulating the variation of the Fabry-Perot cavity between the quartz tuning fork side and the fiber face. An experimental system was setup. The experiment for detection of water vapour in the open environment was carried on. A normalized noise equivalent absorption coefficient of 2.80 x 10(-7) cm(-1) x W x Hz(-1/2) was achieved. The result demonstrated that the sensitivity of the all-optical quartz-enhanced photoacoustic spectroscopy system is about 2.6 times higher than that of the conventional QEPAS system. The all-optical quartz-enhanced photoacoustic spectroscopy system is immune to electromagnetic interference, safe in flammable and explosive gas detection, suitable for high temperature and high humidity environments and realizable for long distance, multi-point and network sensing.

  4. Optical tool for salinity detection by remote sensing spectroscopy: application on Oran watershed, Algeria (United States)

    Abdellatif, Dehni; Mourad, Lounis


    Soil salinity is a complex problem that affects groundwater aquifers and agricultural lands in the semiarid regions. Remote sensing and spectroscopy database systems provide accuracy for salinity autodetection and dynamical delineation. Salinity detection techniques using polychromatic wavebands by field geocomputation and experimental data are time consuming and expensive. This paper presents an automated spectral detection and identification of salt minerals using a monochromatic waveband concept from multispectral bands-Landsat 8 Operational Land Imager (OLI) and Thermal InfraRed Sensor (TIRS) and spectroscopy United States Geological Survey database. For detecting mineral salts related to electrolytes, such as electronical and vibrational transitions, an integrated approach of salinity detection related to the optical monochromatic concept has been addressed. The purpose of this paper is to discriminate waveband intrinsic spectral similarity using the Beer-Lambert and Van 't Hoff laws for spectral curve extraction such as transmittance, reflectance, absorbance, land surface temperature, molar concentration, and osmotic pressure. These parameters are primordial for hydrodynamic salinity modeling and continuity identification using chemical and physical approaches. The established regression fitted models have been addressed for salt spectroscopy validation for suitable calibration and validation. Furthermore, our analytical tool is conducted for better decision interface using spectral salinity detection and identification in the Oran watershed, Algeria.

  5. Detection of Nitroaromatic and Peroxide Explosives in Air Using Infrared Spectroscopy: QCL and FTIR

    Directory of Open Access Journals (Sweden)

    Leonardo C. Pacheco-Londoño


    Full Text Available A methodology for processing spectroscopic information using a chemometrics-based analysis was designed and implemented in the detection of highly energetic materials (HEMs in the gas phase at trace levels. The presence of the nitroaromatic HEM 2,4-dinitrotoluene (2,4-DNT and the cyclic organic peroxide triacetone triperoxide (TATP in air was detected by chemometrics-enhanced vibrational spectroscopy. Several infrared experimental setups were tested using traditional heated sources (globar, modulated and nonmodulated FT-IR, and quantum cascade laser- (QCL- based dispersive IR spectroscopy. The data obtained from the gas phase absorption experiments in the midinfrared (MIR region were used for building the chemometrics models. Partial least-squares discriminant analysis (PLS-DA was used to generate pattern recognition schemes for trace amounts of explosives in air. The QCL-based methodology exhibited a better capacity of discrimination for the detected presence of HEM in air compared to other methodologies.

  6. Spectrum sensing of trace C(2)H(2) detection in differential optical absorption spectroscopy technique. (United States)

    Chen, Xi; Dong, Xiaopeng


    An improved algorithm for trace C(2)H(2) detection is presented in this paper. The trace concentration is accurately calculated by focusing on the absorption spectrum from the frequency domain perspective. The advantage of the absorption spectroscopy frequency domain algorithm is its anti-interference capability. First, the influence of the background noise on the minimum detectable concentration is greatly reduced. Second, the time-consuming preprocess of spectra calibration in the differential optical absorption spectroscopy technique is skipped. Experimental results showed the detection limit of 50 ppm is achieved at a lightpath length of 0.2 m. This algorithm can be used in real-time spectrum analysis with high accuracy.

  7. The Accuracy of Pulse Spectroscopy for Detecting Hypoxemia and Coexisting Methemoglobin or Carboxyhemoglobin. (United States)

    Kulcke, Axel; Feiner, John; Menn, Ingolf; Holmer, Amadeus; Hayoz, Josef; Bickler, Philip


    Pulse spectroscopy is a new noninvasive technology involving hundreds of wavelengths of visible and infrared light, enabling the simultaneous quantitation of multiple types of normal and dysfunctional hemoglobin. We evaluated the accuracy of a first-generation pulse spectroscopy system (V-Spec™ Monitoring System, Senspec, Germany) in measuring oxygen saturation (SpO2) and detecting carboxyhemoglobin (COHb) or methemoglobin (MetHb), alone or simultaneously, with hypoxemia. Nineteen volunteers were fitted with V-Spec probes on the forehead and fingers. A radial arterial catheter was placed for blood sampling during (1) hypoxemia with arterial oxygen saturations (SaO2) of 100% to 58.5%; (2) normoxia with MetHb and COHb increased to approximately 10%; (3) 10% COHb or MetHb combined with hypoxemia with SaO2 of 100% to 80%. Standard measures of pulse-oximetry performance were calculated: bias (pulse spectroscopy measured value - arterial measured value) mean ± SD and root-mean-square error (Arms). The SpO2 bias for SaO2 approximately 60% to 100% was 0.06% ± 1.30% and Arms of 1.30%. COHb bias was 0.45 ± 1.63, with an Arms of 1.69% overall, and did not degrade substantially during moderate hypoxemia. MetHb bias was 0.36 ± 0.80 overall and stayed small with hypoxemia. Arms was 0.88 and was Hypoxemia was also accurately detected by pulse spectroscopy at elevated levels of COHb. At elevated MetHb levels, a substantial negative bias developed, -10.3 at MetHb >10%. Pulse spectroscopy accurately detects hypoxemia, MetHb, and COHb. The technology also accurately detects these dysfunctional hemoglobins during hypoxemia. Future releases of this device may have an improved SpO2 algorithm that is more robust with methemoglobinemia.

  8. Erythrocyte membrane analysis for type II diabetes detection using Raman spectroscopy in high-wavenumber region (United States)

    Lin, Jinyong; Zeng, Yongyi; Lin, Juqiang; Wang, Jing; Li, Ling; Huang, Zufang; Li, Buhong; Zeng, Haishan; Chen, Rong


    Raman spectroscopy was employed to detect lipid variation occurring in type II diabetic erythrocyte membrane (EM) without using exogenous reagents. In high-wavenumber (HW) region, significant Raman spectral differences between diabetic and normal EM are observed at 2850, 2873, 2885, 2935, and 2965 cm-1, which are mainly related to lipid in EM. Based on principal component analysis, the diagnostic accuracy of HW region for diabetes detection is 98.8%, which is much higher than that of low-wavenumber region (82.9%). The results suggest that EM HW Raman region has great promise for the reagent-free and non-invasive detection of type II diabetes.

  9. Quantitative detection of pharmaceuticals using a combination of paper microfluidics and wavelength modulated Raman spectroscopy.

    Directory of Open Access Journals (Sweden)

    Derek Craig

    Full Text Available Raman spectroscopy has proven to be an indispensable technique for the identification of various types of analytes due to the fingerprint vibration spectrum obtained. Paper microfluidics has also emerged as a low cost, easy to fabricate and portable approach for point of care testing. However, due to inherent background fluorescence, combining Raman spectroscopy with paper microfluidics is to date an unmet challenge in the absence of using surface enhanced mechanisms. We describe the first use of wavelength modulated Raman spectroscopy (WMRS for analysis on a paper microfluidics platform. This study demonstrates the ability to suppress the background fluorescence of the paper using WMRS and the subsequent implementation of this technique for pharmaceutical analysis. The results of this study demonstrate that it is possible to discriminate between both paracetamol and ibuprofen, whilst, also being able to detect the presence of each analyte quantitatively at nanomolar concentrations.

  10. Photoacoustic Spectroscopy for Trace Vapor Detection and Standoff Detection of Explosives (United States)


    sensor, quantum cascade laser, MEMS, laser Doppler vibrometer , standoff, explosives detection 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF...Doppler vibrometer , standoff, explosives detection 1. INTRODUCTION There will always be a critical need for detection and identification of...solid or liquid, the expansion and contraction of the surface in synch with the excitation modulation can be measured with a piezoelectric transducer or

  11. Spatial Spectroscopy Approach for Detection of Internal Defect of Component without Zero-Position Sensors

    Directory of Open Access Journals (Sweden)

    Qizhou Wu


    Full Text Available Conventional approach to detect the internal defect of a component needs sensors to mark the “zero” positions, which is time-consuming and lowers down the detecting efficiency. In this study, we proposed a novelty approach that uses spatial spectroscopy to detect internal defect of objects without zero-position sensors. Specifically, the spatial variation wave of distance between the detecting source and object surface is analyzed, from which a periodical cycle is determined with the correlative approaches. Additionally, a wavelet method is adopted to reduce the noise of the periodic distance signal. This approach is validated by the ultrasound detection of a component with round cross section and elliptical shape in axis. The experimental results demonstrate that this approach greatly saves the time spent on the judgment of a complete cycle and improves the detecting efficiency of internal defect in the component. The approach can be expanded to other physical methods for noninvasive detection of internal defect, such as optical spectroscopy or X-ray scanning, and it can be used for hybrid medium, such as biological tissues.

  12. Spatially offset Raman spectroscopy for explosives detection through difficult (opaque) containers (United States)

    Maskall, Guy T.; Bonthron, Stuart; Crawford, David


    With the continuing threat to aviation security from homemade explosive devices, the restrictions on taking a volume of liquid greater than 100 ml onto an aircraft remain in place. From January 2014, these restrictions will gradually be reduced via a phased implementation of technological screening of Liquids, Aerosols and Gels (LAGs). Raman spectroscopy offers a highly sensitive, and specific, technique for the detection and identification of chemicals. Spatially Offset Raman Spectroscopy (SORS), in particular, offers significant advantages over conventional Raman spectroscopy for detecting and recognizing contents within optically challenging (Raman active) containers. Containers vary enormously in their composition; glass type, plastic type, thickness, reflectance, and pigmentation are all variable and cause an infinite range of absorbances, fluorescence backgrounds, Rayleigh backscattered laser light, and container Raman bands. In this paper we show that the data processing chain for Cobalt Light Systems' INSIGHT100 bottlescanner is robust to such variability. We discuss issues of model selection for the detection stage and demonstrate an overall detection rate across a wide range of threats and containers of 97% with an associated false alarm rate of 0.1% or lower.

  13. Dual-modal cancer detection based on optical pH sensing and Raman spectroscopy. (United States)

    Kim, Soogeun; Lee, Seung Ho; Min, Sun Young; Byun, Kyung Min; Lee, Soo Yeol


    A dual-modal approach using Raman spectroscopy and optical pH sensing was investigated to discriminate between normal and cancerous tissues. Raman spectroscopy has demonstrated the potential for in vivo cancer detection. However, Raman spectroscopy has suffered from strong fluorescence background of biological samples and subtle spectral differences between normal and disease tissues. To overcome those issues, pH sensing is adopted to Raman spectroscopy as a dual-modal approach. Based on the fact that the pH level in cancerous tissues is lower than that in normal tissues due to insufficient vasculature formation, the dual-modal approach combining the chemical information of Raman spectrum and the metabolic information of pH level can improve the specificity of cancer diagnosis. From human breast tissue samples, Raman spectra and pH levels are measured using fiber-optic-based Raman and pH probes, respectively. The pH sensing is based on the dependence of pH level on optical transmission spectrum. Multivariate statistical analysis is performed to evaluate the classification capability of the dual-modal method. The analytical results show that the dual-modal method based on Raman spectroscopy and optical pH sensing can improve the performance of cancer classification. (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

  14. Dual-modal cancer detection based on optical pH sensing and Raman spectroscopy (United States)

    Kim, Soogeun; Lee, Seung Ho; Min, Sun Young; Byun, Kyung Min; Lee, Soo Yeol


    A dual-modal approach using Raman spectroscopy and optical pH sensing was investigated to discriminate between normal and cancerous tissues. Raman spectroscopy has demonstrated the potential for in vivo cancer detection. However, Raman spectroscopy has suffered from strong fluorescence background of biological samples and subtle spectral differences between normal and disease tissues. To overcome those issues, pH sensing is adopted to Raman spectroscopy as a dual-modal approach. Based on the fact that the pH level in cancerous tissues is lower than that in normal tissues due to insufficient vasculature formation, the dual-modal approach combining the chemical information of Raman spectrum and the metabolic information of pH level can improve the specificity of cancer diagnosis. From human breast tissue samples, Raman spectra and pH levels are measured using fiber-optic-based Raman and pH probes, respectively. The pH sensing is based on the dependence of pH level on optical transmission spectrum. Multivariate statistical analysis is performed to evaluate the classification capability of the dual-modal method. The analytical results show that the dual-modal method based on Raman spectroscopy and optical pH sensing can improve the performance of cancer classification.

  15. [Research on detecting explosive content of 2, 4-dimitroanisole based on THz spectroscopy]. (United States)

    Wang, Gao; Xu, De-Gang; Yao, Jian-Quan


    In order to detect the content of a new kind of insensitive melting-cast explosive (DNAN), the system detected the THz characteristics wavelength of DNAN, and solved the content of DNAN by the Bill-Lambert law. Time coherent THz spectroscopy detection system was designed, in which the master system controlled stepper motor to get the micro-scanning of the photoelectric detector. The system parameters were calculated and derived for solving the content of DNAN, and THz characteristic spectrum of DNAN was obtained. Experiment used three methods to detect explosives samples with different content of DNAN, and the results show that the accuracy of this system is close to that of MINI-Z terahertz spectrometer currently broadly applied in THz spectroscopy detection equipment at home and abroad. On this basis, the optimization algorithm of characteristic absorption peak was designed, and by the origin software simulation analysis, it shows that the algorithm can further improve accuracy and stability of the detection system.

  16. Accelerated Detection of Viral Particles by Combining AC Electric Field Effects and Micro-Raman Spectroscopy

    Directory of Open Access Journals (Sweden)

    Matthew Robert Tomkins


    Full Text Available A detection method that combines electric field-assisted virus capture on antibody-decorated surfaces with the “fingerprinting” capabilities of micro-Raman spectroscopy is demonstrated for the case of M13 virus in water. The proof-of-principle surface mapping of model bioparticles (protein coated polystyrene spheres captured by an AC electric field between planar microelectrodes is presented with a methodology for analyzing the resulting spectra by comparing relative peak intensities. The same principle is applied to dielectrophoretically captured M13 phage particles whose presence is indirectly confirmed with micro-Raman spectroscopy using NeutrAvidin-Cy3 as a labeling molecule. It is concluded that the combination of electrokinetically driven virus sampling and micro-Raman based signal transduction provides a promising approach for time-efficient and in situ detection of viruses.

  17. Ultra-sensitive chemical vapor detection using micro-cavity photothermal spectroscopy. (United States)

    Hu, Juejun


    In this paper, I systematically investigated Micro-Cavity PhotoThermal Spectroscopy (MC-PTS), a novel technique for ultra-sensitive detection of chemical molecular species. I first derive the photothermal enhancement factor and noise characteristics of the technique using a generic theoretical model, followed by numerical analysis of a design example using chalcogenide glass micro-disk cavities. Guidelines for sensor material selection and device design are formulated based on the theoretical insight. The numerical analysis shows that this technique features a record photothermal enhancement factor of 10(4) with respect to conventional cavity-enhanced (multi-pass) infrared absorption spectroscopy, and is capable of detecting non-preconcentrated chemical vapor molecules down to the ppt level with a moderate cavity quality factor of 10(5) and a pump laser power of 0.1 W. Such performance qualifies this technique as one of the most sensitive methods for chemical vapor spectroscopic analysis.

  18. Gas detection with evanescent-wave quartz-enhanced photoacoustic spectroscopy (United States)

    Cao, Yingchun; Jin, Wei; Ho, Hoi Lut


    Evanescent-wave gas sensing with tapered optical fibers (TOFs) and quartz-enhanced photoacoustic spectroscopy (QEPAS) is reported. The evanescent field of TOFs with diameter down to sub-wavelength is utilized for photoacoustic excitation in photoacoustic spectroscopy. A quartz tuning fork (QTF) with resonant frequency about ~32.75 kHz is used to detect the generated pressure wave. A normalized noise equivalent absorption coefficient of 1.5×10-6 cm-1 W/√Hz is achieved for acetylene detection with a fiber taper with a waist diameter of 1.1 μm. It is found that QEPAS with TOFs of sub-wavelength diameters exhibit comparable sensitivities with open path QEPAS but with additional advantages of lower insertion loss, easier alignment, and multiplexing capability.

  19. Detection of internal quality in kiwi with time-domain diffuse reflectance spectroscopy


    Valero Ubierna, Constantino; Ruiz-Altisent, Margarita; Cubeddu, Rinaldo; Pifferi, Antonio; Taroni, Paola; Torricelli, Alessandro; Valentini, Gianluca; Johnson, David; Dover, Colin


    Time-domain diffuse reflectance spectroscopy (TRS), a medical sensing technique, was used to evaluate internal kiwi fruit quality. The application of this pulsed laser spectroscopic technique was studied as a new, possible non-destructive, method to detect optically different quality parameters: firmness, sugar content, and acidity. The main difference with other spectroscopic techniques is that TRS estimates separately and at the same time absorbed light and scattering inside the sample, at ...

  20. Quartz Enhanced Photoacoustic Spectroscopy for Detection of Improvised Explosive Devices and Precursors


    Roberto Viola; Nicola Liberatore; Domenico Luciani; Sandro Mengali


    A compact portable and standalone point sensor has been developed for the detection and identification of precursors of improvised explosive devices (IEDs) and to be part of a network of sensors for the discovery of hidden bomb factories in homeland security applications. The sensor is based on quartz enhanced photoacoustic spectroscopy (QEPAS), and it implements a broadly tunable external cavity quantum cascade laser source (EC-QCL). It makes use of an optical cell purposely designed with a ...

  1. Investigation of the Sensitivity of Transmission Raman Spectroscopy for Polymorph Detection in Pharmaceutical Tablets. (United States)

    Feng, Hanzhou; Bondi, Robert W; Anderson, Carl A; Drennen, James K; Igne, Benoît


    Polymorph detection is critical for ensuring pharmaceutical product quality in drug substances exhibiting polymorphism. Conventional analytical techniques such as X-ray powder diffraction and solid-state nuclear magnetic resonance are utilized primarily for characterizing the presence and identity of specific polymorphs in a sample. These techniques have encountered challenges in analyzing the constitution of polymorphs in the presence of other components commonly found in pharmaceutical dosage forms. Laborious sample preparation procedures are usually required to achieve satisfactory data interpretability. There is a need for alternative techniques capable of probing pharmaceutical dosage forms rapidly and nondestructively, which is dictated by the practical requirements of applications such as quality monitoring on production lines or when quantifying product shelf lifetime. The sensitivity of transmission Raman spectroscopy for detecting polymorphs in final tablet cores was investigated in this work. Carbamazepine was chosen as a model drug, polymorph form III is the commercial form, whereas form I is an undesired polymorph that requires effective detection. The concentration of form I in a direct compression tablet formulation containing 20% w/w of carbamazepine, 74.00% w/w of fillers (mannitol and microcrystalline cellulose), and 6% w/w of croscarmellose sodium, silicon dioxide, and magnesium stearate was estimated using transmission Raman spectroscopy. Quantitative models were generated and optimized using multivariate regression and data preprocessing. Prediction uncertainty was estimated for each validation sample by accounting for all the main variables contributing to the prediction. Multivariate detection limits were calculated based on statistical hypothesis testing. The transmission Raman spectroscopic model had an absolute prediction error of 0.241% w/w for the independent validation set. The method detection limit was estimated at 1.31% w/w. The

  2. Fourier Transform Infrared Spectroscopy: A Potential Technique for Noninvasive Detection of Spermatogenesis (United States)

    Gilany, Kambiz; Pouracil, Roudabeh Sadat Moazeni; Sadeghi, Mohammad Reza


    Background The seminal plasma is an excellent source for noninvasive detection of spermatogenesis. The seminal plasma of normospermic and azoospermic men has been analyzed for detection of spermatogenesis. Methods Optical spectroscopy (Attenuated Total Reflectance-Infrared spectroscopy (ATR-IR) and Fourier Transform infrared spectroscopy (FT-IR) has been used to analyze the seminal plasma and the metabolome of seminal plasma for detection of spermatogenesis. Results The seminal plasma of normospermic and azoospermic men has been analyzed by ATR-IR. The results show that there is a pattern variation in the azoospermic men compared to normospermic men. However, the seminal plasma is too complex to show significant pattern variation. Therefore, the metabolome which is a subcomponent of the seminal plasma was analyzed. The seminal plasma metabolome of normospermic and azoospermic men has been analyzed by FT-IR. A significant pattern change was observed. The data combined with chemometrics analysis showed that significant changes are observed at metabolome level. Conclusion We suggest that FT-IR has the potential as a diagnostic tool instead of testicular biopsy. PMID:24523955

  3. Detection of lead in paint samples synthesized locally using-laser-induced breakdown spectroscopy. (United States)

    Gondal, Mohammed A; Nasr, Mohamed M; Ahmed, Mubarak M; Yamani, Zain H; Alsalhi, M S


    A laser-induced breakdown spectroscopy (LIBS) setup was developed to detect lead and other toxic contaminants such as chromium in paint emulsion samples manufactured in Saudi Arabia. The lead concentration detected in these samples was in the 327.2-755.3 ppm range, which is much higher than the safe permissible limit set by Saudi regulatory agencies. Similarly, chromium concentration (98.1-149.5 ppm) was found in high concentrations as well. The results obtained with our LIBS setup are comparable with the sample analysis utilizing a standard technique such as ICP, and our LIBS results are comparable to ICP with in an accuracy limit of 2-4 %.

  4. Laser induced breakdown spectroscopy for heavy metal detection in a sand matrix (United States)

    Michel, Anna P. M.; Sonnichsen, Frederick


    Sediments in many locations, including harbors and coastal areas, can become contaminated and polluted, for example, from anthropogenic inputs, shipping, human activities, and poor waste management. Sampling followed by laboratory analysis has been the traditional methodology for such analysis. In order to develop rapid methodologies for field analysis of sediment samples, especially for metals analyses, we look to Laser Induced Breakdown Spectroscopy as an option. Here through laboratory experiments, we demonstrate that dry sand samples can be rapidly analyzed for the detection of the heavy metals chromium, zinc, lead, and copper. We also demonstrate that cadmium and nickel are detectable in sand matrices at high concentrations.

  5. Detection of nitric oxide in exhaled air using cavity enhanced absorption spectroscopy (United States)

    Medrzycki, R.; Wojtas, J.; Rutecka, B.; Bielecki, Z.


    The article describes an application one of the most sensitive optoelectronic method - Cavity Enhanced Absorption Spectroscopy in investigation of nitric oxide in exhaled breath. Measurement of nitric oxide concentration in exhaled breath is a quantitative, non-invasive, simple, and safe method of respiratory inflammation and asthma diagnosis. For detection of nitric oxide by developed optoelectronic sensor the vibronic molecular transitions were used. The wavelength ranges of these transitions are situated in the infrared spectral region. A setup consists of the optoelectronic nitric oxide sensor integrated with sampling and sample conditioning unit. The constructed detection system provides to measure nitric oxide in a sample of 0-97% relative humidity.

  6. Wavelength modulation spectroscopy--digital detection of gas absorption harmonics based on Fourier analysis. (United States)

    Mei, Liang; Svanberg, Sune


    This work presents a detailed study of the theoretical aspects of the Fourier analysis method, which has been utilized for gas absorption harmonic detection in wavelength modulation spectroscopy (WMS). The lock-in detection of the harmonic signal is accomplished by studying the phase term of the inverse Fourier transform of the Fourier spectrum that corresponds to the harmonic signal. The mathematics and the corresponding simulation results are given for each procedure when applying the Fourier analysis method. The present work provides a detailed view of the WMS technique when applying the Fourier analysis method.

  7. Noninvasive detection of intracerebral hemorrhage using near-infrared spectroscopy (NIRS) (United States)

    Hennes, Hans-Juergen; Lott, Carsten; Windirsch, Michael; Hanley, Daniel F.; Boor, Stephan; Brambrink, Ansgar; Dick, Wolfgang


    Intracerebral Hemorrhage (IH) is an important cause of secondary brain injury in neurosurgical patients. Early identification and treatment improve neurologic outcome. We have tested Near Infrared Spectroscopy (NIRS) as an alternative noninvasive diagnostic tool compared to CT-Scans to detect IH. We prospectively studied 212 patients with neurologic symptoms associated with intracranial pathology before performing a CT-scan. NIRS signals indicated pathologies in 181 cases (sensitivity 0.96; specificity 0.29). In a subgroup of subdural hematomas NIRS detected 45 of 46 hematomas (sensitivity 0.96; specificity 0.79). Identification of intracerebral hemorrhage using NIRS has the potential to allow early treatment, thus possibly avoiding further injury.

  8. Detection of Occupancy Differences in Methane Gas Hydrates by Raman Spectroscopy

    DEFF Research Database (Denmark)

    Hansen, Susanne Brunsgaard; Berg, Rolf W.; Stenby, Erling Halfdan


    Gas hydrates are solid crystalline compounds, which grow from micro crystals to bulk masses resembling ordinary slush, snow or ice. Since gas hydrates exist at elevated pressures at temperatures well above the ice point, they can cause severe problems under production and transportation...... of reservoir fluids due to plugging. Methods to prevent hydrate formation are in use, e.g. by injection of inhibitors. From environmental and security points of view an easy way to detect hydrate formation is of interest. We have tried to detect methane hydrate formation by use of Raman spectroscopy....

  9. Precision of Raman Spectroscopy Measurements in Detection of Microcalcifications in Breast Needle Biopsies (United States)

    Saha, Anushree; Barman, Ishan; Dingari, Narahara Chari; Galindo, Luis H.; Sattar, Abdus; Liu, Wendy; Plecha, Donna; Klein, Nina; Dasari, Ramachandra Rao; Fitzmaurice, Maryann


    Microcalcifications are an early mammographic sign of breast cancer and a target for stereotactic breast needle biopsy. We developed Raman spectroscopy decision algorithms to detect breast microcalcifications, based on fit coefficients (FC) derived by modeling tissue Raman spectra as a linear combination of the Raman spectra of 9 chemical and morphologic components of breast tissue. However, little or no information is available on the precision of such measurements and its effect on the ability of Raman spectroscopy to make predictions for breast microcalcification detection. Here we report the precision, that is, the closeness of agreement between replicate Raman spectral measurements - and the model FC derived from them - obtained ex vivo from fresh breast biopsies from patients undergoing stereotactic breast needle biopsy, using a compact clinical Raman system. The coefficients of variation of the model FC averaged 0.03 for normal breast tissue sites, 0.12 for breast lesions without and 0.22 for breast lesions with microcalcifications. Imprecision in the FC resulted in diagnostic discordance among replicates only for line-sitters, that is, tissue sites with FC values near the decision line or plane. The source of this imprecision and their implications for the use of Raman spectroscopy for guidance of stereotactic breast biopsies for microcalcifications are also discussed. In summary, we conclude that the precision of Raman spectroscopy measurements in breast tissue obtained using our compact clinical system is more than adequate to make accurate and repeatable predictions of microcalcifications in breast tissue using decision algorithms based on model FC. This provides strong evidence of the potential of Raman spectroscopy guidance of stereotactic breast needle biopsies for microcalcifications. PMID:22746329

  10. Terahertz spectroscopy and detection of brain tumor in rat fresh-tissue samples (United States)

    Yamaguchi, S.; Fukushi, Y.; Kubota, O.; Itsuji, T.; Yamamoto, S.; Ouchi, T.


    Terahertz (THz) spectroscopy and imaging of biomedical samples is expected to be an important application of THz analysis techniques. Identification and localization of tumor tissue, imaging of biological samples, and analysis of DNA by THz spectroscopy have been reported. THz time-domain spectroscopy (TDS) is useful for obtaining the refractive index over a broad frequency range. However, THz-TDS spectra of fresh tissue samples are sensitive to procedures such as sample preparation, and a standardized measurement protocol is required. Therefore, in this work, we establish a protocol for measurements of THz spectra of fresh tissue and demonstrate reliable detection of rat brain tumor tissue. We use a reflection THz-TDS system to measure the refractive index spectra of the samples mounted on a quartz plate. The tissue samples were measured immediately after sectioning to avoid sample denaturalization during storage. Special care was taken in THz data processing to eliminate parasitic reflections and reduce noise. The error level in our refractive index measurements was as low as 0.02 in the frequency range 0.8-1.5 THz. With increasing frequency, the refractive index in the tumor and normal regions monotonically decreased, similarly to water, and it was 0.02 higher in the tumor regions. The spectral data suggest that the tumor regions have higher water content. Hematoxylin-eosin stained images showed that increased cell density was also responsible for the observed spectral features. A set of samples from 10 rats showed consistent results. Our results suggest that reliable tumor detection in fresh tissue without pretreatment is possible with THz spectroscopy measurements. THz spectroscopy has the potential to become a real-time in vivo diagnostic method.

  11. Neural networks improve brain cancer detection with Raman spectroscopy in the presence of light artifacts (United States)

    Jermyn, Michael; Desroches, Joannie; Mercier, Jeanne; St-Arnaud, Karl; Guiot, Marie-Christine; Petrecca, Kevin; Leblond, Frederic


    It is often difficult to identify cancer tissue during brain cancer (glioma) surgery. Gliomas invade into areas of normal brain, and this cancer invasion is frequently not detected using standard preoperative magnetic resonance imaging (MRI). This results in enduring invasive cancer following surgery and leads to recurrence. A hand-held Raman spectroscopy is able to rapidly detect cancer invasion in patients with grade 2-4 gliomas. However, ambient light sources can produce spectral artifacts which inhibit the ability to distinguish between cancer and normal tissue using the spectral information available. To address this issue, we have demonstrated that artificial neural networks (ANN) can accurately classify invasive cancer versus normal brain tissue, even when including measurements with significant spectral artifacts from external light sources. The non-parametric and adaptive model used by ANN makes it suitable for detecting complex non-linear spectral characteristics associated with different tissues and the confounding presence of light artifacts. The use of ANN for brain cancer detection with Raman spectroscopy, in the presence of light artifacts, improves the robustness and clinical translation potential for intraoperative use. Integration with the neurosurgical workflow is facilitated by accounting for the effect of light artifacts which may occur, due to operating room lights, neuronavigation systems, windows, or other light sources. The ability to rapidly detect invasive brain cancer under these conditions may reduce residual cancer remaining after surgery, and thereby improve patient survival.

  12. Raman spectroscopy method for subsurface detection of food powders through plastic layers (United States)

    Dhakal, Sagar; Chao, Kuanglin; Qin, Jianwei; Schmidt, Walter F.; Kim, Moon S.; Chan, Diane E.; Bae, Abigail


    Proper chemical analyses of materials in sealed containers are important for quality control purpose. Although it is feasible to detect chemicals at top surface layer, it is relatively challenging to detect objects beneath obscuring surface. This study used spatially offset Raman spectroscopy (SORS) method to detect urea, ibuprofen and acetaminophen powders contained within one or more (up to eight) layers of gelatin capsules to demonstrate subsurface chemical detection and identification. A 785 nm point-scan Raman spectroscopy system was used to acquire spatially offset Raman spectra for an offset range of 0 to 10 mm from the surfaces of 24 encapsulated samples, using a step size of 0.1 mm to obtain 101 spectral measurements per sample. With increasing offset distance, the fraction of information from the deeper subsurface material increased compared to that from the top surface material. The series of measurements was analyzed to differentiate and identify the top surface and subsurface materials. Containing mixed contributions from the powder and capsule, the SORS of each sample was decomposed using self modeling mixture analysis (SMA) to obtain pure component spectra of each component and corresponding components were identified using spectral information divergence values. Results show that SORS technique together with SMA method has a potential for non-invasive detection of chemicals at deep subsurface layer.

  13. NIR spectroscopy with multivariate calibration and lock-in amplification to detect chemicals concealed behind fabrics (United States)

    Saleem, Aamer; Canal, Céline; Hutchins, David A.; Green, Roger J.


    The detection of specific chemicals when concealed behind a layer of clothing is reported using near infrared (NIR) spectroscopy. Concealment modifies the spectrum of a particular chemical when recorded at stand-off ranges of three meters in a diffuse reflection experiment. The subsequent analysis to identify a particular chemical has involved employing calibration models such as principal component regression (PCR) and partial least squares regression (PLSR). Additionally, detection has been attempted with good results using neural networks. The latter technique serves to overcome nonlinearities in the calibration/training dataset, affording more robust modelling. Finally, lock-in amplification of spectral data collected in through-transmission arrangement has been shown to allow detection at SNR as low as -60dB. The work has been shown to both allow detection of specific chemicals concealed behind a single intervening layer of fabric material, and to estimate the concentration of certain liquids.

  14. Early detection of emerging street drugs by near infrared spectroscopy and chemometrics. (United States)

    Risoluti, R; Materazzi, S; Gregori, A; Ripani, L


    Near-infrared spectroscopy (NIRs) is spreading as the tool of choice for fast and non-destructive analysis and detection of different compounds in complex matrices. This paper investigated the feasibility of using near infrared (NIR) spectroscopy coupled to chemometrics calibration to detect new psychoactive substances in street samples. The capabilities of this approach in forensic chemistry were assessed in the determination of new molecules appeared in the illicit market and often claimed to contain "non-illegal" compounds, although exhibiting important psychoactive effects. The study focused on synthetic molecules belonging to the classes of synthetic cannabinoids and phenethylamines. The approach was validated comparing results with officials methods and has been successfully applied for "in site" determination of illicit drugs in confiscated real samples, in cooperation with the Scientific Investigation Department (Carabinieri-RIS) of Rome. The achieved results allow to consider NIR spectroscopy analysis followed by chemometrics as a fast, cost-effective and useful tool for the preliminary determination of new psychoactive substances in forensic science. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Non-targeted detection of milk powder adulteration using Raman spectroscopy and chemometrics: melamine case study. (United States)

    Karunathilaka, Sanjeewa R; Farris, Samantha; Mossoba, Magdi M; Moore, Jeffrey C; Yakes, Betsy Jean


    Raman spectroscopy in combination with chemometrics was explored as a rapid, non-targeted screening method for the detection of milk powder (MP) adulteration using melamine as an example contaminant. Raman spectroscopy and an unsupervised pattern-recognition method, principal component analysis (PCA), allowed for the differentiation of authentic MPs from adulterated ones at concentrations > 1.0% for dry-blended (DB) samples and > 0.30% for wet-blended (WB) ones. Soft independent modelling of class analogy (SIMCA), a supervised pattern-recognition method, was also used to classify test samples as adulterated or authentic. Combined statistics at a 97% confidence level from the SIMCA models correctly classified adulteration of MP with melamine at concentrations ≥ 0.5% for DB samples and ≥ 0.30% for WB ones, while no false-positives from authentic MPs were found when the spectra in the 600-700 cm(-)(1) range were pre-processed using standard normal variate (SNV) followed by a gap-segment derivatisation. The combined technique of Raman spectroscopy and chemometrics proved to be a useful tool for the rapid and cost-efficient non-targeted detection of adulteration in MP at per cent spiking levels.

  16. [Study on Soil Elements Detection with Laser-Induced Breakdown Spectroscopy: A Review]. (United States)

    Yu, Ke-qiang; Zhao, Yan-ru; Liu, Fei; Peng, Ji-yu; He, Yong


    Laser-induced breakdown spectroscopy (LIBS), as a kind of atomic emission spectroscopy, has been considered to be a future new tool for chemical analysis due to its unique features, such as no need of sample preparation, stand-off or remote analysis. What's more it can achieve fast and multi-element analysis. Therefore, LIBS technology is regarded as a future "SurperStar" in the field of chemical analysis and green analytical techniques. At present, rapid and accurate detection and prevention of soil contamination (mainly in pollutants of heavy metals and organic matter) is deemed to be a concerned and serious central issue in modern agriculture and agricultural sustainable development. In this paper, the reseach achievements and trends of soil elements detection based on LIBS technology were being reviewed. The structural composition and foundmental of LIBS system is first briefly introduced. And the paper offers a review of on LIBS applications and fruits including the detection and analysis of major element, nutrient element and heavy metal element. Simultaneously, some studies on soil related metials and fields are briefly stated. The research tendency and developing prospects of LIBS in soil detection are presented at last.

  17. Aspects of the Application of Cavity Enhanced Spectroscopy to Nitrogen Oxides Detection

    Directory of Open Access Journals (Sweden)

    Zbigniew Bielecki


    Full Text Available This article presents design issues of high-sensitive laser absorption spectroscopy systems for nitrogen oxides (NOx detection. Examples of our systems and their investigation results are also described. The constructed systems use one of the most sensitive methods, cavity enhanced absorption spectroscopy (CEAS. They operate at different wavelength ranges using a blue—violet laser diode (410 nm as well as quantum cascade lasers (5.27 µm and 4.53 µm. Each of them is configured as a one or two channel measurement device using, e.g., time division multiplexing and averaging. During the testing procedure, the main performance features such as detection limits and measurements uncertainties have been determined. The obtained results are 1 ppb NO2, 75 ppb NO and 45 ppb N2O. For all systems, the uncertainty of concentration measurements does not exceed a value of 13%. Some experiments with explosives are also discussed. A setup equipped with a concentrator of explosives vapours was used. The detection method is based either on the reaction of the sensors to the nitrogen oxides directly emitted by the explosives or on the reaction to the nitrogen oxides produced during thermal decomposition of explosive vapours. For TNT, PETN, RDX and HMX a detection limit better than 1 ng has been achieved.

  18. On the detection of single bond ruptures in dynamic force spectroscopy by AFM. (United States)

    Karácsony, Orsolya; Akhremitchev, Boris B


    Force spectroscopy is a novel tool in physical chemistry and biophysics. This methodology is aimed at providing kinetic parameters of dissociation at a single-molecule level by rupturing molecular bonds subjected to different loading rates. One persistent problem in the implementation of this methodology is a question about the single-bond nature of the rupture events detected in experiments based on atomic force microscopy. Here we address this question by considering the probability that the nearly simultaneous rupture of two molecular bonds might appear as a single bond rupture in the experimental data, complicating the data analysis and contributing to systematic errors in the extracted kinetic parameters. An approximate analytical model predicts that such events might be common in experiments employing soft cantilever force sensors and short tethers to immobilize the interacting molecules. These findings are confirmed by a more elaborate numerical model providing valuable guidelines on performing single-molecule force spectroscopy experiments. © 2011 American Chemical Society

  19. Noninvasive detection of temozolomide in brain tumor xenografts by magnetic resonance spectroscopy

    DEFF Research Database (Denmark)

    Kato, Y.; Holm, David Alberg; Okollie, B.


    detection of drug directly in the tumor can be critically important for accessing, predicting, and eventually improving effectiveness of therapy. In this study, in vivo magnetic resonance spectroscopy (MRS) was used to detect an anticancer agent, temozolomide (TMZ), in vivo in murine xenotransplants of U87......MG human brain cancer. Dynamic magnetic resonance imaging (MRI) with the low-molecular-weight contrast agent, gadolinium diethylenetriaminepentaacetic acid (GdDTPA), was used to evaluate tumor vascular parameters. Carbon-13-labeled TMZ ([C-13]TMZ, 99%) was intraperitoneally administered at a dose...... experiments demonstrated slower recovery of MRI signal following an intravenous bolus injection of GdDTPA, higher vascular flow and volume obtained by T-2*-weighted MRI, as well as enhanced uptake of the contrast agent in the brain tumor compared with normal brain detected by T-1-weighted MRI. These data...

  20. Detection of multiple chemicals based on external cavity quantum cascade laser spectroscopy (United States)

    Sun, Juan; Ding, Junya; Liu, Ningwu; Yang, Guangxiang; Li, Jingsong


    A laser spectroscopy system based on a broadband tunable external cavity quantum cascade laser (ECQCL) and a mini quartz crystal tuning fork (QCTF) detector was developed for standoff detection of volatile organic compounds (VOCs). The self-established spectral analysis model based on multiple algorithms for quantitative and qualitative analysis of VOC components (i.e. ethanol and acetone) was detailedly investigated in both closed cell and open path configurations. A good agreement was obtained between the experimentally observed spectra and the standard reference spectra. For open path detection of VOCs, the sensor system was demonstrated at a distance of 30 m. The preliminary laboratory results show that standoff detection of VOCs at a distance of over 100 m is very promising.

  1. Sensitive and selective detection of OH radicals using Faraday rotation spectroscopy at 2.8 µm. (United States)

    Zhao, Weixiong; Wysocki, Gerard; Chen, Weidong; Fertein, Eric; Le Coq, David; Petitprez, Denis; Zhang, Weijun


    We report on the development of a Faraday rotation spectroscopy (FRS) instrument using a DFB diode laser operating at 2.8 µm for the hydroxyl (OH) free radical detection. The highest absorption line intensity and the largest gJ value make the Q (1.5) double lines of the 2Π3/2 state (υ = 1 ← 0) at 2.8 µm clearly the best choice for sensitive detection in the infrared region by FRS. The prototype instrument shows shot-noise dominated performance and, with an active optical pathlength of only 25 cm and a lock-in time constant of 100 ms, achieves a 1σ detection limit of 8.2 × 10(8) OH radicals/cm3.

  2. Ultrasensitive detection of genetically modified plants by fluorescence cross-correlation spectroscopy (United States)

    Li, Junfeng; Xing, Da; Chen, Tongsheng; Liu, Jinfeng


    In this study, a novel method for the direct detection of GMP without amplified by the general method of PCR is firstly presented and proved by experiments. In our method, fluorescence correlation spectroscopy, cleaving nucleic acid by restriction endonuclease and two nucleic acid probe hybridization techniques are combined to distinguish the caulifiower mosaic virus (CaMV) 35S promoter and determine whether samples contain genetically modified components. The detection principle is as follows: firstly two restriction endonucleases FOKI and BsrDlare used to cleave the genomic DNA and the 169bp fragments of CaMV 35S promoter are retrieved; secondly, two nucleic acid probes labeled by Rhodamine Green and y5 dyes respectively hybridize with cleaved 169bp fragments of CaMV 35S promoter; thirdly, the hybridization products simultaneously with two dye-labeled probes are detected by fluorescence cross-correlation spectroscopy and GMP is distinguished. As the detection and analysis by FCS can be performed at the level of single molecule, there is no need for any type of amplification. Genetically modified tobaccos are measured by this method. The results indicate this method can detect CaMV 35S promoter of GMP exactly and the sensitivity can be down to 3.47X10 -10M. Because no any type of amplification is involved, this method can avoid the non-specffic amplification and false-positive problems of PCR, Due to its high-sensitivity, simplicity, reliability and little need for sample amounts, this method promises to be a highly effective detection method for GMP.

  3. High sensitivity non-invasive detection of calcifications deep inside biological tissue using Transmission Raman Spectroscopy. (United States)

    Ghita, Adrian; Matousek, Pavel; Stone, Nick


    The aim of this research was to develop a novel approach to probe non-invasively the composition of inorganic chemicals buried deep in large volume biological samples. The method is based on advanced Transmission Raman Spectroscopy (TRS) permitting chemical specific detection within a large sampling volume. The approach could be beneficial to chemical identification of the breast calcifications detected during mammographic X-ray procedures. The chemical composition of a breast calcification reflects the pathology of the surrounding tissue, malignant or benign and potentially the grade of malignancy. However, this information is not available from mammography, leading to excisional biopsy and histopathological assessment for a definitive diagnosis. Here we present, for the first time, a design of a new high performance deep Raman instrument and demonstrate its capability to detect type II calcifications (calcium hydroxyapatite) at clinically relevant concentrations and depths of around 40 mm in phantom tissue. This is around double the penetration depth achieved with our previous instrument design and around two orders of magnitude higher than that possible when using conventional Raman spectroscopy. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. [Detection of benzoyl peroxide in wheat flour by NIR diffuse reflectance spectroscopy technique]. (United States)

    Zhang, Zhi-yong; Li, Gang; Liu, Hai-xue; Lin, Ling; Zhang, Bao-ju; Wu, Xiao-rong


    Adding benzoyl peroxide (BPO) into wheat flour was prohibited by the relevant government departments since May 1, 2011. And it is of great importance to detect BPO additive amount in wheat flour quickly and accurately. Part of BPO which was added into wheat flour will be deoxidized into benzoic acid, and this make it complex to detect the original BPO additive amount. The objective of the present research is to investigate the potential of NIR diffuse reflectance spectroscopy as a way for measurement of BPO original adding amount in wheat flour. A total of 133 wheat flour samples were prepared by adding different content of BPO into pure wheat flour. Spectra data were obtained by NIR spectrometer and then denoised by wavelet transform. Ninety seven samples were taken as calibration set and other 36 samples as prediction set. Partial least squares regression (PLSR) was applied to establish the calibration model between BPO original adding contents and the spectra data. The determination coefficient of model for the calibration set is 0.8901, and root mean squared error of calibration (RMSEC) is 40.85 mg x kg(-1). The determination coefficient for the prediction set is 0.8865, and root mean squared error of prediction (RMSEP) is 44.69 mg x kg(-1). The result indicates that it is feasible to detect the BPO adding contents in wheat flour by NIR diffuse reflectance spectroscopy technique and this technique has the potential to measure some other additives in food.

  5. Detection of molecular changes induced by antibiotics in Escherichia coli using vibrational spectroscopy (United States)

    Xuan Nguyen, N. T.; Sarter, Samira; Hai Nguyen, N.; Daniel, Philippe


    This study aimed to test Raman (400-1800 cm- 1) and Infra-red (1900-500 cm- 1) spectroscopies followed by statistical analysis (principal component analysis) to detect molecular changes induced by antibiotics (ampicillin, cefotaxime - cell wall synthesis inhibitors, tetracycline - protein synthesis inhibitor, ciprofloxacin - DNA synthesis inhibitor) against Escherichia coli TOP10. In case of ampicillin and cefotaxime, a decrease in protein bands in both Raman (1240, 1660 cm- 1), and IR spectra (1230, 1530, 1630 cm- 1), and an increase in carbohydrate bands (1150, 1020 cm- 1) in IR spectra were observed. Tetracycline addition caused an increase in nucleic acid bands (775, 1478, 1578 cm- 1), a sharp decrease in phenylalanine (995 cm- 1) in Raman spectra and the amide I and amide II bands (1630, 1530 cm- 1) in IR spectra, an increase in DNA in both Raman (1083 cm- 1) and IR spectra (1080 cm- 1). Regarding ciprofloxacin, an increase in nucleic acids (775, 1478, 1578 cm- 1) in Raman spectra and in protein bands (1230, 1520, 1630 cm- 1), in DNA (1080 cm- 1) in IR spectra were detected. Clear discrimination of antibiotic-treated samples compared to the control was recorded, showing that Raman and IR spectroscopies, coupled to principal component analysis for data, could be used to detect molecular modifications in bacteria exposed to different classes of antibiotics. These findings contribute to the understanding of the mechanisms of action of antibiotics in bacteria.

  6. [The error analysis and experimental verification of laser radar spectrum detection and terahertz time domain spectroscopy]. (United States)

    Liu, Wen-Tao; Li, Jing-Wen; Sun, Zhi-Hui


    Terahertz waves (THz, T-ray) lie between far-infrared and microwave in electromagnetic spectrum with frequency from 0.1 to 10 THz. Many chemical agent explosives show characteristic spectral features in the terahertz. Compared with conventional methods of detecting a variety of threats, such as weapons and chemical agent, THz radiation is low frequency and non-ionizing, and does not give rise to safety concerns. The present paper summarizes the latest progress in the application of terahertz time domain spectroscopy (THz-TDS) to chemical agent explosives. A kind of device on laser radar detecting and real time spectrum measuring was designed which measures the laser spectrum on the bases of Fourier optics and optical signal processing. Wedge interferometer was used as the beam splitter to wipe off the background light and detect the laser and measure the spectrum. The result indicates that 10 ns laser radar pulse can be detected and many factors affecting experiments are also introduced. The combination of laser radar spectrum detecting, THz-TDS, modern pattern recognition and signal processing technology is the developing trend of remote detection for chemical agent explosives.

  7. Saliva surface-enhanced Raman spectroscopy for noninvasive optical detection of nasopharyngeal cancer (United States)

    Lin, Xueliang; Ge, Xiaosong; Xu, Zhihong; Zheng, Zuci; Huang, Wei; Hong, Quanxing; Lin, Duo


    The early cancer detection is of great significance to increase the patient's survival rate and reduce the risk of cancer development. Surface enhanced Raman spectroscopy (SERS) technique, a rapid, convenient, nondestructive optical detection method, can provide a characteristic "fingerprint" information of target substances, even achieving single molecule detection. Its ultra-high detection sensitivity has made it become one of the most potential biochemical detection methods. Saliva, a multi-constituent oral fluid, contains the bio-markers which is capable of reflecting the systemic health condition of human, showing promising potential as an effect medium for disease monitoring. Compared with the serum samples, the collection and processing of saliva is safer, more convenient and noninvasive. Thus, saliva test is becoming the hotspot issues of the noninvasive cancer research field. This review highlights and analyzes current application progress within the field of SERS saliva test in cancer detection. Meanwhile, the primary research results of SERS saliva for the noninvasive differentiation of nasopharyngeal cancer, normal and rhinitis obtained by our group are shown.

  8. Portable fluorescence spectroscopy platform for Huanglongbing (HLB) citrus disease in situ detection (United States)

    Mota, Alessandro D.; Rossi, Giuliano; de Castro, Guilherme Cunha; Ortega, Tiago A.; de Castro N., Jarbas C.


    In this work, the development of a portable fluorescence spectroscopy platform for Huanglongbing (HLB) citrus disease in situ detection is presented. The equipment consists of an excitation blue LED light source, a commercial miniature spectrometer and embedded software. Measurements of healthy, HLB-symptomatic and HLB-asymptomatic citrus leafs were performed. Leafs were excited with the blue LED and their fluorescence spectra collected. Embedded electronics and software were responsible for the spectrum processing and classification via partial least squares regression. Global success rates above 80% and 100% distinction of healthy and HLB-symptomatic leafs were obtained.

  9. Optical-fiber-based laser-induced breakdown spectroscopy for detection of early caries (United States)

    Sasazawa, Shuhei; Kakino, Satoko; Matsuura, Yuji


    A laser-induced breakdown spectroscopy (LIBS) system targeting for the in vivo analysis of tooth enamel is described. The system is planned to enable real-time analysis of teeth during laser dental treatment by utilizing a hollow optical fiber that transmits both Q-switched Nd:YAG laser light for LIBS and infrared Er:YAG laser light for tooth ablation. The sensitivity of caries detection was substantially improved by expanding the spectral region under analysis to ultraviolet (UV) light and by focusing on emission peaks of Zn in the UV region. Subsequently, early caries were distinguished from healthy teeth with accuracy rates above 80% in vitro.

  10. Raman Spectroscopy as a Potential Tool for Detection of Brucella spp. in Milk (United States)

    Meisel, Susann; Stöckel, Stephan; Elschner, Mandy; Melzer, Falk; Popp, Jürgen


    Detection of Brucella, causing brucellosis, is very challenging, since the applied techniques are mostly time-demanding and not standardized. While the common detection system relies on the cultivation of the bacteria, further classical typing up to the biotype level is mostly based on phenotypic or genotypic characteristics. The results of genotyping do not always fit the existing taxonomy, and misidentifications between genetically closely related genera cannot be avoided. This situation gets even worse, when detection from complex matrices, such as milk, is necessary. For these reasons, the availability of a method that allows early and reliable identification of possible Brucella isolates for both clinical and epidemiological reasons would be extremely useful. We evaluated micro-Raman spectroscopy in combination with chemometric analysis to identify Brucella from agar plates and directly from milk: prior to these studies, the samples were inactivated via formaldehyde treatment to ensure a higher working safety. The single-cell Raman spectra of different Brucella, Escherichia, Ochrobactrum, Pseudomonas, and Yersinia spp. were measured to create two independent databases for detection in media and milk. Identification accuracies of 92% for Brucella from medium and 94% for Brucella from milk were obtained while analyzing the single-cell Raman spectra via support vector machine. Even the identification of the other genera yielded sufficient results, with accuracies of >90%. In summary, micro-Raman spectroscopy is a promising alternative for detecting Brucella. The measurements we performed at the single-cell level thus allow fast identification within a few hours without a demanding process for sample preparation. PMID:22660699

  11. Detecting alterations of glucose and lipid components in human serum by near-infrared Raman spectroscopy

    Directory of Open Access Journals (Sweden)

    Rita de Cássia Fernandes Borges

    Full Text Available Introduction Raman spectroscopy may become a tool for the analysis of glucose and triglycerides in human serum in real time. This study aimed to detect spectral differences in lipid and glucose components of human serum, thus evaluating the feasibility of Raman spectroscopy for diagnostic purposes. Methods A total of 44 samples of blood serum were collected from volunteers and submitted for clinical blood biochemical analysis. The concentrations of glucose, cholesterol, triglycerides, and low-density and high-density lipoproteins (LDL and HDL were obtained using standard biochemical assays. Serum samples were placed in Eppendorf tubes (200 µL, kept cooled (5 °C and analyzed with near-infrared Raman spectroscopy (830 nm, 250 mW, 50 s accumulation. The mean spectra of serum with normal or altered concentrations of each parameter were compared to determine which Raman bands were related to the differences between these two groups. Results Differences in peak intensities of altered sera compared to normal ones depended on the parameter under analysis: for glucose, peaks were related to glucose; for lipid compounds the main changes occurred in the peaks related to cholesterol, lipids (mainly triolein and proteins. Principal Components Analysis discriminated altered glucose, cholesterol and triglycerides from the normal serum based on the differences in the concentration of these compounds. Conclusion Differences in the peak intensities of selected Raman bands could be seen in normal and altered blood serum samples, and may be employed as a means of diagnosis in clinical analysis.

  12. The performance of multimodal hyperspectral spectroscopy in the detection of precancerous cervical lesions (United States)

    Trahmono; Lusiana, N.; Indarti, J.


    The aim of this study was to compare the performance of multimodal hyperspectral spectroscopy (MHS), which combines fluorescence and reflectance spectroscopy, with that of conventional laboratory-based screening tests, such as the Papanicolaou (Pap) smear test and human papilloma virus (HPV) DNA test, for detecting precancerous lesions of the cervix. The study utilized a cross-sectional design, and the kappa test was used in the analytical assessment. MHS scans were obtained from a sample of 70 consecutive patients, followed by sample collection for Pap and HPV DNA analysis and colposcopy referral, if indicated. Of the 70 patients evaluated, the results of cervical spectroscopy were normal in 38 (54.3%) patients, and they were abnormal in 32 (45.7%) patients. Based on the cytology results, 45 (64.3%) samples were normal, and 25 (35.7%) samples were abnormal. According to the results of the HPV DNA test, 47 (67.14%) samples were normal, and 17 (24.28%) samples were abnormal. Based on the results of the kappa test, the agreement between MHS and cytology was 0.793 (p < 0.001). The agreement between MHS and the HPV DNA test was 0.195 (p = 0.086), and the agreement between MHS and colposcopy was 0.479 (p < 0.001).

  13. Laser Infrared Desorption Spectroscopy to Detect Complex Organic Molecules on Icy Planetary Surfaces (United States)

    Sollit, Luke S.; Beegle, Luther W.


    Laser Desorption-Infrared Spectroscopy (LD-IR) uses an IR laser pulse to desorb surface materials while a spectrometer measures the emission spectrum of the desorbed materials (Figure 1). In this example, laser desorption operates by having the incident laser energy absorbed by near surface material (10 microns in depth). This desorption produces a plume that exists in an excited state at elevated temperatures. A natural analog for this phenomenon can be observed when comets approach the sun and become active and individual molecular emission spectra can be observed in the IR [1,2,3,4,5]. When this occurs in comets, the same species that initially emit radiation down to the ground state are free to absorb it, reducing the amount of detectable emission features. The nature of our technique results in absorption not occurring, because the laser pulse could easily be moved away form the initial desorption plume, and still have better spatial resolution then reflectance spectroscopy. In reflectance spectroscopy, trace components have a relatively weak signal when compared to the entire active nature of the surface. With LDIR, the emission spectrum is used to identify and analyze surface materials.

  14. Rapid Detection of Volatile Oil in Mentha haplocalyx by Near-Infrared Spectroscopy and Chemometrics. (United States)

    Yan, Hui; Guo, Cheng; Shao, Yang; Ouyang, Zhen


    Near-infrared spectroscopy combined with partial least squares regression (PLSR) and support vector machine (SVM) was applied for the rapid determination of chemical component of volatile oil content in Mentha haplocalyx. The effects of data pre-processing methods on the accuracy of the PLSR calibration models were investigated. The performance of the final model was evaluated according to the correlation coefficient (R) and root mean square error of prediction (RMSEP). For PLSR model, the best preprocessing method combination was first-order derivative, standard normal variate transformation (SNV), and mean centering, which had of 0.8805, of 0.8719, RMSEC of 0.091, and RMSEP of 0.097, respectively. The wave number variables linking to volatile oil are from 5500 to 4000 cm-1 by analyzing the loading weights and variable importance in projection (VIP) scores. For SVM model, six LVs (less than seven LVs in PLSR model) were adopted in model, and the result was better than PLSR model. The and were 0.9232 and 0.9202, respectively, with RMSEC and RMSEP of 0.084 and 0.082, respectively, which indicated that the predicted values were accurate and reliable. This work demonstrated that near infrared reflectance spectroscopy with chemometrics could be used to rapidly detect the main content volatile oil in M. haplocalyx. The quality of medicine directly links to clinical efficacy, thus, it is important to control the quality of Mentha haplocalyx. Near-infrared spectroscopy combined with partial least squares regression (PLSR) and support vector machine (SVM) was applied for the rapid determination of chemical component of volatile oil content in Mentha haplocalyx. For SVM model, 6 LVs (less than 7 LVs in PLSR model) were adopted in model, and the result was better than PLSR model. It demonstrated that near infrared reflectance spectroscopy with chemometrics could be used to rapidly detect the main content volatile oil in Mentha haplocalyx. Abbreviations used: 1(st) der: First

  15. Explosives standoff detection using Raman spectroscopy: from bulk towards trace detection (United States)

    Pettersson, Anna; Wallin, Sara; Östmark, Henric; Ehlerding, Anneli; Johansson, Ida; Nordberg, Markus; Ellis, Hanna; Al-Khalili, Ahmed


    This paper gives a brief overview on our latest progress in the area of standoff detection. Standoff Raman measurements from 200 m and 470 m distance have been performed on bulk amounts of TATP and AN respectively, the former through a double sided window, the latter under heavy rain. Resonance Raman measurements on TNT, DNT and NM vapors in the ppm concentration regime are presented, showing resonance enhancement in the range of 2 200 (NM) to 57 000 (TNT) as compared to 532 nm Raman cross sections. Finally, the application of hyper spectral Raman imaging is described, exemplified by the resolution of four different samples (sulphur, AN, DNT, and TNT) in the form of 5 mm wide discs in one single image.

  16. Development of electrochemical impedance spectroscopy based sensing system for DEHP detection

    KAUST Repository

    Zia, Asif I.


    This research work presents a real time and non invasive technique to detect Di(2-ethylhexyl) phthalate (DEHP)content in purified water and quantify its concentration by Electrochemical Impedance Spectroscopy(E.I.S.). Planar Inter-digital capacitive sensor is employed to evaluate conductivity, permeability and dielectric properties of material under test. This sensor, consisting of inter-digitated microelectrodes, is fabricated on silicon substrate using thin-film Microelectromechanical system (MEMS) based semiconductor device fabrication technology. Impedance spectrums are obtained with various concentrations of DEHP in purified water by using an electric circuit in order to extract sample conductance. Relationship of sample conductance with DEHP concentration is studied in this research work which enables us to show the ability of E.I.S. to detect DEHP concentration in water and hence can be applied in water treatment process for contamination quantification. © 2011 IEEE.

  17. Rapid detection of pesticide residue in apple based on Raman spectroscopy (United States)

    Li, Yongyu; Sun, Yunyun; Peng, Yankun; Dhakal, Sagar; Chao, Kuanglin; Liu, Qiaoqiao


    The potential of Raman spectroscopy in the analysis of low concentration organic contaminants on apples' surface was evidenced in this study. Chlorpyrifos, an organophosphorus pesticide, was used as a probe for this purpose. The characteristic peaks of fingerprints of pesticide on an aluminum substrate and apple fruit cuticle without pesticide residue were acquired first. Then a concentration range of chlorpyrifos (commercial products at 40%) solutions were made using deionised and distilled water. Single 100 μL droplets of the chlorpyrifos solutions were placed gently on apple fruit cuticles and left to dry before analysis. Through comparative analysis of the Raman spectra data collected, 341, 632 and 1237cm-1 were identified to detect the chlorpyrifos pesticide residue on apple surface. Based on the relationship between the Raman intensity of the most prominent peak at around 632cm-1 and the pesticide concentrations, the limit of detection of ordinary Raman spectrum for chlorpyrifos was estimated to be 48ppm.

  18. Optimization of metabolite detection by quantum mechanics simulations in magnetic resonance spectroscopy. (United States)

    Gambarota, Giulio


    Magnetic resonance spectroscopy (MRS) is a well established modality for investigating tissue metabolism in vivo. In recent years, many efforts by the scientific community have been directed towards the improvement of metabolite detection and quantitation. Quantum mechanics simulations allow for investigations of the MR signal behaviour of metabolites; thus, they provide an essential tool in the optimization of metabolite detection. In this review, we will examine quantum mechanics simulations based on the density matrix formalism. The density matrix was introduced by von Neumann in 1927 to take into account statistical effects within the theory of quantum mechanics. We will discuss the main steps of the density matrix simulation of an arbitrary spin system and show some examples for the strongly coupled two spin system. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Sensitive and ultra-fast species detection using pulsed cavity ringdown spectroscopy

    KAUST Repository

    Alquaity, Awad


    Pulsed cavity ringdown spectroscopy (CRDS) is used to develop a novel, ultra-fast, high-sensitivity diagnostic for measuring species concentrations in shock tube experiments. The diagnostic is demonstrated by monitoring trace concentrations of ethylene in the mid-IR region near 949.47 cm-1. Each ringdown measurement is completed in less than 1 μs and the time period between successive pulses is 10 μs. The high sensitivity diagnostic has a noise-equivalent detection limit of 1.08 x 10-5 cm-1 which enables detection of 15 ppm ethylene at fuel pyrolysis conditions (1845 K and 2 bar) and 294 ppb ethylene under ambient conditions (297 K and 1 bar). To our knowledge, this is the first successful application of the cavity ringdown method to the measurement of species time-histories in a shock tube. © 2015 OSA.

  20. Optically Detected Magnetic Resonance and Thermal Activation Spectroscopy Study of Organic Semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chang-Hwan [Iowa State Univ., Ames, IA (United States)


    Organic electronic materials are a new class of emerging materials. Organic light emitting devices (OLEDs) are the most promising candidates for future flat panel display technologies. The photophysical characterization is the basic research step one must follow to understand this new class of materials and devices. The light emission properties are closely related to the transport properties of these materials. The objective of this dissertation is to probe the relation between transport and photophysical properties of organic semiconductors. The transport characteristics were evaluated by using thermally stimulated current and thermally stimulated luminescence techniques. The photoluminescence detected magnetic resonance and photoluminescence quantum yield studies provide valuable photophysical information on this class of materials. OLEDs are already in the market. However, detailed studies on the degradation mechanisms are still lacking. Since both optically detected magnetic resonance and thermal activation spectroscopy probe long-lived defect-related states in organic semiconductors, the combined study generates new insight on the OLED operation and degradation mechanisms.

  1. Magnetic Resonance Spectroscopy for Detection of 2-Hydroxyglutarate as a Biomarker for IDH Mutation in Gliomas (United States)

    Leather, Thomas; Jenkinson, Michael D.; Das, Kumar; Poptani, Harish


    Mutations in the isocitrate dehydrogenase (IDH)1/2 genes are highly prevalent in gliomas and have been suggested to play an important role in the development and progression of the disease. Tumours harbouring these mutations exhibit a significant alteration in their metabolism resulting in the aberrant accumulation of the oncometabolite 2-hydroxygluarate (2-HG). As well as being suggested to play an important role in tumour progression, 2-HG may serve as a surrogate indicator of IDH status through non-invasive detection using magnetic resonance spectroscopy (MRS). In this review, we describe the recent efforts in developing MRS methods for detection and quantification of 2-HG in vivo and provide an assessment of the role of the 2-HG in gliomagenesis and patient prognosis. PMID:28629182

  2. Dental caries detection by optical spectroscopy: a polarized Raman approach with fibre-optic coupling (United States)

    Ko, A. C.-T.; Choo-Smith, L.-P.; Werner, J.; Hewko, M.; Sowa, M. G.; Dong, C.; Cleghorn, B.


    Incipient dental caries lesions appear as white spots on the tooth surface; however, accurate detection of early approximal lesions is difficult due to limited sensitivity of dental radiography and other traditional diagnostic tools. A new fibre-optic coupled spectroscopic method based on polarized Raman spectroscopy (P-RS) with near-IR laser excitation is introduced which provides contrast for detecting and characterizing incipient caries. Changes in polarized Raman spectra are observed in PO 4 3- vibrations arising from hydroxyapatite of mineralized tooth tissue. Demineralization-induced morphological/orientational alteration of enamel crystallites is believed to be responsible for the reduction of Raman polarization anisotropy observed in the polarized Raman spectra of caries lesions. Supporting evidence obtained by polarized Raman spectral imaging is presented. A specially designed fibre-optic coupled setup for simultaneous measurement of parallel- and cross-polarized tooth Raman spectra is demonstrated in this study.

  3. Detection of Ti-rich precipitations in iron by means of positron annihilation spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kuriplach, J.; Dauwe, C.; Segers, D. [Ghent Univ. (Belgium); Sob, M. [Akademie Ved Ceske Republiky, Brno (Czech Republic). Ustav Fyzikalni Metalurgie


    A possibility of detection of various Ti-rich precipitates in iron (steel) using positron annihilation spectroscopy is analysed. First, we investigate precipitates with sulfur (Ti{sub 9}S{sub 9}, Ti{sub 4}C{sub 2}S{sub 2}), which have not been studied yet. We used the ab initio LMTO method and calculate positron affinities of all studied perfect systems. We also employ an improved supercell technique and atomic superimposed method and determine positron lifetimes for systems with vacancies. It turns out that even undefected Ti{sub 9}S{sub 9} and Ti{sub 4}C{sub 2}S{sub 2} precipitates can bind a positron and, therefore, can be detected in positron annihilation experiments in contrast to TiC and TiN precipitates which can trap positrons only if they contain vacancies. (author). 15 refs, 4 tabs, 1 fig.

  4. Investigation of Detectability of Elementary Composition of Rainbow trout muscle with EDS (Energy Dispersive Spectroscopy Method

    Directory of Open Access Journals (Sweden)

    Saltuk Buğrahan CEYHUN


    Full Text Available In present study, it is investigated that detectability of elementary composition of rainbow trout muscle using Energy Dispersive Spectroscopy (EDS. EDS system which has worked with attached to scanning electron microscope can do qualitative and semi-quantitative elementary analyses on selected region of sample using characteristic X-rays. For this purpose, it was performed four point and two mapping analyses from four samples. According to results, it was detected 13 elements which are consist of C, N and O in 87.70 percentage. As a result, although the method is sensitive and reliable, it is concluded that not adequate for elemental analysis alone but can be used as a support for analyzes with systems such as especially atomic absorption and ICP-MS.

  5. Application of NIR Raman spectroscopy for detecting and characterizing early dental caries (United States)

    Ko, A. C.; Choo-Smith, L.-P.; Zhu, R.; Hewko, M.; Dong, C.; Cleghorn, B.; Sowa, M. G.


    Early dental caries detection facilitates implementation of non-surgical methods for arresting caries progression and promoting tooth remineralization. We present a method based on Raman spectroscopy with near-IR laser excitation to provide biochemical contrast for detecting and characterizing incipient carious lesions found in extracted human teeth. Changes in Raman spectra are observed in PO 4 3- vibrations arising from hydroxyapatite of mineralized tooth tissue. Examination of various intensities of the PO 4 3- ν2, ν3, ν4 vibrations showed consistent increased intensities in spectra of carious lesions compared to sound enamel. The spectral changes are attributed to demineralization-induced alterations of enamel crystallite morphology and/or orientation. This hypothesis is supported by reduced Raman polarization anisotropy derived from polarized Raman spectra of carious lesions. Polarized Raman spectral imaging of carious lesions found on whole (i.e. un-sectioned) tooth samples will also be presented.

  6. Quartz Enhanced Photoacoustic Spectroscopy for Detection of Improvised Explosive Devices and Precursors

    Directory of Open Access Journals (Sweden)

    Roberto Viola


    Full Text Available A compact portable and standalone point sensor has been developed for the detection and identification of precursors of improvised explosive devices (IEDs and to be part of a network of sensors for the discovery of hidden bomb factories in homeland security applications. The sensor is based on quartz enhanced photoacoustic spectroscopy (QEPAS, and it implements a broadly tunable external cavity quantum cascade laser source (EC-QCL. It makes use of an optical cell purposely designed with a miniaturized internal volume, to achieve fast response and high sensitivity, and that can also be heated to improve sensitivity towards less volatile compounds. The sensor has been assembled and successfully tested in the lab with several compounds, including IED’s precursors such as acetone, nitromethane, nitric acid, and hydrogen peroxide. The identification capability and limits of detection near the ppm level have been estimated for all these compounds.

  7. Serum albumin analysis for type II diabetes detection using surface-enhanced Raman spectroscopy (United States)

    Lin, Jinyong; Cao, Gang; Lin, Juqiang; Liu, Nenrong; Liao, Fadian; Ruan, Qiuyong; Wu, Shanshan; Huang, Zufang; Li, Ling; Chen, Rong


    Surface-enhanced Raman scattering (SERS) spectroscopy combined with membrane electrophoresis (ME) was firstly employed to detect albumin variation in type II diabetic development. Albumin was first purified from human serum by ME and then mixed with silver nanoparticles to perform SERS spectral analysis. SERS spectra were obtained from blood albumin samples of 20 diabetic patients and 19 healthy volunteers. Subtle but discernible changes in the acquired mean spectra of the two groups were observed. Tentative assignment of albumin SERS bands indicated specific structural changes of albumin molecule with diabetic development. Meanwhile, PCA-LDA diagnostic algorithms were employed to classify the two kinds of albumin SERS spectra, yielding the diagnostic sensitivity of 90% and specificity of 94.7%. The results from this exploratory study demonstrated that the EM-SERS method in combination with multivariate statistical analysis has great potential for the label-free detection of albumin variation for improving type II diabetes screening.

  8. Deep learning approaches for detection and removal of ghosting artifacts in MR spectroscopy. (United States)

    Kyathanahally, Sreenath P; Döring, André; Kreis, Roland


    To make use of deep learning (DL) methods to detect and remove ghosting artifacts in clinical magnetic resonance spectra of human brain. Deep learning algorithms, including fully connected neural networks, deep-convolutional neural networks, and stacked what-where auto encoders, were implemented to detect and correct MR spectra containing spurious echo ghost signals. The DL methods were trained on a huge database of simulated spectra with and without ghosting artifacts that represent complex variations of ghost-ridden spectra, transformed to time-frequency spectrograms. The trained model was tested on simulated and in vivo spectra. The preliminary results for ghost detection are very promising, reaching almost 100% accuracy, and the DL ghost removal methods show potential in simulated and in vivo spectra, but need further refinement and quantitative testing. Ghosting artifacts in spectroscopy are problematic, as they superimpose with metabolites and lead to inaccurate quantification. Detection and removal of ghosting artifacts using traditional machine learning approaches with feature extraction/selection is difficult, as ghosts appear at different frequencies. Here, we show that DL methods perform extremely well for ghost detection if the spectra are treated as images in the form of time-frequency representations. Further optimization for in vivo spectra will hopefully confirm their "ghostbusting" capacity. Magn Reson Med, 2018. © 2018 International Society for Magnetic Resonance in Medicine. © 2018 International Society for Magnetic Resonance in Medicine.

  9. Rapid Detection of Pathogenic Bacteria from Fresh Produce by Filtration and Surface-Enhanced Raman Spectroscopy (United States)

    Wu, Xiaomeng; Han, Caiqin; Chen, Jing; Huang, Yao-Wen; Zhao, Yiping


    The detection of Salmonella Poona from cantaloupe cubes and E. coli O157:H7 from lettuce has been explored by using a filtration method and surface-enhanced Raman spectroscopy (SERS) based on vancomycin-functionalized silver nanorod array substrates. It is found that with a two-step filtration process, the limit of detection (LOD) of Salmonella Poona from cantaloupe cubes can be as low as 100 CFU/mL in less than 4 h, whereas the chlorophyll in the lettuce causes severe SERS spectral interference. To improve the LOD of lettuce, a three-step filtration method with a hydrophobic filter is proposed. The hydrophobic filter can effectively eliminate the interferences from chlorophyll and achieve a LOD of 1000 CFU/mL detection of E. coli O157:H7 from lettuce samples within 5 h. With the low LODs and rapid detection time, the SERS biosensing platform has demonstrated its potential as a rapid, simple, and inexpensive means for pathogenic bacteria detection from fresh produce.

  10. Detection of canine skin and subcutaneous tumors by visible and near-infrared diffuse reflectance spectroscopy (United States)

    Cugmas, Blaž; Plavec, Tanja; Bregar, Maksimilijan; Naglič, Peter; Pernuš, Franjo; Likar, Boštjan; Bürmen, Miran


    Cancer is the main cause of canine morbidity and mortality. The existing evaluation of tumors requires an experienced veterinarian and usually includes invasive procedures (e.g., fine-needle aspiration) that can be unpleasant for the dog and the owner. We investigate visible and near-infrared diffuse reflectance spectroscopy (DRS) as a noninvasive optical technique for evaluation and detection of canine skin and subcutaneous tumors ex vivo and in vivo. The optical properties of tumors and skin were calculated in a spectrally constrained manner, using a lookup table-based inverse model. The obtained optical properties were analyzed and compared among different tumor groups. The calculated parameters of the absorption and reduced scattering coefficients were subsequently used for detection of malignant skin and subcutaneous tumors. The detection sensitivity and specificity of malignant tumors ex vivo were 90.0% and 73.5%, respectively, while corresponding detection sensitivity and specificity of malignant tumors in vivo were 88.4% and 54.6%, respectively. The obtained results show that the DRS is a promising noninvasive optical technique for detection and classification of malignant and benign canine skin and subcutaneous tumors. The method should be further investigated on tumors with common origin.

  11. Detection of renal cell carcinoma using neutron time of flight spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Viana, Rodrigo S.; Yoriyaz, Helio, E-mail: [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Lakshmanan, Manu N.; Agasthya, Greeshma A.; Kapadia, Anuj J. [Duke University Medical Center, Durham, NC, (United States). Ravin Advanced Imaging Labs, Radiology


    The diagnosis of renal cell carcinoma (RCC) is challenging because the symptoms accompanying it are not unique to the disease, and can therefore be misdiagnosed as other diseases. Due to this characteristic, detection of renal cancer is incidental most of time, occurring via abdominal radiographic examinations unrelated to the disease. Presently, biopsy, which is invasive and an unpleasant procedure for the patient, is the most commonly used technique to diagnose RCC. In this study, we demonstrate the application of a novel noninvasive technique for detecting and imaging RCC in vivo. The elemental composition of biological tissues including kidneys has been investigated using a new technique called Neutron Stimulated Emission Computed Tomography (NSECT). This technique is based on detecting the energy signature emitted by the stable isotopes of elements in the body, which are stimulated to emit gamma radiation via inelastic neutron scattering. Methods for improving detection sensitivity and reducing dose, such as time-of-flight neutron spectroscopy have been explored. MCNP5 simulations were used to model the NSECT scanning of the human kidney where the energy and time of arrival of gamma photons were recorded in an ideal detector placed around the human torso. A 5 MeV collimated neutron beam was used to irradiate the kidney containing an RCC lesion. The resulting spectra were resolved in 100 picosecond and 1 keV time and energy bins, respectively. The preliminary results demonstrate the ability to localize the lesion through neutron time of flight spectroscopy and generate a tomographic image at a low dose to the patient. (author)

  12. Raman spectroscopy and imaging to detect contaminants for food safety applications (United States)

    Chao, Kuanglin; Qin, Jianwei; Kim, Moon S.; Peng, Yankun; Chan, Diane; Cheng, Yu-Che


    This study presents the use of Raman chemical imaging for the screening of dry milk powder for the presence of chemical contaminants and Raman spectroscopy for quantitative assessment of chemical contaminants in liquid milk. For image-based screening, melamine was mixed into dry milk at concentrations (w/w) between 0.2% and 10.0%, and images of the mixtures were analyzed by a spectral information divergence algorithm. Ammonium sulfate, dicyandiamide, and urea were each separately mixed into dry milk at concentrations (w/w) between 0.5% and 5.0%, and an algorithm based on self-modeling mixture analysis was applied to these sample images. The contaminants were successfully detected and the spatial distribution of the contaminants within the sample mixtures was visualized using these algorithms. Liquid milk mixtures were prepared with melamine at concentrations between 0.04% and 0.30%, with ammonium sulfate and with urea at concentrations between 0.1% and 10.0%, and with dicyandiamide at concentrations between 0.1% and 4.0%. Analysis of the Raman spectra from the liquid mixtures showed linear relationships between the Raman intensities and the chemical concentrations. Although further studies are necessary, Raman chemical imaging and spectroscopy show promise for use in detecting and evaluating contaminants in food ingredients.

  13. Nondestructive detection of lead chrome green in tea by Raman spectroscopy. (United States)

    Li, Xiao-Li; Sun, Chan-Jun; Luo, Liu-Bin; He, Yong


    Raman spectroscopy was first adopted for rapid detecting a hazardous substance of lead chrome green in tea, which was illegally added to tea to disguise as high-quality. 160 samples of tea infusion with different concentrations of lead chrome green were prepared for Raman spectra acquirement in the range of 2804 cm(-1)-230 cm(-1) and the spectral intensities were calibrated with relative intensity standards. Then wavelet transformation (WT) was adopted to extract information in different time and frequency domains from Raman spectra, and the low-frequency approximation signal (ca4) was proved as the most important information for establishment of lead chrome green measurement model, and the corresponding partial least squares (PLS) regression model obtained good performance in prediction with Rp and RMSEP of 0.936 and 0.803, respectively. To further explore the important wavenumbers closely related to lead chrome green, successive projections algorithm (SPA) was proposed. Finally, 8 characteristic wavenumbers closely related to lead chrome green were obtained and a more convenient and fast model was also developed. These results proved the feasibility of Raman spectroscopy for nondestructive detection of lead chrome green in tea quality control.

  14. Radiocarbon Dioxide detection based on Cavity Ring-Down Spectroscopy and a Quantum Cascade Laser

    CERN Document Server

    Genoud, Guillaume; Phillips, Hilary; Dean, Julian; Merimaa, Mikko


    Monitoring of radiocarbon ($^{14}$C) in carbon dioxide is demonstrated using mid-infrared spectroscopy and a quantum cascade laser. The measurement is based on cavity ring-down spectroscopy, and a high sensitivity is achieved with a simple setup. The instrument was tested using a standardised sample containing elevated levels of radiocarbon. Radiocarbon dioxide could be detected from samples with an isotopic ratio $^{14}$C/C as low as 50 parts-per-trillion, corresponding to an activity of 5 kBq/m$^3$ in pure CO$_2$, or 2 Bq/m$^3$ in air after extraction of the CO$_2$ from an air sample. The instrument is simple, compact and robust, making it the ideal tool for on-site measurements. It is aimed for monitoring of radioactive gaseous emissions in nuclear power environment, during the operation and decommissioning of nuclear power plants. Its high sensitivity also makes it the ideal tool for the detection of leaks in radioactive waste repositories.

  15. Rapid detection of talcum powder in tea using FT-IR spectroscopy coupled with chemometrics. (United States)

    Li, Xiaoli; Zhang, Yuying; He, Yong


    This paper investigated the feasibility of Fourier transform infrared transmission (FT-IR) spectroscopy to detect talcum powder illegally added in tea based on chemometric methods. Firstly, 210 samples of tea powder with 13 dose levels of talcum powder were prepared for FT-IR spectra acquirement. In order to highlight the slight variations in FT-IR spectra, smoothing, normalize and standard normal variate (SNV) were employed to preprocess the raw spectra. Among them, SNV preprocessing had the best performance with high correlation of prediction (RP = 0.948) and low root mean square error of prediction (RMSEP = 0.108) of partial least squares (PLS) model. Then 18 characteristic wavenumbers were selected based on a hybrid of backward interval partial least squares (biPLS) regression, competitive adaptive reweighted sampling (CARS) algorithm and successive projections algorithm (SPA). These characteristic wavenumbers only accounted for 0.64% of the full wavenumbers. Following that, 18 characteristic wavenumbers were used to build linear and nonlinear determination models by PLS regression and extreme learning machine (ELM), respectively. The optimal model with RP = 0.963 and RMSEP = 0.137 was achieved by ELM algorithm. These results demonstrated that FT-IR spectroscopy with chemometrics could be used successfully to detect talcum powder in tea.

  16. Towards a low-cost mobile subcutaneous vein detection solution using near-infrared spectroscopy. (United States)

    Juric, Simon; Flis, Vojko; Debevc, Matjaz; Holzinger, Andreas; Zalik, Borut


    Excessive venipunctures are both time- and resource-consuming events, which cause anxiety, pain, and distress in patients, or can lead to severe harmful injuries. We propose a low-cost mobile health solution for subcutaneous vein detection using near-infrared spectroscopy, along with an assessment of the current state of the art in this field. The first objective of this study was to get a deeper overview of the research topic, through the initial team discussions and a detailed literature review (using both academic and grey literature). The second objective, that is, identifying the commercial systems employing near-infrared spectroscopy, was conducted using the PubMed database. The goal of the third objective was to identify and evaluate (using the IEEE Xplore database) the research efforts in the field of low-cost near-infrared imaging in general, as a basis for the conceptual model of the upcoming prototype. Although the reviewed commercial devices have demonstrated usefulness and value for peripheral veins visualization, other evaluated clinical outcomes are less conclusive. Previous studies regarding low-cost near-infrared systems demonstrated the general feasibility of developing cost-effective vein detection systems; however, their limitations are restricting their applicability to clinical practice. Finally, based on the current findings, we outline the future research direction.

  17. Towards a Low-Cost Mobile Subcutaneous Vein Detection Solution Using Near-Infrared Spectroscopy

    Directory of Open Access Journals (Sweden)

    Simon Juric


    Full Text Available Excessive venipunctures are both time- and resource-consuming events, which cause anxiety, pain, and distress in patients, or can lead to severe harmful injuries. We propose a low-cost mobile health solution for subcutaneous vein detection using near-infrared spectroscopy, along with an assessment of the current state of the art in this field. The first objective of this study was to get a deeper overview of the research topic, through the initial team discussions and a detailed literature review (using both academic and grey literature. The second objective, that is, identifying the commercial systems employing near-infrared spectroscopy, was conducted using the PubMed database. The goal of the third objective was to identify and evaluate (using the IEEE Xplore database the research efforts in the field of low-cost near-infrared imaging in general, as a basis for the conceptual model of the upcoming prototype. Although the reviewed commercial devices have demonstrated usefulness and value for peripheral veins visualization, other evaluated clinical outcomes are less conclusive. Previous studies regarding low-cost near-infrared systems demonstrated the general feasibility of developing cost-effective vein detection systems; however, their limitations are restricting their applicability to clinical practice. Finally, based on the current findings, we outline the future research direction.

  18. Micro-Raman spectroscopy Detects Individual Neoplastic and Normal Hematopoietic Cells

    Energy Technology Data Exchange (ETDEWEB)

    Chan, J W; Taylor, D; Zwerdling, T; Lane, S M; Ihara, K; Huser, T


    Current methods for identifying neoplastic cells and discerning them from their normal counterparts are often non-specific, slow, biologically perturbing, or a combination, thereof. Here, we show that single-cell micro-Raman spectroscopy averts these shortcomings and can be used to discriminate between unfixed normal human lymphocytes and transformed Jurkat and Raji lymphocyte cell lines based on their biomolecular Raman signatures. We demonstrate that single-cell Raman spectra provide a highly reproducible biomolecular fingerprint of each cell type. Characteristic peaks, mostly due to different DNA and protein concentrations, allow for discerning normal lymphocytes from transformed lymphocytes with high confidence (p << 0.05). Spectra are also compared and analyzed by principal component analysis (PCA) to demonstrate that normal and transformed cells form distinct clusters that can be defined using just two principal components. The method is shown to have a sensitivity of 98.3% for cancer detection, with 97.2% of the cells being correctly classified as belonging to the normal or transformed type. These results demonstrate the potential application of confocal micro-Raman spectroscopy as a clinical tool for single cell cancer detection based on intrinsic biomolecular signatures, therefore eliminating the need for exogenous fluorescent labeling.

  19. Detection of Pistachio Aflatoxin Using Raman Spectroscopy and Artificial Neural Networks

    Directory of Open Access Journals (Sweden)

    R Mohammadigol


    Full Text Available Pistachio contamination to aflatoxin has been known as a serious problem for pistachio exportation. With regards to the increasing demand for Raman spectroscopy to detect and classify different materials and also the current experimental and technical problems for measuring toxin (such as being expensive and time-consuming, the main objective of this study was to detect aflatoxin contamination in pistachio by using Raman spectroscopy technique and artificial neural networks. Three sets of samples were prepared: non-contaminated (healthy and contaminated samples with 20 and 100 ppb of the total aflatoxins (B1+B2+G1+G2. After spectral acquisition, considering to the results, spectral data were normalized and then principal components (PCs were extracted to reduce the data dimensions. For classification of the samples spectra, an artificial neural network was used with a feed forward back propagation algorithm for 4 inputs and 3 neurons in hidden layer. Mean overall accuracy was achieved to be 98 percent; therefore, non-liner Raman spectra data modeling by ANN for samples classification was successful.

  20. Chemical and explosives point detection through opaque containers using spatially offset Raman spectroscopy (SORS) (United States)

    Loeffen, Paul W.; Maskall, Guy; Bonthron, Stuart; Bloomfield, Matthew; Tombling, Craig; Matousek, Pavel


    Spatially Offset Raman Spectroscopy (SORS) is a novel technique used to identify the chemical Raman signature of threat materials within a few seconds through common non-metallic containers, including those containers which may not yield to inspection by conventional backscatter Raman. In particular, some opaque plastic containers and coloured glass bottles can be difficult to analyze using conventional backscatter Raman because the signal from the contents is often overwhelmed by the much stronger Raman signal and/or fluorescence originating from the container itself. SORS overcomes these difficulties and generates clean Raman spectra from both the container and the contents with no prior knowledge of either. This is achieved by making two, or more, Raman measurements at various offsets between the collection and illumination areas, each containing different proportions of the fingerprint signals from the container and content materials. Using scaled subtraction, or multivariate statistical methods, the two orthogonal signals can be separated numerically, thereby providing a clean Raman spectrum of the contents without contamination from the container. Consequently, SORS promises to significantly improve threat detection capability and decrease the falsealarm rate compared with conventional Raman spectroscopy making it considerably more suitable as an alarm resolution methodology (e.g. at airports). In this paper, the technique and method are described and a study of offset value optimization is described illustrating the difference between one and two fixed spatial offsets. It is concluded that two fixed offsets yield an improvement in the SORS measurement which will help maximize the threat detection capability.

  1. [Preliminary Study on the Detection of Pork Tenderness by Three-Dimensional Diffuse Reflectance Spectroscopy]. (United States)

    Zhang, Zhi-yong; Zuo, Yue-ming; Chen, Jin-ming; Li, Gang; Chen, Chen; Yang, Wei


    Tenderness is an important index to evaluate the pork's quality, in this paper a method called three-dimensional diffuse reflectance spectroscopy was proposed to detect pork tenderness. Because pork has a strong scattering impact on light, this method introduced more scattering information of pork samples into spectral analysis of tenderness. Using the special data acquisition system, three-dimensional diffuse reflectance spectra of 64 pork samples were constructed by collecting the emergent light signals of different distances away from the light incident point. And n-way partial least squares (NPLS) regression was applied to establish the calibration model between the pork tenderness and three-dimensional diffuse reflectance spectra which were denoised by wavelet transform. The determination coefficient of model for the calibration set (R2(Cal)) is 0.883 1, and the root mean squared error of calibration (RMSEC) is 3.685 0N. The determination coefficient of model for the prediction set (R2(Pred)) is 0.874 7, and the root mean squared error of prediction (RMSEP) is 3.975 6N. The result indicates that the NPLS model of pork tenderness built by three-dimensional diffuse reflectance spectra has higher calibration accuracy and prediction stability than the traditional diffuse reflectance spectra. Three-dimensional diffuse reflectance spectroscopy can be expected to be a new method to quickly detect the tenderness and the other qualities of pork.

  2. Rapid detection of talcum powder in tea using FT-IR spectroscopy coupled with chemometrics (United States)

    Li, Xiaoli; Zhang, Yuying; He, Yong


    This paper investigated the feasibility of Fourier transform infrared transmission (FT-IR) spectroscopy to detect talcum powder illegally added in tea based on chemometric methods. Firstly, 210 samples of tea powder with 13 dose levels of talcum powder were prepared for FT-IR spectra acquirement. In order to highlight the slight variations in FT-IR spectra, smoothing, normalize and standard normal variate (SNV) were employed to preprocess the raw spectra. Among them, SNV preprocessing had the best performance with high correlation of prediction (RP = 0.948) and low root mean square error of prediction (RMSEP = 0.108) of partial least squares (PLS) model. Then 18 characteristic wavenumbers were selected based on a hybrid of backward interval partial least squares (biPLS) regression, competitive adaptive reweighted sampling (CARS) algorithm and successive projections algorithm (SPA). These characteristic wavenumbers only accounted for 0.64% of the full wavenumbers. Following that, 18 characteristic wavenumbers were used to build linear and nonlinear determination models by PLS regression and extreme learning machine (ELM), respectively. The optimal model with RP = 0.963 and RMSEP = 0.137 was achieved by ELM algorithm. These results demonstrated that FT-IR spectroscopy with chemometrics could be used successfully to detect talcum powder in tea. PMID:27468701

  3. Detection of tire tread particles using laser-induced breakdown spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Prochazka, David, E-mail: [Brno University of Technology, Institute of Physical Engineering, Technická 2, 616 00 Brno (Czech Republic); Brno University of Technology, Central European Institute of Technology, Technická 3058/10, CZ-616 00 Brno (Czech Republic); Bilík, Martin [Brno University of Technology, Institute of Forensic Engineering, Údolní 244/53, 602 00 Brno (Czech Republic); Prochazková, Petra [Masaryk University, Faculty of Science, Department of Chemistry, Kamenice 735/5, 625 00 Brno (Czech Republic); Klus, Jakub; Pořízka, Pavel; Novotný, Jan [Brno University of Technology, Central European Institute of Technology, Technická 3058/10, CZ-616 00 Brno (Czech Republic); Novotný, Karel [Masaryk University, Faculty of Science, Department of Chemistry, Kamenice 735/5, 625 00 Brno (Czech Republic); Brno University of Technology, Central European Institute of Technology, Technická 3058/10, CZ-616 00 Brno (Czech Republic); Ticová, Barbora [Masaryk University, Faculty of Science, Department of Chemistry, Kamenice 735/5, 625 00 Brno (Czech Republic); Bradáč, Albert; Semela, Marek [Brno University of Technology, Institute of Forensic Engineering, Údolní 244/53, 602 00 Brno (Czech Republic); and others


    The objective of this paper is a study of the potential of laser induced breakdown spectroscopy (LIBS) for detection of tire tread particles. Tire tread particles may represent pollutants; simultaneously, it is potentially possible to exploit detection of tire tread particles for identification of optically imperceptible braking tracks at locations of road accidents. The paper describes the general composition of tire treads and selection of an element suitable for detection using the LIBS method. Subsequently, the applicable spectral line is selected considering interferences with lines of elements that might be present together with the detected particles, and optimization of measurement parameters such as incident laser energy, gate delay and gate width is performed. In order to eliminate the matrix effect, measurements were performed using 4 types of tires manufactured by 3 different producers. An adhesive tape was used as a sample carrier. The most suitable adhesive tape was selected from 5 commonly available tapes, on the basis of their respective LIBS spectra. Calibration standards, i.e. an adhesive tape with different area content of tire tread particles, were prepared for the selected tire. A calibration line was created on the basis of the aforementioned calibration standards. The linear section of this line was used for determination of the detection limit value applicable to the selected tire. Considering the insignificant influence of matrix of various types of tires, it is possible to make a simple recalculation of the detection limit value on the basis of zinc content in a specific tire. - Highlights: • LIBS experimental measurement parameters for tire tread particles were optimize. • Calibration curve was prepared. • Limit of detection was determined.

  4. Removal of heavy metal ions from aqueous solution using rice ...

    African Journals Online (AJOL)

    The prepared materials were characterized by acid titration, Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy, Scanning Electron Microscopy-Energy Dispersive X-ray (SEM-EDX) spectroscopy and nitrogen physisorption analysis. Results from the ATR-FTIR analysis indicated that pure silica ...

  5. Frequency Modulated Spectroscopy (FMS) - A Novel Method for Standoff Trace Gas Detection (United States)

    Fessenden, J. E.; Clegg, S. M.; Nowak-Lovato, K.; Martinez, R.; Dobeck, L. M.; Spangler, L.


    Geologic storage of carbon rich gases captured from the emissions of fossil fuel combustion is a promising option to mitigate against greenhouse warming scenarios. Monitoring surface gas seepage is a strategy to create a successful geologic storage facility. At Los Alamos National Laboratory, new laser systems have been engineered which can measure concentration and isotope ratios of CO2, CH4, and H2S in real time and up to 1 km distances. These systems can work in closed and open path (LIght Detection And Ranging or LIDAR) settings where we use Frequency Modulated Spectroscopy (FMS) to measure the harmonics of the primary absorption peak for CO2, CH4, and H2S absorptions. This provides between 100-1000 times sensitivity to allow for small concentrations or low abundance isotopes to be observed at distance. We tested these systems at various locations around Los Alamos National Laboratory and at the ZERT Controlled Release site in Bozeman Montana. Results show pollution signatures, ecologically productive fluxes, and carbon storage signatures depending upon location monitored. We will present these results and share unique features of this novel system. Remote detection of concentration and isotope profiles of greenhouse and toxic gases can provide a new method for stand-off detection and mapping of gas in the environment. For geologic storage scenarios, this will allow for larger areas to be interrogated for subsurface CO2 leak detection and can accelerate the Monitoring Verification and Accounting (MVA) mission goals for the Carbon Sequestration and Storage (CCS) communities.

  6. Research on fiber-optic cantilever-enhanced photoacoustic spectroscopy for trace gas detection (United States)

    Chen, Ke; Zhou, Xinlei; Gong, Zhenfeng; Yu, Shaochen; Qu, Chao; Guo, Min; Yu, Qingxu


    We demonstrate a new scheme of cantilever-enhanced photoacoustic spectroscopy, combining a sensitivity-improved fiber-optic cantilever acoustic sensor with a tunable high-power fiber laser, for trace gas detection. The Fabry-Perot interferometer based cantilever acoustic sensor has advantages such as high sensitivity, small size, easy to install and immune to electromagnetic. Tunable erbium-doped fiber ring laser with an erbium-doped fiber amplifier is used as the light source for acoustic excitation. In order to improve the sensitivity for photoacoustic signal detection, a first-order longitudinal resonant photoacoustic cell with the resonant frequency of 1624 Hz and a large size cantilever with the first resonant frequency of 1687 Hz are designed. The size of the cantilever is 2.1 mm×1 mm, and the thickness is 10 μm. With the wavelength modulation spectrum and second-harmonic detection methods, trace ammonia (NH3) has been measured. The gas detection limits (signal-to-noise ratio = 1) near the wavelength of 1522.5 nm is achieved to be 3 ppb.

  7. Detection of carcinogenic metals in kidney stones using ultraviolet laser-induced breakdown spectroscopy. (United States)

    Khalil, Ahmed Asaad I; Gondal, Mohammed A; Shemis, Mohamed; Khan, Irfan S


    The UV single-pulsed (SP) laser-induced breakdown spectroscopy (LIBS) system was developed to detect the carcinogenic metals in human kidney stones extracted through the surgical operation. A neodymium yttrium aluminium garnet laser operating at 266 nm wavelength and 20 Hz repetition rate along with a spectrometer interfaced with an intensified CCD (ICCD) was applied for spectral analysis of kidney stones. The ICCD camera shutter was synchronized with the laser-trigger pulse and the effect of laser energy and delay time on LIBS signal intensity was investigated. The experimental parameters were optimized to obtain the LIBS plasma in local thermodynamic equilibrium. Laser energy was varied from 25 to 50 mJ in order to enhance the LIBS signal intensity and attain the best signal to noise ratio. The parametric dependence studies were important to improve the limit of detection of trace amounts of toxic elements present inside stones. The carcinogenic metals detected in kidney stones were chromium, cadmium, lead, zinc, phosphate, and vanadium. The results achieved from LIBS system were also compared with the inductively coupled plasma-mass spectrometry analysis and the concentration detected with both techniques was in very good agreement. The plasma parameters (electron temperature and density) for SP-LIBS system were also studied and their dependence on incident laser energy and delay time was investigated as well.

  8. Irradiation dose detection of irradiated milk powder using visible and near-infrared spectroscopy and chemometrics. (United States)

    Kong, W W; Zhang, C; Liu, F; Gong, A P; He, Y


    The objective of this study was to examine the possibility of applying visible and near-infrared spectroscopy to the quantitative detection of irradiation dose of irradiated milk powder. A total of 150 samples were used: 100 for the calibration set and 50 for the validation set. The samples were irradiated at 5 different dose levels in the dose range 0 to 6.0 kGy. Six different pretreatment methods were compared. The prediction results of full spectra given by linear and nonlinear calibration methods suggested that Savitzky-Golay smoothing and first derivative were suitable pretreatment methods in this study. Regression coefficient analysis was applied to select effective wavelengths (EW). Less than 10 EW were selected and they were useful for portable detection instrument or sensor development. Partial least squares, extreme learning machine, and least squares support vector machine were used. The best prediction performance was achieved by the EW-extreme learning machine model with first-derivative spectra, and correlation coefficients=0.97 and root mean square error of prediction=0.844. This study provided a new approach for the fast detection of irradiation dose of milk powder. The results could be helpful for quality detection and safety monitoring of milk powder. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  9. Electrochemical impedance spectroscopy aptasensor for ultrasensitive detection of adenosine with dual backfillers. (United States)

    Wang, Yitan; Feng, Juanjuan; Tan, Zhian; Wang, Haiyan


    A highly sensitive and label-free electrochemical impedance spectroscopy (EIS) aptasensor for the detection of adenosine was fabricated by co-assembling thiolated aptamer, dithiothreitol (DTT) and 6-mercaptohexanol (MCH) on gold electrode surface, forming Au/aptamer-DTT/MCH. The interfacial electron transfer resistance (Ret) of the aptasensor using [Fe(CN)6](3-/4-) as the probe increased with adenosine concentration, and the change in Ret (∆Ret) against the logarithm of adenosine concentration was linear over the range from 0.05 pM to 17 pM with a detection limit of 0.02 pM. Compared to that of aptasensors fabricated with MCH or DTT alone as the backfiller, the detection limit was improved dramatically (LOD was 0.03 nM and 0.2 pM for Au/aptamer/MCH and Au/aptamer-DTT, respectively), which was attributed primarily to the coupling of the cyclic- and linear -configuration backfillers. The coupling showed remarkably higher resistance to nonspecific adsorption, leading to low background noise and high response signal. The aptasensor reported herein is applicable for the detection of other kinds of aptamer-binding chemicals and biomolecules. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Highly sensitive electrochemical impedance spectroscopy immunosensor for the detection of AFB1 in olive oil. (United States)

    Yu, Lili; Zhang, Yang; Hu, Chenyi; Wu, Hui; Yang, Yayun; Huang, Chusen; Jia, Nengqin


    Aflatoxin produced by Aspergillus flavus and Aspergillus parasiticus are commonly found in olive and its derivatives. Aflatoxin B1 (AFB1) is a predominant toxin detected abundantly and has been implicated in the etiology of human hepatocellular carcinoma. This study proposes a sensitive and convenient electrochemical impedance spectroscopy (EIS) method for determining AFB1 by MWCNTs/RTIL composite films-based immunosensor. The calibration curve for AFB1 was linear in the range of 0.1-10ngmL(-1) with the limit of detection (LOD) 0.03ngmL(-1). The presence of MWCNTs warrant fast electron transfer, and the ionic liquid provides a benign microenvironment for antibody. The experimental parameters, such as pH and incubating time, have been investigated and optimized. Furthermore, the detection of AFB1 is presented to test this method after extracted from olive oils. It can be anticipated that this method would be used for the detection of AFB1 in various agriculture products and vegetable oils. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. High-Throughput, Protein-Targeted Biomolecular Detection Using Frequency-Domain Faraday Rotation Spectroscopy. (United States)

    Murdock, Richard J; Putnam, Shawn A; Das, Soumen; Gupta, Ankur; Chase, Elyse D Z; Seal, Sudipta


    A clinically relevant magneto-optical technique (fd-FRS, frequency-domain Faraday rotation spectroscopy) for characterizing proteins using antibody-functionalized magnetic nanoparticles (MNPs) is demonstrated. This technique distinguishes between the Faraday rotation of the solvent, iron oxide core, and functionalization layers of polyethylene glycol polymers (spacer) and model antibody-antigen complexes (anti-BSA/BSA, bovine serum albumin). A detection sensitivity of ≈10 pg mL(-1) and broad detection range of 10 pg mL(-1) ≲ cBSA ≲ 100 µg mL(-1) are observed. Combining this technique with predictive analyte binding models quantifies (within an order of magnitude) the number of active binding sites on functionalized MNPs. Comparative enzyme-linked immunosorbent assay (ELISA) studies are conducted, reproducing the manufacturer advertised BSA ELISA detection limits from 1 ng mL(-1) ≲ cBSA ≲ 500 ng mL(-1) . In addition to the increased sensitivity, broader detection range, and similar specificity, fd-FRS can be conducted in less than ≈30 min, compared to ≈4 h with ELISA. Thus, fd-FRS is shown to be a sensitive optical technique with potential to become an efficient diagnostic in the chemical and biomolecular sciences. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Active Mode Remote Infrared Spectroscopy Detection of TNT and PETN on Aluminum Substrates

    Directory of Open Access Journals (Sweden)

    John R. Castro-Suarez


    Full Text Available Two standoff detection systems were assembled using an infrared telescope coupled to a Fourier transform infrared spectrometer, a cryocooled mercury-cadmium telluride detector, and a telescope-coupled midinfrared excitation source. Samples of the highly energetic materials (HEMs 2,4,6-trinitrotoluene (TNT and pentaerythritol tetranitrate (PETN were deposited on aluminum plates and detected at several source-target distances by carrying out remote infrared spectroscopy (RIRS measurements on the aluminum substrates in active mode. The samples tested were placed at 1–30 m for the RIRS detection experiments. The effect of the angle of incidence/collection of the IR beams on the vibrational band intensities and the signal-to-noise ratios (S/N were investigated. Experiments were performed at ambient temperature. Surface concentrations from 50 to 400 μg/cm2 were studied. Partial least squares regression analysis was applied to the spectra obtained. Overall, RIRS detection in active mode was useful for quantifying the HEMs deposited on the aluminum plates with a high confidence level up to the target-collector distances of 1–25 m.

  13. Detection of early stage changes associated with adipogenesis using Raman spectroscopy under aseptic conditions. (United States)

    Mitchell, Adam; Ashton, Lorna; Yang, Xuebin B; Goodacre, Royston; Smith, Alistair; Kirkham, Jennifer


    There is growing interest in the development of methods capable of non-invasive characterization of stem cells prior to their use in cell-based therapies. Raman spectroscopy has previously been used to detect biochemical changes commensurate with the osteogenic, cardiogenic, and neurogenic differentiation of stem cells. The aim of this study was to characterize the adipogenic differentiation of live adipose derived stem cells (ASCs) under aseptic conditions. ASCs were cultured in adipogenic or basal culture medium for 14 days in customized culture flasks containing quartz windows. Raman spectra were acquired every 3 days. Principal component analysis (PCA) was used to identify spectral changes in the cultures over time. Adipogenic differentiation was confirmed using quantitative reverse transcription polymerase chain reaction for the marker genes PPARγ and ADIPOQ and Oil red O staining performed. PCA demonstrated that lipid associated spectral features varied throughout ASC differentiation with the earliest detection of the lipid associated peak at 1,438 cm(-1) after 3 days of induction. After 7 days of culture there were clear differences between the spectra acquired from ASCs in adipogenic or basal culture medium. No changes were observed in the spectra acquired from undifferentiated ASCs. Significant up-regulation in the expression of both PPARγ and ADIPOQ genes (P Raman sampling process resulted in weaker gene expression compared with ASCs that had not undergone Raman analysis. This study demonstrated that Raman spectroscopy can be used to detect biochemical changes associated with adipogenic differentiation in a non-invasive and aseptic manner and that this can be achieved as early as three days into the differentiation process. © 2015 The Authors. Published by Wiley Periodicals, Inc. on behalf of the International Society for Advancement of Cytometry.

  14. Ultrabroadband 2D electronic spectroscopy with high-speed, shot-to-shot detection. (United States)

    Son, Minjung; Mosquera-Vázquez, Sandra; Schlau-Cohen, Gabriela S


    Two-dimensional electronic spectroscopy (2DES) is an incisive tool for disentangling excited state energies and dynamics in the condensed phase by directly mapping out the correlation between excitation and emission frequencies as a function of time. Despite its enhanced frequency resolution, the spectral window of detection is limited to the laser bandwidth, which has often hindered the visualization of full electronic energy relaxation pathways spread over the entire visible region. Here, we describe a high-sensitivity, ultrabroadband 2DES apparatus. We report a new combination of a simple and robust setup for increased spectral bandwidth and shot-to-shot detection. We utilize 8-fs supercontinuum pulses generated by gas filamentation spanning the entire visible region (450 - 800 nm), which allows for a simultaneous interrogation of electronic transitions over a 200-nm bandwidth, and an all-reflective interferometric delay system with angled nanopositioner stages achieves interferometric precision in coherence time control without introducing wavelength-dependent dispersion to the ultrabroadband spectrum. To address deterioration of detection sensitivity due to the inherent instability of ultrabroadband sources, we introduce a 5-kHz shot-to-shot, dual chopping acquisition scheme by combining a high-speed line-scan camera and two optical choppers to remove scatter contributions from the signal. Comparison of 2D spectra acquired by shot-to-shot detection and averaged detection shows a 15-fold improvement in the signal-to-noise ratio. This is the first direct quantification of detection sensitivity on a filamentation-based ultrabroadband 2DES apparatus.

  15. [Fast detection of sugar content in fruit vinegar using NIR spectroscopy]. (United States)

    Wang, Li; Li, Zeng-fang; He, Yong; Liu, Fei


    For the fast and exact detection of sugar content of fruit vinegar, near infrared (NIR) spectroscopy technique combined with least squares support vector machines (LS-SVM) algorithm was used to build the prediction model of sugar content in the present research. NIR spectroscopy is a nondestructive, fast and accurate technique for the measurement of chemical compo nents based on overtone and combination bands of specific functional groups. The pivotal step for spectroscopy technique is how to extract quantitative data from mass spectral data and eliminate spectral interferences. Principal component analysis (PCA) is a method which has been widely used in the spectroscopic analysis, and LS-SVM is a new data mining algorithm developed from the machine learning community. In the present study, they were used for the spectroscopic analysis. First, the near infrared transmittance spectra of three hundred samples were obtained, then PCA was applied for reducing the dimensionality of the original spectra, and six principal components (PCs) were selected according the accumulative reliabilities (AR). The six PCs could be used to replace the complex spectral data. The three hundred samples were randomly separated into calibration set and validation set. Least squares support vector machines (LS-SVM) algorithm was used to build prediction model of sugar content based on the calibration set, then this model was employed for the prediction of the validation set. Correlation coefficient (r) of prediction and root mean square error prediction (RMSEP) were used as the evaluation standards, and the results indicated that the r and RMSEP for the prediction of sugar content were 0.9939 and 0.363, respectively. Hence, PCA and LS-SVM model with high prediction precision could be applied to the determination of sugar content in fruit vinegar.

  16. [Research on the blood components detecting by multi-optical path length spectroscopy technique]. (United States)

    Li, Gang; Zhao, Zhe; Liu, Rui; Wang, Hui-quan; Wu, Hong-jie; Lin, Ling


    To discuss the feasibility of using the serum's multi-optical path length spectroscopy information for measuring the concentration of the human blood components, the automatic micro-displacement measuring device was designed, which can obtain the near-infrared multi-optical path length from 0 to 4.0 mm (interval is 0.2 mm) spectra of 200 serum samples with multioptical path length spectrum of serum participated in building the quantitative analysis model of four components of the human blood: glucose (GLU), total cholesterol (TC), total protein (TP) and albumin (ALB), by mean of the significant non-linear spectral characteristic of blood. Partial least square (PLS) was used to set up the calibration models of the multi-optical path length near-infrared absorption spectrum of 160 experimental samples against the biochemical analysis results of them. The blood components of another 40 samples were predicted according to the model. The prediction effect of four blood components was favorable, and the correlation coefficient (r) of predictive value and biochemical analysis value were 0.9320, 0.9712, 0.9462 and 0.9483, respectively. All of the results proved the feasibility of the multi-optical path length spectroscopy technique for blood components analysis. And this technique established the foundation of detecting the components of blood and other liquid conveniently and rapidly.

  17. Determination of total trans fats and oils by infrared spectroscopy for regulatory compliance. (United States)

    Mossoba, M M; Milosevic, V; Milosevic, M; Kramer, J K G; Azizian, H


    The mandatory requirement in many countries to declare the amount of trans fat present in food products and dietary supplements has led to a need for sensitive and accurate methodologies for the rapid quantitation of total trans fats and oils. Capillary gas chromatography (GC) and infrared spectroscopy (IR) are the two methods most commonly used to identify and quantify trans fatty acids for food labeling purposes (see the article by Delmonte and Rader in this ABC issue for a detailed presentation of GC methodology). The present article provides a comprehensive review of the IR technique and the current attenuated total reflection (ATR) Fourier-transform (FT) IR methodologies for the rapid determination of total trans fats and oils. This review also addresses potential sources of interferences and inaccuracies in FTIR determinations, particularly those done at low trans levels. Recent observations have shown that the presence of saturated fats caused interferences in the FTIR spectra observed for trans triacylglycerols. The recognition and resolution of previously unresolved quantitative issues improved the accuracy and sensitivity of the FTIR methodology. Once validated, it is anticipated that the new negative second-derivative ATR-FTIR procedure will make IR spectroscopy more suitable than ever, and a rapid alternative and/or complementary method to GC, for the rapid determination of total trans fats for regulatory compliance. Figure Infrared light bouncing inside an internal reflection crystal.

  18. Ectomycorrhizal identification in environmental samples of tree roots by Fourier-transform infrared (FTIR spectroscopy

    Directory of Open Access Journals (Sweden)

    Rodica ePena


    Full Text Available Roots of forest trees are associated with various ectomycorrhizal (ECM fungal species that are involved in nutrient exchange between host plant and the soil compartment. The identification of ECM fungi in small environmental samples is difficult. The present study tested the feasibility of attenuated total reflection Fourier-transform infrared (ATR-FTIR spectroscopy followed by hierarchical cluster analysis (HCA to discriminate in situ collected ECM fungal species. Root tips colonized by distinct ECM fungal species, i.e., Amanita rubescens, Cenococcum geophilum, Lactarius subdulcis, Russula ochroleuca, and Xerocomus pruinatus were collected in mono-specific beech (Fagus sylvatica and mixed deciduous forests in different geographic areas to investigate the environmental variability of the ECM FTIR signatures.A clear HCA discrimination was obtained for ECM fungal species independent of individual provenance. Environmental variability neither limited the discrimination between fungal species nor provided sufficient resolution to discern species sub-clusters for different sites. However, the de-convoluted FTIR spectra contained site-related spectral information for fungi with wide nutrient ranges, but not for Lactarius subdulcis, a fungus residing only in the litter layer. Specific markers for distinct ECM were identified in spectral regions associated with carbohydrates (i.e. mannans, lipids, and secondary protein structures. The present results support that FTIR spectroscopy coupled with multivariate analysis is a reliable and fast method to identify ECM fungal species in minute environmental samples. Moreover, our data suggest that the FTIR spectral signatures contain information on physiological and functional traits of ECM fungi.

  19. Detection and chemical profiling of medicine counterfeits by Raman spectroscopy and chemometrics. (United States)

    Dégardin, Klara; Roggo, Yves; Been, Frederic; Margot, Pierre


    Raman spectroscopy combined with chemometrics has recently become a widespread technique for the analysis of pharmaceutical solid forms. The application presented in this paper is the investigation of counterfeit medicines. This increasingly serious issue involves networks that are an integral part of industrialized organized crime. Efficient analytical tools are consequently required to fight against it. Quick and reliable authentication means are needed to allow the deployment of measures from the company and the authorities. For this purpose a method in two steps has been implemented here. The first step enables the identification of pharmaceutical tablets and capsules and the detection of their counterfeits. A nonlinear classification method, the Support Vector Machines (SVM), is computed together with a correlation with the database and the detection of Active Pharmaceutical Ingredient (API) peaks in the suspect product. If a counterfeit is detected, the second step allows its chemical profiling among former counterfeits in a forensic intelligence perspective. For this second step a classification based on Principal Component Analysis (PCA) and correlation distance measurements is applied to the Raman spectra of the counterfeits. Copyright © 2011 Elsevier B.V. All rights reserved.

  20. Label-Free Aptasensor for Lysozyme Detection Using Electrochemical Impedance Spectroscopy

    Directory of Open Access Journals (Sweden)

    Dionisia Ortiz-Aguayo


    Full Text Available This research develops a label-free aptamer biosensor (aptasensor based on graphite-epoxy composite electrodes (GECs for the detection of lysozyme protein using Electrochemical Impedance Spectroscopy (EIS technique. The chosen immobilization technique was based on covalent bonding using carbodiimide chemistry; for this purpose, carboxylic moieties were first generated on the graphite by electrochemical grafting. The detection was performed using [Fe(CN6]3−/[Fe(CN6]4− as redox probe. After recording the frequency response, values were fitted to its electric model using the principle of equivalent circuits. The aptasensor showed a linear response up to 5 µM for lysozyme and a limit of detection of 1.67 µM. The sensitivity of the established method was 0.090 µM−1 in relative charge transfer resistance values. The interference response by main proteins, such as bovine serum albumin and cytochrome c, has been also characterized. To finally verify the performance of the developed aptasensor, it was applied to wine analysis.

  1. Non-invasive optical detection of HBV based on serum surface-enhanced Raman spectroscopy (United States)

    Zheng, Zuci; Wang, Qiwen; Weng, Cuncheng; Lin, Xueliang; Lin, Yao; Feng, Shangyuan


    An optical method of surface-enhanced Raman spectroscopy (SERS) was developed for non-invasive detection of hepatitis B surface virus (HBV). Hepatitis B virus surface antigen (HBsAg) is an established serological marker that is routinely used for the diagnosis of acute or chronic hepatitis B virus(HBV) infection. Utilizing SERS to analyze blood serum for detecting HBV has not been reported in previous literature. SERS measurements were performed on two groups of serum samples: one group for 50 HBV patients and the other group for 50 healthy volunteers. Blood serum samples are collected from healthy control subjects and patients diagnosed with HBV. Furthermore, principal components analysis (PCA) combined with linear discriminant analysis (LDA) were employed to differentiate HBV patients from healthy volunteer and achieved sensitivity of 80.0% and specificity of 74.0%. This exploratory work demonstrates that SERS serum analysis combined with PCA-LDA has tremendous potential for the non-invasive detection of HBV.

  2. A surface enhanced Raman spectroscopy platform based on nanoshells for detection of β-amyloid (United States)

    Beier, Hope T.; Cowan, Christopher B.; Good, Theresa A.; Coté, Gerard L.


    A major limitation of many surfaced enhanced Raman spectroscopy (SERS) approaches is the dependence of the Raman enhancement on the local nanostructure. While these local "hot spots" may provide areas of extremely strong enhancement, which make trace analyte detection possible, they also make quantitative measurements problematic. Gold nanoshells however, with the ratio of the radius of their silica core to gold shell tuned to the near infrared excitation wavelength, have been used as a platform for uniform SERS enhancement. By using nanoshells, the SERS enhancement is dependent on the resonance of single nanoshells, without relying on the uncontrolled contribution from localized "hot spots". The nanoshell platform is functionalized with sialic acid to mimic neuronal cells surfaces to allow for the specific binding of β-amyloid, the primary protein component of the senile plaques found in Alzheimer's disease patients. We ultimately hope that this mechanism will provide insight into the relationship between the progression of Alzheimer's disease and β-amyloid through detection of the toxic form of the protein with structural and concentration information. With this approach, we have obtained concentration dependent spectra, consistent across the platform surface, which indicate the feasibility of detecting β-amyloid oligomers into the picomolar range. Additionally, by monitoring SERS spectra as β-amyloid changes its structural conformation from monomer to fibril, we have demonstrated conformational dependence of the SERS signals.

  3. Brain changes detected by functional magnetic resonance imaging and spectroscopy in patients with Crohn's disease. (United States)

    Lv, Kun; Fan, Yi-Hong; Xu, Li; Xu, Mao-Sheng


    Crohn's disease (CD) is a chronic, non-specific granulomatous inflammatory disorder that commonly affects the small intestine and is a phenotype of inflammatory bowel disease (IBD). CD is prone to relapse, and its incidence displays a persistent increase in developing countries. However, the pathogenesis of CD is poorly understood, with some studies emphasizing the link between CD and the intestinal microbiota. Specifically, studies point to the brain-gut-enteric microbiota axis as a key player in the occurrence and development of CD. Furthermore, investigations have shown white-matter lesions and neurologic deficits in patients with IBD. Based on these findings, brain activity changes in CD patients have been detected by blood oxygenation level dependent functional magnetic resonance imaging (BOLD-fMRI). BOLD-fMRI functions by detecting a local increase in relative blood oxygenation that results from neurotransmitter activity and thus reflects local neuronal firing rates. Therefore, biochemical concentrations of neurotransmitters or metabolites may change in corresponding brain regions of CD patients. To further study this phenomenon, brain changes of CD patients can be detected non-invasively, effectively and accurately by BOLD-fMRI combined with magnetic resonance spectroscopy (MRS). This approach can further shed light on the mechanisms of the occurrence and development of neurological CD. Overall, this paper reviews the current status and prospects on fMRI and MRS for evaluation of patients with CD based on the brain-gut-enteric microbiota axis.

  4. Detection of Ractopamine and Clenbuterol Hydrochloride Residues in Pork Using Surface Enhanced Raman Spectroscopy (United States)

    Zhao, J. H.; Yuan, H. C.; Peng, Y. J.; Hong, Q.; Liu, M. H.


    Surface enhanced Raman spectroscopy (SERS) coupled with chemometric methods, such as adaptive iteratively reweighted penalized least squares (AIR-PLS), wavelet transform, and least squares support vector machine (LSSVM), was investigated to realize the rapid detection and identifi cation of ractopamine (RAC) and clenbuterol hydrochloride (CL) residues in pork. First-level wavelet detail signal intensities at 1168 cm-1 were used to establish a standard curve of the RAC residues in pork, and the linear regression equation and the correlation coefficient were y = -4. 3683x - 11.059 and -0.9726. Second-level wavelet detail signal intensities at 1258 cm-1 were used to establish a standard curve of the CL residues in pork, and the linear regression equation and the correlation coeffi cient were y=33.595x + 36.538 and 0.9842. The second-level wavelet detail signals of the SERS spectra were selected as the inputs of the LSSVM classifi cation model for the identifi cation of the RAC and CL residues in pork, with a total accuracy rate reaching 100%. The experimental results demonstrate that the proposed method based on SERS is a good detection scheme for the rapid detection and identifi cation of RAC and CL residues in pork.

  5. Rapid detection of Listeria monocytogenes in milk using confocal micro-Raman spectroscopy and chemometric analysis. (United States)

    Wang, Junping; Xie, Xinfang; Feng, Jinsong; Chen, Jessica C; Du, Xin-jun; Luo, Jiangzhao; Lu, Xiaonan; Wang, Shuo


    Listeria monocytogenes is a facultatively anaerobic, Gram-positive, rod-shape foodborne bacterium causing invasive infection, listeriosis, in susceptible populations. Rapid and high-throughput detection of this pathogen in dairy products is critical as milk and other dairy products have been implicated as food vehicles in several outbreaks. Here we evaluated confocal micro-Raman spectroscopy (785 nm laser) coupled with chemometric analysis to distinguish six closely related Listeria species, including L. monocytogenes, in both liquid media and milk. Raman spectra of different Listeria species and other bacteria (i.e., Staphylococcus aureus, Salmonella enterica and Escherichia coli) were collected to create two independent databases for detection in media and milk, respectively. Unsupervised chemometric models including principal component analysis and hierarchical cluster analysis were applied to differentiate L. monocytogenes from Listeria and other bacteria. To further evaluate the performance and reliability of unsupervised chemometric analyses, supervised chemometrics were performed, including two discriminant analyses (DA) and soft independent modeling of class analogies (SIMCA). By analyzing Raman spectra via two DA-based chemometric models, average identification accuracies of 97.78% and 98.33% for L. monocytogenes in media, and 95.28% and 96.11% in milk were obtained, respectively. SIMCA analysis also resulted in satisfied average classification accuracies (over 93% in both media and milk). This Raman spectroscopic-based detection of L. monocytogenes in media and milk can be finished within a few hours and requires no extensive sample preparation. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Rapid detection of drugs of abuse in saliva using surface enhanced Raman spectroscopy and microfluidics. (United States)

    Andreou, Chrysafis; Hoonejani, Mehran R; Barmi, Meysam R; Moskovits, Martin; Meinhart, Carl D


    We present a microfluidic device that detects trace concentrations of drugs of abuse in saliva within minutes using surface-enhanced Raman spectroscopy (SERS). Its operation is demonstrated using methamphetamine. The detection scheme exploits concentration gradients of chemicals, fostered by the laminar flow in the device, to control the interactions between the analyte, silver nanoparticles (Ag-NPs), and a salt. Also, since all species interact while advecting downstream, the relevant reaction coordinates occur with respect to the position in the channel. The system was designed to allow the analyte first to diffuse into the side stream containing the Ag-NPs, on which it is allowed to adsorb, before salt ions are introduced, causing the Ag-NPs to aggregate, and so creating species with strong SERS signal. The device allows partial separation via diffusion of the analyte from the complex mixture. Also, the reproducible salt-induced NP aggregation decouples the aggregation reaction (necessary for strong SERS) from the analyte concentration or charge. This method enables the creation of a region where detection of the analyte of interest via SERS is optimal, and dramatically extends the classes of molecules and quality of signals that can be measured using SERS, compared to bulk solution methods. The spatial distribution of the SERS signals was used to map the degree of nanoparticle aggregation and species diffusion in the channel, which, together with numerical simulations, was used to describe the kinetics of the colloid aggregation reaction, and to determine the optimal location in the channel for SERS interrogation.

  7. [Detecting Thallium in Water Samples using Dispersive Liquid Phase Microextraction-Graphite Furnace Atomic Absorption Spectroscopy]. (United States)

    Zhu, Jing; Li, Yan; Zheng, Bo; Tang, Wei; Chen, Xiao; Zou, Xiao-li


    To develope a method of solvent demulsification dispersive liquid phase microextraction (SD-DLPME) based on ion association reaction coupled with graphite furnace atomic absorption spectroscopy (GFAAS) for detecting thallium in water samples. Methods Thallium ion in water samples was oxidized to Tl(III) with bromine water, which reacted with Cl- to form TlCl4-. The ionic associated compound with trioctylamine was obtained and extracted. DLPME was completed with ethanol as dispersive solvent. The separation of aqueous and organic phase was achieved by injecting into demulsification solvent without centrifugation. The extractant was collected and injected into GFAAS for analysis. With palladium colloid as matrix modifier, a two step drying and ashing temperature programming process was applied for high precision and sensitivity. The linear range was 0.05-2.0 microg/L, with a detection limit of 0.011 microg/L. The relative standard derivation (RSD) for detecting Tl in spiked water sample was 9.9%. The spiked recoveries of water samples ranged from 94.0% to 103.0%. The method is simple, sensitive and suitable for batch analysis of Tl in water samples.

  8. Noninvasive detection of concealed explosives: depth profiling through opaque plastics by time-resolved Raman spectroscopy. (United States)

    Petterson, Ingeborg E Iping; López-López, María; García-Ruiz, Carmen; Gooijer, Cees; Buijs, Joost B; Ariese, Freek


    The detection of explosives concealed behind opaque, diffusely scattering materials is a challenge that requires noninvasive analytical techniques for identification without having to manipulate the package. In this context, this study focuses on the application of time-resolved Raman spectroscopy (TRRS) with a picosecond pulsed laser and an intensified charge-coupled device (ICCD) detector for the noninvasive identification of explosive materials through several millimeters of opaque polymers or plastic packaging materials. By means of a short (250 ps) gate which can be delayed several hundred picoseconds after the laser pulse, the ICCD detector allows for the temporal discrimination between photons from the surface of a sample and those from deeper layers. TRRS was applied for the detection of the two main isomers of dinitrotoluene, 2,4-dinitrotoluene, and 2,6-dinitrotoluene as well as for various other components of explosive mixtures, including akardite II, diphenylamine, and ethyl centralite. Spectra were obtained through different diffuse scattering white polymer materials: polytetrafluoroethylene (PTFE), polyoxymethylene (POM), and polyethylene (PE). Common packaging materials of various thicknesses were also selected, including polystyrene (PS) and polyvinyl chloride (PVC). With the demonstration of the ability to detect concealed, explosives-related compounds through an opaque first layer, this study may have important applications in the security and forensic fields.

  9. In vivo Raman spectroscopy detects increased epidermal antioxidative potential with topically applied carotenoids (United States)

    Lademann, J.; Caspers, P. J.; van der Pol, A.; Richter, H.; Patzelt, A.; Zastrow, L.; Darvin, M.; Sterry, W.; Fluhr, J. W.


    In the present study, the distribution of the carotenoids as a marker for the complete antioxidative potential in human skin was investigated before and after the topical application of carotenoids by in vivo Raman spectroscopy with an excitation wavelength of 785 nm. The carotenoid profile was assessed after a short term topical application in 4 healthy volunteers. In the untreated skin, the highest concentration of natural carotenoids was detected in different layers of the stratum corneum (SC) close to the skin surface. After topical application of carotenoids, an increase in the antioxidative potential in the skin could be observed. Topically applied carotenoids penetrate deep into the epidermis down to approximately 24 μm. This study supports the hypothesis that antioxidative substances are secreted via eccrine sweat glands and/or sebaceous glands to the skin surface. Subsequently they penetrate into the different layers of the SC.

  10. Inclusion Detection in Aluminum Alloys Via Laser-Induced Breakdown Spectroscopy (United States)

    Hudson, Shaymus W.; Craparo, Joseph; De Saro, Robert; Apelian, Diran


    Laser-induced breakdown spectroscopy (LIBS) has shown promise as a technique to quickly determine molten metal chemistry in real time. Because of its characteristics, LIBS could also be used as a technique to sense for unwanted inclusions and impurities. Simulated Al2O3 inclusions were added to molten aluminum via a metal-matrix composite. LIBS was performed in situ to determine whether particles could be detected. Outlier analysis on oxygen signal was performed on LIBS data and compared to oxide volume fraction measured through metallography. It was determined that LIBS could differentiate between melts with different amounts of inclusions by monitoring the fluctuations in signal for elements of interest. LIBS shows promise as an enabling tool for monitoring metal cleanliness.

  11. Detection of biological contaminants on foods and food surfaces using laser-induced breakdown spectroscopy (LIBS). (United States)

    Multari, Rosalie A; Cremers, David A; Dupre, Jo Anne M; Gustafson, John E


    The rapid detection of biological contaminants, such as Escherichia coli O157:H7 and Salmonella enterica , on foods and food-processing surfaces is important to ensure food safety and streamline the food-monitoring process. Laser-induced breakdown spectroscopy (LIBS) is an ideal candidate technology for this application because sample preparation is minimal and results are available rapidly (seconds to minutes). Here, multivariate regression analysis of LIBS data is used to differentiate the live bacterial pathogens E. coli O157:H7 and S. enterica on various foods (eggshell, milk, bologna, ground beef, chicken, and lettuce) and surfaces (metal drain strainer and cutting board). The type (E. coli or S. enterica) of bacteria could be differentiated in all cases studied along with the metabolic state (viable or heat killed). This study provides data showing the potential of LIBS for the rapid identification of biological contaminants using spectra collected directly from foods and surfaces.

  12. Laser spectroscopy for totally non-intrusive detection of oxygen in modified atmosphere food packages (United States)

    Cocola, L.; Fedel, M.; Poletto, L.; Tondello, G.


    A device for measuring the oxygen concentration inside packages in modified atmosphere working in a completely non-intrusive way has been developed and tested. The device uses tunable diode laser spectroscopy in a geometry similar to a short distance LIDAR: A laser beam is sent through the top film of a food package, and the absorption is measured by detecting the light scattered by the bottom of the container or by a portion of the food herein contained. The device can operate completely in a contactless way from the package, and the distances of absorption both outside and inside the package are measured with a triangulation system. The performances of the device have been tested for various types of containers, and absolute values for the oxygen concentration have been compared with standard albeit destructive measurements.

  13. Detection and quantification of dithiocarbamate pesticides by Surface Enhanced Raman Spectroscopy (SERS) (United States)

    Saute, Benjamin Calvin

    Dithiocarbamates are a subclass of carbamate pesticides that are widely used as insecticidal agents on food crops in the US and abroad. Quantitative determination of trace quantities of dithiocarbamates is necessary in order to mitigate potential human exposure via pesticide residues left on inadequately washed food items as well as groundwater contamination from agricultural runoff. The focus of this research is on the development and optimization of a Surface Enhanced Raman Spectroscopy (SERS) based analytical technique for the quantitative determination of trace amounts of dithiocarbamate pesticides in different matrices. Gold nanoparticles of different shapes and sizes will be investigated to determine the suitability of these materials as SERS active substrates for the trace analysis of dithiocarbamate pesticides. Analytical sensitivity will be evaluated by determining the limits of detection using established statistical methods.

  14. Polythiophene synthesis coupled to quartz crystal microbalance and Raman spectroscopy for detecting bacteria. (United States)

    Kengne-Momo, R P; Lagarde, F; Daniel, Ph; Pilard, J F; Durand, M J; Thouand, G


    A simple electrochemical procedure was used for the synthesis of a polythiophene containing para-benzenesulfonyl chloride groups. The obtained polymer was shown to be very reactive and directly able to covalently bind nucleophile biomolecules. Protein A and a specific antibody were then successively immobilized on the conductive polymer through a covalent bonding of Protein A with the as-prepared linker for bacteria trapping purpose. All reactions were controlled in situ by cyclic voltammetry, quartz crystal microbalance and Raman spectroscopy. The results were compared to those previously obtained on gold surface modified with the same chemical linker. The conductive polymer led to a very high rate of antibody recognition compared to the gold surface and to literature, probably due to a large available surface obtained after polymerization. One example of pathogenic bacteria "Salmonella enterica paratyphi" detection was successfully tested on the substrates. The presented results are promising for the future design of simple and inexpensive immunocapture-based sensors.

  15. Detection of whitening agents in illegal cosmetics using attenuated total reflectance-infrared spectroscopy. (United States)

    Deconinck, E; Bothy, J L; Desmedt, B; Courselle, P; De Beer, J O


    Cosmetic products containing illegal whitening agents are still found on the European market. They represent a considerable risk to public health, since they are often characterised by severe side effects when used chronically. The detection of such products at customs is not always simple, due to misleading packaging and the existence of products containing only legal components. Therefore there is a need for easy to use equipment and techniques to perform an initial screening of samples. The use of attenuated total reflectance-infrared (ATR-IR) spectroscopy, combined with chemometrics, was evaluated for that purpose. It was found that the combination of ATR-IR with the simple chemometric technique k-nearest neighbours gave good results. A model was obtained in which a minimum of illegal samples was categorised as legal. The correctly classified illegal samples could be attributed to the illegal components present. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Detectability of Neuronal Currents in Human Brain with Magnetic Resonance Spectroscopy.

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Howland D. T. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Thomas, Edward V. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Harper, Jason C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Mayer, Andrew R. [Mind Research Network, Albuquerque, NM (United States); Univ. of New Mexico, Albuquerque, NM (United States); Caprihan, Arvind [Mind Research Network, Albuquerque, NM (United States); Gasparovic, Charles [Mind Research Network, Albuquerque, NM (United States); Univ. of New Mexico, Albuquerque, NM (United States); Blagoev, Krastan B. [Mind Research Network, Albuquerque, NM (United States); Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Haaland, David M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)


    Magnetic resonance spectroscopy has been used in a high-risk, high-payoff search for neuronal current (NC) signals in the free induction decay (FID) data from the visual cortex of human subjects during visual stimulation. If successful, this approach could make possible the detection of neuronal currents in the brain at high spatial and temporal resolution. Our initial experiments indicated the presence of a statistically significant change in the FID containing the NC relative to FIDs with the NC absent, and this signal was consistent with the presence of NC. Unfortunately, two follow-on experiments were not able to confirm or replicate the positive findings of the first experiment. However, even if the result from the first experiment were evidence of NC in the FID, it is clear that its effect is so small, that a true NC imaging experiment would not be possible with the current instrumentation and experimental protocol used here.

  17. Precision of coherence analysis to detect cerebral autoregulation by near-infrared spectroscopy in preterm infants

    DEFF Research Database (Denmark)

    Hahn, GH; Christensen, KB; Leung, TS


    Coherence between spontaneous fluctuations in arterial blood pressure (ABP) and the cerebral near-infrared spectroscopy signal can detect cerebral autoregulation. Because reliable measurement depends on signals with high signal-to-noise ratio, we hypothesized that coherence is more precisely...... determined when fluctuations in ABP are large rather than small. Therefore, we investigated whether adjusting for variability in ABP (variabilityABP) improves precision. We examined the impact of variabilityABP within the power spectrum in each measurement and between repeated measurements in preterm infants....... We also examined total monitoring time required to discriminate among infants with a simulation study. We studied 22 preterm infants (GAABP within the power spectrum did not improve the precision. However, adjusting...

  18. Application of UV-Raman spectroscopy to the detection of chemical and biological threats (United States)

    Sedlacek, Arthur J., III; Christesen, Steven D.; Chyba, Tom; Ponsardin, Pat


    Brookhaven National Laboratory (BNL), Edgewood Chemical and Biological Center (ECBC) and ITT Industries Advanced Engineering and Sciences Division (AES) have been collaborating on the transitioning and subsequent development of a short-range, non-contact Raman lidar system specifically designed to detect and identify chemical agents on the battlefield. [The instrument, referred to as LISA (Laser Interrogation of Surface Agents), will the subject of an accompanying paper.] As part of this collaboration, BNL has the responsibility for developing a spectral database (library) of surrogates and precursors for use with LISA"s pattern recognition algorithms. In this paper, the authors discuss the phenomenon of UV Raman and resonance-enhanced Raman spectroscopy, the development of an instrument-independent Raman spectral library, and highlight the exploitable characteristics present in the acquired spectral signatures that suggest potential utility in our country"s efforts on Homeland Security.

  19. Laser frequency-offset locking based on the frequency modulation spectroscopy with higher harmonic detection (United States)

    Wang, Anqi; Meng, Zhixin; Feng, Yanying


    We design a fiber electro-optic modulator (FEOM)-based laser frequency-offset locking system using frequency modulation spectroscopy (FMS) with the 3F modulation. The modulation signal and the frequency-offset control signal are simultaneously loaded on the FEOM by a mixer in order to suppress the frequency and power jitter caused by internal modulation on the current or piezoelectric ceramic transducer (PZT). It is expected to accomplish a fast locking, a widely tunable frequency-offset, a sensitive and rapid detection of narrow spectral features with the 3F modulation. The laser frequency fluctuation is limited to +/-1MHz and its overlapping Allan deviation is around 10-12 in twenty minutes, which successfully meets the requirements of the cold atom interferometer.

  20. Second Harmonic Generation Guided Raman Spectroscopy for Sensitive Detection of Polymorph Transitions

    Energy Technology Data Exchange (ETDEWEB)

    Chowdhury, Azhad U.; Ye, Dong Hye; Song, Zhengtian; Zhang, Shijie; Hedderich, Hartmut G.; Mallick, Babita; Thirunahari, Satyanarayana; Ramakrishnan, Srividya; Sengupta, Atanu; Gualtieri, Ellen J.; Bouman, Charles A.; Simpson, Garth J. (Purdue); (IPDO)


    Second harmonic generation (SHG) was integrated with Raman spectroscopy for the analysis of pharmaceutical materials. Particulate formulations of clopidogrel bisulfate were prepared in two crystal forms (Form I and Form II). Image analysis approaches enable automated identification of particles by bright field imaging, followed by classification by SHG. Quantitative SHG microscopy enabled discrimination of crystal form on a per particle basis with 99.95% confidence in a total measurement time of ~10 ms per particle. Complementary measurements by Raman and synchrotron XRD are in excellent agreement with the classifications made by SHG, with measurement times of ~1 min and several seconds per particle, respectively. Coupling these capabilities with at-line monitoring may enable real-time feedback for reaction monitoring during pharmaceutical production to favor the more bioavailable but metastable Form I with limits of detection in the ppm regime.

  1. Detection of cerebral hemorrhage in rabbits by time-difference magnetic inductive phase shift spectroscopy.

    Directory of Open Access Journals (Sweden)

    Wencai Pan

    Full Text Available Cerebral hemorrhage, a difficult issue in clinical practice, is often detected and studied with computed tomography (CT, magnetic resonance imaging (MRI, and positron emission tomography (PET. However, these expensive devices are not readily available in economically underdeveloped regions, and hence are unable to provide bedside and emergency on-site monitoring. The magnetic inductive phase shift (MIPS is an emerging technology that may become a new tool to detect cerebral hemorrhage and to serve as an inexpensive partial substitute to medical imaging. In order to study a wider band of cerebral hemorrhage MIPS and to provide more useful information for measuring cerebral hemorrhage, we established a cerebral hemorrhage magnetic induction phase shift spectroscopy (MIPSS detection system. Thirteen rabbits with five cerebral hemorrhage states were studied using a single coil-coil within a 1 MHz-200 MHz frequency range in linear sweep. A feature band (FB with the highest detection sensitivity and the greatest stability was selected for further analysis and processing. In addition, a maximum conductivity cerebrospinal fluid (CSF MRI was performed to verify and interpret the MIPSS result. The average phase shift change induced by a 3 ml injection of autologous blood under FB was -7.7503° ± 1.4204°, which was considerably larger than our previous work. Data analysis with a non-parametric statistical Friedman M test showed that in the FB, MIPSS could distinguish the five states of cerebral hemorrhage in rabbits, with a statistical significance of p<0.05. A B-F distribution profile was designed according to the MIPSS under FB that can provide instantaneous diagnostic information about the cerebral hemorrhage severity from a single set of measurements. The results illustrate that the MIPSS detection method is able to provide a new possibility for real-time monitoring and diagnosis of the severity of cerebral hemorrhage.

  2. Neural networks improve brain cancer detection with Raman spectroscopy in the presence of operating room light artifacts (United States)

    Jermyn, Michael; Desroches, Joannie; Mercier, Jeanne; Tremblay, Marie-Andrée; St-Arnaud, Karl; Guiot, Marie-Christine; Petrecca, Kevin; Leblond, Frederic


    Invasive brain cancer cells cannot be visualized during surgery and so they are often not removed. These residual cancer cells give rise to recurrences. In vivo Raman spectroscopy can detect these invasive cancer cells in patients with grade 2 to 4 gliomas. The robustness of this Raman signal can be dampened by spectral artifacts generated by lights in the operating room. We found that artificial neural networks (ANNs) can overcome these spectral artifacts using nonparametric and adaptive models to detect complex nonlinear spectral characteristics. Coupling ANN with Raman spectroscopy simplifies the intraoperative use of Raman spectroscopy by limiting changes required to the standard neurosurgical workflow. The ability to detect invasive brain cancer under these conditions may reduce residual cancer remaining after surgery and improve patient survival.

  3. Adulteration detection in milk using infrared spectroscopy combined with two-dimensional correlation analysis (United States)

    He, Bin; Liu, Rong; Yang, Renjie; Xu, Kexin


    Adulteration of milk and dairy products has brought serious threats to human health as well as enormous economic losses to the food industry. Considering the diversity of adulterants possibly mixed in milk, such as melamine, urea, tetracycline, sugar/salt and so forth, a rapid, widely available, high-throughput, cost-effective method is needed for detecting each of the components in milk at once. In this paper, a method using Fourier Transform Infrared spectroscopy (FTIR) combined with two-dimensional (2D) correlation spectroscopy is established for the discriminative analysis of adulteration in milk. Firstly, the characteristic peaks of the raw milk are found in the 4000-400 cm-1 region by its original spectra. Secondly, the adulterant samples are respectively detected with the same method to establish a spectral database for subsequent comparison. Then, 2D correlation spectra of the samples are obtained which have high time resolution and can provide information about concentration-dependent intensity changes not readily accessible from one-dimensional spectra. And the characteristic peaks in the synchronous 2D correlation spectra of the suspected samples are compared with those of raw milk. The differences among their synchronous spectra imply that the suspected milk sample must contain some kinds of adulterants. Melamine, urea, tetracycline and glucose adulterants in milk are identified respectively. This nondestructive method can be used for a correct discrimination on whether the milk and dairy products are adulterated with deleterious substances and it provides a new simple and cost-effective alternative to test the components of milk.

  4. Diode laser detection of greenhouse gases in the near-infrared region by wavelength modulation spectroscopy: pressure dependence of the detection sensitivity. (United States)

    Asakawa, Takashi; Kanno, Nozomu; Tonokura, Kenichi


    We have investigated the pressure dependence of the detection sensitivity of CO(2), N(2)O and CH(4) using wavelength modulation spectroscopy (WMS) with distributed feed-back diode lasers in the near infrared region. The spectral line shapes and the background noise of the second harmonics (2f) detection of the WMS were analyzed theoretically. We determined the optimum pressure conditions in the detection of CO(2), N(2)O and CH(4), by taking into consideration the background noise in the WMS. At the optimum total pressure for the detection of CO(2), N(2)O and CH(4), the limits of detection in the present system were determined.

  5. Mid-infrared spectroscopy combined with chemometrics to detect Sclerotinia stem rot on oilseed rape (Brassica napus L.) leaves. (United States)

    Zhang, Chu; Feng, Xuping; Wang, Jian; Liu, Fei; He, Yong; Zhou, Weijun


    Detection of plant diseases in a fast and simple way is crucial for timely disease control. Conventionally, plant diseases are accurately identified by DNA, RNA or serology based methods which are time consuming, complex and expensive. Mid-infrared spectroscopy is a promising technique that simplifies the detection procedure for the disease. Mid-infrared spectroscopy was used to identify the spectral differences between healthy and infected oilseed rape leaves. Two different sample sets from two experiments were used to explore and validate the feasibility of using mid-infrared spectroscopy in detecting Sclerotinia stem rot (SSR) on oilseed rape leaves. The average mid-infrared spectra showed differences between healthy and infected leaves, and the differences varied among different sample sets. Optimal wavenumbers for the 2 sample sets selected by the second derivative spectra were similar, indicating the efficacy of selecting optimal wavenumbers. Chemometric methods were further used to quantitatively detect the oilseed rape leaves infected by SSR, including the partial least squares-discriminant analysis, support vector machine and extreme learning machine. The discriminant models using the full spectra and the optimal wavenumbers of the 2 sample sets were effective for classification accuracies over 80%. The discriminant results for the 2 sample sets varied due to variations in the samples. The use of two sample sets proved and validated the feasibility of using mid-infrared spectroscopy and chemometric methods for detecting SSR on oilseed rape leaves. The similarities among the selected optimal wavenumbers in different sample sets made it feasible to simplify the models and build practical models. Mid-infrared spectroscopy is a reliable and promising technique for SSR control. This study helps in developing practical application of using mid-infrared spectroscopy combined with chemometrics to detect plant disease.

  6. Electrochemical impedance spectroscopy based MEMS sensors for phthalates detection in water and juices

    KAUST Repository

    Zia, Asif I


    Phthalate esters are ubiquitous environmental and food pollutants well known as endocrine disrupting compounds (EDCs). These developmental and reproductive toxicants pose a grave risk to the human health due to their unlimited use in consumer plastic industry. Detection of phthalates is strictly laboratory based time consuming and expensive process and requires expertise of highly qualified and skilled professionals. We present a real time, non-invasive, label free rapid detection technique to quantify phthalates\\' presence in deionized water and fruit juices. Electrochemical impedance spectroscopy (EIS) technique applied to a novel planar inter-digital (ID) capacitive sensor plays a vital role to explore the presence of phthalate esters in bulk fluid media. The ID sensor with multiple sensing gold electrodes was fabricated on silicon substrate using micro-electromechanical system (MEMS) device fabrication technology. A thin film of parylene C polymer was coated as a passivation layer to enhance the capacitive sensing capabilities of the sensor and to reduce the magnitude of Faradic current flowing through the sensor. Various concentrations, 0.002ppm through to 2ppm of di (2-ethylhexyl) phthalate (DEHP) in deionized water, were exposed to the sensing system by dip testing method. Impedance spectra obtained was analysed to determine sample conductance which led to consequent evaluation of its dielectric properties. Electro-chemical impedance spectrum analyser algorithm was employed to model the experimentally obtained impedance spectra. Curve fitting technique was applied to deduce constant phase element (CPE) equivalent circuit based on Randle\\'s equivalent circuit model. The sensing system was tested to detect different concentrations of DEHP in orange juice as a real world application. The result analysis indicated that our rapid testing technique is able to detect the presence of DEHP in all test samples distinctively.

  7. Fructose-water-dimethylsulfoxide interactions by vibrational spectroscopy and molecular dynamics simulations. (United States)

    Nikolakis, Vladimiros; Mushrif, Samir H; Herbert, Bryon; Booksh, Karl S; Vlachos, Dionisios G


    The solvation of fructose in dimethyl sulfoxide (DMSO) and DMSO-H(2)O (or DMSO-D(2)O) mixtures was investigated using vibrational spectroscopy (Raman, ATR/FTIR) and molecular dynamics (MD) simulations. The analysis of the fructose hydroxyl hydrogen-DMSO oxygen radial distribution function showed that the coordination number of DMSO around the furanose form of fructose is ~3.5. This number is smaller than the number of hydroxyl groups of fructose because one DMSO molecule is shared between two hydroxyl groups and because intramolecular hydrogen bonds are formed. In the case of fructose-DMSO mixtures, a red shift of the Raman S═O asymmetric stretch is observed, which indicates that fructose breaks the DMSO clusters through strong hydrogen bonding between the hydrogen atoms of its hydroxyl groups and the oxygen atom of DMSO. The Raman scattering cross sections of the DMSO S═O stretch when a DMSO molecule interacts with another DMSO molecule, a fructose molecule, or a water molecule were estimated from the spectra of the binary mixtures using the coordination numbers from MD simulations. It was also possible to use these values together with the MD-estimated coordination numbers to satisfactorily predict the effect of the water fraction on the Raman scattering intensity of the S═O stretching band in ternary mixtures. MD simulations also showed that, with increasing water content, the DMSO orientation around fructose changed, with the sulfur atom moving away from the carbohydrate. The deconvolution of the fructose IR OH stretching region revealed that the hydroxyls of fructose can be separated into two groups that participate in hydrogen bonds of different strengths. MD simulations showed that the three hydroxyls of the fructose ring form stronger hydrogen bonds with the solvent than the remaining hydroxyls, providing an explanation for the experimental observations. Finally, analysis of ATR/FTIR spectra revealed that, with increasing water content, the average

  8. Detection of citrus Huanglongbing by Fourier transform infrared-attenuated total reflection spectroscopy. (United States)

    Hawkins, Samantha A; Park, Bosoon; Poole, Gavin H; Gottwald, Timothy; Windham, William R; Lawrence, Kurt C


    Citrus Huanglongbing (HLB, also known as citrus greening disease) was discovered in Florida in 2005 and is spreading rapidly amongst the citrus growing regions of the state. Detection via visual symptoms of the disease is not a long-term viable option. New techniques are being developed to test for the disease in its earlier presymptomatic stages. Fourier transform infrared-attenuated total reflection (FT-IR-ATR) spectroscopy is a candidate for rapid, inexpensive, early detection of the disease. The mid-infrared region of the spectrum reveals dramatic changes that take place in the infected leaves when compared to healthy non-infected leaves. The carbohydrates that give rise to peaks in the 900-1180 cm(-1) range are reliable in distinguishing leaves from infected plants versus non-infected plants. A model based on chemometrics was developed using the spectra from 179 plants of known disease status. This model then correctly predicted the status of >95% of the plants tested.

  9. Early detection of colorectal cancer relapse by infrared spectroscopy in ``normal'' anastomosis tissue (United States)

    Salman, Ahmad; Sebbag, Gilbert; Argov, Shmuel; Mordechai, Shaul; Sahu, Ranjit K.


    Colorectal cancer is one of the most aggressive cancers usually occurring in people above the age of 50 years. In the United States, colorectal cancer is the third most diagnosed cancer. The American Cancer Society has estimated 96,830 new cases of colon cancer and 40,000 new cases of rectal cancer in 2014 in the United States. According to the literature, up to 55% of colorectal cancer patients experience a recurrence within five years from the time of surgery. Relapse of colorectal cancer has a deep influence on the quality of patient life. Infrared (IR) spectroscopy has been widely used in medicine. It is a noninvasive, nondestructive technique that can detect changes in cells and tissues that are caused by different disorders, such as cancer. Abnormalities in the colonic crypts, which are not detectable using standard histopathological methods, could be determined using IR spectroscopic methods. The IR measurements were performed on formalin-fixed, paraffin-embedded colorectal tissues from eight patients (one control, four local recurrences, three distant recurrences). A total of 128 crypts were measured. Our results showed the possibility of differentiating among control, local, and distant recurrence crypts with more than a 92% success rate using spectra measured from the crypts' middle sites.

  10. Potential of Cathodoluminescence Microscopy and Spectroscopy for the Detection of Prokaryotic Cells on Minerals (United States)

    Rommevaux-Jestin, Céline; Ménez, Bénédicte


    Detecting mineral-hosted ecosystems to assess the extent and functioning of the biosphere from the surface to deep Earth requires appropriate techniques that provide, beyond the morphological criteria, indubitable clues of the presence of prokaryotic cells. Here, we evaluate the capability of cathodoluminescence microscopy and spectroscopy, implemented on a scanning electron microscope, to identify prokaryotes on mineral surfaces. For this purpose, we used, as a first step, a simple model of either unstained or stained cultivable cells (Escherichia coli, Deinococcus radiodurans) deposited on minerals that are common in the oceanic crust (basaltic glass, amphibole, pyroxene, and magnetite). Our results demonstrate that the detection of cells is possible at the micrometric level on the investigated minerals through the intrinsic fluorescence of their constituting macromolecules (aromatic amino and nucleic acids, coenzymes). This allows us to distinguish biomorph inorganic phases from cells. This easily implemented technique permits an exploration of colonized rock samples. In addition, the range of spectrometric techniques available on a scanning electron microscope can provide additional information on the nature and chemistry of the associated mineral phases, which would lead to a simultaneous characterization of cells, their microhabitats, and a better understanding of their potential relationships.

  11. Detection of the mycotoxin citrinin using silver substrates and Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Dheeraj K.; Ganbold, Erdene-Ochir [Department of Chemistry, Soongsil University, Seoul 156-743 (Korea, Republic of); Cho, Eun-Min [College of Environment and Applied Chemistry, Kyung Hee University, Yongin 446-701 (Korea, Republic of); Cho, Kwang-Hwi [School of Systems Biomedical Science, Soongsil University, Sangdo-dong, Dongjak-gu, Seoul (Korea, Republic of); Kim, Doseok [Department of Physics, Sogang University, Seoul 121-742 (Korea, Republic of); Choo, Jaebum [Department of Bionano Engineering, Hanyang University, Sa-1-dong 1271, Ansan 426-791 (Korea, Republic of); Kim, Sehun [Molecular-level Interface Research Center and Department of Chemistry, KAIST, Daejeon 305-701 (Korea, Republic of); Lee, Cheol Min, E-mail: [Institute of Environmental and Industrial Medicine, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Yang, Sung Ik, E-mail: [College of Environment and Applied Chemistry, Kyung Hee University, Yongin 446-701 (Korea, Republic of); Joo, Sang-Woo, E-mail: [Department of Chemistry, Soongsil University, Seoul 156-743 (Korea, Republic of)


    Highlights: • The mycotoxin citrinin was detected using Ag substrates and Raman spectroscopy. • Prepared Ag substrates were characterized by electron microscopic tools. • Density functional theory calculation predicted the most stable geometry on Ag. -- Abstract: We detected a trace amount of the mycotoxin citrinin using surface-enhanced Raman scattering (SERS) on silver nanoparticle (Ag NP) surfaces. The SERS substrate on hydrophobic Teflon films was also introduced to observe the citrinin peaks. A broad band at ∼1382 cm{sup −1}, which was ascribed to the symmetric carboxylate stretching mode, was observed in addition to an antisymmetric carboxylate stretching mode at ∼1568 cm{sup −1} in the Raman spectra. The spectral feature indicated that citrinin would adsorb on Ag NPs via its carboxylate form. Based on density functional theory (DFT) calculations, vibrational mode analysis was performed to compare the Raman spectra of citrinin. DFT calculations also predicted that a bidentate bridge configuration through O15 and O16 atoms in citrinin would be the most stable on three Ag atoms. After treating with Ag NPs, observation of citrinin peaks was attempted in fungal cells of Penicillium citrinum. This work may provide useful insights into the direct observation of the hazardous citrinin mycotoxin using SERS by understanding its adsorption behaviors on Ag surfaces.

  12. Differential excitation spectroscopy for detection of common explosives: ammonium nitrate and urea nitrate (United States)

    Hunter, Boyd V.; Cox, Jason M.; Miller, Michael A.; Hunter, Richard V.; Van Bastian, Levi; Harrison, Paul; Walters, William P.


    Differential Excitation Spectroscopy (DES) is a new pump-probe detection technique (patent-pending) which characterizes molecules based on a multi-dimensional parameterization of the rovibrational excited state structure, pump and probe interrogation frequencies, as well as the lifetimes of the excited states. Under appropriate conditions, significant modulation of the ground state can result. DES results provide a unique, simple mechanism to probe various molecules. In addition, the DES multi-dimensional parameterization provides an identification signature that is highly unique and has demonstrated high levels of immunity from interferents, providing significant practical value for high-specificity material identification. Ammonium nitrate (AN) and urea nitrate (UN) are both components commonly used in IEDs; the ability to reliably detect these chemicals is key to finding, identifying and defeating IEDs. AN and UN are complicated materials, having a number of different phases and because they are molecular crystals, there are a number of different types of interactions between the constituent atoms which must be characterized in order to understand their DES behavior. Ab initio calculations were performed on both AN and UN for various rovibrational states up to J' ≤ 3 and validated experimentally, demonstrating good agreement between theory and experiment and the very specific responses generated.

  13. Detection of polycyclic aromatic hydrocarbons (PAHs) in raw menhaden fish oil using fluorescence spectroscopy: Method development. (United States)

    Pena, Edwin A; Ridley, Lauren M; Murphy, Wyatt R; Sowa, John R; Bentivegna, Carolyn S


    Raw menhaden fish oil was developed for biomonitoring polycyclic aromatic hydrocarbons (PAHs) using fluorescence spectroscopy. Menhaden (Genus Brevoortia) were collected in 2010 and/or 2011 from Delaware Bay, New Jersey, USA; James River, Virginia, USA; Vermillion Bay, Louisiana, USA (VBLA); and Barataria Bay, Louisiana, USA (BBLA). Barataria Bay, Louisiana received heavy oiling from the Deepwater Horizon oil spill. Method development included determining optimal wavelengths for PAH detection, fish oil matrix interferences, and influence of solvent concentration on extraction. Results showed that some fish oils contained high molecular weight PAH-like compounds in addition to other fluorescent compounds such as albumin and vitamin A and vitamin E. None of these naturally occurring compounds interfered with detection of high molecular weight PAHs. However, data suggested that the lipid component of fish oil was altering fluorescence spectra by supporting the formation of PAH excimers. For example, the most intense excitation wavelength for hydroxypyrene shifted from Ex285/Em430 to Ex340/Em430. Comparison of Deepwater Horizon crude oil and fish oil spectra indicated that some fish oils contained crude oil-like PAHs. Using wavelengths of Ex360/Em430, fish oil concentrations were calculated as 3.92 μg/g, 0.61 μg/g, and 0.14 μg/g for a Delaware Bay sample, BBLA 2011, and VBLA 2011, respectively. Overall, these results supported using menhaden fish oil to track PAH exposures spatially and temporally. © 2015 SETAC.

  14. Detection of hydroxyl ions in bone mineral by solid-state NMR spectroscopy. (United States)

    Cho, Gyunggoo; Wu, Yaotang; Ackerman, Jerome L


    Previous measurements of the hydroxyl (OH-) ion content of the calcium phosphate crystals of bone mineral have indicated a substantial depletion or near-absence of OH-, despite its presumed status as a constituent of the hydroxyapatite lattice. Analytical methods for determining bone crystal OH- content have depended on procedures or assumptions that may have biased the results, such as chemical pretreatment to eliminate interference from the organic matrix. We demonstrate a two-dimensional solid-state nuclear magnetic resonance (NMR) spectroscopy technique that detects the proton spectrum of bone crystals while suppressing the interfering matrix signals, eliminating the need for specimen pretreatment other than cryogenic grinding. Results on fresh-frozen and ground whole bone of several mammalian species show that the bone crystal OH- is readily detectable; a rough estimate yields an OH- content of human cortical bone of about 20% of the amount expected in stoichiometric hydroxyapatite. This finding sheds light on the biochemical processes underlying normal and abnormal bone mineral metabolism.

  15. Use of nonlocal helium microplasma for gas impurities detection by the collisional electron spectroscopy method

    Energy Technology Data Exchange (ETDEWEB)

    Kudryavtsev, Anatoly A., E-mail: [St. Petersburg State University, 7-9 Universitetskaya nab., 199034 St. Petersburg (Russian Federation); Stefanova, Margarita S.; Pramatarov, Petko M. [Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee blvd., 1784 Sofia (Bulgaria)


    The collisional electron spectroscopy (CES) method, which lays the ground for a new field for analytical detection of gas impurities at high pressures, has been verified. The CES method enables the identification of gas impurities in the collisional mode of electron movement, where the advantages of nonlocal formation of the electron energy distribution function (EEDF) are fulfilled. Important features of dc negative glow microplasma and probe method for plasma diagnostics are applied. A new microplasma gas analyzer design is proposed. Admixtures of 0.2% Ar, 0.6% Kr, 0.1% N{sub 2}, and 0.05% CO{sub 2} are used as examples of atomic and molecular impurities to prove the possibility for detecting and identifying their presence in high pressure He plasma (50–250 Torr). The identification of the particles under analysis is made from the measurements of the high energy part of the EEDF, where maxima appear, resulting from the characteristic electrons released in Penning reactions of He metastable atoms with impurity particles. Considerable progress in the development of a novel miniature gas analyzer for chemical sensing in gas phase environments has been made.

  16. Indirect glyphosate detection based on ninhydrin reaction and surface-enhanced Raman scattering spectroscopy. (United States)

    Xu, Meng-Lei; Gao, Yu; Li, Yali; Li, Xueliang; Zhang, Huanjie; Han, Xiao Xia; Zhao, Bing; Su, Liang


    Glyphosate is one of the most commonly-used and non-selective herbicides in agriculture, which may directly pollute the environment and threaten human health. A simple and effective approach to assessment of its damage to the natural environment is thus quite necessary. However, traditional chromatography-based detection methods usually suffer from complex pretreatment procedures. Herein, we propose a simple and sensitive method for the determination of glyphosate by combining ninhydrin reaction and surface-enhanced Raman scattering (SERS) spectroscopy. The product (purple color dye, PD) of the ninhydrin reaction is found to SERS-active and directly correlate with the glyphosate concentration. The limit of detection of the proposed method for glyphosate is as low as 1.43×10 -8 mol·L -1 with a relatively wider linear concentration range (1.0×10 -7 -1.0×10 -4 mol·L -1 ), which demonstrates its great potential in rapid, highly sensitive concentration determination of glyphosate in practical applications for safety assessment of food and environment. Copyright © 2018 Elsevier B.V. All rights reserved.

  17. Potential of cathodoluminescence microscopy and spectroscopy for the detection of prokaryotic cells on minerals. (United States)

    Rommevaux-Jestin, Céline; Ménez, Bénédicte


    Detecting mineral-hosted ecosystems to assess the extent and functioning of the biosphere from the surface to deep Earth requires appropriate techniques that provide, beyond the morphological criteria, indubitable clues of the presence of prokaryotic cells. Here, we evaluate the capability of cathodoluminescence microscopy and spectroscopy, implemented on a scanning electron microscope, to identify prokaryotes on mineral surfaces. For this purpose, we used, as a first step, a simple model of either unstained or stained cultivable cells (Escherichia coli, Deinococcus radiodurans) deposited on minerals that are common in the oceanic crust (basaltic glass, amphibole, pyroxene, and magnetite). Our results demonstrate that the detection of cells is possible at the micrometric level on the investigated minerals through the intrinsic fluorescence of their constituting macromolecules (aromatic amino and nucleic acids, coenzymes). This allows us to distinguish biomorph inorganic phases from cells. This easily implemented technique permits an exploration of colonized rock samples. In addition, the range of spectrometric techniques available on a scanning electron microscope can provide additional information on the nature and chemistry of the associated mineral phases, which would lead to a simultaneous characterization of cells, their microhabitats, and a better understanding of their potential relationships.

  18. Sensitive Detection of Competitive Molecular Adsorption by Surface-Enhanced Raman Spectroscopy. (United States)

    Altun, Ali O; Bond, Tiziana; Pronk, Wouter; Park, Hyung Gyu


    Surface adsorption plays a critical role in a wide variety of fields from surface catalysis to molecular separation. Despite the importance, limited access to simultaneously sensitive and selective detection mechanisms has hampered the acquisition of comprehensive and versatile experimental data needed to understand the complex aspects of mixture adsorption, calling for a molecular detection method capable of obtaining the surface adsorption isotherms over a wide range of concentrations as well as distinguishing the competitive adsorption of different adsorbates. Here, we test surface-enhanced Raman spectroscopy (SERS) as an effective analysis tool of surface adsorption phenomena. Using a sensitive SERS substrate, we characterize the adsorption isotherms of chemical species of various binding energies. We obtained the isotherms for strongly binding species in a concentration range from subpicomolar to micromolar. A log-sigmoidal dependency of the SERS signals to the analyte concentration could be modeled by surface binding theories accurately using molecular dynamics simulations, thereby bringing out the potential capability of sensitive SERS for describing a single-compound adsorption process. SERS also enabled the determination of competitive adsorption isotherms from a multiple-compound solution for the first time. The successful demonstration of the sensitive and selective characterization of surface adsorption lends SERS adaptability to a cheap, facile, and effective solution for chemical analysis.

  19. Detection of underground structures using UAV and field spectroscopy for defence and security in Cyprus (United States)

    Melillos, George; Themistocleous, Kyriacos; Prodromou, Maria; Hadjimitsis, Diofantos G.


    The purpose of this paper is to present the results obtained from unmanned aerial vehicle (UAV) and field spectroscopy campaigns for detecting underground structures. Underground structures can affect their surrounding landscapes in different ways, such as soil moisture content, soil composition and vegetation vigor. The last is often observed on the ground as a crop mark; a phenomenon which can be used as a proxy to denote the presence of underground non-visible structures. A number of vegetation indices such as the Normalized Difference Vegetation Index (NDVI), Simple Ratio (SR), Difference Vegetation Index (DVI) and Soil Adjusted Vegetation Index (SAVI) were utilized for the development of a vegetation index-based procedure aiming at the detection of underground military structures by using existing vegetation indices or other in-band algorithms. The measurements were taken at the following test areas such as: (a) vegetation area covered with the vegetation (barley), in the presence of an underground military structure (b) vegetation area covered with the vegetation (barley), in the absence of an underground military structure.

  20. Detection of Glucose with Atomic Absorption Spectroscopy by Using Oligonucleotide Functionalized Gold Nanoparticle. (United States)

    Zhang, Hong; Yan, Honglian; Ling, Liansheng


    A novel method for the detection of glucose was established with atomic absorption spectroscopy by using the label of gold nanoparticle (AuNP). Silver-coated glass assembled with oligonucleotide 5'-SH-T12-AGA CAA GAG AGG-3' (Oligo 1) was acted as separation probe, oligonucleotide 5'-CAA CAG AGA ACG-T12-SH-3' modified gold nanoparticle (AuNP-Oligo 2) was acted as signal-reporting probe. Oligonucleotide 5'-CGT TCT CTG TTG CCT CTC TTG TCT-3' (Oligo 3) could hybridize with Oligo 1 on the surface of silver-coated glass and AuNP-Oligo 2, and free AuNP-Oligo 2 could be removed by rinsing with buffer. Hence the concentration of Oligo 3 was transformed into the concentration of gold element. In addition, Oligo 3 could be cleaved into DNA fragments by glucose, glucose oxidase and Fe(2+)-EDTA through Fenton reaction. Thereby the concentration of glucose could be transformed to the absorbance of gold element. Under the optimum conditions, the integrated absorbance decreased proportionally to the concentration of glucose over the range from 50.0 μM to 1.0 mM with a detection limit of 40.0 μM. Moreover, satisfactory result was obtained when the assay was used to determinate glucose in human serum.

  1. Clinical research device for ovarian cancer detection by optical spectroscopy in the ultraviolet C-visible (United States)

    George, Ronie; Chandrasekaran, Archana; Brewer, Molly A.; Hatch, Kenneth D.; Utzinger, Urs


    Early detection of ovarian cancer could greatly increase the likelihood of successful treatment. However, present detection techniques are not very effective, and symptoms are more commonly seen in later stage disease. Amino acids, structural proteins, and enzymatic cofactors have endogenous optical properties influenced by precancerous changes and tumor growth. We present the technical details of an optical spectroscopy system used to quantify these properties. A fiber optic probe excites the surface epithelium (origin of 90% of cases) over 270 to 580 nm and collects fluorescence and reflectance at 300 to 800 nm with four or greater orders of magnitude instrument to background suppression. Up to four sites per ovary are investigated on patients giving consent to oophorectomy and the system's in vivo optical evaluation. Data acquisition is completed within 20 s per site. We illustrate design, selection, and development of the components used in the system. Concerns relating to clinical use, performance, calibration, and quality control are addressed. In the future, spectroscopic data will be compared with histological biopsies from the corresponding tissue sites. If proven effective, this technique can be useful in screening women at high risk of developing ovarian cancer to determine whether oophorectomy is necessary.

  2. Isotopologue-Sensitive Detection Using Chirped-Pulse Ft-Mw Spectroscopy: Minor Species of Propofol (United States)

    Lesarri, Alberto; Neill, Justin; Muckle, Matt; Shipman, Steven T.; Pate, Brooks H.; Suenram, Richard D.; Caminati, Walther


    The capabilities of chirped-pulse FT-microwave spectroscopy to achieve full-bandwidth (11 GHz) isotopologue-sensitive detection have been tested on the 13-heavy atoms molecule of propofol (2,6-diisopropylphenol). The analysis of the rotational spectrum using moderate signal averaging (10 k FIDs) had previously detected the presence of two conformers arising from the combined internal rotations of the hydroxyl and the two isopropyl groups. In the new experiment reported here 600 k FID's were coherently averaged, using three pulsed nozzle sources and reading multiple FIDs per sample injection cycle to reduce the total acquisition time and sample consumption. The new spectrum revealed a very large number of weak transitions, suggesting that full-band ^{13}C sensitivity had been surpassed. The new data have resulted in the assignment of a third conformer of propofol, followed by all twelve ^{13}C-monosubstituted species in natural abundance for the most stable conformer. The isotopic information confirmed the molecular structure for the preferred conformation of propofol, validating the ab initio predictions for this compound. The potential function for the OH internal rotation has been determined using a flexible model. A. Lesarri, S. T. Shipman, G. G. Brown, L. Alvarez-Valtierra, R. D. Suenram and B. H. Pate, 63^rd OSU Int. Symp. On Mol. Spectrosc., Columbus, OH, 2008, RH07 In the

  3. Scanning elastic scattering spectroscopy detects metastatic breast cancer in sentinel lymph nodes (United States)

    Austwick, Martin R.; Clark, Benjamin; Mosse, Charles A.; Johnson, Kristie; Chicken, D. Wayne; Somasundaram, Santosh K.; Calabro, Katherine W.; Zhu, Ying; Falzon, Mary; Kocjan, Gabrijela; Fearn, Tom; Bown, Stephen G.; Bigio, Irving J.; Keshtgar, Mohammed R. S.


    A novel method for rapidly detecting metastatic breast cancer within excised sentinel lymph node(s) of the axilla is presented. Elastic scattering spectroscopy (ESS) is a point-contact technique that collects broadband optical spectra sensitive to absorption and scattering within the tissue. A statistical discrimination algorithm was generated from a training set of nearly 3000 clinical spectra and used to test clinical spectra collected from an independent set of nodes. Freshly excised nodes were bivalved and mounted under a fiber-optic plate. Stepper motors raster-scanned a fiber-optic probe over the plate to interrogate the node's cut surface, creating a 20×20 grid of spectra. These spectra were analyzed to create a map of cancer risk across the node surface. Rules were developed to convert these maps to a prediction for the presence of cancer in the node. Using these analyses, a leave-one-out cross-validation to optimize discrimination parameters on 128 scanned nodes gave a sensitivity of 69% for detection of clinically relevant metastases (71% for macrometastases) and a specificity of 96%, comparable to literature results for touch imprint cytology, a standard technique for intraoperative diagnosis. ESS has the advantage of not requiring a pathologist to review the tissue sample.

  4. Mid-infrared spectroscopy for detection of Huanglongbing (greening) in citrus leaves. (United States)

    Sankaran, Sindhuja; Ehsani, Reza; Etxeberria, Edgardo


    In recent years, Huanglongbing (HLB) also known as citrus greening has greatly affected citrus orchards in Florida. This disease has caused significant economic and production losses costing about $750/acre for HLB management. Early and accurate detection of HLB is a critical management step to control the spread of this disease. This work focuses on the application of mid-infrared spectroscopy for the detection of HLB in citrus leaves. Leaf samples of healthy, nutrient-deficient, and HLB-infected trees were processed in two ways (process-1 and process-2) and analyzed using a rugged, portable mid-infrared spectrometer. Spectral absorbance data from the range of 5.15-10.72 μm (1942-933 cm(-1)) were preprocessed (baseline correction, negative offset correction, and removal of water absorbance band) and used for data analysis. The first and second derivatives were calculated using the Savitzky-Golay method. The preprocessed raw dataset, first derivatives dataset, and second derivatives dataset were first analyzed by principal component analysis. Then, the selected principal component scores were classified using two classification algorithms, quadratic discriminant analysis (QDA) and k-nearest neighbor (kNN). When the spectral data from leaf samples processed using process-1 were used for data analysis, the kNN-based algorithm yielded higher classification accuracies (especially nutrient-deficient leaf class) than that of the other spectral data (process-2). The performance of the kNN-based algorithm (higher than 95%) was better than the QDA-based algorithm. Moreover, among different types of datasets, preprocessed raw dataset resulted in higher classification accuracies than first and second derivatives datasets. The spectral peak in the region of 9.0-10.5 μm (952-1112 cm(-1)) was found to be distinctly different between the healthy and HLB-infected leaf samples. This carbohydrate peak could be attributed to the starch accumulation in the HLB-infected citrus leaves

  5. Detection of reactive oxygen species in isolated, perfused lungs by electron spin resonance spectroscopy

    Directory of Open Access Journals (Sweden)

    Schudt Christian


    Full Text Available Abstract Background The sources and measurement of reactive oxygen species (ROS in intact organs are largely unresolved. This may be related to methodological problems associated with the techniques currently employed for ROS detection. Electron spin resonance (ESR with spin trapping is a specific method for ROS detection, and may address some these technical problems. Methods We have established a protocol for the measurement of intravascular ROS release from isolated buffer-perfused and ventilated rabbit and mouse lungs, combining lung perfusion with the spin probe l-hydroxy-3-carboxy-2,2,5,5-tetramethylpyrrolidine (CPH and ESR spectroscopy. We then employed this technique to characterize hypoxia-dependent ROS release, with specific attention paid to NADPH oxidase-dependent superoxide formation as a possible vasoconstrictor pathway. Results While perfusing lungs with CPH over a range of inspired oxygen concentrations (1–21 %, the rate of CP• formation exhibited an oxygen-dependence, with a minimum at 2.5 % O2. Addition of superoxide dismutase (SOD to the buffer fluid illustrated that a minor proportion of this intravascular ROS leak was attributable to superoxide. Stimulation of the lungs by injection of phorbol-12-myristate-13-acetate (PMA into the pulmonary artery caused a rapid increase in CP• formation, concomitant with pulmonary vasoconstriction. Both the PMA-induced CPH oxidation and the vasoconstrictor response were largely suppressed by SOD. When the PMA challenge was performed at different oxygen concentrations, maximum superoxide liberation and pulmonary vasoconstriction occurred at 5 % O2. Using a NADPH oxidase inhibitor and NADPH-oxidase deficient mice, we illustrated that the PMA-induced superoxide release was attributable to the stimulation of NADPH oxidases. Conclusion The perfusion of isolated lungs with CPH is suitable for detection of intravascular ROS release by ESR spectroscopy. We employed this technique to

  6. Detection and characterization of serine and threonine hydroxyl protons in Bacillus circulans xylanase by NMR spectroscopy. (United States)

    Brockerman, Jacob A; Okon, Mark; McIntosh, Lawrence P


    Hydroxyl protons on serine and threonine residues are not well characterized in protein structures determined by both NMR spectroscopy and X-ray crystallography. In the case of NMR spectroscopy, this is in large part because hydroxyl proton signals are usually hidden under crowded regions of (1)H-NMR spectra and remain undetected by conventional heteronuclear correlation approaches that rely on strong one-bond (1)H-(15)N or (1)H-(13)C couplings. However, by filtering against protons directly bonded to (13)C or (15)N nuclei, signals from slowly-exchanging hydroxyls can be observed in the (1)H-NMR spectrum of a uniformly (13)C/(15)N-labeled protein. Here we demonstrate the use of a simple selective labeling scheme in combination with long-range heteronuclear scalar correlation experiments as an easy and relatively inexpensive way to detect and assign these hydroxyl proton signals. Using auxtrophic Escherichia coli strains, we produced Bacillus circulans xylanase (BcX) labeled with (13)C/(15)N-serine or (13)C/(15)N-threonine. Signals from two serine and three threonine hydroxyls in these protein samples were readily observed via (3)JC-OH couplings in long-range (13)C-HSQC spectra. These scalar couplings (~5-7 Hz) were measured in a sample of uniformly (13)C/(15)N-labeled BcX using a quantitative (13)C/(15)N-filtered spin-echo difference experiment. In a similar approach, the threonine and serine hydroxyl hydrogen exchange kinetics were measured using a (13)C/(15)N-filtered CLEANEX-PM pulse sequence. Collectively, these experiments provide insights into the structural and dynamic properties of several serine and threonine hydroxyls within this model protein.

  7. Ultrasound tagged near infrared spectroscopy does not detect hyperventilation-induced reduction in cerebral blood flow. (United States)

    Lund, Anton; Secher, Niels H; Hirasawa, Ai; Ogoh, Shigehiko; Hashimoto, Takeshi; Schytz, Henrik W; Ashina, Messoud; Sørensen, Henrik


    Continuous non-invasive monitoring of cerebral blood flow (CBF) may be important during anaesthesia and several options are available. We evaluated the CerOx monitor that employs ultrasound tagged near infrared spectroscopy to estimate changes in a CBF index (CFI). Seven healthy males (age 21-26 years) hyperventilated and were administered phenylephrine to increase mean arterial pressure by 20-30 mmHg. Frontal lobe tissue oxygenation (ScO2) and CFI were obtained using the CerOx and mean blood flow velocity in the middle cerebral artery (MCAv mean) was determined by transcranial Doppler. Blood flow in the internal and external carotid artery (ICAf and ECAf) was determined using duplex ultrasonography and forehead skin blood flow (SkBF) and oxygenation (S skin O2) by laser Doppler and white light spectroscopy. During hyperventilation MCAv mean and ICAf decreased by 44% (median; interquartile range 40-49; p = 0.016) and 46% (40-53; p = 0.03), respectively. Conversely, CFI increased by 9% (2-31; p = 0.016), while no significant change was observed in ScO2. SkBF increased by 19% (9-53; p = 0.016) and S skin O2 by 6% (1-7; p = 0.047), although ECAf was unchanged. Administration of phenylephrine was not associated with any changes in MCAv mean, ICAf, ECAf, ScO2, SkBF, S skin O2, or CFI. The CerOx was able to detect a stable CBF during administration of phenylephrine. However, during hyperventilation MCAv mean and ICAf decreased while CFI increased, likely due to an increase in superficial tissue oxygenation. Thus, CFI does not provide an unbiased evaluation of changes in CBF.

  8. Detection of Be+sdO Evolved Binaries from Ultraviolet Spectroscopy (United States)

    Gies, Douglas; Wang, Luqian; Peters, Geraldine


    Be stars are rapidly rotating, non-supergiant B-type stars that eject equatorial disks. Many of these stars may have been spun up through mass transfer in a close binary system, in which case the former mass donor star is now a hot, stripped-down, subdwarf. There are five known cases of Be stars with hot subdwarf (sdO) companions that were discovered through International Ultraviolet Explorer (IUE) spectroscopy. Here we expand the search for Be+sdO candidates using archival FUV spectra from IUE. Our search strategy involves calculation of a cross-correlation funtion (CCF) of each observed spectrum with a model spectrum for T_eff = 45 kK, the typical value for the known subdwarf companions. We collected IUE spectra for 264 targets, and selected for closer examination those with a CCF peak greater than three times the background CCF noise. We applied two selection criteria to select candidate Be+sdO binaries: targets showing a significant and narrow CCF feature (with a half-width much smaller than the projected rotational velocity of the Be star) and also displayed radial velocity shifts indicative of orbital motion. We identified eight candidate systems that met both criteria plus four other candidate systems with strong peaks but too few spectra to confirm orbital motion. These are important targets for follow up spectroscopy. The new plus known Be+sdO binaries comprise about 6% of the sample. This fraction is consistent with the idea that we only find sdO companions in their relatively short and bright evolutionary stage of He-shell burning, while the majority of He-core burning companions are too faint to detect with current methods.

  9. Rapid detection of benzoyl peroxide in wheat flour by using Raman scattering spectroscopy (United States)

    Zhao, Juan; Peng, Yankun; Chao, Kuanglin; Qin, Jianwei; Dhakal, Sagar; Xu, Tianfeng


    Benzoyl peroxide is a common flour additive that improves the whiteness of flour and the storage properties of flour products. However, benzoyl peroxide adversely affects the nutritional content of flour, and excess consumption causes nausea, dizziness, other poisoning, and serious liver damage. This study was focus on detection of the benzoyl peroxide added in wheat flour. A Raman scattering spectroscopy system was used to acquire spectral signal from sample data and identify benzoyl peroxide based on Raman spectral peak position. The optical devices consisted of Raman spectrometer and CCD camera, 785 nm laser module, optical fiber, prober, and a translation stage to develop a real-time, nondestructive detection system. Pure flour, pure benzoyl peroxide and different concentrations of benzoyl peroxide mixed with flour were prepared as three sets samples to measure the Raman spectrum. These samples were placed in the same type of petri dish to maintain a fixed distance between the Raman CCD and petri dish during spectral collection. The mixed samples were worked by pretreatment of homogenization and collected multiple sets of data of each mixture. The exposure time of this experiment was set at 0.5s. The Savitzky Golay (S-G) algorithm and polynomial curve-fitting method was applied to remove the fluorescence background from the Raman spectrum. The Raman spectral peaks at 619 cm-1, 848 cm-1, 890 cm-1, 1001 cm-1, 1234 cm-1, 1603cm-1, 1777cm-1 were identified as the Raman fingerprint of benzoyl peroxide. Based on the relationship between the Raman intensity of the most prominent peak at around 1001 cm-1 and log values of benzoyl peroxide concentrations, the chemical concentration prediction model was developed. This research demonstrated that Raman detection system could effectively and rapidly identify benzoyl peroxide adulteration in wheat flour. The experimental result is promising and the system with further modification can be applicable for more products in near

  10. Detection of visually unrecognizable braking tracks using Laser-Induced Breakdown Spectroscopy, a feasibility study (United States)

    Prochazka, David; Bilík, Martin; Prochazková, Petra; Brada, Michal; Klus, Jakub; Pořízka, Pavel; Novotný, Jan; Novotný, Karel; Ticová, Barbora; Bradáč, Albert; Semela, Marek; Kaiser, Jozef


    Identification of the position, length and mainly beginning of a braking track has proven to be essential for determination of causes of a road traffic accident. With the introduction of modern safety braking systems and assistance systems such as the Anti-lock Braking System (ABS) or Electronic Stability Control (ESC), the visual identification of braking tracks that has been used up until the present is proving to be rather complicated or even impossible. This paper focuses on identification of braking tracks using a spectrochemical analysis of the road surface. Laser-Induced Breakdown Spectroscopy (LIBS) was selected as a method suitable for fast in-situ element detection. In the course of detailed observations of braking tracks it was determined that they consist of small particles of tire treads that are caught in intrusions in the road surface. As regards detection of the "dust" resulting from wear and tear of tire treads in the environment, organic zinc was selected as the identification element in the past. The content of zinc in tire treads has been seen to differ with regard to various sources and tire types; however, the arithmetic mean and modus of these values are approximately 1% by weight. For in-situ measurements of actual braking tracks a mobile LIBS device equipped with a special module was used. Several measurements were performed for 3 different cars and tire types respectively which slowed down with full braking power. Moreover, the influence of different initial speed, vehicle mass and braking track length on detected signal is discussed here.

  11. Indirectly detected chemical shift correlation NMR spectroscopy in solids under fast magic angle spinning

    Energy Technology Data Exchange (ETDEWEB)

    Mao, Kanmi [Iowa State Univ., Ames, IA (United States)


    The development of fast magic angle spinning (MAS) opened up an opportunity for the indirect detection of insensitive low-γ nuclei (e.g., 13C and 15N) via the sensitive high-{gamma} nuclei (e.g., 1H and 19F) in solid-state NMR, with advanced sensitivity and resolution. In this thesis, new methodology utilizing fast MAS is presented, including through-bond indirectly detected heteronuclear correlation (HETCOR) spectroscopy, which is assisted by multiple RF pulse sequences for 1H-1H homonuclear decoupling. Also presented is a simple new strategy for optimization of 1H-1H homonuclear decoupling. As applications, various classes of materials, such as catalytic nanoscale materials, biomolecules, and organic complexes, are studied by combining indirect detection and other one-dimensional (1D) and two-dimensional (2D) NMR techniques. Indirectly detected through-bond HETCOR spectroscopy utilizing refocused INEPT (INEPTR) mixing was developed under fast MAS (Chapter 2). The time performance of this approach in 1H detected 2D 1H{l_brace}13C{r_brace} spectra was significantly improved, by a factor of almost 10, compared to the traditional 13C detected experiments, as demonstrated by measuring naturally abundant organic-inorganic mesoporous hybrid materials. The through-bond scheme was demonstrated as a new analytical tool, which provides complementary structural information in solid-state systems in addition to through-space correlation. To further benefit the sensitivity of the INEPT transfer in rigid solids, the combined rotation and multiple-pulse spectroscopy (CRAMPS) was implemented for homonuclear 1H decoupling under fast MAS (Chapter 3). Several decoupling schemes (PMLG5m$\\bar{x}$, PMLG5mm$\\bar{x}$x and SAM3) were analyzed to maximize the performance of through-bond transfer based

  12. High sensitivity detection of NO2 employing cavity ringdown spectroscopy and an external cavity continuously tunable quantum cascade laser. (United States)

    Rao, Gottipaty N; Karpf, Andreas


    A trace gas sensor for the detection of nitrogen dioxide based on cavity ringdown spectroscopy (CRDS) and a continuous wave external cavity tunable quantum cascade laser operating at room temperature has been designed, and its features and performance characteristics are reported. By measuring the ringdown times of the cavity at different concentrations of NO(2), we report a sensitivity of 1.2 ppb for the detection of NO(2) in Zero Air.

  13. Symmetry-resolved spectroscopy by detection of a metastable hydrogen atom for investigating the doubly excited states of molecular hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Odagiri, Takeshi; Kumagai, Yoshiaki; Tanabe, Takehiko; Nakano, Motoyoshi; Kouchi, Noriyuki [Department of Chemistry, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8551 (Japan); Suzuki, Isao H, E-mail: [Photon Factory, IMSS, KEK, Tsukuba, Ibaraki 305-0801 (Japan)


    Symmetry-resolved spectroscopy for investigating the doubly excited states of molecular hydrogen has been newly developed, where a metastable hydrogen atom dissociating in a direction parallel and perpendicular to the electric vector of the linearly polarized incident light is detected.

  14. Rapid and non-destructive detection and identification two strains of Wolbachia in Aedes aegypti by near-infrared spectroscopy (United States)

    We investigated the potential of using near-infrared spectroscopy (NIRS) to detect the presence of Wolbachia pipientis (wMel) in male and female laboratory-reared Aedes aegypti mosquitoes. The release of Wolbachia transinfected mosquitoes is likely to form a key component of disease control strategi...

  15. Cavity ring-down spectroscopy for detection in liquid chromatography: Extension to tunable sources and ultraviolet wavelengths

    NARCIS (Netherlands)

    van der Sneppen, L.; Wiskerke, A.E.; Ariese, F.; Gooijer, C.; Ubachs, W.M.G.


    In earlier studies, it was demonstrated that the sensitivity of absorbance detection in liquid chromatography (LC) can be improved significantly by using cavity ring-down spectroscopy (CRDS). Thus far, CRDS experiments have been performed using visible laser light at fixed standard wavelengths, such

  16. Time Resolved Spectroscopy of SGR J1550-5418 Bursts Detected with Fermi/Gamma-Ray Burst Monitor

    NARCIS (Netherlands)

    Younes, G.; Kouveliotou, C.; van der Horst, A.J.; Baring, M.G.; Granot, J.; Watts, A.L.; Bhat, P.N.; Collazzi, A.; Gehrels, N.; Gorgone, N.; Göğüş, E.; Gruber, D.; Grunblatt, S.; Huppenkothen, D.; Kaneko, Y.; von Kienlin, A.; van der Klis, M.; Lin, L.; Mcenery, J.; van Putten, T.; Wijers, R.A.M.J.


    We report on a time-resolved spectroscopy of the 63 brightest bursts of SGR J1550-5418, detected with the Fermi/Gamma-ray Burst Monitor during its 2008-2009 intense bursting episode. We performed spectral analysis down to 4 ms timescales to characterize the spectral evolution of the bursts. Using a

  17. Characterizing aeroallergens by infrared spectroscopy of fungal spores and pollen.

    Directory of Open Access Journals (Sweden)

    Boris Zimmermann

    Full Text Available Fungal spores and plant pollen cause respiratory diseases in susceptible individuals, such as asthma, allergic rhinitis and hypersensitivity pneumonitis. Aeroallergen monitoring networks are an important part of treatment strategies, but unfortunately traditional analysis is time consuming and expensive. We have explored the use of infrared spectroscopy of pollen and spores for an inexpensive and rapid characterization of aeroallergens.The study is based on measurement of spore and pollen samples by single reflectance attenuated total reflectance Fourier transform infrared spectroscopy (SR-ATR FTIR. The experimental set includes 71 spore (Basidiomycota and 121 pollen (Pinales, Fagales and Poales samples. Along with fresh basidiospores, the study has been conducted on the archived samples collected within the last 50 years.The spectroscopic-based methodology enables clear spectral differentiation between pollen and spores, as well as the separation of confamiliar and congeneric species. In addition, the analysis of the scattering signals inherent in the infrared spectra indicates that the FTIR methodology offers indirect estimation of morphology of pollen and spores. The analysis of fresh and archived spores shows that chemical composition of spores is well preserved even after decades of storage, including the characteristic taxonomy-related signals. Therefore, biochemical analysis of fungal spores by FTIR could provide economical, reliable and timely methodologies for improving fungal taxonomy, as well as for fungal identification and monitoring. This proof of principle study shows the potential for using FTIR as a rapid tool in aeroallergen studies. In addition, the presented method is ready to be immediately implemented in biological and ecological studies for direct measurement of pollen and spores from flowers and sporocarps.

  18. Hydrogen isotope detection in metal matrix using double-pulse laser-induced breakdown-spectroscopy (United States)

    Fantoni, Roberta; Almaviva, Salvatore; Caneve, Luisa; Colao, Francesco; Maddaluno, Giorgio; Gasior, Pawel; Kubkowska, Monika


    The amount of hydrogen isotopes retained in plasma facing components (PFCs) and the determination of their surface layer composition are among the most critical issues for the next generation fusion device, ITER, under construction in Cadarache (France). Laser Induced Breakdown Spectroscopy (LIBS) is currently under evaluation as a technique suitable for quantitative, in situ, non-invasive measurements of these quantities. In order to detect traces of contaminant in metallic samples and improve its limit of detection (LOD), the Double Pulse LIBS (DP-LIBS) variant can be used instead of the standard Single Pulse LIBS (SP-LIBS), as it has been proven by several authors that DP-LIBS can considerably raise the analytical performances of the technique. In this work Mo samples coated with a 1.5-1.8 μm thick W-Al mixed layer, contaminated with co-deposited deuterium (D) were measured by SP- and DP-LIBS under vacuum (p 5 × 10- 5 mbar), with an experimental set-up simulating conditions that can be found in a real fusion device between plasma discharges. A partial Calibration Free procedure (pCF) was applied to the LIBS data in order to retrieve the relative concentration of W and Al in the mixed layer. The amount of deuterium was then inferred by using tungsten as internal standard, accounting for the intensity ratio between the Dα line and nearby W I lines. The results are in satisfactory agreement with those obtained from preliminary Ion Beam Analysis measurements performed immediately after the specimen's realization.

  19. Advanced Ultrafast Spectroscopy for Chemical Detection of Nuclear Fuel Cycle Materials

    Energy Technology Data Exchange (ETDEWEB)

    Villa-Aleman, E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Houk, A. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Spencer, W. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)


    The development of new signatures and observables from processes related to proliferation activities are often related to the development of technologies. In our physical world, the intensity of observables is linearly related to the input drivers (light, current, voltage, etc.). Ultrafast lasers with high peak energies, opens the door to a new regime where the intensity of the observables is not necessarily linear with the laser energy. Potential nonlinear spectroscopic applications include chemical detection via remote sensing through filament generation, material characterization and processing, chemical reaction specificity, surface phenomena modifications, X-ray production, nuclear fusion, etc. The National Security Directorate laser laboratory is currently working to develop new tools for nonproliferation research with femtosecond and picosecond lasers. Prior to this project, we could only achieve laser energies in the 5 nano-Joule range, preventing the study of nonlinear phenomena. To advance our nonproliferation research into the nonlinear regime we require laser pulses in the milli-Joule (mJ) energy range. We have procured and installed a 35 fs-7 mJ laser, operating at one-kilohertz repetition rate, to investigate elemental and molecular detection of materials in the laboratory with potential applications in remote sensing. Advanced, nonlinear Raman techniques will be used to study materials of interest that are in a matrix of many materials and currently with these nonlinear techniques we can achieve greater than three orders of magnitude signal enhancement. This work studying nuclear fuel cycle materials with nonlinear spectroscopies will advance SRNL research capabilities and grow a core capability within the DOE complex.

  20. The Promise of Many Worlds: Detection and Characterization of Exoplanets with Extreme Precision Spectroscopy (United States)

    Roy, Arpita


    Two decades ago, technological advancement aligned with some of mankind's oldest and most compelling questions to give birth to exoplanet science. Since then, the study of exoplanets, more than any other field of astrophysics, has grown in direct consonance with new instrumentation. In this dissertation talk I will discuss the development of three precision spectrographs that are pushing the limits on current radial velocity (RV) precision: (a) PARAS, a workhorse optical instrument achieving ~1m/s over several months, (b) the Habitable Zone Planet Finder, an upcoming NIR instrument for the 10m Hobby Eberly Telescope, and (c) NEID, an extreme precision instrument that will be the centerpiece of the NASA-NSF Exoplanet Observational Research (NN-EXPLORE) partnership. The path to the extreme precisions required to detect Earth analogs (~10cm/s), requires severe technical artistry and demands unprecedented performance from both hardware and software. I will summarize the most challenging sources of measurement error and the hardware solutions we have innovated, including my work on the invention of an efficient ball lens double scrambler (patent pending) that essentially retires issues of illumination instability. As software architect of these instruments, I will also describe the pathways to extreme precision data analysis pipelines, rooted firmly in the heritage of current instruments in the field. Fortunately, the scientific return from these meticulously produced spectra will be manifold, extending beyond precision RVs. I will briefly discuss my work leveraging the stability and resolution of similar instruments for stellar activity diagnosis and the determination of insidious false positives, as well as for the direct detection of reflected light from exoplanets. These efforts together underline both the formidable demands and rich rewards of extreme precision spectroscopy, which remains our fundamental tool for the discovery of potentially habitable non

  1. Laser-induced breakdown spectroscopy for the remote detection of explosives at level of fingerprints (United States)

    Almaviva, S.; Palucci, A.; Lazic, V.; Menicucci, I.; Nuvoli, M.; Pistilli, M.; De Dominicis, L.


    We report the results of the application of Laser-Induced Breakdown Spectroscopy (LIBS) for the detection of some common military explosives and theirs precursors deposited on white varnished car's external and black car's internal or external plastic. The residues were deposited by an artificial silicon finger, to simulate material manipulation by terrorists when preparing a car bomb, leaving traces of explosives on the parts of a car. LIBS spectra were acquired by using a first prototype laboratory stand-off device, developed in the framework of the EU FP7 313077 project EDEN (End-user driven DEmo for CBRNe). The system operates at working distances 8-30 m and collects the LIBS in the spectral range 240-840 nm. In this configuration, the target was moved precisely in X-Y direction to simulate the scanning system, to be implemented successively. The system is equipped with two colour cameras, one for wide scene view and another for imaging with a very high magnification, capable to discern fingerprints on a target. The spectral features of each examined substance were identified and compared to those belonging to the substrate and the surrounding air, and those belonging to possible common interferents. These spectral differences are discussed and interpreted. The obtained results show that the detection and discrimination of nitro-based compounds like RDX, PETN, ammonium nitrate (AN), and urea nitrate (UN) from organic interfering substances like diesel, greasy lubricants, greasy adhesives or oils in fingerprint concentration, at stand-off distance of some meters or tenths of meters is feasible.

  2. Elemental detection of arabica and robusta green bean coffee using laser-induced plasma spectroscopy (United States)

    Abdulmadjid, Syahrun Nur; Meilina, Hesti; Hedwig, Rinda; Kurniawan, Koo Hendrik


    The elemental detection of green bean of arabica and robusta coffee from Gayo Highland, Aceh-Indonesia, has been identified by using fundamental Nd-YAG Laser at 10 Torr of surrounding air gas pressure for distinguishing the characteristics of both coffees. As the preliminary study, we have detected the elements of K 766.49 nm, Na 588.9 nm, Ca 393.3 nm, CN band at 388.3 nm, N 337.13 nm and C 247.8 nm of both coffees. It is noticed that the order of elements concentration from highest to lowest are Ca>K>CN> Na>N> C for arabica and K>Ca>CN >Na>C>N for robusta. The emission intensity of K 766.49 nm is almost same for both of coffee. However, the emission intensity of Na 588.9 nm is lower in Arabica coffee. To distinguish the Arabica coffee and Robusta Coffee, we take the ratio intensity of K/C, Na/C, CN/C, and Ca/C. It is found that the ratio intensities of CN/C and Ca/C in arabica bean are significantly different with robusta bean. That ratio intensities can be used as a marker to discriminate kind of coffee. We also noted that the arabica green bean is 1.3 harder than robusta green bean. These findings prove that the technique of laser-induced plasma spectroscopy can be used to make rapid identification of elements in coffee and can potentially be applied to measure the concentration of blended coffee for the purpose of authentication.

  3. Application of Commercial Non-Dispersive Infrared Spectroscopy Sensors for Sub-Ambient Carbon Dioxide Detection (United States)

    Swickrath, Michael J.; Anderson, Molly; McMillin, Summer; Broerman, Craig


    Monitoring carbon dioxide (CO2) concentration within a spacecraft or spacesuit is critically important to ensuring the safety of the crew. Carbon dioxide uniquely absorbs light at wavelengths of 3.95 micrometers and 4.26 micrometers. As a result, non-dispersive infrared (NDIR) spectroscopy can be employed as a reliable and inexpensive method for the quantification of CO2 within the atmosphere. A multitude of commercial off-the-shelf (COTS) NDIR sensors exist for CO2 quantification. The COTS sensors provide reasonable accuracy as long as the measurements are attained under conditions close to the calibration conditions of the sensor (typically 21.1 C (70.0 F) and 1 atmosphere). However, as pressure deviates from atmospheric to the pressures associated with a spacecraft (8.0{10.2 pounds per square inch absolute (psia)) or spacesuit (4.1{8.0 psia), the error in the measurement grows increasingly large. In addition to pressure and temperature dependencies, the infrared transmissivity through a volume of gas also depends on the composition of the gas. As the composition is not known a priori, accurate sub-ambient detection must rely on iterative sensor compensation techniques. This manuscript describes the development of recursive compensation algorithms for sub-ambient detection of CO2 with COTS NDIR sensors. In addition, the source of the exponential loss in accuracy is developed theoretically. The basis of the loss can be explained through thermal, Doppler, and Lorentz broadening effects that arise as a result of the temperature, pressure, and composition of the gas mixture under analysis. This manuscript provides an approach to employing COTS sensors at sub-ambient conditions and may also lend insight into designing future NDIR sensors for aerospace application.

  4. Surface enhanced Raman spectroscopy detection of biomolecules using EBL fabricated nanostructured substrates. (United States)

    Peters, Robert F; Gutierrez-Rivera, Luis; Dew, Steven K; Stepanova, Maria


    Fabrication and characterization of conjugate nano-biological systems interfacing metallic nanostructures on solid supports with immobilized biomolecules is reported. The entire sequence of relevant experimental steps is described, involving the fabrication of nanostructured substrates using electron beam lithography, immobilization of biomolecules on the substrates, and their characterization utilizing surface-enhanced Raman spectroscopy (SERS). Three different designs of nano-biological systems are employed, including protein A, glucose binding protein, and a dopamine binding DNA aptamer. In the latter two cases, the binding of respective ligands, D-glucose and dopamine, is also included. The three kinds of biomolecules are immobilized on nanostructured substrates by different methods, and the results of SERS imaging are reported. The capabilities of SERS to detect vibrational modes from surface-immobilized proteins, as well as to capture the protein-ligand and aptamer-ligand binding are demonstrated. The results also illustrate the influence of the surface nanostructure geometry, biomolecules immobilization strategy, Raman activity of the molecules and presence or absence of the ligand binding on the SERS spectra acquired.

  5. Nanostructured organic semiconductor films for molecular detection with surface-enhanced Raman spectroscopy (United States)

    Yilmaz, Mehmet; Babur, Esra; Ozdemir, Mehmet; Gieseking, Rebecca L.; Dede, Yavuz; Tamer, Ugur; Schatz, George C.; Facchetti, Antonio; Usta, Hakan; Demirel, Gokhan


    π-Conjugated organic semiconductors have been explored in several optoelectronic devices, yet their use in molecular detection as surface-enhanced Raman spectroscopy (SERS)-active platforms is unknown. Herein, we demonstrate that SERS-active, superhydrophobic and ivy-like nanostructured films of a molecular semiconductor, α,ω-diperfluorohexylquaterthiophene (DFH-4T), can be easily fabricated by vapour deposition. DFH-4T films without any additional plasmonic layer exhibit unprecedented Raman signal enhancements up to 3.4 × 103 for the probe molecule methylene blue. The combination of quantum mechanical computations, comparative experiments with a fluorocarbon-free α,ω-dihexylquaterthiophene (DH-4T), and thin-film microstructural analysis demonstrates the fundamental roles of the π-conjugated core fluorocarbon substitution and the unique DFH-4T film morphology governing the SERS response. Furthermore, Raman signal enhancements up to ~1010 and sub-zeptomole (films with a thin gold layer. Our results offer important guidance for the molecular design of SERS-active organic semiconductors and easily fabricable SERS platforms for ultrasensitive trace analysis.

  6. Noninvasive detection of nasopharyngeal carcinoma based on saliva proteins using surface-enhanced Raman spectroscopy (United States)

    Lin, Xueliang; Lin, Duo; Ge, Xiaosong; Qiu, Sufang; Feng, Shangyuan; Chen, Rong


    The present study evaluated the capability of saliva analysis combining membrane protein purification with surface-enhanced Raman spectroscopy (SERS) for noninvasive detection of nasopharyngeal carcinoma (NPC). A rapid and convenient protein purification method based on cellulose acetate membrane was developed. A total of 659 high-quality SERS spectra were acquired from purified proteins extracted from the saliva samples of 170 patients with pathologically confirmed NPC and 71 healthy volunteers. Spectral analysis of those saliva protein SERS spectra revealed specific changes in some biochemical compositions, which were possibly associated with NPC transformation. Furthermore, principal component analysis combined with linear discriminant analysis (PCA-LDA) was utilized to analyze and classify the saliva protein SERS spectra from NPC and healthy subjects. Diagnostic sensitivity of 70.7%, specificity of 70.3%, and diagnostic accuracy of 70.5% could be achieved by PCA-LDA for NPC identification. These results show that this assay based on saliva protein SERS analysis holds promising potential for developing a rapid, noninvasive, and convenient clinical tool for NPC screening.

  7. Raman spectroscopy complements optical coherent tomography in tissue classification and cancer detection (United States)

    Qi, Ji; Sudheendran, Narendran; Liu, Chih-Hao; Santos, Greggy M.; Young, Eric D.; Lazar, Alexander J.; Lev, Dina C.; Pollock, Raphael E.; Larin, Kirill V.; Shih, Wei-Chuan


    Optical coherence tomography (OCT) provides significant advantages of high-resolution (approaching the histopathology level) real-time imaging of tissues without use of contrast agents. Based on these advantages, the microstructural features of tumors can be visualized and detected intra-operatively. However, it is still not clinically accepted for tumor margin delineation due to poor specificity and accuracy. In contrast, Raman spectroscopy (RS) can obtain tissue information at the molecular level, but does not provide real-time imaging capability. Therefore, combining OCT and RS could provide synergy. To this end, we present a tissue analysis and classification method using both the slope of OCT intensity signal versus depth and the principle components from the RS spectrum as the indicators for tissue characterization. Our pilot experiments were performed on mouse kidneys, livers, and small intestines. The prediction accuracy with five-fold cross validation of the method has been evaluated by support vector machine method. The results demonstrate that RS can effectively improve tissue classification compared to OCT alone. Next, we demonstrate that the boundary between myxoid liposarcoma and normal fat which is easily identifiable both Raman and OCT. In cases where structural images are indistinguishable, for example, in normal fat and well differentiated liposarcoma (WDLS) or gastrointestinal sarcoma tumor (GIST) and Myxoma, distinct molecular spectra have been obtained. The results suggest RS can effectively complement OCT to tumor boundary demarcation with high specificity.

  8. Use of an Endoscope Compatible Probe to Detect Colonic Dysplasia with Fourier Transform Infrared (FTIR) Spectroscopy (United States)

    Mackanos, Mark A.; Hargrove, John T.; Du, Christine B.; Friedland, Shai; Soetikno, Roy M.; Contag, Christopher H.; Wolters, Rolf; Arroyo, May R.; Crawford, James M.; Wang, Thomas D.


    FTIR spectroscopy is sensitive to the molecular composition of tissue and has the potential to identify pre-malignant tissue (dysplasia) as an adjunct to endoscopy. We demonstrate collection of mid-infrared absorption spectra with a silver halide (AgCl0.4Br0.6) optical fiber and use spectral pre-processing to identify optimal sub-ranges that classify colonic mucosa as normal, hyperplasia, or dysplasia. We collected spectra (n = 83) in the 950 to 1800 cm−1 regime on biopsy specimens obtained from human subjects (n = 37). Subtle differences in the magnitude of the absorbance peaks at specific wavenumbers were observed. The best double binary algorithm for distinguishing normal-versus-dysplasia and hyperplasia-versus-dysplasia was determined from an exhaustive search of spectral intervals and pre-processing techniques. Partial least squares discriminant analysis was used to classify the spectra using a leave-one-subject-out cross-validation strategy. The results were compared with histology reviewed independently by two gastrointestinal pathologists. The optimal thresholds identified resulted in an overall sensitivity, specificity, accuracy, and positive predictive value of 96%, 92%, 93%, and 82%, respectively. These results indicated that mid-infrared absorption spectra collected remotely with an optical fiber can be used to identify colonic dysplasia with high accuracy, suggesting that continued development of this technique for the early detection of cancer is promising. PMID:19725718

  9. The performance of spatially offset Raman spectroscopy for liquid explosive detection (United States)

    Loeffen, Paul W.; Maskall, Guy; Bonthron, Stuart; Bloomfield, Matthew; Tombling, Craig; Matousek, Pavel


    Aviation security requirements adopted in 2014 require liquids to be screened at most airports throughout Europe, North America and Australia. Cobalt's unique Spatially Offset Raman Spectroscopy (SORS™) technology has proven extremely effective at screening liquids, aerosols and gels (LAGS) with extremely low false alarm rates. SORS is compatible with a wide range of containers, including coloured, opaque or clear plastics, glass and paper, as well as duty-free bottles in STEBs (secure tamper-evident bags). Our award-winning Insight range has been specially developed for table-top screening at security checkpoints. Insight systems use our patented SORS technology for rapid and accurate chemical analysis of substances in unopened non-metallic containers. Insight100M™ and the latest member of the range - Insight200M™ - also screen metallic containers. Our unique systems screen liquids, aerosols and gels with the highest detection capability and lowest false alarm rates of any ECAC-approved scanner, with several hundred units already in use at airports including eight of the top ten European hubs. This paper presents an analysis of real performance data for these systems.

  10. Detection and Classification of Live and Dead Escherichia coli by Laser-Induced Breakdown Spectroscopy (United States)

    Sivakumar, P.; Fernández-Bravo, A.; Taleh, L.; Biddle, J.F.


    Abstract A common goal for astrobiology is to detect organic materials that may indicate the presence of life. However, organic materials alone may not be representative of currently living systems. Thus, it would be valuable to have a method with which to determine the health of living materials. Here, we present progress toward this goal by reporting on the application of laser-induced breakdown spectroscopy (LIBS) to study characteristics of live and dead cells using Escherichia coli (E. coli) strain K12 cells as a model organism since its growth and death in the laboratory are well understood. Our goal is to determine whether LIBS, in its femto- and/or nanosecond forms, could ascertain the state of a living organism. E. coli strain K12 cells were grown, collected, and exposed to one of two types of inactivation treatments: autoclaving and sonication. Cells were also kept alive as a control. We found that LIBS yields key information that allows for the discrimination of live and dead E. coli bacteria based on ionic shifts reflective of cell membrane integrity. Key Words: E. coli—Trace elements—Live and dead cells—Laser-induced breakdown spectroscopy—Atomic force microscopy. Astrobiology 15, 144–153. PMID:25683088

  11. Fabry-Perot spectroscopy: a powerful method for detecting superbubbles in galaxy discs (United States)

    Camps-Fariña, A.; Beckman, J.; Zaragoza-Cardiel, J.; Font, J.; Fathi, K.


    We present a new method for the detection and characterization of large scale expansion in galaxy discs based on Hα Fabry-Perot spectroscopy, taking advantage of the high spatial and velocity resolution of our instrument (GHαFaS). The method analyses multi-peaked emission line profiles to find expansion along the line of sight on a pixel-by-pixel basis. At this stage we have centred our attention on the large scale structures of expansive gas which show a coherent gradient of velocities from their centres as a result of both bubble shape and projection effect. The results show a wide range of expansion velocities in these superbubbles, ranging from 30-150 km/s, with the expected trend of finding the higher velocities in the more violent areas of the galaxies. We have applied the technique to the Antennae and M83, obtaining spectacular results, and used these to investigate to what extent kinematically derived ages can be found and used to characterize the ages of their massive star clusters.

  12. Detection of complex molecular samples by low-cost surface enhanced raman spectroscopy (SERS) substrate (United States)

    Hou, Hsuan-Chao; Banadaki, Yaser Mohammadi; Sharifi, Safura


    Raman scattering is a well-known technique for detecting and identifying complex molecular samples. The weak Raman signals are enormously enhanced in the presence of a nano-patterned metallic surface next to the specimen. This paper reports new techniques to obtain the nanostructures required for Surface Enhanced Raman Scattering (SERS) without costly and sophisticated fabrication steps, which are nanoimprint lithography (NIL), electrochemical deposition, electron beam induced deposition, and focus ion beam (FIB). 20 nm Au thicknesses of sputtered Au were deposited on etched household aluminum foil (base substrate) for vitro application. The Raman signal were caused by the Aluminum pre-etched times. In preliminary results, enhancement factors of 106 times were observed from SERS substrate for in vitro measurements. Moreover, the ability to perform in vivo measurements was demonstrated after removing the base aluminum foil substrate. This application allows Raman signals to be obtained from the surface or interior of opaque specimens. The nano-patterned gold may also be coupled in a probe to a remote spectrometer via an articulated arm. This opens up Raman spectroscopy for use in a clinical environment.

  13. Detection and Classification of Individual Airborne Microparticles using Laser Ablation Mass Spectroscopy and Multivariate Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Gieray, R.A.; Lazar, A.; Parker, E.P.; Ramsey, J. M.; Reilly, P.T.A.; Rosenthal, S.E.; Trahan, M.W.; Wagner, J.S.; Whitten, W.B.


    We are developing a method for the real-time analysis of airborne microparticles based on laser ablation mass spectroscopy. Airborne particles enter an ion trap mass spectrometer through a differentially-pumped inlet, are detected by light scattered from two CW laser beams, and sampled by a 10 ns excimer laser pulse at 308 nm as they pass through the center of the ion trap electrodes. After the laser pulse, the stored ions are separated by conventional ion trap methods. In this work thousands of positive and negative ion spectra were collected for eighteen different species: six bacteria, six pollen, and six particulate samples. The data were then averaged and analyzed using the Multivariate Patch Algorithm (MPA), a variant of traditional multivariate anal ysis. The MPA correctly identified all of the positive ion spectra and 17 of the 18 negative ion spectra. In addition, when the average positive and negative spectra were combined the MPA correctly identified all 18 species. Finally, the MPA is also able to identify the components of computer synthesized mixtures of the samples studied

  14. Spectroscopic detection of health hazardous contaminants in lipstick using Laser Induced Breakdown Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Gondal, M.A., E-mail: [Physics Department and Center of Excellence in Nanotechnology, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Seddigi, Z.S. [Chemistry Department, Umm Al-Qura University, Makkah (Saudi Arabia); Nasr, M.M. [Natural Science Departments, Riyadh College of Dentistry and Pharmacy, P.O. Box 321815, Riyadh 11343 (Saudi Arabia); Gondal, B. [Plastic and Reconstructive Aesthetic Surgery, Whitfield Hospital, Waterford (Ireland)


    Laser Induced Breakdown Spectroscopy (LIBS) technique was applied to determine the concentrations of different toxic elements like lead, chromium, cadmium and zinc in four different lipstick brands sold at local markets in Saudi Arabia. These samples contain toxic elements like lead, cadmium and chromium which are carcinogen dermatitis, allergic and eczematous. Their extraction from human body takes over 40 years and accumulation in the body cause problems like disruption of nervous systems and kidney damage. They could trigger to systemic lupus erythematosus (SLE). In order to test the validity of our LIBS results, standard technique like (ICP-AES) was also applied. To the best of our knowledge, this is the first study where LIBS technique was applied for the measurement of toxic substances in lipsticks. The maximum concentration detected in four lipstick brands was much higher than the permissible safe limits for human use and could lead to serious health problems. It is worth mentioning that the lipstick is not a solid rather is in fluid state which is not trivial to analyze using LIBS technique. For this purpose, special treatment of the lipstick samples was necessary to analyze with our LIBS method.

  15. Fast detection of tobacco mosaic virus infected tobacco using laser-induced breakdown spectroscopy (United States)

    Peng, Jiyu; Song, Kunlin; Zhu, Hongyan; Kong, Wenwen; Liu, Fei; Shen, Tingting; He, Yong


    Tobacco mosaic virus (TMV) is one of the most devastating viruses to crops, which can cause severe production loss and affect the quality of products. In this study, we have proposed a novel approach to discriminate TMV-infected tobacco based on laser-induced breakdown spectroscopy (LIBS). Two different kinds of tobacco samples (fresh leaves and dried leaf pellets) were collected for spectral acquisition, and partial least squared discrimination analysis (PLS-DA) was used to establish classification models based on full spectrum and observed emission lines. The influences of moisture content on spectral profile, signal stability and plasma parameters (temperature and electron density) were also analysed. The results revealed that moisture content in fresh tobacco leaves would worsen the stability of analysis, and have a detrimental effect on the classification results. Good classification results were achieved based on the data from both full spectrum and observed emission lines of dried leaves, approaching 97.2% and 88.9% in the prediction set, respectively. In addition, support vector machine (SVM) could improve the classification results and eliminate influences of moisture content. The preliminary results indicate that LIBS coupled with chemometrics could provide a fast, efficient and low-cost approach for TMV-infected disease detection in tobacco leaves.

  16. Tunable Diode Laser Atomic Absorption Spectroscopy for Detection of Potassium under Optically Thick Conditions. (United States)

    Qu, Zhechao; Steinvall, Erik; Ghorbani, Ramin; Schmidt, Florian M


    Potassium (K) is an important element related to ash and fine-particle formation in biomass combustion processes. In situ measurements of gaseous atomic potassium, K(g), using robust optical absorption techniques can provide valuable insight into the K chemistry. However, for typical parts per billion K(g) concentrations in biomass flames and reactor gases, the product of atomic line strength and absorption path length can give rise to such high absorbance that the sample becomes opaque around the transition line center. We present a tunable diode laser atomic absorption spectroscopy (TDLAAS) methodology that enables accurate, calibration-free species quantification even under optically thick conditions, given that Beer-Lambert's law is valid. Analyte concentration and collisional line shape broadening are simultaneously determined by a least-squares fit of simulated to measured absorption profiles. Method validation measurements of K(g) concentrations in saturated potassium hydroxide vapor in the temperature range 950-1200 K showed excellent agreement with equilibrium calculations, and a dynamic range from 40 pptv cm to 40 ppmv cm. The applicability of the compact TDLAAS sensor is demonstrated by real-time detection of K(g) concentrations close to biomass pellets during atmospheric combustion in a laboratory reactor.

  17. Spectroscopic detection of health hazardous contaminants in lipstick using Laser Induced Breakdown Spectroscopy. (United States)

    Gondal, M A; Seddigi, Z S; Nasr, M M; Gondal, B


    Laser Induced Breakdown Spectroscopy (LIBS) technique was applied to determine the concentrations of different toxic elements like lead, chromium, cadmium and zinc in four different lipstick brands sold at local markets in Saudi Arabia. These samples contain toxic elements like lead, cadmium and chromium which are carcinogen dermatitis, allergic and eczematous. Their extraction from human body takes over 40 years and accumulation in the body cause problems like disruption of nervous systems and kidney damage. They could trigger to systemic lupus erythematosus (SLE). In order to test the validity of our LIBS results, standard technique like (ICP-AES) was also applied. To the best of our knowledge, this is the first study where LIBS technique was applied for the measurement of toxic substances in lipsticks. The maximum concentration detected in four lipstick brands was much higher than the permissible safe limits for human use and could lead to serious health problems. It is worth mentioning that the lipstick is not a solid rather is in fluid state which is not trivial to analyze using LIBS technique. For this purpose, special treatment of the lipstick samples was necessary to analyze with our LIBS method. (c) 2009 Elsevier B.V. All rights reserved.

  18. Pancreatic tumor detection using hypericin-based fluorescence spectroscopy and cytology (United States)

    Lavu, Harish; Geary, Kevin; Fetterman, Harold R.; Saxton, Romaine E.


    Hypericin is a novel, highly fluorescent photosensitizer that exhibits selective tumor cell uptake properties and is particularly resistant to photobleaching. In this study, we have characterized hypericin uptake in human pancreatic tumor cells with relation to incubation time, cell number, and drug concentration. Ex vivo hypericin based fluorescence spectroscopy was performed to detect the presence of MIA PaCa-2 pancreatic tumor cells in the peritoneal cavity of BALB/c nude mice, as well as to quantify gross tumor burden. Hypericin based cytology of peritoneal lavage samples, using both one and two photon laser confocal microscopy, demonstrated more than a two-fold increase in fluorescence emission of pancreatic tumor cells as compared to control samples. In vitro treatment of pancreatic cancer cells with hypericin based photodynamic therapy showed tumor cell cytotoxicity in a drug dose, incident laser power, and time dependent manner. For these experiments, a continuous wavelength solid-state laser source (532 nm) was operated at power levels in the range of 100-400 mW. Potential applications of hypericin in tumor diagnosis, staging, and therapy will be presented.

  19. Non-invasive detection of periodontal disease using diffuse reflectance spectroscopy: a clinical study (United States)

    Prasanth, Chandra Sekhar; Betsy, Joseph; Subhash, Narayanan; Jayanthi, Jayaraj L.; Prasanthila, Janam


    In clinical diagnostic procedures, gingival inflammation is considered as the initial stage of periodontal breakdown. This is often detected clinically by bleeding on probing as it is an objective measure of inflammation. Since conventional diagnostic procedures have several inherent drawbacks, development of novel non-invasive diagnostic techniques assumes significance. This clinical study was carried out in 15 healthy volunteers and 25 patients to demonstrate the applicability of diffuse reflectance (DR) spectroscopy for quantification and discrimination of various stages of inflammatory conditions in periodontal disease. The DR spectra of diseased lesions recorded using a point monitoring system consisting of a tungsten halogen lamp and a fiber-optic spectrometer showed oxygenated hemoglobin absorption dips at 545 and 575 nm. Mean DR spectra on normalization shows marked differences between healthy and different stages of gingival inflammation. Among the various DR intensity ratios investigated, involving oxy Hb absorption peaks, the R620/R575 ratio was found to be a good parameter of gingival inflammation. In order to screen the entire diseased area and its surroundings instantaneously, DR images were recorded with an EMCCD camera at 620 and 575 nm. We have observed that using the DR image intensity ratio R620/R575 mild inflammatory tissues could be discriminated from healthy with a sensitivity of 92% and specificity of 93%, and from moderate with a sensitivity of 83% and specificity of 96%. The sensitivity and specificity obtained between moderate and severe inflammation are 82% and 76% respectively.

  20. Towards radiation detected resonance ionization spectroscopy on transfermium elements in a buffer gas cell

    Energy Technology Data Exchange (ETDEWEB)

    Lautenschlaeger, Felix; Walther, Thomas [Institut fuer Angewandte Physik, TU Darmstadt, 64289 Darmstadt (Germany); Laatiaoui, Mustapha; Block, Michael [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Helmholtz-Institut Mainz, 55128 Mainz (Germany); Lauth, Werner; Backe, Hartmut [Institut fuer Kernphysik, JGU Mainz, 55128 Mainz (Germany); Hessberger, Fritz-Peter [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, 64291 Darmstadt (Germany)


    The study of the atomic structure of transfermium elements like nobelium (No) and lawrencium (Lr) via Radiation Detected Resonance Ionization Spectroscopy (RADRIS) is one of the most fascinating disciplines of modern atomic physics. It allows the determination of relativistic effects at the heaviest elements and provides a critical test of theoretical predictions. For these transfermium elements no experimental data on atomic level schemes are available at present. First experiments on {sup 254}No were performed in 2007, in which a buffer gas cell with an overall efficiency of 1%. In this experiment the evaporation temperature of nobelium was determined for the first time. To increase the efficiency of the buffer gas cell, off-line measurements have been performed with nat. ytterbium, the chemical homologue of nobelium. Also on-line experiments during a parasitic beam-time in 2012 provided an insight into the critical parameters of our setup. The results of the off-line and on-line measurements are briefly summarized in this talk.

  1. Non-Destructive Evaluation of Polyolefin Thermal Aging Using Infrared Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Fifield, Leonard S.; Shin, Yongsoon; Simmons, Kevin L.


    Fourier transform infrared (FTIR) spectroscopy is an information-rich method that reveals chemical bonding near the surface of polymer composites. FTIR can be used to verify composite composition, identify chemical contaminants and expose composite moisture content. Polymer matrix changes due to thermal exposure including loss of additives, chain scission, oxidation and changes in crystallinity may also be determined using FTIR spectra. Portable handheld instruments using non-contact reflectance or surface contact attenuated total reflectance (ATR) may be used for non-destructive evaluation (NDE) of thermal aging in polymer and composite materials of in-service components. We report the use of ATR FTIR to track oxidative thermal aging in ethylene-propylene rubber (EPR) and chlorinated polyethylene (CPE) materials used in medium voltage nuclear power plant electrical cable insulation and jacketing. Mechanical property changes of the EPR and CPE materials with thermal degradation for correlation with FTIR data are tracked using indenter modulus (IM) testing. IM is often used as a local NDE metric of cable jacket health. The FTIR-determined carbonyl index was found to increase with IM and may be a valuable NDE metric with advantages over IM for assessing cable remaining useful life.

  2. Non-destructive evaluation of polyolefin thermal aging using infrared spectroscopy (United States)

    Fifield, Leonard S.; Shin, Yongsoon; Simmons, Kevin L.


    Fourier transform infrared (FTIR) spectroscopy is an information-rich method that reveals chemical bonding near the surface of polymer composites. FTIR can be used to verify composite composition, identify chemical contaminants and expose composite moisture content. Polymer matrix changes due to thermal exposure including loss of additives, chain scission, oxidation and changes in crystallinity may also be determined using FTIR spectra. Portable handheld instruments using non-contact reflectance or surface contact attenuated total reflectance (ATR) may be used for nondestructive evaluation (NDE) of thermal aging in polymer and composite materials of in-service components. We report the use of ATR FTIR to track oxidative thermal aging in ethylene-propylene rubber (EPR) and chlorinated polyethylene (CPE) materials used in medium voltage nuclear power plant electrical cable insulation and jacketing. Mechanical property changes of the EPR and CPE materials with thermal degradation for correlation with FTIR data are tracked using indenter modulus (IM) testing. IM is often used as a local NDE metric of cable jacket health. The FTIR-determined carbonyl index was found to increase with IM and may be a valuable NDE metric with advantages over IM for assessing cable remaining useful life.

  3. Analysis of degraded papers by infrared and Raman spectroscopy for forensic purposes (United States)

    Zięba-Palus, J.; Wesełucha-Birczyńska, A.; Trzcińska, B.; Kowalski, R.; Moskal, P.


    Paper being the basis of different documents is often the subject of forensic examination. Growing number of bogus or in other manner fraudulently alternated documents causes necessity of identification of individual paper sheets and discrimination between sheets being the parts of analyzed questioned document. Frequently it is necessary to distinguish between paper of the same type but of a different age. Thus, it is essential to know whether the degradation process of paper influences the possibility of differentiation between paper samples. Samples of five types of office paper from different manufacturers were artificially aged in a climatic chamber under 65% relative humidity in air at 90 °C for various periods of time up to 35 days. The conditioned samples were examined by the use of infrared and Raman spectroscopy. Three cards of each paper type were chosen for the experiment. Three different spots on each paper card were measured to assure reproducibility of the experiment in both spectroscopic methods. The possibility of differentiation between aged samples was evaluated. The 2D correlation analysis based on the Noda's method was carried out using ATR FTIR spectra as an input data for generating the correlation maps. It was found that pattern of 2D maps allow to distinguish tested paper samples, identified its components and get insight into paper degradation mechanism.

  4. Organic and inorganic content of fluorotic rat incisors measured by FTIR spectroscopy (United States)

    Porto, Isabel Maria; Saiani, Regina Aparecida; Chan, K. L. Andrew; Kazarian, Sergei G.; Gerlach, Raquel Fernanda; Bachmann, Luciano


    Details on how fluoride interferes in enamel mineralization are still controversial. Therefore, this study aimed at analyzing the organic contents of fluorosis-affected teeth using Fourier Transformation Infrared spectroscopy. To this end, 10 male Wistar rats were divided into two groups: one received 45 ppm fluoride in distilled water for 60 days; the other received distilled water only. Then, the lower incisors were removed and prepared for analysis by two FTIR techniques namely, transmission and micro-ATR. For the first technique, the enamel was powdered, whereas in the second case one fluorotic incisor was cut longitudinally for micro-ATR. Using transmission and powdered samples, FTIR showed a higher C-H content in the fluorotic enamel compared with control enamel ( p enamel, with values decreasing toward the dentine-enamel junction, and reaching the lowest values at the subsuperficial enamel. These results agree with the morphological data, which indicate that in the rat incisor the fluorotic lesion is superficial, rather than subsuperficial, as in the case of human enamel. The results also suggest that the increased C-H bond content may extend toward the more basal enamel (intraosseous), indicating that fluorotic enamel may intrinsically contain more protein. Finally, particularly when coupled to ATR, FTIR is a suitable tool to study the rat incisor enamel, which is a largely used model of normal and abnormal amelogenesis. Further studies along this line may definitely answer some questions regarding protein content in fluorotic enamel as well as their origin.

  5. FTIR spectroscopy offers hints towards widespread molecular changes in cobalt-acclimated freshwater bacteria. (United States)

    Kardas, Mehmet; Gozen, Ayse Gul; Severcan, Feride


    High concentrations of heavy metals can be toxic for bacteria. However, after prolonged exposure, bacteria can become acclimated and begin to be able to grow in the presence of heavy metals. Acclimation can involve alterations of metabolism and molecular structures. Our aim was to examine these alterations in cobalt-acclimated bacteria via attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy on viable samples. Bacillus sp. and Pseudomonas sp. isolated from a temperate shallow lake and a well-established strain of E. coli were investigated. Our results revealed consistent, wide-spread changes in cell membrane and cell wall dynamics of Bacillus sp. and E. coli, including a decrease in peptidoglycan content of Bacillus sp. and increased lipid ordering of the membrane in both bacteria. Furthermore, a decrease in RNA and protein concentrations of Bacillus sp. was measured. All three bacteria studied showed a decrease in conformational freedom of proteins following cobalt acclimation. Interestingly, both Bacillus sp. and E. coli showed slight but significant alterations in their DNA conformations which might imply a methylation-mediated memory formation leading to epigenetic modulation for cobalt adaptation. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Micro-Raman spectroscopy for the detection of stacking fault density in InAs and GaAs nanowires (United States)

    Tanta, Rawa; Lindberg, Caroline; Lehmann, Sebastian; Bolinsson, Jessica; Carro-Temboury, Miguel R.; Dick, Kimberly A.; Vosch, Tom; Jespersen, Thomas Sand; Nygârd, Jesper


    We investigate the relation between crystal stacking faults in individual wurtzite InAs and GaAs nanowires and the intensity of the forbidden longitudinal optical (LO) phonon mode in the Raman spectra. Micro-Raman spectroscopy and transmission electron microscopy are combined on the same individual nanowires to evaluate the LO mode intensity as a function of the stacking fault density. A clear increase in the LO mode intensity was observed when the stacking fault density was increased. Our results confirm the utility of Raman spectroscopy as a powerful tool for detecting crystal defects in nanowires.

  7. To the application of the emission Mössbauer and positron annihilation spectroscopies for detection of carcinogens (United States)

    Bokov, A. V.; Byakov, V. M.; Kulikov, L. A.; Perfiliev, Yu. D.; Stepanov, S. V.


    Being the main cause of cancer, almost all chemical carcinogens are strong electrophiles, that is, they have a high affinity for the electron. We have shown that positron annihilation lifetime spectroscopy (PALS) is able to detect chemical carcinogens by their inhibition of positronium (Ps) formation in liquid media. Electrophilic carcinogens intercept thermalized track electrons, which are precursors of Ps, and as a result, when they are present Ps atom does not practically form. Available biophysical data seemingly indicate that frozen solutions model better an intracellular medium than the liquid ones. So it is reasonable to use emission Mössbauer spectroscopy (EMS) to detect chemical carcinogens, measuring the yield of 57Fe2+ions formed in reactions of Auger electrons and other secondary electrons they produced with 57Fe3+. These reactions are similar to the Ps formation process in the terminal part the positron track: e++ e- =>Ps. So EMS and PALS are complementary methods for detection of carcinogenic compounds.

  8. Raman Spectroscopy an Option for the Early Detection of Citrus Huanglongbing. (United States)

    Pérez, Moisés Roberto Vallejo; Mendoza, María Guadalupe Galindo; Elías, Miguel Ghebre Ramírez; González, Francisco Javier; Contreras, Hugo Ricardo Navarro; Servín, Carlos Contreras


    This research describes the application of portable field Raman spectroscopy combined with a statistical analysis of the resulting spectra, employing principal component analysis (PCA) and linear discriminant analysis (LDA), in which we determine that this method provides a high degree of reliability in the early detection of Huanglongbing (HLB) on Sweet Orange, disease caused by the bacteria Candidatus Liberibacter asiaticus. Symptomatic and asymptomatic plant samples of Sweet Orange (Citrus sinensis), Persian Lime (C. latifolia), and Mexican Lime (C. aurantifolia) trees were collected from several municipalities, three at Colima State and three at Jalisco State (HLB presence). In addition, Sweet Orange samples were taken from two other Mexican municipalities, one at San Luis Potosí and the other at Veracruz (HLB absent). All samples were analyzed by real-time PCR to determine its phytosanitary condition, and its spectral signatures were obtained with an ID-Raman mini. Spectral anomalies in orange trees HLB-positive, were identified in bands related to carbohydrates (905 cm(-1), 1043 cm(-1), 1127 cm(-1), 1208 cm(-1), 1370 cm(-1), 1272 cm(-1), 1340 cm(-1), and 1260-1280 cm(-1)), amino acids, proteins (815 cm(-1), 830 cm(-1), 852 cm(-1), 918 cm(-1), 926 cm(-1), 970 cm(-1), 1002 cm(-1), 1053 cm(-1), and 1446 cm(-1)), and lipids (1734 cm(-1), 1736 cm(-1), 1738 cm(-1), 1745 cm(-1), and 1746 cm(-1)). Moreover, PCA-LDA showed a sensitivity of 86.9 % (percentage of positives, which are correctly identified), a specificity of 91.4 % (percentage of negatives, which are correctly identified), and a precision of 89.2 % (the proportion of all tests that are correct) in discriminating between orange plants HLB-positive and healthy plants. The Raman spectroscopy technique permitted rapid diagnoses, was low-cost, simple, and practical to administer, and produced immediate results. These are essential features for phytosanitary

  9. Assembling a prototype resonance electrical impedance spectroscopy system for breast tissue signal detection: preliminary assessment (United States)

    Sumkin, Jules; Zheng, Bin; Gruss, Michelle; Drescher, John; Leader, Joseph; Good, Walter; Lu, Amy; Cohen, Cathy; Shah, Ratan; Zuley, Margarita; Gur, David


    Using electrical impedance spectroscopy (EIS) technology to detect breast abnormalities in general and cancer in particular has been attracting research interests for decades. Large clinical tests suggest that current EIS systems can achieve high specificity (>= 90%) at a relatively low sensitivity ranging from 15% to 35%. In this study, we explore a new resonance frequency based electrical impedance spectroscopy (REIS) technology to measure breast tissue EIS signals in vivo, which aims to be more sensitive to small tissue changes. Through collaboration between our imaging research group and a commercial company, a unique prototype REIS system has been assembled and preliminary signal acquisition has commenced. This REIS system has two detection probes mounted in the two ends of a Y-shape support device with probe separation of 60 mm. During REIS measurement, one probe touches the nipple and the other touches to an outer point of the breast. The electronic system continuously generates sweeps of multi-frequency electrical pulses ranging from 100 to 4100 kHz. The maximum electric voltage and the current applied to the probes are 1.5V and 30mA, respectively. Once a "record" command is entered, multi-frequency sweeps are recorded every 12 seconds until the program receives a "stop recording" command. In our imaging center, we have collected REIS measurements from 150 women under an IRB approved protocol. The database includes 58 biopsy cases, 78 screening negative cases, and other "recalled" cases (for additional imaging procedures). We measured eight signal features from the effective REIS sweep of each breast. We applied a multi-feature based artificial neural network (ANN) to classify between "biopsy" and normal "non-biopsy" breasts. The ANN performance is evaluated using a leave-one-out validation method and ROC analysis. We conducted two experiments. The first experiment attempted to classify 58 "biopsy" breasts and 58 "non-biopsy" breasts acquired on 58 women

  10. Biogenic unmodified gold nanoparticles for selective and quantitative detection of cerium using UV-vis spectroscopy and photon correlation spectroscopy (DLS). (United States)

    Priyadarshini, E; Pradhan, N; Panda, P K; Mishra, B K


    The ability of self-functionalized biogenic GNPs towards highly selective colorimetric detection of rare earth element cerium is being reported for the first time. GNPs underwent rapid aggregation on addition of cerium indicated by red shift of SPR peak followed by complete precipitation. Hereby, this concept of co-ordination of cerium ions onto the GNP surface has been utilized for detection of cerium. The remarkable capacity of GNPs to sensitively detect Ce without proves beneficial compared to previous reports of colorimetric sensing. MDL was 15 and 35 ppm by DLS and UV-vis spectroscopy respectively, suggesting DLS to be highly sensitive and a practical alternative in ultrasensitive detection studies. The sensing system showed a good linear fit favouring feasible detection of cerium in range of 2-50 ppm. Similar studies further showed the superior selectivity of biogenic GNPs compared to chemically synthesized counterparts. The sensing system favours on-site analysis as it overcomes need of complex instrumentation, lengthy protocols and surface modification of GNP. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Computerized detection of breast cancer using resonance-frequency-based electrical impedance spectroscopy (United States)

    Gao, Wei; Fan, Ming; Zhao, Weijie; Zheng, Bin; Li, Lihua


    This study developed and tested a multi-probe resonance-frequency-based electrical impedance spectroscopy (REIS) system aimed at detection of breast cancer. The REIS system consists of specially designed mechanical supporting device that can be easily lifted to fit women of different height, a seven probe sensor cup, and a computer providing software for system control and management. The sensor cup includes one central probe for direct contact with the nipple, and other six probes uniformly distributed at a distance of 35mm away from the center probe to enable contact with breast skin surface. It takes about 18 seconds for this system to complete a data acquisition process. We utilized this system for examination of breast cancer, collecting a dataset of 289 cases including biopsy verified 74 malignant and 215 benign tumors. After that, 23 REIS based features, including seven frequency, fifteen magnitude features were extracted, and an age feature. To reduce redundancy we selected 6 features using the evolutionary algorithm for classification. The area under a receiver operating characteristic curve (AUC) was computed to assess classifier performance. A multivariable logistic regression method was performed for detection of the tumors. The results of our study showed for the 23 REIS features AUC and ACC, Sensitivity and Specificity of 0.796, 0.727, 0.731 and 0.726, respectively. The AUC and ACC, Sensitivity and Specificity for the 6 REIS features of 0.840, 0.80, 0.703 and 0.833, respectively, and AUC of 0.662 and 0.619 for the frequency and magnitude based REIS features, respectively. The performance of the classifiers using all the 6 features was significantly better than solely using magnitude features (p=3.29e-08) and frequency features (5.61e-07). Smote algorithm was used to expand small samples to balance the dataset, the AUC after data balance of 0.846 increased than the original data classification performance. The results indicated that the REIS system is

  12. Nanoparticle detection in aqueous solutions using Raman and Laser Induced Breakdown Spectroscopy

    NARCIS (Netherlands)

    Sovago, M.; Buis, E.-J.; Sandtke, M.


    We show the chemical identification and quantification of the concentration and size of nanoparticle (NP) dispersions in aqueous solutions by using a combination of Raman Spectroscopy and Laser Induced Breakdown Spectroscopy (LIBS). The two spectroscopic techniques are applied to demonstrate the NP

  13. Challenging Near InfraRed Spectroscopy discriminating ability for counterfeit pharmaceuticals detection

    Energy Technology Data Exchange (ETDEWEB)

    Storme-Paris, I. [Groupe de Chimie Analytique de Paris-Sud, EA 4041, IFR 141, School of Pharmacy, Univ Paris-Sud, 5 rue Jean Baptiste Clement, 92296 Chatenay-Malabry (France); Rebiere, H. [Laboratories and Control Department, French Health Products Safety Agency (AFSSAPS), 635 rue de la Garenne, 34740 Vendargues (France); Matoga, M. [Groupe de Chimie Analytique de Paris-Sud, EA 4041, IFR 141, School of Pharmacy, Univ Paris-Sud, 5 rue Jean Baptiste Clement, 92296 Chatenay-Malabry (France); Civade, C.; Bonnet, P.-A.; Tissier, M.H. [Laboratories and Control Department, French Health Products Safety Agency (AFSSAPS), 635 rue de la Garenne, 34740 Vendargues (France); Chaminade, P., E-mail: [Groupe de Chimie Analytique de Paris-Sud, EA 4041, IFR 141, School of Pharmacy, Univ Paris-Sud, 5 rue Jean Baptiste Clement, 92296 Chatenay-Malabry (France)


    This study was initiated by the laboratories and control department of the French Health Products Safety Agency (AFSSAPS) as part of the fight against the public health problem of rising counterfeit and imitation medicines. To test the discriminating ability of Near InfraRed Spectroscopy (NIRS), worse cases scenarios were first considered for the discrimination of various pharmaceutical final products containing the same Active Pharmaceutical Ingredient (API) with different excipients, such as generics of proprietary medicinal products (PMP). Two generic databases were explored: low active strength hard capsules of Fluoxetine and high strength tablets of Ciprofloxacin. Then 4 other cases involving suspicious samples, counterfeits and imitations products were treated. In all these cases, spectral differences between samples were studied, giving access to API or excipient contents information, and eventually allowing manufacturing site identification. A chemometric background is developed to explain the optimisation methodology, consisting in the choices of appropriate pretreatments, algorithms for data exploratory analyses (unsupervised Principal Component Analysis), and data classification (supervised cluster analysis, and Soft Independent Modelling of Class Analogy). Results demonstrate the high performance of NIRS, highlighting slight differences in formulations, such as 2.5% (w/w) in API strength, 1.0% (w/w) in excipient and even coating variations (<1%, w/w) with identical contents, approaching the theoretical limits of NIRS sensitivity. All the different generic formulations were correctly discriminated and foreign PMP, constituted of formulations slightly different from the calibration ones, were also all discriminated. This publication addresses the ability of NIRS to detect counterfeits and imitations and presents the NIRS as an ideal tool to master the global threat of counterfeit drugs.

  14. An Approach for Routine Analytical Detection of Beeswax Adulteration Using FTIR-ATR Spectroscopy

    Directory of Open Access Journals (Sweden)

    Svečnjak Lidija


    Full Text Available Although beeswax adulteration represents one of the main beeswax quality issues, there are still no internationally standardised analytical methods for routine quality control. The objective of this study was to establish an analytical procedure suitable for routine detection of beeswax adulteration using FTIR-ATR spectroscopy. For the purpose of this study, reference IR spectra of virgin beeswax, paraffin, and their mixtures containing different proportions of paraffin (5 - 95%, were obtained. Mixtures were used for the establishment of calibration curves. To determine the prediction strength of IR spectral data for the share of paraffin in mixtures, the Partial Least Squares Regression method was used. The same procedure was conducted on beeswax-beef tallow mixtures. The model was validated using comb foundation samples of an unknown chemical background which had been collected from the international market (n = 56. Selected physico-chemical parameters were determined for comparison purposes. Results revealed a strong predictive power (R2 = 0.999 of IR spectra for the paraffin and beef tallow share in beeswax. The results also revealed that the majority of the analysed samples (89% were adulterated with paraffin; only 6 out of 56 (11% samples were identified as virgin beeswax, 28% of the samples exhibited a higher level of paraffin adulteration (>46% of paraffin, while the majority of the analysed samples (50% were found to be adulterated with 5 - 20% of paraffin. These results indicate an urgent need for routine beeswax authenticity control. In this study, we demonstrated that the analytical approach defining the standard curves for particular adulteration levels in beeswax, based on chemometric modelling of specific IR spectral region indicative for adulteration, enables reliable determination of the adulterant proportions in beeswax.

  15. Raman spectroscopy detection of biomolecules in biocrusts from differing environmental conditions. (United States)

    Miralles, I; Jorge-Villar, S E; van Wesemael, B; Lázaro, R


    Lichens and cyanobacteria colonize inhospitable places covering a wide climate range due to their different survival strategies, such as the synthesis of protective biomolecules. The effect of ecological factors on the synthesis of biomolecules has not been widely analysed. This study aimed to assess the effects of four factors (species, microclimate, seasonality and hydration state) and their interactions on the biomolecule frequency detected by Raman Spectroscopy. We included cyanobacterial biocrusts, and the lichens Diploschistes diacapsis, Squamarina lentigera, and Lepraria isidiata; two contrasted microclimates (typical and marginal), two contrasted seasons (hot and dry vs cool and wet) and two hydration states (dry and wet). "Species" was the most influential factor in the identity and frequency of the main biomolecules. Microclimatic differences in the range of the local specific habitats only influenced the biomolecules in cyanobacteria. There was a quadruple interaction among the factors, the effects being different mainly depending on the species. At D. diacapsis, the production of their main biomolecules depended on microclimate, although it also depended on seasonality. Nevertheless, in L. isidiata and S. lentigera microclimatic differences did not significantly affect the production of biomolecules. In the lichen species, the microhabitats exposed to relatively larger incident radiation did not show significantly larger relative frequency of photoprotective biomolecules. No clear connection between higher production of oxalates and drier microhabitats was found, suggesting that the synthesis of oxalates is not related to water reserve strategy. The pros and cons of monitor biomolecules in biocrust by Raman spectrometry were also discussed. Copyright © 2016. Published by Elsevier B.V.

  16. Detection of advanced glycation end products (AGEs) on human skin by in vivo confocal Raman spectroscopy (United States)

    Martin, A. A.; Pereira, L.; Ali, S. M.; Pizzol, C. D.; Tellez, C. A.; Favero, P. P.; Santos, L.; da Silva, V. V.; Praes, C. E. O.


    The aging process involves the reduction in the production of the major components of skin tissue. During intrinsic aging and photoaging processes, in dermis of human skin, fibroblasts become senescent and have decreased activity, which produce low levels of collagen. Moreover, there is accumulation of advanced glycation end products (AGEs). AGEs have incidence in the progression of age-related diseases, principally in diabetes mellitus and in Alzheimer's diseases. AGEs causes intracellular damage and/or apoptosis leading to an increase of the free radicals, generating a crosslink with skin proteins and oxidative stress. The aim of this study is to detect AGEs markers on human skin by in vivo Confocal Raman spectroscopy. Spectra were obtained by using a Rivers Diagnostic System, 785 nm laser excitation and a CCD detector from the skin surface down to 120 μm depth. We analyzed the confocal Raman spectra of the skin dermis of 30 women volunteers divided into 3 groups: 10 volunteers with diabetes mellitus type II, 65-80 years old (DEW); 10 young healthy women, 20-33 years old (HYW); and 10 elderly healthy women, 65-80 years old (HEW). Pentosidine and glucosepane were the principally identified AGEs in the hydroxyproline and proline Raman spectral region (1000-800 cm-1), in the 1.260-1.320 cm-1 region assignable to alpha-helical amide III modes, and in the Amide I region. Pentosidine and glucosepane calculated vibrational spectra were performed through Density Functional Theory using the B3LYP functional with 3-21G basis set. Difference between the Raman spectra of diabetic elderly women and healthy young women, and between healthy elderly women and healthy young women were also obtained with the purpose of identifying AGEs Raman bands markers. AGEs peaks and collagen changes have been identified and used to quantify the glycation process in human skin.

  17. A portable device for detecting fruit quality by diffuse reflectance Vis/NIR spectroscopy (United States)

    Sun, Hongwei; Peng, Yankun; Li, Peng; Wang, Wenxiu


    Soluble solid content (SSC) is a major quality parameter to fruit, which has influence on its flavor or texture. Some researches on the on-line non-invasion detection of fruit quality were published. However, consumers desire portable devices currently. This study aimed to develop a portable device for accurate, real-time and nondestructive determination of quality factors of fruit based on diffuse reflectance Vis/NIR spectroscopy (520-950 nm). The hardware of the device consisted of four units: light source unit, spectral acquisition unit, central processing unit, display unit. Halogen lamp was chosen as light source. When working, its hand-held probe was in contact with the surface of fruit samples thus forming dark environment to shield the interferential light outside. Diffuse reflectance light was collected and measured by spectrometer (USB4000). ARM (Advanced RISC Machines), as central processing unit, controlled all parts in device and analyzed spectral data. Liquid Crystal Display (LCD) touch screen was used to interface with users. To validate its reliability and stability, 63 apples were tested in experiment, 47 of which were chosen as calibration set, while others as prediction set. Their SSC reference values were measured by refractometer. At the same time, samples' spectral data acquired by portable device were processed by standard normalized variables (SNV) and Savitzky-Golay filter (S-G) to eliminate the spectra noise. Then partial least squares regression (PLSR) was applied to build prediction models, and the best predictions results was achieved with correlation coefficient (r) of 0.855 and standard error of 0.6033° Brix. The results demonstrated that this device was feasible to quantitatively analyze soluble solid content of apple.

  18. Nondestructive detection of pork quality based on dual-band VIS/NIR spectroscopy (United States)

    Wang, Wenxiu; Peng, Yankun; Li, Yongyu; Tang, Xiuying; Liu, Yuanyuan


    With the continuous development of living standards and the relative change of dietary structure, consumers' rising and persistent demand for better quality of meat is emphasized. Colour, pH value, and cooking loss are important quality attributes when evaluating meat. To realize nondestructive detection of multi-parameter of meat quality simultaneously is popular in production and processing of meat and meat products. The objectives of this research were to compare the effectiveness of two bands for rapid nondestructive and simultaneous detection of pork quality attributes. Reflectance spectra of 60 chilled pork samples were collected from a dual-band visible/near-infrared spectroscopy system which covered 350-1100 nm and 1000-2600 nm. Then colour, pH value and cooking loss were determined by standard methods as reference values. Standard normal variables transform (SNVT) was employed to eliminate the spectral noise. A spectrum connection method was put forward for effective integration of the dual-band spectrum to make full use of the whole efficient information. Partial least squares regression (PLSR) and Principal component analysis (PCA) were applied to establish prediction models using based on single-band spectrum and dual-band spectrum, respectively. The experimental results showed that the PLSR model based on dual-band spectral information was superior to the models based on single band spectral information with lower root means quare error (RMSE) and higher accuracy. The PLSR model based on dual-band (use the overlapping part of first band) yielded the best prediction result with correlation coefficient of validation (Rv) of 0.9469, 0.9495, 0.9180, 0.9054 and 0.8789 for L*, a*, b*, pH value and cooking loss, respectively. This mainly because dual-band spectrum can provide sufficient and comprehensive information which reflected the quality attributes. Data fusion from dual-band spectrum could significantly improve pork quality parameters prediction

  19. Quantitative elemental detection of size-segregated particles using laser-induced breakdown spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhen Zhen [State Key Laboratory of Multiphase Flow in Power Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Graduate School of Advanced Technology and Science, The University of Tokushima, Tokushima 770-8501 (Japan); Deguchi, Yoshihiro, E-mail: [Graduate School of Advanced Technology and Science, The University of Tokushima, Tokushima 770-8501 (Japan); Kuwahara, Masakazu; Taira, Takuya [Graduate School of Advanced Technology and Science, The University of Tokushima, Tokushima 770-8501 (Japan); Zhang, Xiao Bo [State Key Laboratory of Multiphase Flow in Power Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Graduate School of Advanced Technology and Science, The University of Tokushima, Tokushima 770-8501 (Japan); Yan, Jun Jie; Liu, Ji Ping [State Key Laboratory of Multiphase Flow in Power Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Watanabe, Hiroaki [Energy Engineering Research Laboratory, Central Research Institute of Electric Power Industry, Kanagawa 240-0196 (Japan); Kurose, Ryoichi [Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540 (Japan)


    In order to simulate coal combustion and develop optimal and stable boiler control systems in real power plants, it is imperative to obtain the detailed information in coal combustion processes as well as to measure species contents in fly ash, which should be controlled and analyzed for enhancing boiler efficiency and reducing environmental pollution. The fly ash consists of oxides (SiO{sub 2}, Al{sub 2}O{sub 3}, Fe{sub 2}O{sub 3}, CaO, and so on), unburned carbon, and other minor elements. Recently laser-induced breakdown spectroscopy (LIBS) technique has been applied to coal combustion and other industrial fields because of the fast response, high sensitivity, real-time and non-contact features. In these applications it is important to measure controlling factors without any sample preparation to maintain the real-time measurement feature. The relation between particle content and particle diameter is also one of the vital researches, because compositions of particles are dependent on their diameter. In this study, we have detected the contents of size-segregated particles using LIBS. Particles were classified by an Anderson cascade impactor and their contents were measured using the output of 1064 nm YAG laser, a spectrograph and an ICCD camera. The plasma conditions such as plasma temperature are dependent on the size of particles and these effects must be corrected to obtain quantitative information. The plasma temperature was corrected by the emission intensity ratio from the same atom. Using this correction method, the contents of particles can be measured quantitatively in fixed experimental parameters. This method was applied to coal and fly ash from a coal-fired burner to measure unburned carbon and other contents according to the particle diameter. The acquired results demonstrate that the LIBS technique is applicable to measure size-segregated particle contents in real time and this method is useful for the analysis of coal combustion and its control

  20. Detection and correction of laser induced breakdown spectroscopy spectral background based on spline interpolation method (United States)

    Tan, Bing; Huang, Min; Zhu, Qibing; Guo, Ya; Qin, Jianwei


    Laser-induced breakdown spectroscopy (LIBS) is an analytical technique that has gained increasing attention because of many applications. The production of continuous background in LIBS is inevitable because of factors associated with laser energy, gate width, time delay, and experimental environment. The continuous background significantly influences the analysis of the spectrum. Researchers have proposed several background correction methods, such as polynomial fitting, Lorenz fitting and model-free methods. However, less of them apply these methods in the field of LIBS Technology, particularly in qualitative and quantitative analyses. This study proposes a method based on spline interpolation for detecting and estimating the continuous background spectrum according to its smooth property characteristic. Experiment on the background correction simulation indicated that, the spline interpolation method acquired the largest signal-to-background ratio (SBR) over polynomial fitting, Lorenz fitting and model-free method after background correction. These background correction methods all acquire larger SBR values than that acquired before background correction (The SBR value before background correction is 10.0992, whereas the SBR values after background correction by spline interpolation, polynomial fitting, Lorentz fitting, and model-free methods are 26.9576, 24.6828, 18.9770, and 25.6273 respectively). After adding random noise with different kinds of signal-to-noise ratio to the spectrum, spline interpolation method acquires large SBR value, whereas polynomial fitting and model-free method obtain low SBR values. All of the background correction methods exhibit improved quantitative results of Cu than those acquired before background correction (The linear correlation coefficient value before background correction is 0.9776. Moreover, the linear correlation coefficient values after background correction using spline interpolation, polynomial fitting, Lorentz

  1. Diffuse-light absorption spectroscopy by fiber optics for detecting and quantifying the adulteration of extra virgin olive oil (United States)

    Mignani, A. G.; Ciaccheri, L.; Ottevaere, H.; Thienpont, H.; Conte, L.; Marega, M.; Cichelli, A.; Attilio, C.; Cimato, A.


    A fiber optic setup for diffuse-light absorption spectroscopy in the wide 400-1700 nm spectral range is experimented for detecting and quantifying the adulteration of extra virgin olive oil caused by lower-grade olive oils. Absorption measurements provide spectral fingerprints of authentic and adulterated oils. A multivariate processing of spectroscopic data is applied for discriminating the type of adulterant and for predicting its fraction.

  2. Culture-Free Detection of Crop Pathogens at the Single-Cell Level by Micro-Raman Spectroscopy. (United States)

    Gan, Qinhua; Wang, Xuetao; Wang, Yun; Xie, Zhenyu; Tian, Yang; Lu, Yandu


    The rapid and sensitive identification of invasive plant pathogens has important applications in biotechnology, plant quarantine, and food security. Current methods are far too time-consuming and need a pre-enrichment period ranging from hours to days. Here, a micro-Raman spectroscopy-based bioassay for culture-free pathogen quarantine inspection at the single cell level within 40 min is presented. The application of this approach can readily and specifically detect plant pathogens Burkholderia gladioli pv. alliicola and Erwinia chrysanthemi that are closely related pathogenically. Furthermore, the single-bacterium detection was able to discriminate them from a reference Raman spectral library including multiple quarantine-relevant pathogens with broad host ranges and an array of pathogenic variants. To show the usefulness of this assay, Burkholderia gladioli pv. alliicola and Erwinia chrysanthemi are detected at single-bacterium level in plant tissue lesions without pre-enrichment. The results are confirmed by the plate-counting method and a genetic molecular approach, which display comparable recognition ratios to the Raman spectroscopy-based bioassay. The results represent a critical step toward the use of micro-Raman spectroscopy in rapid and culture-free discrimination of quarantine relevant plant pathogens.

  3. Quantitative Detection of Ethanol/Acetone in Complex Solutions Using Raman Spectroscopy Based on Headspace Gas Analysis. (United States)

    Zhao, Yubin; Yamaguchi, Yoshinori; Liu, Chenchen; Sekine, Shinichi; Dou, Xiaoming


    This paper demonstrated the quantitative detection of ethanol and acetone mixtures in complex solutions with Raman spectroscopy based on headspace gas analysis. By analyzing the volatile components in the headspace, their concentrations in liquid solutions were determined. We constructed our own Raman spectroscopy system to detect the headspace gas quantitatively over a solution in a sealed vial. The Raman spectra of the headspace gases over standard solutions were standardized for finding the concentrations of ethanol, acetone, and ethanol-acetone in mixture solutions. The results showed that the concentration of a gaseous component in the headspace gas was proportional to its ratio in the liquid solution. We obtained a linear relationship between the spectral intensity of volatile components in headspace and the concentration of the liquid solutions. Then, we analyzed the alcohol concentration in a white wine and a Chinese liquor called Fen Chiew by measuring the Raman spectra of the headspace gas over their liquids. For the river water sample, we also implemented our headspace gas detection with Raman spectra to obtain the concentration of acetone in the river sample. This work demonstrated the facilitation of headspace gas analysis by the qualitative and quantitative determination of volatile substances from liquid samples using Raman spectroscopy.

  4. Detection of rhodopsin dimerization in situ by PIE-FCCS, a time-resolved fluorescence spectroscopy. (United States)

    Smith, Adam W


    Rhodopsin self-associates in the plasma membrane. At low concentrations, the interactions are consistent with a monomer-dimer equilibrium (Comar et al., J Am Chem Soc 136(23):8342-8349, 2014). At high concentrations in native tissue, higher-order clusters have been observed (Fotiadis et al., Nature 421:127-128, 2003). The physiological role of rhodopsin dimerization is still being investigated, but it is clear that a quantitative assessment is essential to determining the function of rhodopsin clusters in vision. To quantify rhodopsin interactions, I will outline the theory and methodology of a specialized time-resolved fluorescence spectroscopy for measuring membrane protein-protein interactions called pulsed-interleaved excitation fluorescence cross-correlation spectroscopy (PIE-FCCS). The strength of this technique is its ability to quantify rhodopsin interactions in situ (i.e., a live cell plasma membrane). There are two reasons for restricting the scope to live cell membranes. First, the compositional heterogeneity of the plasma membrane creates a complex milieu with thousands of lipid, protein, and carbohydrate species. This makes it difficult to infer quaternary interactions from detergent solubilized samples or construct a model phospholipid bilayer that recapitulates all of the interactions present in native membranes. Second, organizational structure and dynamics is a key feature of the plasma membrane, and fixation techniques like formaldehyde cross-linking and vitrification will modulate the interactions. PIE-FCCS is based on two-color fluorescence imaging with time-correlated single-photon counting (TCSPC) (Becker et al., Rev Sci Instrum 70:1835-1841, 1999). By time-tagging every detected photon, the data can be analyzed as a fluorescence intensity distribution, fluorescence lifetime histogram, or fluorescence (cross-)correlation spectra (FCS/FCCS) (Becker, Advanced time-correlated single-photon counting techniques, Springer, Berlin, 2005). These

  5. Engineering and Characterization of Peptides and Proteins at Surfaces and Interfaces: A Case Study in Surface-Sensitive Vibrational Spectroscopy. (United States)

    Ding, Bei; Jasensky, Joshua; Li, Yaoxin; Chen, Zhan


    Understanding molecular structures of interfacial peptides and proteins impacts many research fields by guiding the advancement of biocompatible materials, new and improved marine antifouling coatings, ultrasensitive and highly specific biosensors and biochips, therapies for diseases related to protein amyloid formation, and knowledge on mechanisms for various membrane proteins and their interactions with ligands. Developing methods for measuring such unique systems, as well as elucidating the structure and function relationship of such biomolecules, has been the goal of our lab at the University of Michigan. We have made substantial progress to develop sum frequency generation (SFG) vibrational spectroscopy into a powerful technique to study interfacial peptides and proteins, which lays a foundation to obtain unique and valuable insights when using SFG to probe various biologically relevant systems at the solid/liquid interface in situ in real time. One highlighting feature of this Account is the demonstration of the power of combining SFG with other techniques and methods such as ATR-FTIR, surface engineering, MD simulation, liquid crystal sensing, and isotope labeling in order to study peptides and proteins at interfaces. It is necessary to emphasize that SFG plays a major role in these studies, while other techniques and methods are supplemental. The central role of SFG is to provide critical information on interfacial peptide and protein structure (e.g., conformation and orientation) in order to elucidate how surface engineering (e.g., to vary the structure) can ultimately affect surface function (e.g., to optimize the activity). This Account focuses on the most significant recent progress in research on interfacial peptides and proteins carried out by our group including (1) the development of SFG analysis methods to determine orientations of regular as well as disrupted secondary structures, and the successful demonstration and application of an isotope

  6. Comprehensive Detection and Discrimination of Campylobacter Species by Use of Confocal Micro-Raman Spectroscopy and Multilocus Sequence Typing (United States)

    Lu, Xiaonan; Huang, Qian; Miller, William G.; Aston, D. Eric; Xu, Jie; Xue, Feng; Zhang, Hongwei; Rasco, Barbara A.


    A novel strategy for the rapid detection and identification of traditional and emerging Campylobacter strains based upon Raman spectroscopy (532 nm) is presented here. A total of 200 reference strains and clinical isolates of 11 different Campylobacter species recovered from infected animals and humans from China and North America were used to establish a global Raman spectroscopy-based dendrogram model for Campylobacter identification to the species level and cross validated for its feasibility to predict Campylobacter-associated food-borne outbreaks. Bayesian probability coupled with Monte Carlo estimation was employed to validate the established Raman classification model on the basis of the selected principal components, mainly protein secondary structures, on the Campylobacter cell membrane. This Raman spectroscopy-based typing technique correlates well with multilocus sequence typing and has an average recognition rate of 97.21%. Discriminatory power for the Raman classification model had a Simpson index of diversity of 0.968. Intra- and interlaboratory reproducibility with different instrumentation yielded differentiation index values of 4.79 to 6.03 for wave numbers between 1,800 and 650 cm−1 and demonstrated the feasibility of using this spectroscopic method at different laboratories. Our Raman spectroscopy-based partial least-squares regression model could precisely discriminate and quantify the actual concentration of a specific Campylobacter strain in a bacterial mixture (regression coefficient, >0.98; residual prediction deviation, >7.88). A standard protocol for sample preparation, spectral collection, model validation, and data analyses was established for the Raman spectroscopic technique. Raman spectroscopy may have advantages over traditional genotyping methods for bacterial epidemiology, such as detection speed and accuracy of identification to the species level. PMID:22740711

  7. Detection and Identification of potentially toxic elements in urban soil using in situ spectroscopy (United States)

    Brook, Anna; Kopel, Daniella; Wittenberg, Lea


    Anthropogenic urban soils are the foundation of the urban green infrastructure, the green net quality is as good as each of its patches. In early days of pedology urban soil has been recognized with respect to contamination and the risks for human health but in study performed since the 70s, the importance of urban soil for the urban ecology became increasingly significant. Urban soils are highly disturbed land that was created by the process of urbanization. The dominant agent in the creation of urban soils is human activity which modifies the natural soil through mixing, filling or by contamination of land surfaces so as to create a layer of urban soil which can be more than 50 cm thick. The objective of this study is to determine the extent to which field spectroscopy methods can be used to extend the knowledge of toxic elements in urban soils. The majority of the studies on urban soils concentrate on identifying and mapping of known pollution mostly certain heavy metals, we are focusing on almost non disturbed soils where no direct disturbance occurred but the urban matrix inflicted on it. The elements in those soils where an-knowns features. In this study a top-down analysis is applied for detecting the presence of minerals, organic matter and pollutants in mixed soil samples. Results of the proposed top-down unmixing method suggest that the analysis is made very fast due to the simplified hierarchy which avoids the high-learning curve associated with unmixing algorithms showed that the most abundant components were coarse organic matter 12% followed by concrete dust, plastic crumbs, other man made materials, clay and other minerals. The results of the soils pH, measured electrometrically and the particle size distribution, measured by Laser diffraction, indicate there is no big different between the samples particle size distribution and the pH values of the samples but they are not significantly different from the expected, except for the OM percentage which

  8. Rapid isolation and detection of erythropoietin in blood plasma by magnetic core gold nanoparticles and portable Raman spectroscopy. (United States)

    Agoston, Roland; Izake, Emad L; Sivanesan, Arumugam; Lott, William B; Sillence, Martin; Steel, Rohan


    Isolating, purifying, and identifying proteins in complex biological matrices are often difficult, time consuming, and unreliable. Herein we describe a rapid screening technique for proteins in biological matrices that combines selective protein isolation with direct surface enhanced Raman spectroscopy (SERS) detection. Magnetic core gold nanoparticles were synthesized, characterized, and subsequently functionalized with recombinant human erythropoietin (rHuEPO)-specific antibody. The functionalized nanoparticles were used to capture rHuEPO from horse blood plasma within 15 min. The selective binding between the protein and the functionalized nanoparticles was monitored by SERS. The purified protein was then released from the nanoparticles' surface and directly spectroscopically identified on a commercial nanopillar SERS substrate. ELISA independently confirmed the SERS identification and quantified the released rHuEPO. Finally, the direct SERS detection of the extracted protein was successfully demonstrated for in-field screening by a handheld Raman spectrometer within 1 min sample measurement time. The rapid detection of recombinant human erythropoietin (rHuEPO) is important in competitive sports to screen for doping offences. In this article, the authors reported their technique of direct surface enhanced Raman spectroscopy (SERS) detection using magnetic core gold nanoparticles functionalized with recombinant human erythropoietin-specific antibody. The findings should open a new way for future detection of other proteins. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Investigation of Two Novel Approaches for Detection of Sulfate Ion and Methane Dissolved in Sediment Pore Water Using Raman Spectroscopy

    Directory of Open Access Journals (Sweden)

    Zengfeng Du


    Full Text Available The levels of dissolved sulfate and methane are crucial indicators in the geochemical analysis of pore water. Compositional analysis of pore water samples obtained from sea trials was conducted using Raman spectroscopy. It was found that the concentration of SO42− in pore water samples decreases as the depth increases, while the expected Raman signal of methane has not been observed. A possible reason for this is that the methane escaped after sampling and the remaining concentration of methane is too low to be detected. To find more effective ways to analyze the composition of pore water, two novel approaches are proposed. One is based on Liquid Core Optical Fiber (LCOF for detection of SO42−. The other one is an enrichment process for the detection of CH4. With the aid of LCOF, the Raman signal of SO42− is found to be enhanced over 10 times compared to that obtained by a conventional Raman setup. The enrichment process is also found to be effective in the investigation to the prepared sample of methane dissolved in water. By CCl4 extraction, methane at a concentration below 1.14 mmol/L has been detected by conventional Raman spectroscopy. All the obtained results suggest that the approach proposed in this paper has great potential to be developed as a sensor for SO42− and CH4 detection in pore water.

  10. Detection of Mycoplasma pneumoniae in simulated and true clinical throat swab specimens by nanorod array-surface-enhanced Raman spectroscopy.

    Directory of Open Access Journals (Sweden)

    Suzanne L Hennigan

    Full Text Available The prokaryote Mycoplasma pneumoniae is a major cause of respiratory disease in humans, accounting for 20% of all community-acquired pneumonia and the leading cause of pneumonia in older children and young adults. The limitations of existing options for mycoplasma diagnosis highlight a critical need for a new detection platform with high sensitivity, specificity, and expediency. Here we evaluated silver nanorod arrays (NA as a biosensing platform for detection and differentiation of M. pneumoniae in culture and in spiked and true clinical throat swab samples by surface-enhanced Raman spectroscopy (SERS. Three M. pneumoniae strains were reproducibly differentiated by NA-SERS with 95%-100% specificity and 94-100% sensitivity, and with a lower detection limit exceeding standard PCR. Analysis of throat swab samples spiked with M. pneumoniae yielded detection in a complex, clinically relevant background with >90% accuracy and high sensitivity. In addition, NA-SERS correctly classified with >97% accuracy, ten true clinical throat swab samples previously established by real-time PCR and culture to be positive or negative for M. pneumoniae. Our findings suggest that the unique biochemical specificity of Raman spectroscopy, combined with reproducible spectral enhancement by silver NA, holds great promise as a superior platform for rapid and sensitive detection and identification of M. pneumoniae, with potential for point-of-care application.

  11. In-vivo optical detection of cancer using chlorin e6 – polyvinylpyrrolidone induced fluorescence imaging and spectroscopy (United States)


    Background Photosensitizer based fluorescence imaging and spectroscopy is fast becoming a promising approach for cancer detection. The purpose of this study was to examine the use of the photosensitizer chlorin e6 (Ce6) formulated in polyvinylpyrrolidone (PVP) as a potential exogenous fluorophore for fluorescence imaging and spectroscopic detection of human cancer tissue xenografted in preclinical models as well as in a patient. Methods Fluorescence imaging was performed on MGH human bladder tumor xenografted on both the chick chorioallantoic membrane (CAM) and the murine model using a fluorescence endoscopy imaging system. In addition, fiber optic based fluorescence spectroscopy was performed on tumors and various normal organs in the same mice to validate the macroscopic images. In one patient, fluorescence imaging was performed on angiosarcoma lesions and normal skin in conjunction with fluorescence spectroscopy to validate Ce6-PVP induced fluorescence visual assessment of the lesions. Results Margins of tumor xenografts in the CAM model were clearly outlined under fluorescence imaging. Ce6-PVP-induced fluorescence imaging yielded a specificity of 83% on the CAM model. In mice, fluorescence intensity of Ce6-PVP was higher in bladder tumor compared to adjacent muscle and normal bladder. Clinical results confirmed that fluorescence imaging clearly captured the fluorescence of Ce6-PVP in angiosarcoma lesions and good correlation was found between fluorescence imaging and spectral measurement in the patient. Conclusion Combination of Ce6-PVP induced fluorescence imaging and spectroscopy could allow for optical detection and discrimination between cancer and the surrounding normal tissues. Ce6-PVP seems to be a promising fluorophore for fluorescence diagnosis of cancer. PMID:19133127

  12. Development of fiber optic spectroscopy for in-vitro and in-planta detection of fluorescent proteins (United States)

    Liew, Oi Wah; Chen, Jun-Wei; Asundi, Anand K.


    The objective of this project is to apply photonics technology to bio-safety management of genetically modified (GM) plants. The conventional method for screening GM plants is through selection using antibiotic resistance markers. There is public concern with such approaches and these are associated with food safety issues, escape of antibiotic resistance genes to pathogenic microorganisms and interference with antibiotic therapy. Thus, the strategy taken in this project is to replace antibiotic resistance markers with fluorescent protein markers that allow for rapid and non-invasive optical screening of genetically modified plants. In this paper, fibre optic spectroscopy was developed to detect and quantify recombinant green (EGFP) and red (DsRED) fluorescent proteins in vitro and in planta. In vitro detection was first carried out to optimize the sensitivity of the optical system. The bacterial expression vectors carrying the coding regions of EGFP and DsRED were introduced into Escherichia coli host cells and fluorescent proteins were produced following induction with IPTG. Soluble EGFP and DsRED proteins were isolated from lysed bacterial cells and serially diluted for quantitative analysis by fibre optic spectroscopy using different light sources, namely, blue LED (475 nm), tungsten halogen (350 - 1000 nm) and double frequency Nd:YAG green laser (532 nm). Fluorescence near the expected emission wavelengths could be detected up to 320X dilution for EGFP and DsRED with blue LED and 532 nm green laser, respectively, as the excitation source. Tungsten halogen was found to be unsuitable for excitation of both EGFP and DsRED. EGFP was successfully purified by size separation under non-denaturing electrophoretic conditions and quantified. The minimum concentration of EGFP detectable with blue LED excitation was 5 mg/ml. To determine the capability of spectroscopy detection in planta, transgenic potato hairy roots and whole modified plant lines expressing the

  13. Time-resolved FTIR spectroscopy for monitoring protein dynamics exemplified by functional studies of Ras protein bound to a lipid bilayer

    Energy Technology Data Exchange (ETDEWEB)

    Koetting, Carsten, E-mail: [Lehrstuhl fuer Biophysik, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany); Gueldenhaupt, Joern [Lehrstuhl fuer Biophysik, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany); Gerwert, Klaus, E-mail: [Lehrstuhl fuer Biophysik, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany)


    Graphical abstract: The first time resolved FTIR investigation of a GTPase reaction of a protein anchored at a single lipid bilayer. Display Omitted Highlights: Black-Right-Pointing-Pointer FTIR difference spectroscopy monitors protein dynamics with atomic detail. Black-Right-Pointing-Pointer ATR-FTIR allows the measurement of a monolayer sample. Black-Right-Pointing-Pointer Membrane proteins can be investigated near physiological conditions. Black-Right-Pointing-Pointer The hydrolysis reaction of Ras was investigated in this condition for the first time. - Abstract: Time-resolved Fourier transform infrared (FTIR) difference spectroscopy is a valuable tool for monitoring the dynamics of protein reactions and interactions. Absorbance changes can be monitored with time resolutions down to nanoseconds and followed for time periods that range over nine orders of magnitude. Membrane proteins bound to solid supported lipid bilayers can be investigated in near physiological conditions with the attenuated total reflection (ATR) technique. Here, we review the basics of time-resolved FTIR with a focus on Ras, a GTPase that is mutated in 25% of human tumors. We show the first time-resolved measurements of membrane anchored Ras and observed the switching between its activated and its inactivated state. We compared those measurements with measurements of the truncated Ras in solution. We found that both the kinetics and the functional groups involved were very similar. This suggested that the membrane did not have a major influence on the hydrolysis reaction.

  14. Detection of cyanobacteria and methanogens embedded in Mars analogue minerals by the use of Raman spectroscopy (United States)

    de Vera, J.-P. P.; Böttger, U.; Fritz, J.; Weber, I.; Malaszkiewicz, J.; Serrano, P.; Meessen, J.; Ott, S.; Wagner, D.; Hübers, H.-W.


    RLS (Raman Laser Spectrometer - one of the Pasteur Payload Instruments onboard ExoMars 2018) will perform Raman measurements on Mars to identify organic compounds and mineral products as an indication of biological activity. The measurements will be performed on crushed powdered samples inside the Rover's ALD (Analytical Laboratory Drawer). Raman analytics with the same specifications as those onboard the future ExoMars mission are conducted to test their potential of identifying biological material on martian analogue material. Appropriate measurement parameters for the detection of biological material as well as for the determination of the mineral composition will be derived. In addition, we report on problems using Raman spectroscopy to discriminate cells of microorganisms from the mineral background. Two organisms are chosen as test candidates for potential life on Mars: cyanobacteria and methane producing archaea. Prokaryotes like archaea and bacteria appeared on early Earth at least 3.8 to 3.5 billion years ago (Gya). At this time on Mars the climate was more temperate and wet compared to the present day as inferred from geological evidence for liquid water on the ancient martian surface. Thus life might have developed under similar conditions as on Earth or might have been transferred from Earth (or vice versa). Methane is known to be present on Mars, although the origin (if geothermal or biological activity) is still unknown. Cyanobacteria and prokaryotes using photosystem I belong to the oldest microbes on Earth. These organisms use pigments such as scytonemin and β-carotene as UV protection. Especially β-carotene emits a strong Raman signal. Raman analytics are used for detection of biofilm forming cyanobacteria Nostoc commune strain on the below described Mars analogue mineral mixtures. N. commune is known to be resistant to desiccation, UV B radiation and low temperatures, and thus suitable as a candidate for a potential life form on Mars

  15. Combined autofluorescence and Raman spectroscopy method for skin tumor detection in visible and near infrared regions (United States)

    Zakharov, V. P.; Bratchenko, I. A.; Artemyev, D. N.; Myakinin, O. O.; Khristoforova, Y. A.; Kozlov, S. V.; Moryatov, A. A.


    The combined application of Raman and autofluorescence spectroscopy in visible and near infrared regions for the analysis of malignant neoplasms of human skin was demonstrated. Ex vivo experiments were performed for 130 skin tissue samples: 28 malignant melanomas, 19 basal cell carcinomas, 15 benign tumors, 9 nevi and 59 normal tissues. Proposed method of Raman spectra analysis allows for malignant melanoma differentiating from other skin tissues with accuracy of 84% (sensitivity of 97%, specificity of 72%). Autofluorescence analysis in near infrared and visible regions helped us to increase the diagnostic accuracy by 5-10%. Registration of autofluorescence in near infrared region is realized in one optical unit with Raman spectroscopy. Thus, the proposed method of combined skin tissues study makes possible simultaneous large skin area study with autofluorescence spectra analysis and precise neoplasm type determination with Raman spectroscopy.

  16. Detection of toxic metals in waste water from dairy products plant using laser induced breakdown spectroscopy. (United States)

    Hussain, T; Gondal, M A


    Laser Induced Breakdown Spectroscopy (LIBS) System was developed locally for determination of toxic metals in liquid samples and the system was tested for analysis of waste water collected from dairy products processing plant. The plasma was generated by focusing a pulsed Nd: YAG laser at 1064 nm on waste water samples. Optimal experimental conditions were evaluated for improving the sensitivity of our LIBS system through parametric dependence investigations. The Laser-Induced Breakdown Spectroscopy (LIBS) results were then compared with the results obtained using standard analytical technique such as Inductively Coupled Plasma Emission Spectroscopy (ICP). The evaluation of the potential and capabilities of LIBS as a rapid tool for liquid sample analysis are discussed in brief.

  17. Feasibility Study of Using Short Wave Infrared Cavity Ringdown Spectroscopy (SWIR-CRDS) for Biological Agent Detection

    Energy Technology Data Exchange (ETDEWEB)

    Aker, Pam M.; Johnson, Timothy J.; Williams, Richard M.; Valentine, Nancy B.


    This project focused on determining the feasibility of using short wave infrared (SWIR) cavity ring down spectroscopy (CRDS) as a means for real-time detection of biological aerosols. The first part of the project involved identifying biological agent signatures that could be detected with SWIR CRDS. After an exhaustive search of the open literature it was determined that whole biological spores and/or cells would not be good candidates for direct SWIR CRDS probing because they have no unique SWIR signatures. It was postulated that while whole cells or spores are not good candidates for SWIR CRDS detection, their pyrolysis break-down products might be. A literature search was then conducted to find biological pyrolysis products with low molecular weights and high symmetry since these species most likely would have overtone and combination vibrational bands that can be detected in the SWIR. It was determined that pyrrole, pyridine and picolinamide were good candidates for evaluation. These molecules are formed when proteins and porphyrins, proteins and dipicolinic acid, and dipicolinic acid are pyrolyzed, respectively. The second part of the project involved measuring quantitative SWIR spectra of pyrrole, pyridine and picolinamide in PNNL’s FTIR Spectroscopy Laboratory. Spectral information about these molecules, in the vapor phase is sparse – there were only a few prior studies that measured line positions and no information on absorption cross sections. Absorption cross sections are needed in order to estimate the SWIR CRDS detection sensitivity, and line position determines what type of laser will be needed for the sensor. The results of the spectroscopy studies allowed us to estimate the SWIR CRDS detection sensitivity for pyrrole to be 3 x 1012 molec cm-3 or 0.1 ppmv, and for pyridine it was 1.5 x 1015 molec cm-3 or 0.6 ppmv. These detection sensitivity limits are close what we have measured for ammonia. Given these detection limits we then estimated the

  18. Understanding the Application of Raman Spectroscopy to the Detection of Traces of Life (United States)

    Marshall, Craig P.; Edwards, Howell G. M.; Jehlicka, Jan


    Investigating carbonaceous microstructures and material in Earth's oldest sedimentary rocks is an essential part of tracing the origins of life on our planet; furthermore, it is important for developing techniques to search for traces of life on other planets, for example, Mars. NASA and ESA are considering the adoption of miniaturized Raman spectrometers for inclusion in suites of analytical instrumentation to be placed on robotic landers on Mars in the near future to search for fossil or extant biomolecules. Recently, Raman spectroscopy has been used to infer a biological origin of putative carbonaceous microfossils in Early Archean rocks. However, it has been demonstrated that the spectral signature obtained from kerogen (of known biological origin) is similar to spectra obtained from many poorly ordered carbonaceous materials that arise through abiotic processes. Yet there is still confusion in the literature as to whether the Raman spectroscopy of carbonaceous materials can indeed delineate a signature of ancient life. Despite the similar nature in spectra, rigorous structural interrogation between the thermal alteration products of biological and nonbiological organic materials has not been undertaken. Therefore, we propose a new way forward by investigating the second derivative, deconvolution, and chemometrics of the carbon first-order spectra to build a database of structural parameters that may yield distinguishable characteristics between biogenic and abiogenic carbonaceous material. To place Raman spectroscopy as a technique to delineate a biological origin for samples in context, we will discuss what is currently accepted as a spectral signature for life; review Raman spectroscopy of carbonaceous material; and provide a historical overview of Raman spectroscopy applied to Archean carbonaceous materials, interpretations of the origin of the ancient carbonaceous material, and a future way forward for Raman spectroscopy.

  19. Understanding the application of Raman spectroscopy to the detection of traces of life. (United States)

    Marshall, Craig P; Edwards, Howell G M; Jehlicka, Jan


    Investigating carbonaceous microstructures and material in Earth's oldest sedimentary rocks is an essential part of tracing the origins of life on our planet; furthermore, it is important for developing techniques to search for traces of life on other planets, for example, Mars. NASA and ESA are considering the adoption of miniaturized Raman spectrometers for inclusion in suites of analytical instrumentation to be placed on robotic landers on Mars in the near future to search for fossil or extant biomolecules. Recently, Raman spectroscopy has been used to infer a biological origin of putative carbonaceous microfossils in Early Archean rocks. However, it has been demonstrated that the spectral signature obtained from kerogen (of known biological origin) is similar to spectra obtained from many poorly ordered carbonaceous materials that arise through abiotic processes. Yet there is still confusion in the literature as to whether the Raman spectroscopy of carbonaceous materials can indeed delineate a signature of ancient life. Despite the similar nature in spectra, rigorous structural interrogation between the thermal alteration products of biological and nonbiological organic materials has not been undertaken. Therefore, we propose a new way forward by investigating the second derivative, deconvolution, and chemometrics of the carbon first-order spectra to build a database of structural parameters that may yield distinguishable characteristics between biogenic and abiogenic carbonaceous material. To place Raman spectroscopy as a technique to delineate a biological origin for samples in context, we will discuss what is currently accepted as a spectral signature for life; review Raman spectroscopy of carbonaceous material; and provide a historical overview of Raman spectroscopy applied to Archean carbonaceous materials, interpretations of the origin of the ancient carbonaceous material, and a future way forward for Raman spectroscopy.

  20. UV-Visible Spectroscopy Detection of Iron(III) Ion on Modified Gold Nanoparticles With a Hydroxamic Acid (United States)

    Karami, C.; Alizadeh, A.; Taher, M. A.; Hamidi, Z.; Bahrami, B.


    The present work describes the preparation of gold nanoparticles (AuNPs) functionalized with hydroxamic acid and the use of them in UV-visible spectroscopy detection of iron(III) ions. The prepared AuNPs were thoroughly characterized by using UV-visible spectroscopy, TEM, and 1H NMR techniques. The newly synthesized hydroxamic acid-AuNPs are brown in color due to the intense surface plasmon absorption band centered at 527 nm. In the presence of Fe(III), the surface plasmon absorption band is centered at 540 nm. However, the sensitivity of hydroxamic acid-AuNPs towards other metal ions such as Mg(II), Ca(II), Ag(I), Cu(II), Mn(II), Cr(II), Ni(II), Co(II),Fe(II), Hg(II), and Pb(II) can be negligible. This highly selective sensor allows a direct quantitative assay of Fe(III) with a UVvisible spectroscopy detection limited to 45.8 nM.

  1. Optical-feedback cavity-enhanced absorption spectroscopy with a quantum-cascade laser yields the lowest formaldehyde detection limit (United States)

    Gorrotxategi-Carbajo, P.; Fasci, E.; Ventrillard, I.; Carras, M.; Maisons, G.; Romanini, D.


    We report on the first application of Optical Feedback-Cavity Enhanced Absorption Spectroscopy to formaldehyde trace gas analysis at mid-infrared wavelengths. A continuous-wave room-temperature, distributed-feedback quantum cascade laser emitting around 1,769 cm-1 has been successfully coupled to an optical cavity with finesse 10,000 in an OF-CEAS spectrometer operating on the ν2 fundamental absorption band of formaldehyde. This compact setup (easily transportable) is able to monitor H2CO at ambient concentrations within few seconds, presently limited by the sample exchange rate. The minimum detectable absorption is 1.6 × 10-9 cm-1 for a single laser scan (100 ms, 100 data points), with a detectable H2CO mixing ratio of 60 pptv at 10 Hz. The corresponding detection limit at 1 Hz is 5 × 10-10 cm-1, with a normalized figure of merit of 5 × 10-11cm^{-1}/sqrtHz (100 data points recorded in each spectrum taken at 10 Hz rate). A preliminary Allan variance analysis shows white noise averaging down to a minimum detection limit of 5 pptv at an optimal integration time of 10 s, which is significantly better than previous results based on multi-pass or cavity-enhanced tunable QCL absorption spectroscopy.

  2. A novel aptasensor based on single-molecule force spectroscopy for highly sensitive detection of mercury ions. (United States)

    Li, Qing; Michaelis, Monika; Wei, Gang; Colombi Ciacchi, Lucio


    We have developed a novel aptasensor based on single-molecule force spectroscopy (SMFS) capable of detecting mercury ions (Hg(2+)) with sub-nM sensitivity. The single-strand (ss) DNA aptamer used in this work is rich in thymine (T) and readily forms T-Hg(2+)-T complexes in the presence of Hg(2+). The aptamer was conjugated to an atomic force microscope (AFM) probe, and the adhesion force between the probe and a flat graphite surface was measured by single-molecule force spectroscopy (SMFS). The presence of Hg(2+) ions above a concentration threshold corresponding to the affinity constant of the ions for the aptamer (about 5 × 10(9) M(-1)) could be easily detected by a change of the measured adhesion force. With our chosen aptamer, we could reach an Hg(2+) detection limit of 100 pM, which is well below the maximum allowable level of Hg(2+) in drinking water. In addition, this aptasensor presents a very high selectivity for Hg(2+) over other metal cations, such as K(+), Ca(2+), Zn(2+), Fe(2+), and Cd(2+). Furthermore, the effects of the ionic strength and loading rate on the Hg(2+) detection were evaluated. Its simplicity, reproducibility, high selectivity and sensitivity make our SMFS-based aptasensor advantageous with respect to other current Hg(2+) sensing methods. It is expected that our strategy can be exploited for monitoring the pollution of water environments and the safety of potentially contaminated food.

  3. Polydopamine Thin Films as Protein Linker Layer for Sensitive Detection of Interleukin-6 by Surface Plasmon Enhanced Fluorescence Spectroscopy. (United States)

    Toma, Mana; Tawa, Keiko


    Polydopamine (PDA) thin films are introduced to the surface modification of biosensor surfaces utilizing surface plasmon enhanced fluorescence spectroscopy (SPFS) as the linker layer of capture antibody on to the sensor surfaces. The capture antibody can be directly attached to the sensor surface without using any coupling agent by functionalizing the gold sensor surface with PDA thin films. The PDA coating is performed by a single-step preparation process by applying the dopamine solution on the sensor surface, which requires an extremely short incubation time (10 min). The real-time in situ measurement of the adsorption kinetics of the capture antibody onto the PDA-coated sensor surface is studied by surface plasmon resonance (SPR) spectroscopy. It reveals that the immobilization of capture antibody immediately occurs after introduction of a solution containing capture antibody, and the sensor surface is fully covered with the capture antibody. The sensitive detection of the cytokine marker interleukin-6 (IL-6) is performed by SPFS using a sandwich assay format with fluorescently labeled detection antibody. The sensor chips functionalized by PDA chemistry exhibited sensitive sensor responses with low nonspecific adsorption of the detection antibody onto the sensor surface. The detection limit of IL-6 with the developed SPFS biosensor is determined to be 2 pg/mL (100 fM), which is within the range of the diagnostic criteria. Our observation elucidates the remarkable utility of PDA coatings for chemical modification of the metallic sensor surfaces by a simple, brief, and inexpensive manner.

  4. Trace-Gas Detection with Off-Beam Quartz Enhanced Photoacoustic Spectroscopy (United States)

    Liu, Kun; Wang, Lei; Tan, Tu; Zhang, Weijun; Chen, Weidong; Gao, Xiaoming


    Trace-gas sensors have a wide range of potential applications such as environmental monitoring, climate research, agriculture, workplace safety, medical diagnostics, and industrial process control. A recently introduced technique called quartz-enhanced photoacoustic spectroscopy (QEPAS) is described. QEPAS use a quartz tuning fork as an acoustic transducer for a photoacoustic signal induced in an absorbing gas by modulated optical radiation. Advantages of the QEPAS compared to conventional photoacoustic spectroscopy include immunity to environmental acoustic noise and ultra-small sample volume. Trace gases of , and were monitored with a novel off-beam QEPAS approach and are described in detail.

  5. Cyclohexane photo-catalytic oxidation on TiO2, an in situ ATR-FTIR mechanistic and kinetic study

    NARCIS (Netherlands)

    Almeida, A.R.


    Chemical processes are generally operated at elevated temperatures and pressures, and energy intensive separations are usually necessary. This thesis focuses on the production of cyclohexanone, which is an intermediate of high commercial importance as a result of its use in nylon-6 and nylon-6,6

  6. Combined ATR-FTIR and DFT study of cyclohexanone adsorption on hydrated TiO2 anatase surfaces

    NARCIS (Netherlands)

    Almeida, A.R.; Almeida, Ana Rita; Calatayud, Monica; Tielens, Frederik; Moulijn, Jacob A.; Mul, Guido


    The adsorption of cyclohexanone on different planes ((100), (101), and (001)) of anatase TiO2, with variable level of hydration, was evaluated by density functional theory (DFT) calculations. Surface hydration was found to affect the cyclohexanone adsorption enthalpy and the calculated infrared

  7. Optical properties of human radicular dentin: ATR-FTIR characterization and dentine tubule direction influence on radicular post adhesion (United States)

    Quinto, Jose; Zamataro, Claudia B.; Benetti, Carolina; Dias, Derly A.; Blay, Alberto; Zezell, Denise Maria


    Knowledge of dental structures is essential for understanding of laser interaction and its consequences during adhesion processes. Tubule density in dentin ranges from 4.900 to 90.000 per mm2, for diameters from 1 to 3 μm. Light propagation inside the tubules is associated with tubules orientation. To the best of our knowledge, there is no previous work in literature characterizing physical-chemical alterations in dentin. The dentin samples were irradiated with a Er,Cr:YSGG Laser at wavelength 2.78 μm, with an energy density of 9.46 J/cm2 , above the ablation threshold. ATRFTIR at wavenumbers 2000 to 700 cm-1 was used to evaluate the differences among third root region and tubules orientation.

  8. Structural properties of monoclonal antibody aggregates induced by freeze-thawing and thermal stress. (United States)

    Hawe, Andrea; Kasper, Julia Christina; Friess, Wolfgang; Jiskoot, Wim


    Aggregation of monoclonal antibodies can be induced by freeze-thawing and elevated temperature, typical stress factors during development, production and storage. Our aim was to characterize structural properties of aggregates formed after freeze-thawing and thermal stressing of humanized monoclonal IgG(1) antibody (IgG). Formulations with 1.0mg/ml IgG in 100mM phosphate pH 7.2 were subjected to freeze-thawing and heating and characterized by spectroscopic techniques (UV-absorption, CD, ATR-FTIR and fluorescence), light obscuration, dynamic light scattering, SDS-PAGE, AF4 with UV and MALLS detection, and HP-SEC with UV and online fluorescent dye detection. Thermal stress led to an increased formation of dimers and soluble oligomers (HP-SEC, AF4). Aggregates smaller than 30nm were measured (DLS), next to slightly elevated particle levels in the mum range (light obscuration). Aggregates created by heating were in part covalently linked (SDS-PAGE) and made up of conformationally perturbed monomers (CD, ATR-FTIR, extrinsic dye fluorescence). Aggregation after freeze-thawing was manifested primarily in particle formation in the mum range. These aggregates were noncovalently linked (SDS-PAGE) and composed of native-like monomers, as obvious from CD, ATR-FTIR and extrinsic dye fluorescence spectroscopy. In conclusion, the complementary methods used in this study revealed that heating and freeze-thawing induced aggregates differ significantly in their physico-chemical characteristics.

  9. Quantitative 19F MR spectroscopy at 3 T to detect heterogeneous capecitabine metabolism in human liver.

    NARCIS (Netherlands)

    Klomp, D.W.J.; Laarhoven, H.W.M. van; Scheenen, T.W.J.; Kamm, Y.J.L.; Heerschap, A.


    Chemotherapy in non-responding cancer patients leads to unnecessary toxicity. A marker is therefore required that can predict the sensitivity of a specific tumour to chemotherapy, which would enable individualisation of therapy. 19F MR spectroscopy (19F MRS) can be used to monitor the metabolism of

  10. Detection of starch adulteration in onion powder by FT-NIR and FT-IR spectroscopy (United States)

    Adulteration of onion powder with cornstarch was identified by Fourier transform near-infrared (FT-NIR) and Fourier transform infrared (FT-IR) spectroscopy. The reflectance spectra of 180 pure and adulterated samples (1–35 wt% starch) were collected and preprocessed to generate calibration and predi...

  11. Chilling injury in stored nectarines and its detection by time-resolved reflectance spectroscopy

    NARCIS (Netherlands)

    Lurie, S.; Vanoli, M.; Dagar, A.; Weksler, A.; Eccher Zerbini, P.C.; Spinelli, L.; Torricelli, A.; Lovati, F.; Feng, R.; Rizzolo, A.


    Nectarine fruit after cold storage soften normally, but become dry instead of juicy and can develop flesh browning, bleeding and a gel-like or glassy formation of the flesh near the pit. An experiment was conducted to see if time-resolved reflectance spectroscopy could distinguish these internal

  12. Ultrasound tagged near infrared spectroscopy does not detect hyperventilation-induced reduction in cerebral blood flow

    DEFF Research Database (Denmark)

    Lund, Anton; Secher, Niels H.; Hirasawa, Ai


    Introduction: Continuous non-invasive monitoring of cerebral blood flow (CBF) may be important during anaesthesia and several options are available. We evaluated the CerOx monitor that employs ultrasound tagged near infrared spectroscopy to estimate changes in a CBF index (CFI).Methods: Seven hea...

  13. Accuracy of optical spectroscopy for the detection of cervical intraepithelial neoplasia: testing a device as an adjunct to colposcopy (United States)

    Cantor, Scott B.; Yamal, Jose-Miguel; Guillaud, Martial; Cox, Dennis D.; Atkinson, E. Neely; Benedet, J. L.; Miller, Dianne; Ehlen, Thomas; Matisic, Jasenka; van Niekerk, Dirk; Bertrand, Monique; Milbourne, Andrea; Rhodes, Helen; Malpica, Anais; Staerkel, Gregg; Nader-Eftekhari, Shahla; Adler-Storthz, Karen; Scheurer, Michael E.; Basen-Engquist, Karen; Shinn, Eileen; West, Loyd A.; Vlastos, Anne-Therese; Tao, Xia; Beck, J. Robert; MacAulay, Calum; Follen, Michele


    Testing emerging technologies involves the evaluation of biologic plausibility, technical efficacy, clinical effectiveness, patient satisfaction, and cost-effectiveness. The objective of this study was to select an effective classification algorithm for optical spectroscopy as an adjunct to colposcopy and obtain preliminary estimates of its accuracy for the detection of CIN 2 or worse. We recruited 1000 patients from screening and prevention clinics and 850 patients from colposcopy clinics at two comprehensive cancer centers and a community hospital. Optical spectroscopy was performed and 4864 biopsies were obtained from the sites measured, including abnormal and normal colposcopic areas. The gold standard was the histologic report of biopsies, read 2–3 times by histopathologists blinded to the cytologic, histopathologic, and spectroscopic results. We calculated sensitivities, specificities, receiver operating characteristic (ROC) curves, and areas under the ROC curves. We identified a cutpoint for an algorithm based on optical spectroscopy that yielded an estimated sensitivity of 1.00 [95% confidence interval (CI) = 0.92 – 1.00] and an estimated specificity of 0.71 [95% CI = 0.62 – 0.79] in a combined screening and diagnostic population. The positive and negative predictive values were 0.58 and 1.00, respectively. The area under the ROC curve was 0.85 (95% CI 0.81 – 0.89). The per-patient and per-site performance were similar in the diagnostic and poorer in the screening settings. Like colposcopy, the device performs best in a diagnostic population. Alternative statistical approaches demonstrate that the analysis is robust and that spectroscopy works as well as or slightly better than colposcopy for the detection of CIN 2 to cancer. PMID:20830707

  14. Fluorescence spectroscopy for the detection of potentially malignant disorders and squamous cell carcinoma of the oral cavity. (United States)

    Francisco, Ana Lucia Noronha; Correr, Wagner Rafael; Azevedo, Luciane Hiramatsu; Kern, Vivian Galletta; Pinto, Clóvis Antônio Lopes; Kowalski, Luiz Paulo; Kurachi, Cristina


    Oral cancer is a public health problem with relevant incidence in the world population. The affected patient usually presents advanced stage disease and the consequence of this delay is a reduction in survival rates. Given this, it is essential to detect oral cancer at early stages. Fluorescence spectroscopy is a non-invasive diagnostic tool that can improve cancer detection in real time. It is a fast and accurate technique, relatively simple, which evaluates the biochemical composition and structure using the tissue fluorescence spectrum as interrogation data. Several studies have positive data regarding the tools for differentiating between normal mucosa and cancer, but the difference between cancer and potentially malignant disorders is not clear. The aim of this study was to evaluate the efficacy of fluorescence spectroscopy in the discrimination of normal oral mucosa, oral cancer, and potentially malignant disorders. The fluorescence spectroscopy was evaluated in 115 individuals, of whom 55 patients presented oral squamous cell carcinoma, 30 volunteers showing normal oral mucosa, and 30 patients having potentially malignant disorders. The spectra were classified and compared to histopathology to evaluate the efficiency in diagnostic discrimination employing fluorescence. In order to classify the spectra, a decision tree algorithm (C4.5) was applied. Despite of the high variance observed in spectral data, the specificity and sensitivity obtained were 93.8% and 88.5%, respectively at 406 nm excitation. These results point to the potential use of fluorescence spectroscopy as an important tool for oral cancer diagnosis and potentially malignant disorders. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Fluorescent core-shell star polymers based bioassays for ultrasensitive DNA detection by surface plasmon fluorescence spectroscopy. (United States)

    Feng, Chuan Liang; Yin, Meizhen; Zhang, Di; Zhu, Shenmin; Caminade, Anne Marie; Majoral, Jean Pierre; Müllen, Klaus


    Multilayers containing a perylene diimide labelled star polymers (FSP) donor adjacent to phosphorus dendrimer layer on a silver substrate were constructed by layer by layer (LBL) approach. Using Surface Plasmon Enhanced Fluorescence Spectroscopy (SPFS) technique, a time-resolved ultrasensitive and selective detection of DNA targets relying on enhanced optical fields associated with energy transfer (ET) were achieved under the excitation at 543 nm. The detection limit is about 8 orders of magnitude better than the achieved one under the excitation at 632 nm, which is ascribed to no energy transfer from the donor to the acceptor under the excitation at 632 nm, resulting in much weak detection signal in turn. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Early detection of dental fluorosis using Raman spectroscopy and principal component analysis. (United States)

    González-Solís, José Luis; Martínez-Cano, Evelia; Magaña-López, Yolanda


    Raman spectroscopic technique has the potential to provide vibrational spectra of minerals by analyzing scattered light caused by monochromatic laser excitation. In this paper, recent applications of Raman spectroscopy in the study of dental hard tissues are reported. Special attention is given to mineral components in enamel and to calcium fluoride formed in/on enamel. The criteria used to classify the dental hard samples were according to the Dean Index (DI), which consists into healthy or control, mild, moderate, and severe, indicating the amount of dental fluorosis observed on enamel. A total of 39 dental samples (9 control, 9 mild, 10 moderate, and 11 severe) were analyzed in the study. Dental samples were positioned under an Olympus microscope, and around 10 points were chosen for Raman measurement. All spectra were collected by a Horiba Jobin-Yvon LabRAM HR800 Raman Spectrometer with a laser of 830-nm and 17-mW power irradiation. Raw spectra were processed by carrying out baseline correction, smoothing, and normalization to remove noise, florescence, and shot noise and then analyzed using principal component analysis (PCA). In the spectra of dental samples, we observed the main bands as the broad band due to CO[Formula: see text] (240-300 cm (-1)), CaF 2 (322 cm (-1)), PO[Formula: see text] vibrations (437 and 450 cm (-1)), PO[Formula: see text] vibrations (582, 598, and 609 cm (-1)), PO[Formula: see text] vibrations (960 cm (-1)), PO[Formula: see text] vibrations (1,045 cm (-1)), and CO[Formula: see text] vibration (1,073 cm (-1)). Nevertheless, the intensity of the band at 960 cm (-1) associated to symmetric stretch of phosphate, PO[Formula: see text], decreases as the amount of dental fluorosis increases, suggesting that the intensity of this band could be used to quantitatively measure the level of fluorosis on a dental sample. On the other hand, PCA allowed to identify two large clusters discriminating between control, and severe and moderate samples

  17. Pursuing shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) for concomitant detection of breast lesions and microcalcifications (United States)

    Zheng, Chao; Shao, Wanting; Paidi, Santosh Kumar; Han, Bing; Fu, Tong; Wu, Di; Bi, Lirong; Xu, Weiqing; Fan, Zhimin; Barman, Ishan


    Although tissue staining followed by morphologic identification remains the gold standard for diagnosis of most cancers, such determinations relying solely on morphology are often hampered by inter- and intra-observer variability. Vibrational spectroscopic techniques, in contrast, offer objective markers for diagnoses and can afford disease detection prior to alterations in cellular and extracellular architecture by furnishing a rapid ``omics''-like view of the biochemical status of the probed specimen. Here, we report a classification approach to concomitantly detect microcalcification status and local pathological state in breast tissue, featuring a combination of vibrational spectroscopy that focuses on the tumor and its microenvironment, and multivariate data analysis of spectral markers reflecting molecular expression. We employ the unprecedented sensitivity and exquisite molecular specificity offered by Au@SiO2 shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) to probe the presence of calcified deposits and distinguish between normal breast tissues, fibroadenoma, atypical ductal hyperplasia, ductal carcinoma in situ (DCIS), and invasive ductal carcinoma (IDC). By correlating the spectra with the corresponding histologic assessment, we developed partial least squares-discriminant analysis derived decision algorithm that provides excellent diagnostic power in the fresh frozen sections (overall accuracy of 99.4% and 93.6% using SHINs for breast lesions with and without microcalcifications, respectively). The performance of this decision algorithm is competitive with or supersedes that of analogous algorithms employing spontaneous Raman spectroscopy while enabling facile detection due to the considerably higher intensity of SHINERS. Our results pave the way for rapid tissue spectral pathology measurements using SHINERS that can offer a novel stain-free route to accurate and economical diagnoses without human interpretation.Although tissue staining

  18. Detection of precancerous lesions in the oral cavity using oblique polarized reflectance spectroscopy: a clinical feasibility study (United States)

    Bailey, Maria J.; Verma, Nishant; Fradkin, Leonid; Lam, Sylvia; MacAulay, Calum; Poh, Catherine; Markey, Mia K.; Sokolov, Konstantin


    We developed a multifiber optical probe for oblique polarized reflectance spectroscopy (OPRS) in vivo and evaluated its performance in detection of dysplasia in the oral cavity. The probe design allows the implementation of a number of methods to enable depth resolved spectroscopic measurements including polarization gating, source-detector separation, and differential spectroscopy; this combination was evaluated in carrying out binary classification tasks between four major diagnostic categories: normal, benign, mild dysplasia (MD), and severe dysplasia (SD). Multifiber OPRS showed excellent performance in the discrimination of normal from benign, MD, SD, and MD plus SD yielding sensitivity/specificity values of 100%/93%, 96%/95%, 100%/98%, and 100%/100%, respectively. The classification of benign versus dysplastic lesions was more challenging with sensitivity and specificity values of 80%/93%, 71%/93%, and 74%/80% in discriminating benign from SD, MD, and SD plus MD categories, respectively; this challenge is most likely associated with a strong and highly variable scattering from a keratin layer that was found in these sites. Classification based on multiple fibers was significantly better than that based on any single detection pair for tasks dealing with benign versus dysplastic sites. This result indicates that the multifiber probe can perform better in the detection of dysplasia in keratinized tissues.

  19. Location and detection of explosive-contaminated human fingerprints on distant targets using standoff laser-induced breakdown spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Lucena, P.; Gaona, I.; Moros, J.; Laserna, J.J., E-mail:


    Detection of explosive-contaminated human fingerprints constitutes an analytical challenge of high significance in security issues and in forensic sciences. The use of a laser-induced breakdown spectroscopy (LIBS) sensor working at 31 m distance to the target, fitted with 2D scanning capabilities and designed for capturing spectral information from laser-induced plasmas of fingerprints is presented. Distribution chemical maps based on Na and CN emissions are used to locate and detect chloratite, DNT, TNT, RDX and PETN residues that have been deposited on the surface of aluminum and glass substrates. An effectiveness of 100% on fingerprints detection, regardless the substrate scanned, is reached. Environmental factors that affect the prevalence of the fingerprint LIBS response are discussed. - Highlights: • Explosive remnants left behind by fingerprints have been detected from afar. • Operating in scanning mode, LIBS boasts high ability to locate traces over a surface. • Effectiveness in trace detection plainly depends on the scanning spatial resolution. • The detection capability of LIBS shrinks as the fingerprints deteriorate over time.

  20. Differentiation and detection of microorganisms using Fourier transform infrared photoacoustic spectroscopy (United States)

    Irudayaraj, Joseph; Yang, Hong; Sakhamuri, Sivakesava


    Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS) was used to differentiate and identify microorganisms on a food (apple) surface. Microorganisms considered include bacteria (Lactobacillus casei, Bacillus cereus, and Escherichia coli), yeast (Saccharomyces cerevisiae), and fungi (Aspergillus niger and Fusarium verticilliodes). Discriminant analysis was used to differentiate apples contaminated with the different microorganisms from uncontaminated apple. Mahalanobis distances were calculated to quantify the differences. The higher the value of the Mahalanobis distance metric between different microorganisms, the greater is their difference. Additionally, pathogenic (O157:H7) E. coli was successfully differentiated from non-pathogenic strains. Results demonstrate that FTIR-PAS spectroscopy has the potential to become a non-destructive analysis tool in food safety related research.

  1. Preliminary research on organics recognition by x-ray absorption spectroscopy detection and classification (United States)

    Wang, Qian; Wu, Xiaomei; Zhang, Wei; He, Shuting; Feng, Haifeng; Fang, Zheng


    X-ray Absorption Spectroscopy (XAS) was been applied for the material recognition in this paper. Twelve kinds of plastics were selected as specimens. Each specimen was tested for 100 times by different operators for data processing. Seventy sets of spectral data of each specimen were randomly selected as training set and the other 30 sets were selected as testing set. Training set was calculated with Principal Component Analysis (PCA) to get the first four Principal Components, which totally explain 99% of the original spectrum. The first four Principal Components were built plastic classification model respectively through K-Nearest Neighbor (KNN) and Support Vector Machine (SVM) methods. The classification accuracy reached 89.22%-98.17%. Experimental results demonstrate that organics could be recognized by XAS. It shows that the X-ray absorption spectroscopy contains the potential of other organics recognition or even organisms.

  2. A study of Raman spectroscopy for the early detection and classification of malignancy in oesophageal tissue

    CERN Document Server

    Kendall, C A


    Raman Spectroscopy for the identification and classification of malignancy in the oesophagus has been demonstrated in this thesis. The potential of Raman spectroscopy in this field is twofold; as an adjunct for the pathologist and as a biopsy targeting tool at endoscopy. This study has demonstrated the feasibility of these potential applications in vitro. Spectral diagnostic models have been developed by correlating spectral information with histopathology. This is the current 'gold standard' diagnostic method for the identification of dysplasia, the established risk factor for the development of oesophageal cancer. Histopathology is a subjective assessment and widely acknowledged to have limitations. A more rigorous gold standard was therefore developed, as part of this study, using the consensus opinion of three independent expert pathologists to train the diagnostic models. Raman spectra have been measured from oesophageal tissue covering the full spectrum of malignant disease in the oesophagus, using a ne...

  3. Detection of adulteration in acetonitrile using near infrared spectroscopy coupled with pattern recognition techniques. (United States)

    Hu, Le-Qian; Yin, Chun-Ling; Zeng, Zhi-Peng


    In this paper, near infrared spectroscopy (NIR) in cooperation with the pattern recognition techniques were used to determine the type of neat acetonitrile and the adulteration in acetonitrile. NIR spectra were collected between 400 nm and 2498 nm. The experimental data were first subjected to analysis of principal component analysis (PCA) to reveal significant differences and potential patterns between samples. Then support vector machine (SVM) were applied to develop classification models and the best parameter combination was selected by grid search. Under the best parameter combination, the classification accuracy rates of three types of neat acetonitrile reached 87.5%, and 100% for the adulteration with different concentration levels. The results showed that NIR spectroscopy combined with SVM could be utilized for determining the potential adulterants including water, ethanol, isopropyl alcohol, acrylonitrile, methanol, and by-products associated with the production of acetonitrile. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Application of FT-Raman spectroscopy for in situ detection of microorganisms on the surface of textiles. (United States)

    Rygula, Anna; Jekiel, Katarzyna; Szostak-Kot, Jadwiga; Wrobel, Tomasz P; Baranska, Malgorzata


    In this work we present the usefulness of FT-Raman spectroscopy for microbiological analysis of textiles. This technique was used for non-destructive identification of Escherichia coli bacteria on cotton and polyester fabrics. It was possible to discriminate between infected and non-infected materials. Moreover, this technique allowed detection of detergent traces as well as investigation of the influence of microorganisms on different textiles. Raman analysis supported by chemometrics (cluster analysis and principal component analysis) was shown to be a method for identification of textiles with inoculum of microorganisms in a short time. The results can be potentially used in the fabric industry and related areas.

  5. Detection of Explosives on Surfaces Using UV Raman Spectroscopy: Effect of Substrate Color (United States)


    nanoporous multifunctional microcantilever. Anal Chem. 2014;86:5077–5082. 9. Bharadwaj R, Mukherji S. Gold nanoparticle coated U-bend fiber optic probe...Strickland D, Li F, Meng X. Surface-enhanced Raman scattering spectroscopy of explosive 2,4-dinitroanisole using modified silver nanoparticles . Langmuir...electrostatic surface potential and surface enhanced Raman spectroscopic studies on biosynthesized silver nanoparticles : observation of 400 pM sensitivity to

  6. Surface Enhanced Raman Spectroscopy for the Rapid Detection and Identification of Microbial Pathogens in Human Serum (United States)


    those of the authors and do not necessarily reflect the official policy or position of the Department of the Navy, Department of Defense, nor the U.S...the medical field, Raman spectroscopy is under investigation for use in prediction of preterm birth [10], identification of basal cell carcinoma [ peak intensity at 735 cm -1 was considered positive for microbial presence. Variability in Raman signal across SERS spectra was determined by

  7. Active and passive infrared spectroscopy for the detection of environmental threats (United States)

    Deutsch, Erik R.; Kotidis, Petros; Zhu, Ninghui; Goyal, Anish K.; Ye, Jim; Mazurenko, Alex; Norman, Mark; Zafiriou, Kostas; Baier, Mark; Connors, Ray


    Block MEMS/Engineering develops mid-infrared spectroscopy systems based on both Fourier transform infrared (FTIR) spectrometers and quantum cascade lasers (QCLs). Our recently developed miniaturized external-cavity QCLs are widely tunable over a spectral range of >250 cm-1 and tuning can be accomplished at rates of military and commercial applications. This paper provides an overview of our FTIR and QCL systems and their defense-related applications.

  8. Inductive-detection electron-spin resonance spectroscopy with 65 spins/ √{Hz } sensitivity (United States)

    Probst, S.; Bienfait, A.; Campagne-Ibarcq, P.; Pla, J. J.; Albanese, B.; Da Silva Barbosa, J. F.; Schenkel, T.; Vion, D.; Esteve, D.; Mølmer, K.; Morton, J. J. L.; Heeres, R.; Bertet, P.


    We report electron spin resonance spectroscopy measurements performed at millikelvin temperatures in a custom-built spectrometer comprising a superconducting micro-resonator at 7 GHz and a Josephson parametric amplifier. Owing to the small ( ˜10-12λ3 ) magnetic resonator mode volume and to the low noise of the parametric amplifier, the spectrometer's single shot sensitivity reaches 260 ± 40 spins/echo translating into 65 ±10 spins/√{Hz } for repeated acquisition.

  9. High Resolution FTIR Spectroscopy of Trisulfane Hsssh: a Candidate for Detecting Parity Violation in Chiral Molecules (United States)

    Albert, Sieghard; Bolotova, Irina; Chen, Ziqiu; Fábri, Csaba; Quack, Martin; Seyfang, Georg; Zindel, Daniel


    The measurement of the parity violating energy difference Δ_{pv}{E} between the enantiomers of chiral molecules is among the major current challenges in high resolution spectroscopy and physical-chemical stereochemistry. Theoretical predictions have recently identified dithiine^{b} and trisulfane as suitable candidates for such experiments. We report the first successful high-resolution analyses of the Fourier transform infrared (FTIR) spectra of trisulfane. A band centered at 861.0292 cm^{-1} can be assigned unambiguously to the chiral trans conformer by means of ground state combination differences in comparison with known pure rotational spectra. A second band near 864.698 cm^{-1} is tentatively assigned to the cis conformer by comparison with theory. M. Quack , Fundamental Symmetries and Symmetry Violations from High-resolution Spectroscopy, Handbook of High Resolution Spectroscopy, M. Quack and F. Merkt eds.,John Wiley & Sons Ltd, Chichester, New York, 2001, vol. 1, ch. 18, pp. 659-722. S. Albert, I. Bolotova, Z. Chen, C. Fábri, L. Horný, M. Quack, G. Seyfang and D. Zindel, Phys.Chem.Chem.Phys.18, 21976-21993 (2016). C. Fábri, L. Horný and M. Quack, ChemPhysChem16, 3584-3589 (2015). M. Liedtke, K. M. T. Yamada, G. Winnewisser and J. Hahn, J.Mol.Struct.413, 265-270 (1997).

  10. Raman spectroscopy of bio fluids: an exploratory study for oral cancer detection (United States)

    Brindha, Elumalai; Rajasekaran, Ramu; Aruna, Prakasarao; Koteeswaran, Dornadula; Ganesan, Singaravelu


    ion for various disease diagnosis including cancers. Oral cancer is one of the most common cancers in India and it accounts for one third of the global oral cancer burden. Raman spectroscopy of tissues has gained much attention in the diagnostic oncology, as it provides unique spectral signature corresponding to metabolic alterations under different pathological conditions and micro-environment. Based on these, several studies have been reported on the use of Raman spectroscopy in the discrimination of diseased conditions from their normal counterpart at cellular and tissue level but only limited studies were available on bio-fluids. Recently, optical characterization of bio-fluids has also geared up for biomarker identification in the disease diagnosis. In this context, an attempt was made to study the metabolic variations in the blood, urine and saliva of oral cancer patients and normal subjects using Raman spectroscopy. Principal Component based Linear Discriminant Analysis (PC-LDA) followed by Leave-One-Out Cross-Validation (LOOCV) was employed to find the statistical significance of the present technique in discriminating the malignant conditions from normal subjects.

  11. A nanoaggregate-on-mirror platform for molecular and biomolecular detection by surface-enhanced Raman spectroscopy. (United States)

    Wallace, Gregory Q; Tabatabaei, Mohammadali; Zuin, Mariachiara S; Workentin, Mark S; Lagugné-Labarthet, François


    A nanoaggregate-on-mirror (NAOM) structure has been developed for molecular and biomolecular detection using surface-enhanced Raman spectroscopy (SERS). The smooth surface of the gold mirror allows for simple and homogeneous functionalization, while the introduction of the nanoaggregates enhances the Raman signal of the molecule(s) in the vicinity of the aggregate-mirror junction. This is evidenced by functionalizing the gold mirror with 4-nitrothiophenol, and the further addition of gold nanoaggregates promotes local SERS activity only in the areas with the nanoaggregates. The application of the NAOM platform for biomolecular detection is highlighted using glucose and H2O2 as molecules of interest. In both cases, the gold mirror is functionalized with 4-mercaptophenylboronic acid (4-MPBA). Upon exposure to glucose, the boronic acid moiety of 4-MPBA forms a cyclic boronate ester. Once the nanoaggregates are added to the surface, detection of glucose is possible without the use of an enzyme. This method of indirect detection provides a limit of detection of 0.05 mM, along with a linear range of detection from 0.1 to 15 mM for glucose, encompassing the physiological range of blood glucose concentration. The detection of H2O2 is achieved with optical inspection and SERS. The H2O2 interferes with the coating of the gold mirror, enabling qualitative detection by visual inspection. Simultaneously, the H2O2 reacts with the boronic acid to form a phenol, a change that is detected by SERS.

  12. Phase-Resolved Heterodyne-Detected Transient Grating Enhances the Capabilities of 2D IR Echo Spectroscopy. (United States)

    Jin, Geun Young; Kim, Yung Sam


    2D IR echo spectroscopy, with high sensitivity and femtosecond time resolution, enables us to understand structure and ultrafast dynamics of molecular systems. Application of this experimental technique on weakly absorbing samples, however, had been limited by the precise and unambiguous phase determination of the echo signals. In this study, we propose a new experimental scheme that significantly increases the phase stability of the involved IR pulses. We have demonstrated that the incorporation of phase-resolved heterodyne-detected transient grating (PR-HDTG) spectroscopy greatly enhances the capabilities of 2D IR spectroscopy. The new experimental scheme has been used to obtain 2D IR spectra on weakly absorbing azide ions (N3-) in H2O (absorbance ∼0.025), free of phase ambiguity even at large waiting times. We report the estimated spectral diffusion time scale (1.056 ps) of azide ions in aqueous solution from the 2D IR spectra and the vibrational lifetime (750 ± 3 fs) and the reorientation time (1108 ± 24 fs) from the PR-HDTG spectra.

  13. The detection of carbon dioxide leaks using quasi-tomographic laser absorption spectroscopy measurements in variable wind (United States)

    Levine, Zachary H.; Pintar, Adam L.; Dobler, Jeremy T.; Blume, Nathan; Braun, Michael; Scott Zaccheo, T.; Pernini, Timothy G.


    Laser absorption spectroscopy (LAS) has been used over the last several decades for the measurement of trace gasses in the atmosphere. For over a decade, LAS measurements from multiple sources and tens of retroreflectors have been combined with sparse-sample tomography methods to estimate the 2-D distribution of trace gas concentrations and underlying fluxes from point-like sources. In this work, we consider the ability of such a system to detect and estimate the position and rate of a single point leak which may arise as a failure mode for carbon dioxide storage. The leak is assumed to be at a constant rate giving rise to a plume with a concentration and distribution that depend on the wind velocity. We demonstrate the ability of our approach to detect a leak using numerical simulation and also present a preliminary measurement. PMID:27453761

  14. Laser-induced Breakdown Spectroscopy used to Detect Endophyte-mediated Accumulation of Metals by Tall Fescue

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Madhavi Z [ORNL; Stewart, Arthur J [ORNL; Gwinn, Dr. Kimberley [University of Tennessee, Knoxville (UTK); Waller, John C [ORNL


    Laser-induced breakdown spectroscopy was used to determine the impact of endophyte (Neotyphodium sp.) infection on elemental composition of tall fescue (Festuca arundinacea). Leaf material from endophyte-infected (E+) and endophyte-free (E-) tall fescue populations in established plots was examined. Leaf-tissue digestates were also tested for metals, by ICP-MS. Seven of eleven metals (Ca, Mg, Fe, Mn, Cu, Ni and Zn) were measured by both techniques at concentrations great enough to reliably compare. Mg, Zn, and Cd, a toxic metal that can be present in forage, were readily detected by LIBS, even though Cd concentrations in the plants were below levels typically achieved using ICP-MS detection. Implications of these results for research on forage analysis and phytoremediation are discussed.

  15. Laser-induced breakdown spectroscopy used to detect endophyte-mediated accumulation of metals by tall fescue

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Madhavi Z.; Stewart, Arthur J.; Gwinn, Kimberley D.; Waller, John C.


    Laser-induced breakdown spectroscopy (LIBS) was used to determine the impact of endophyte (Neotyphodium sp.) infection on elemental composition of tall fescue (Festuca arundinacea). Leaf material from endophyte-infected (E+) and endophyte-free (E-) tall fescue populations in established plots was examined. Leaf-tissue digestates were also tested for metals, by inductively coupled plasma (ICP) mass spectrometry (MS). Seven of eleven metals (Ca, Mg, Fe, Mn, Cu, Ni, and Zn) were measured by both techniques at concentrations great enough for a reliable comparison. Mg, Zn, and Cd, a toxic metal that can be present in forage, were readily detected by LIBS, even though Cd concentrations in the plants were below levels typically achieved using ICP MS detection. Implications of these results for research on forage analysis and phytoremediation are discussed.

  16. A potential method for non-invasive acute myocardial infarction detection based on saliva Raman spectroscopy and multivariate analysis (United States)

    Cao, Gang; Chen, Maowen; Chen, Yuanxiang; Huang, Zufang; Lin, Jinyong; Lin, Jia; Xu, Zhihong; Wu, Shanshan; Huang, Wei; Weng, Guoxing; Chen, Guannan


    Raman spectroscopy (RS) was employed for human saliva biochemical analysis with the aim to develop a rapidly non-invasive test for acute myocardial infarction (AMI) detection. High-quality Raman spectra were obtained from human saliva samples of 46 AMI patients and 43 healthy controls. Significant differences in Raman intensities of prominent bands were observed between AMI and normal saliva. The tentative assignment of the observed Raman bands indicated constituent and conformational differences between the two groups. Furthermore, principal component analysis (PCA) combined with linear discriminant analysis (LDA) was employed to analyze and classify the Raman spectra acquired from AMI and healthy saliva, yielding a diagnostic sensitivity of 80.4% and specificity of 81.4%. The results from this exploratory study demonstrated the feasibility and potential for developing RS analysis of human saliva into a clinical tool for rapid AMI detection and screening.

  17. Quartz-enhanced photoacoustic spectroscopy-based sensor system for sulfur dioxide detection using a CW DFB-QCL (United States)

    Waclawek, J. P.; Lewicki, R.; Moser, H.; Brandstetter, M.; Tittel, F. K.; Lendl, B.


    Sulfur dioxide (SO2) trace gas detection based on quartz-enhanced photoacoustic spectroscopy (QEPAS) using a continuous wave, distributed feedback quantum cascade laser operating at 7.24 μm was performed. Influence of water vapor addition on monitored QEPAS SO2 signal was also investigated. A normalized noise equivalent absorption coefficient of NNEA (1 σ) = 1.21 × 10-8 cm-1 W Hz-1/2 was obtained for the ν 3 SO2 line centered at 1,380.93 cm-1 when the gas sample was moisturized with 2.3 % H2O. This corresponds to a minimum detection limit (1 σ) of 63 parts per billion by volume for a 1 s lock-in time constant.

  18. Compact quantum cascade laser based quartz-enhanced photoacoustic spectroscopy sensor system for detection of carbon disulfide. (United States)

    Waclawek, Johannes P; Moser, Harald; Lendl, Bernhard


    A compact gas sensor system based on quartz-enhanced photoacoustic spectroscopy (QEPAS) employing a continuous wave (CW) distributed feedback quantum cascade laser (DFB-QCL) operating at 4.59 µm was developed for detection of carbon disulfide (CS2) in air at trace concentration. The influence of water vapor on monitored QEPAS signal was investigated to enable compensation of this dependence by independent moisture sensing. A 1 σ limit of detection of 28 parts per billion by volume (ppbv) for a 1 s lock-in amplifier time constant was obtained for the CS2 line centered at 2178.69 cm-1 when the gas sample was moisturized with 2.3 vol% H2O. The work reports the suitability of the system for monitoring CS2 with high selectivity and sensitivity, as well as low sample gas volume requirements and fast sensor response for applications such as workplace air and process monitoring at industry.

  19. Optimization of Surface-Enhanced Raman Spectroscopy Conditions for Implementation into a Microfluidic Device for Drug Detection. (United States)

    Kline, Neal D; Tripathi, Ashish; Mirsafavi, Rustin; Pardoe, Ian; Moskovits, Martin; Meinhart, Carl; Guicheteau, Jason A; Christesen, Steven D; Fountain, Augustus W


    A microfluidic device is being developed by University of California-Santa Barbara as part of a joint effort with the United States Army to develop a portable, rapid drug detection device. Surface-enhanced Raman spectroscopy (SERS) is used to provide a sensitive, selective detection technique within the microfluidic platform employing metallic nanoparticles as the SERS medium. Using several illicit drugs as analytes, the work presented here describes the efforts of the Edgewood Chemical Biological Center to optimize the microfluidic platform by investigating the role of nanoparticle material, nanoparticle size, excitation wavelength, and capping agents on the performance, and drug concentration detection limits achievable with Ag and Au nanoparticles that will ultimately be incorporated into the final design. This study is particularly important as it lays out a systematic comparison of limits of detection and potential interferences from working with several nanoparticle capping agents-such as tannate, citrate, and borate-which does not seem to have been done previously as the majority of studies only concentrate on citrate as the capping agent. Morphine, cocaine, and methamphetamine were chosen as test analytes for this study and were observed to have limits of detection (LOD) in the range of (1.5-4.7) × 10 -8 M (4.5-13 ng/mL), with the borate capping agent having the best performance.

  20. Rapid molecular detection of invasive species in ballast and harbor water by integrating environmental DNA and light transmission spectroscopy. (United States)

    Egan, Scott P; Grey, Erin; Olds, Brett; Feder, Jeffery L; Ruggiero, Steven T; Tanner, Carol E; Lodge, David M


    Invasive species introduced via the ballast water of commercial ships cause enormous environmental and economic damage worldwide. Accurate monitoring for these often microscopic and morphologically indistinguishable species is challenging but critical for mitigating damages. We apply eDNA sampling, which involves the filtering and subsequent DNA extraction of microscopic bits of tissue suspended in water, to ballast and harbor water sampled during a commercial ship's 1400 km voyage through the North American Great Lakes. Using a lab-based gel electrophoresis assay and a rapid, field-ready light transmission spectroscopy (LTS) assay, we test for the presence of two invasive species: quagga (Dreissena bugensis) and zebra (D. polymorpha) mussels. Furthermore, we spiked a set of uninfested ballast and harbor samples with zebra mussel tissue to further test each assay's detection capabilities. In unmanipulated samples, zebra mussel was not detected, while quagga mussel was detected in all samples at a rate of 85% for the gel assay and 100% for the LTS assay. In the spiked experimental samples, both assays detected zebra mussel in 94% of spiked samples and 0% of negative controls. Overall, these results demonstrate that eDNA sampling is effective for monitoring ballast-mediated invasions and that LTS has the potential for rapid, field-based detection.

  1. Detection of unexpected frauds: Screening and quantification of maleic acid in cassava starch by Fourier transform near-infrared spectroscopy. (United States)

    Fu, Hai-Yan; Li, He-Dong; Xu, Lu; Yin, Qiao-Bo; Yang, Tian-Ming; Ni, Chuang; Cai, Chen-Bo; Yang, Ji; She, Yuan-Bin


    Fourier transform near-infrared (FT-NIR) spectroscopy and chemometrics were adopted for the rapid analysis of a toxic additive, maleic acid (MA), which has emerged as a new extraneous adulterant in cassava starch (CS). After developing an untargeted screening method for MA detection in CS using one-class partial least squares (OCPLS), multivariate calibration models were subsequently developed using least squares support vector machine (LS-SVM) to quantitatively analyze MA. As a result, the OCPLS model using the second-order derivative (D2) spectra detected 0.6%(w/w) adulterated MA in CS, with a sensitivity of 0.954 and specificity of 0.956. The root mean squared error of prediction (RMSEP) was 0.192(w/w, %) by using the standard normal variate (SNV) transformation LS-SVM. In conclusion, the potential of FT-NIR spectroscopy and chemometrics was demonstrated for application in rapid screening and quantitative analysis of MA in CS, which also implies that they have other promising applications for untargeted analysis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. High-Energy Resolution Fluorescence Detected X-Ray Absorption Spectroscopy: A Powerful New Structural Tool in Environmental Biogeochemistry Sciences. (United States)

    Proux, Olivier; Lahera, Eric; Del Net, William; Kieffer, Isabelle; Rovezzi, Mauro; Testemale, Denis; Irar, Mohammed; Thomas, Sara; Aguilar-Tapia, Antonio; Bazarkina, Elena F; Prat, Alain; Tella, Marie; Auffan, Mélanie; Rose, Jérôme; Hazemann, Jean-Louis


    The study of the speciation of highly diluted elements by X-ray absorption spectroscopy (XAS) is extremely challenging, especially in environmental biogeochemistry sciences. Here we present an innovative synchrotron spectroscopy technique: high-energy resolution fluorescence detected XAS (HERFD-XAS). With this approach, measurement of the XAS signal in fluorescence mode using a crystal analyzer spectrometer with a ∼1-eV energy resolution helps to overcome restrictions on sample concentrations that can be typically measured with a solid-state detector. We briefly describe the method, from both an instrumental and spectroscopic point of view, and emphasize the effects of energy resolution on the XAS measurements. We then illustrate the positive impact of this technique in terms of detection limit with two examples dealing with Ce in ecologically relevant organisms and with Hg species in natural environments. The sharp and well-marked features of the HERFD-X-ray absorption near-edge structure spectra obtained enable us to determine unambiguously and with greater precision the speciation of the probed elements. This is a major technological advance, with strong benefits for the study of highly diluted elements using XAS. It also opens new possibilities to explore the speciation of a target chemical element at natural concentration levels, which is critical in the fields of environmental and biogeochemistry sciences. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  3. [Research on detection method of adulterated olive oil by Raman spectroscopy and least squares support vector machine]. (United States)

    Zhang, Ying-Qiang; Dong, Wei; Zhang, Bing; Wang, Xiao-Ping


    For the purpose of the authentication of sorts as well as the prediction of contents of the oils which were adulterated into olive oil, 117 olive oil samples adulterated with sunflower seed oil, soybean oil and corn oil were detected by Raman spectroscopy, and least squares support vector machine (LS-SVM) based on multiple iterative optimization was used to identify the type of the adulterant oil, and the composite recognition rate was 97%. In addition, methods such as LS-SVM, ANNs and PLSR were used to build the Raman spectra calibration model of the adulterant oil (sunflower seed oil, soybean oil and corn oil) contents respectively, the results indicated that LS-SVM had the best predictive performance, and the root mean square error of prediction (RMSEP) ranged from 0.007 4 to 0.014 2. Research results showed the method based on Raman spectroscopy and LS-SVM was accurate, fast, simple and non-destructive for adulterated olive oil detection.

  4. The Detection of Water Flow in Rectangular Microchannels by Terahertz Time Domain Spectroscopy. (United States)

    Song, Yan; Zhao, Kun; Zuo, Jian; Wang, Cuicui; Li, Yizhang; Miao, Xinyang; Zhao, Xiaojing


    Flow characteristics of water were tested in a rectangular microchannel for Reynolds number (Re) between 0 and 446 by terahertz time domain spectroscopy (THz-TDS). Output THz peak trough intensities and the calculated absorbances of the flow were analyzed theoretically. The results show a rapid change for Re flow beginning nearly at Re = 250. Then this finding is confirmed in the plot of the flow resistant. Our results demonstrate that the THz-TDS could be a valuable tool to monitor and character the flow performance in microscale structures.

  5. Detection of citrus canker and Huanglongbing using fluorescence imaging spectroscopy and support vector machine technique. (United States)

    Wetterich, Caio Bruno; Felipe de Oliveira Neves, Ruan; Belasque, José; Marcassa, Luis Gustavo


    Citrus canker and Huanglongbing (HLB) are citrus diseases that represent a serious threat to the citrus production worldwide and may cause large economic losses. In this work, we combined fluorescence imaging spectroscopy (FIS) and a machine learning technique to discriminate between these diseases and other ordinary citrus conditions that may be present at citrus orchards, such as citrus scab and zinc deficiency. Our classification results are highly accurate when discriminating citrus canker from citrus scab (97.8%), and HLB from zinc deficiency (95%). These results show that it is possible to accurately identify citrus diseases that present similar symptoms.

  6. Raman spectroscopy as a new tool for early detection of bacteria in patients with cystic fibrosis (United States)

    Rusciano, Giulia; Capriglione, Paola; Pesce, Giuseppe; Abete, Pasquale; Carnovale, Vincenzo; Sasso, Antonio


    Respiratory infections represent a major threat for people affected by cystic fibrosis, leading to pulmonary deterioration and lung transplantation as a therapeutic option for end-stage patients. A fast and correct identification of pathogens in airway fluid of these patients is crucial to establish appropriate therapies, to prevent cross-infections and, ultimately, to preserve lung function. In this study, we used Raman spectroscopy to reveal bacteria in the sputa of patients such as Pseudomonas aeruginosa and Staphylococcus aureus, which are among the earliest and the most frequent bacteria affecting cystic fibrosis patients. We found that Raman analysis, combined with principal component analysis, is able to provide a correct identification of these bacteria, with a global accuracy higher than 95%. Interestingly, bacterial identification is performed by analysing patients’ sputa as a whole, avoiding, therefore, time-consuming procedures involving bacterial isolation or even bacterial cultures. This study suggests that Raman spectroscopy could be a suitable candidate for the development of innovative and non-invasive procedures for a fast and reliable identification of respiratory infections in cystic fibrosis patients.

  7. Detection Limits of DLS and UV-Vis Spectroscopy in Characterization of Polydisperse Nanoparticles Colloids

    Directory of Open Access Journals (Sweden)

    Emilia Tomaszewska


    Full Text Available Dynamic light scattering is a method that depends on the interaction of light with particles. This method can be used for measurements of narrow particle size distributions especially in the range of 2–500 nm. Sample polydispersity can distort the results, and we could not see the real populations of particles because big particles presented in the sample can screen smaller ones. Although the theory and mathematical basics of DLS technique are already well known, little has been done to determine its limits experimentally. The size and size distribution of artificially prepared polydisperse silver nanoparticles (NPs colloids were studied using dynamic light scattering (DLS and ultraviolet-visible (UV-Vis spectroscopy. Polydisperse colloids were prepared based on the mixture of chemically synthesized monodisperse colloids well characterized by atomic force microscopy (AFM, transmission electron microscopy (TEM, DLS, and UV-Vis spectroscopy. Analysis of the DLS results obtained for polydisperse colloids reveals that several percent of the volume content of bigger NPs could screen completely the presence of smaller ones. The presented results could be extremely important from nanoparticles metrology point of view and should help to understand experimental data especially for the one who works with DLS and/or UV-Vis only.

  8. Optical fluorescence spectroscopy to detect hepatic necrosis after normothermic ischemia: animal model (United States)

    Romano, Renan A.; Vollet-Filho, Jose D.; Pratavieira, Sebastião.; Fernandez, Jorge L.; Kurachi, Cristina; Bagnato, Vanderlei S.; Castro-e-Silva, Orlando; Sankarankutty, Ajith K.


    Liver transplantation is a well-established treatment for liver failure. However, the success of the transplantation procedure depends on liver graft conditions. The tissue function evaluation during the several transplantation stages is relevant, in particular during the organ harvesting, when a decision is made concerning the viability of the graft. Optical fluorescence spectroscopy is a good option because it is a noninvasive and fast technique. A partial normothermic hepatic ischemia was performed in rat livers, with a vascular occlusion of both median and left lateral lobes, allowing circulation only for the right lateral lobe and the caudate lobe. Fluorescence spectra under excitation at 532 nm (doubled frequency Nd:YAG laser) were collected using a portable spectrometer (USB2000, Ocean Optics, USA). The fluorescence emission was collected before vascular occlusion, after ischemia, and 24 hours after reperfusion. A morphometric histology analysis was performed as the gold standard evaluation - liver samples were analyzed, and the percentage of necrotic tissue was obtained. The results showed that changes in the fluorescence emission after ischemia can be correlated with the amount of necrosis evaluated by a morphometric analysis, the Pearson correlation coefficient of the generated model was 0.90 and the root mean square error was around 20%. In this context, the laser-induced fluorescence spectroscopy technique after normothermic ischemia showed to be a fast and efficient method to differentiate ischemic injury from viable tissues.

  9. Detection of urinary estrogen conjugates and creatinine using near infrared spectroscopy in Bornean orangutans (Pongo Pygmaeus). (United States)

    Kinoshita, Kodzue; Kuze, Noko; Kobayashi, Toshio; Miyakawa, Etsuko; Narita, Hiromitsu; Inoue-Murayama, Miho; Idani, Gen'ichi; Tsenkova, Roumiana


    For promoting in situ conservation, it is important to estimate the density distribution of fertile individuals, and there is a need for developing an easy monitoring method to discriminate between physiological states. To date, physiological state has generally been determined by measuring hormone concentration using radioimmunoassay or enzyme immunoassay (EIA) methods. However, these methods have rarely been applied in situ because of the requirements for a large amount of reagent, instruments, and a radioactive isotope. In addition, the proper storage of the sample (including urine and feces) on site until analysis is difficult. On the other hand, near infrared (NIR) spectroscopy requires no reagent and enables rapid measurement. In the present study, we attempted urinary NIR spectroscopy to determine the estrogen levels of orangutans in Japanese zoos and in the Danum Valley Conservation Area, Sabah, Malaysia. Reflectance NIR spectra were obtained from urine stored using a filter paper. Filter paper is easy to use to store dried urine, even in the wild. Urinary estrogen and creatinine concentrations measured by EIA were used as the reference data of partial least square (PLS) regression of urinary NIR spectra. High accuracies (R(2) > 0.68) were obtained in both estrogen and creatinine regression models. In addition, the PLS regressions in both standards showed higher accuracies (R(2) > 0.70). Therefore, the present study demonstrates that urinary NIR spectra have the potential to estimate the estrogen and creatinine concentrations.

  10. Electronic states in vertically ordered Ge/Si quantum dots detected by photocurrent spectroscopy (United States)

    Yakimov, A. I.; Kirienko, V. V.; Armbrister, V. A.; Bloshkin, A. A.; Dvurechenskii, A. V.


    We report on intraband photocurrent spectroscopy of sixfold stacked Ge/Si quantum dots embedded in a Si matrix and aligned along the growth direction. The dots are formed in a shape of pyramids with the average lateral size of 18 nm. The n-type heterostructures show broad spectral response ranging from 5 to 20 μm, depending on the polarization of the incoming infrared light. The normal incidence photocurrent peak centered around 12-15 μm is attributed to the transitions from the electron states localized in the Si region adjacent to the dots to continuum states of the Si matrix. The electron confinement is caused by a modification of the conduction band alignment induced by inhomogeneous tensile strain in Si around the buried Ge/Si quantum dots. Using the Ge content and dot shape determined by Raman and scanning tunneling microscopy analysis as input parameters for three-dimensional band structure simulations, a good agreement between measured and calculated electron binding energy is obtained. Photoluminescence spectroscopy and measurements of temperature dependence of dark conductance are used to correlate photocurrent results.

  11. Detection of carotenoids present in blood of various animal species using Raman spectroscopy (United States)

    Liaqat, Maryam; Younus, Ayesha; Saleem, Muhammad; Rashid, Imaad; Yaseen, Maria; Jabeen, Saher

    Raman spectroscopy is simple stable powerful diagnostic tool for body fluids, tissues and other biomolecules. Human blood possesses different kind of carotenoids that play a key role for protecting the cells from damaging by different viral and bacterial diseases. Carotenoids are antioxidative components which are capable to overcome the attack of different free radicals and reactive oxygen species. Carotenoids are not prepared by human body, therefore it is recommended to eat carotenoids enrich vegetable foods. No standard data is available on the concentration of useful carotenoids component in non-vegetable consumed items. In present research work, Raman spectroscopy is used to compare various blood components like plasma, serum, carotenoids present in blood of different animal species like goat, sheep, cow and buffalo consumed by human. Especially beta carotene is investigated. The Raman shift ranges from 600-1700 cm-1 for samples. Different characteristic peaks of the blood components are found which are not characterized before in animal samples. Doctrate Student in Photonics Deparatment of Electrical Engineering.

  12. Optical nerve detection by diffuse reflectance spectroscopy for feedback controlled oral and maxillofacial laser surgery. (United States)

    Stelzle, Florian; Zam, Azhar; Adler, Werner; Tangermann-Gerk, Katja; Douplik, Alexandre; Nkenke, Emeka; Schmidt, Michael


    Laser surgery lacks haptic feedback, which is accompanied by the risk of iatrogenic nerve damage. It was the aim of this study to investigate diffuse reflectance spectroscopy for tissue differentiation as the base of a feedback control system to enhance nerve preservation in oral and maxillofacial laser surgery. Diffuse reflectance spectra of nerve tissue, salivary gland and bone (8640 spectra) of the mid-facial region of ex vivo domestic pigs were acquired in the wavelength range of 350-650 nm. Tissue differentiation was performed using principal component (PC) analysis followed by linear discriminant analysis (LDA). Specificity and sensitivity were calculated using receiver operating characteristic (ROC) analysis and the area under curve (AUC). Five PCs were found to be adequate for tissue differentiation with diffuse reflectance spectra using LDA. Nerve tissue could be differed from bone as well as from salivary gland with AUC results of greater than 88%, sensitivity of greater than 83% and specificity in excess of 78%. Diffuse reflectance spectroscopy is an adequate technique for nerve identification in the vicinity of bone and salivary gland. The results set the basis for a feedback system to prevent iatrogenic nerve damage when performing oral and maxillofacial laser surgery.

  13. A study of Raman spectroscopy for the early detection and classification of malignancy in oesophageal tissue

    Energy Technology Data Exchange (ETDEWEB)

    Kendall, C.A


    Raman Spectroscopy for the identification and classification of malignancy in the oesophagus has been demonstrated in this thesis. The potential of Raman spectroscopy in this field is twofold; as an adjunct for the pathologist and as a biopsy targeting tool at endoscopy. This study has demonstrated the feasibility of these potential applications in vitro. Spectral diagnostic models have been developed by correlating spectral information with histopathology. This is the current 'gold standard' diagnostic method for the identification of dysplasia, the established risk factor for the development of oesophageal cancer. Histopathology is a subjective assessment and widely acknowledged to have limitations. A more rigorous gold standard was therefore developed, as part of this study, using the consensus opinion of three independent expert pathologists to train the diagnostic models. Raman spectra have been measured from oesophageal tissue covering the full spectrum of malignant disease in the oesophagus, using a near infrared Raman spectrometer customised for tissue spectral measurements. Two spectral datasets were measured with different volumes of tissue probed using twenty and eighty times magnification ultra long working distance objectives. Multivariate statistical analysis has been used to extract the required spectral information with the greatest discriminative power. Principal component fed linear discriminant spectral models have been tested with leave one out cross validation procedures. Three pathology group models have correctly classified up to 91% of spectra, and eight group models have correctly classified up to 82% of spectra. Optimisation of the spectral models by selection of significant principal components, filtering the data and using staggered models was investigated. Effort has been made to understand the findings in their clinical context, with review of patient history and clinical progress, long term follow up is required. Preliminary

  14. PCR-free detection of genetically modified organisms using magnetic capture technology and fluorescence cross-correlation spectroscopy.

    Directory of Open Access Journals (Sweden)

    Xiaoming Zhou


    Full Text Available The safety of genetically modified organisms (GMOs has attracted much attention recently. Polymerase chain reaction (PCR amplification is a common method used in the identification of GMOs. However, a major disadvantage of PCR is the potential amplification of non-target DNA, causing false-positive identification. Thus, there remains a need for a simple, reliable and ultrasensitive method to identify and quantify GMO in crops. This report is to introduce a magnetic bead-based PCR-free method for rapid detection of GMOs using dual-color fluorescence cross-correlation spectroscopy (FCCS. The cauliflower mosaic virus 35S (CaMV35S promoter commonly used in transgenic products was targeted. CaMV35S target was captured by a biotin-labeled nucleic acid probe and then purified using streptavidin-coated magnetic beads through biotin-streptavidin linkage. The purified target DNA fragment was hybridized with two nucleic acid probes labeled respectively by Rhodamine Green and Cy5 dyes. Finally, FCCS was used to detect and quantify the target DNA fragment through simultaneously detecting the fluorescence emissions from the two dyes. In our study, GMOs in genetically engineered soybeans and tomatoes were detected, using the magnetic bead-based PCR-free FCCS method. A detection limit of 50 pM GMOs target was achieved and PCR-free detection of GMOs from 5 microg genomic DNA with magnetic capture technology was accomplished. Also, the accuracy of GMO determination by the FCCS method is verified by spectrophotometry at 260 nm using PCR amplified target DNA fragment from GM tomato. The new method is rapid and effective as demonstrated in our experiments and can be easily extended to high-throughput and automatic screening format. We believe that the new magnetic bead-assisted FCCS detection technique will be a useful tool for PCR-free GMOs identification and other specific nucleic acids.

  15. Automatic laser beam alignment using blob detection for an environment monitoring spectroscopy (United States)

    Khidir, Jarjees; Chen, Youhua; Anderson, Gary


    This paper describes a fully automated system to align an infra-red laser beam with a small retro-reflector over a wide range of distances. The component development and test were especially used for an open-path spectrometer gas detection system. Using blob detection under OpenCV library, an automatic alignment algorithm was designed to achieve fast and accurate target detection in a complex background environment. Test results are presented to show that the proposed algorithm has been successfully applied to various target distances and environment conditions.

  16. Characterization of the adsorption of Ru-bpy dyes on mesoporous TiO2 films with UV-Vis, Raman, and FTIR spectroscopies. (United States)

    Pérez León, C; Kador, L; Peng, B; Thelakkat, M


    In the present work the adsorption of a new dye, [Ru(dcbpyH(2))(2)(bpy-TPA(2))](PF(6))(2), and the well-known (Bu(4)N)(2)[Ru(dcbpyH)(2)(NCS)(2)] complex on mesoporous anatase films were investigated to clarify the role of the carboxylate groups in the anchoring process of the dyes on the semiconductor surface. For this purpose UV-vis, Raman, resonance Raman, and ATR-FTIR spectroscopies have been used. The results of the Raman experiments at different excitation wavelengths demonstrate that photoinduced charge-transfer processes take place efficiently between the adsorbate and the substrate. Moreover, this is the first time that the Raman spectrum of a Ru-bpy dye (in this case, the dye N719) adsorbed on TiO(2) has been obtained without the resonance condition, only by means of SERS enhancement. The coordination of both complexes on the TiO(2) paste films is proposed to occur via bidentate or bridging linkage.

  17. Intraoperative detection of sentinel lymph node metastases in breast carcinoma by Fourier transform infrared spectroscopy. (United States)

    Tian, P; Zhang, W; Zhao, H; Lei, Y; Cui, L; Zhang, Y; Xu, Z


    dissection. The results of this research indicate that Fourier transform infrared (FTIR) spectroscopy is a rapid, accurate, non-destructive and cost-effective molecular method that can be used to detect SLN metastasis during surgery. FTIR analysis could be useful for the intraoperative diagnosis of lymph node metastases at large institutions, thereby reducing the workload of pathologists, as well as in regions lacking pathologists such as in developing countries. © 2015 BJS Society Ltd Published by John Wiley & Sons Ltd.

  18. Detection of chemical residues in food oil via surface-enhanced Raman spectroscopy (United States)

    Sun, Kexi; Huang, Qing


    Highly ordered hexagonally patterned Ag-nanorod (Ag-NR) arrays for surface-enhanced Raman scattering (SERS) detection of unhealthy chemical residues in food oil was reported, which was obtained by sputtering Ag on the alumina nanotip arrays stuck out of conical-pore anodic aluminum oxide (AAO) templates. SERS measurements demonstrate that the as-fabricated large-scale Ag-nanostructures can serve as highly sensitive and reproducible SERS substrates for detection of trace amount of chemicals in oil with the lower detection limits of 2×10-6 M for thiram and 10-7 M for rhodamine B, showing the potential of application of SERS in rapid trace detection of pesticide residues and illegal additives in food oils.

  19. Potentials and limits of mid-infrared laser spectroscopy for the detection of explosives (United States)

    Bauer, C.; Sharma, A. K.; Willer, U.; Burgmeier, J.; Braunschweig, B.; Schade, W.; Blaser, S.; Hvozdara, L.; Müller, A.; Holl, G.


    Optical methods are well-established for trace gas detection in many applications, such as industrial process control or environmental sensing. Consequently, they gain much interest in the discussion of sensing methods for counterterrorism, e.g., the detection of explosives. Explosives as well as their decomposition products possess strong absorption features in the mid-infrared (MIR) spectral region between λ=5 and 11 μm. In this report we present two different laser spectroscopic approaches based on quantum cascade lasers (QCLs) operating at wavelengths around λ=5 and 8 μm, respectively. Stand-off configuration for the remote detection of nitro-based explosives (e.g., trinitrotoluene, TNT) and a fiber coupled sensor device for the detection of triacetone triperoxide (TATP) are discussed.

  20. Electrical Impedance Spectroscopy for Detection of Cells in Suspensions Using Microfluidic Device with Integrated Microneedles


    Muhammad Asraf Mansor; Masaru Takeuchi; Masahiro Nakajima; Yasuhisa Hasegawa; Mohd Ridzuan Ahmad


    In this study, we introduce novel method of flow cytometry for cell detection based on impedance measurements. The state of the art method for impedance flow cytometry detection utilizes an embedded electrode in the microfluidic to perform measurement of electrical impedance of the presence of cells at the sensing area. Nonetheless, this method requires an expensive and complicated electrode fabrication process. Furthermore, reuse of the fabricated electrode also requires an intensive and ted...

  1. Remote detection of chem/bio hazards via coherent anti-Stokes Raman spectroscopy (United States)


    system that drive the limits of applicability. We will formulate a semiclassical theory of nonlinear scattering to estimate the number of...semiclassical theory of nonlinear sca.ttering to estimate the number of detectable photons from a prototype molecule at a distance. The theory incorporated...made use of a semiclassiciJl theory of nonlinear scattering presented in [2] to estimate the number of detectable photons from a prototype molecule at

  2. Reliable diagnosis of IDH-mutant glioblastoma by 2-hydroxyglutarate detection: a study by 3-T magnetic resonance spectroscopy. (United States)

    Natsumeda, Manabu; Motohashi, Kunio; Igarashi, Hironaka; Nozawa, Takanori; Abe, Hideaki; Tsukamoto, Yoshihiro; Ogura, Ryosuke; Okada, Masayasu; Kobayashi, Tsutomu; Aoki, Hiroshi; Takahashi, Hitoshi; Kakita, Akiyoshi; Okamoto, Kouichirou; Nakada, Tsutomu; Fujii, Yukihiko


    We have previously reported that reliable detection of 2-hydroxyglutarate (2HG) in isocitrate dehydrogenase (IDH)-mutant WHO grade 2 and 3 gliomas is possible utilizing 3.0-T single-voxel magnetic resonance spectroscopy (SVMRS). We set out to determine whether the same method could be applied to detect 2HG in IDH-mutant glioblastoma. Forty-four patients harboring glioblastoma underwent pre-operative MRS evaluation to detect 2HG and other metabolites. Presence of IDH-mutations was determined by IDH1 R132H immunohistochemical analysis and DNA sequencing of surgically obtained tissues. Six out of 44 (13.6%) glioblastomas were IDH-mutant. IDH-mutant glioblastoma exhibited significantly higher accumulation of 2HG (median 3.191 vs. 0.000 mM, p IDH-mutation in glioblastoma. Glioblastoma with high 2HG accumulation did not have significantly longer overall survival than glioblastoma with low 2HG accumulation (p = 0.107, log-rank test). Non-invasive and reliable detection of 2HG in IDH-mutant glioblastoma was possible by 3.0-T SVMRS.

  3. Surrogate measurement of chlorine concentration on steel surfaces by alkali element detection via laser-induced breakdown spectroscopy (United States)

    Xiao, X.; Le Berre, S.; Hartig, K. C.; Motta, A. T.; Jovanovic, I.


    Chlorine can play an important role in the process of stress corrosion cracking of dry cask storage canisters for used nuclear fuel, which are frequently located in marine environments. It is of significant interest to determine the surface concentration of chlorine on the stainless steel canister surface, but measurements are often limited by difficult access and challenging conditions, such as high temperature and high radiation fields. Laser-induced breakdown spectroscopy (LIBS) could enable chlorine concentration measurements while meeting the other constraints of this application, but suffers from high excitation energy of chlorine and the interference of the atomic emission lines of iron, thus limiting the sensitivity of detection, especially when LIBS has to be delivered over an optical fiber. We demonstrate that chlorine surface concentrations in the range of 0.5-100 mg/m2 can be inferred by the detection and quantification of sodium contained in chlorine salts if the speciation and neutralization of salts are not of major concern, whereas minor components of sea salt such as magnesium and potassium are less attractive as surrogates for chlorine due to the lower sensitivity of LIBS for their detection and quantification. The limit of detection, measurement accuracy, and other features and limitations of this surrogate measurement approach are discussed.

  4. Mid-infrared carbon monoxide detection system using differential absorption spectroscopy technique (United States)

    Dong, Ming; Sui, Yue; Li, Guo-lin; Zheng, Chuan-tao; Chen, Mei-mei; Wang, Yi-ding


    A differential carbon monoxide (CO) concentration sensing device using a self-fabricated spherical mirror (e.g. light-collector) and a multi-pass gas-chamber is presented in this paper. Single-source dual-channel detection method is adopted to suppress the interferences from light source, optical path and environmental changes. Detection principle of the device is described, and both the optical part and the electrical part are developed. Experiments are carried out to evaluate the sensing performance on CO concentration. The results indicate that at 1.013×105 Pa and 298 K, the limit of detection (LoD) is about 11.5 mg/m3 with an absorption length of 40 cm. As the gas concentration gets larger than 115 mg/m3 (1.013×105 Pa, 298 K), the relative detection error falls into the range of -1.7%—+1.9%. Based on 12 h long-term measurement on the 115 mg/m3 and 1 150 mg/m3 CO samples, the maximum detection errors are about 0.9% and 5.5%, respectively. Due to the low cost and competitive characteristics, the proposed device shows potential applications in CO detection in the circumstances of coal-mine production and environmental protection.

  5. Detection of trace amount of arsenic in groundwater by laser-induced breakdown spectroscopy and adsorption (United States)

    Haider, A. F. M. Y.; Hedayet Ullah, M.; Khan, Z. H.; Kabir, Firoza; Abedin, K. M.


    LIBS technique coupled with adsorption has been applied for the efficient detection of arsenic in liquid. Several adsorbents like tea leaves, bamboo slice, charcoal and zinc oxide have been used to enable sensitive detection of arsenic presence in water using LIBS. Among these, zinc oxide and charcoal show the better results. The detection limits for arsenic in water were 1 ppm and 8 ppm, respectively, when ZnO and charcoal were used as adsorbents of arsenic. To date, the determination of 1 ppm of As in water is the lowest concentration of detected arsenic in water by the LIBS technique. The detection limit of As was lowered to even less than 100 ppb by a combination of LIBS technique, adsorption by ZnO and concentration enhancement technique. Using the combination of these three techniques the ultimate concentration of arsenic was found to be 0.083 ppm (83 ppb) for arsenic polluted water collected from a tube-well of Farajikandi union (longitude 90.64°, latitude 23.338° north) of Matlab Upozila of Chandpur district in Bangladesh. This result compares fairly well with the finding of arsenic concentration of 0.078 ppm in the sample by the AAS technique at the Bangladesh Council of Scientific and Industrial Research (BCSIR) lab. Such a low detection limit (1 ppm) of trace elements in liquid matrix has significantly enhanced the scope of LIBS as an analytical tool.

  6. Detection of coronary atherosclerotic plaques with superficial proteoglycans and foam cells using real-time intrinsic fluorescence spectroscopy. (United States)

    Angheloiu, George O; Haka, Abigail S; Georgakoudi, Irene; Arendt, Joseph; Müller, Markus G; Scepanovic, Obrad R; Evanko, Stephen P; Wight, Thomas N; Mukherjee, Prasun; Waldeck, David H; Dasari, Ramachandra R; Fitzmaurice, Maryann; Kramer, John R; Feld, Michael S


    The protein components of low-density lipoprotein (LDL), oxidized LDL and proteoglycans such as versican contain tryptophan, an amino acid with characteristic fluorescence features at 308 nm excitation wavelength. We hypothesize that intrinsic fluorescence spectroscopy at 308 nm excitation wavelength IFS308, a method suitable for clinical use, can identify coronary artery lesions with superficial foam cells (SFCs) and/or proteoglycans. We subjected 119 human coronary artery specimens to in vitro fluorescence and reflectance spectroscopy. We used 5 basis spectra to model IFS308, and extracted their contributions to each individual IFS308 spectrum. A diagnostic algorithm using the contributions of Total Tryptophan and fibrous cap to IFS308 was built to identify specimens with SFCs and/or proteoglycans in their top 50 μm. We detected SFCs and/or proteoglycans, such as versican or the glycosaminoglycan hyaluronan, in 24 fibrous cap atheromas or pathologic intimal thickening (PIT) lesions. An algorithm using the contributions of Total Tryptophan and fibrous cap to IFS308 was able to identify these segments with 92% sensitivity and 80% specificity. We were able to establish a set of characteristic LDL, oxidized LDL, versican and hyaluronan fluorescence spectra, ready to be used for real-time diagnosis. The IFS(308) technique detects SFCs and/or proteoglycans in fibrous cap atheromas and PIT lesions. SFCs and proteoglycans are histological markers of vulnerable plaques, and this study is a step further in developing an invasive clinical tool to detect the vulnerable atherosclerotic plaque. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  7. Impedance spectroscopy in biodynamics: Detection of specific cells (pathogens using immune coated electrodes

    Directory of Open Access Journals (Sweden)

    Eugen Gheorghiu


    Full Text Available We describe the theoretical and experimental approaches for monitoring the interfacial biomolecular reaction between immobilized antibody and the antigen binding partner (the analyte, or the targeted cell using Impedance Spectroscopy, IS. The key idea is to reveal the presence of the analyte by investigating the dynamics of the impedance changes at the interface between transducer and bulk during the process of antibody-antigen binding (coupling of specific compounds to sensor surface. In this work, antibody-antigen (Ab-Ag reaction was directly monitored using an impedance analyzer capable of ~ 1 measurement/second and covalent immobilization chemistry and modified electrodes in the absence of a redox probe. The proposed approach may be applicable to monitoring other surface interfacial reactions such as protein-protein interactions, DNA-DNA interactions, DNA-protein interactions and DNA-small molecule interactions.

  8. Application of Nonlinear Elastic Resonance Spectroscopy For Damage Detection In Concrete: An Interesting Story

    Energy Technology Data Exchange (ETDEWEB)

    Byers, Loren W. [Los Alamos National Laboratory; Ten Cate, James A. [Los Alamos National Laboratory; Johnson, Paul A. [Los Alamos National Laboratory


    Nonlinear resonance ultrasound spectroscopy experiments conducted on concrete cores, one chemically and mechanically damaged by alkali-silica reactivity, and one undamaged, show that this material displays highly nonlinear wave behavior, similar to many other damaged materials. They find that the damaged sample responds more nonlinearly, manifested by a larger resonant peak and modulus shift as a function of strain amplitude. The nonlinear response indicates that there is a hysteretic influence in the stress-strain equation of state. Further, as in some other materials, slow dynamics are present. The nonlinear response they observe in concrete is an extremely sensitive indicator of damage. Ultimately, nonlinear wave methods applied to concrete may be used to guide mixing, curing, or other production techniques, in order to develop materials with particular desired qualities such as enhanced strength or chemical resistance, and to be used for damage inspection.

  9. Detection of Elemental Composition of Lubricating Grease Using Laser Induced Breakdown Spectroscopy

    Directory of Open Access Journals (Sweden)

    Cherry Dhiman


    Full Text Available The elemental composition of lubricating soft grease used in rail engines are studied using laser induced breakdown spectroscopy (LIBS technique. LIBS spectra of fresh, partially used and fully used grease samples are recorded using time-gated ICCD spectrometer for verification of compositional degradation of the used grease. LIBS spectra of grease samples are analyzed by comparing with emission spectra of elements published by NIST standard database. Many spectral lines of impurity elements like Fe, Cu, Ba, Mg, Mn, Ni, S, Zn, Si, Pb, Ti, Ca and Al present in the grease in ppm or ppb level in trace level concentrations are observed in excess in the used grease mainly due to wear and tear. On the other hand in fresh grease, spectral lines of Ca, Al and Na are observed predominantly.

  10. Detection and quantitative analysis of ferrocyanide and ferricyanide: FY 93 Florida State University Raman spectroscopy report

    Energy Technology Data Exchange (ETDEWEB)

    Mann, C.K.; Vickers, T.J. [Florida State Univ., Tallahassee, FL (United States). Dept. of Chemistry


    This report provides a summary of work to develop and investigate the feasibility of using Raman spectroscopy with tank waste materials. It contains Raman spectra from organics, such as ethylenediaminetetraacetic acid (EDTA), hydroxyethylenediaminetetraacteic acid (HEDTA), imino diacetic acid (IDA), kerosene, tributyl phosphate (TBP), acetone and butanol, anticipated to be present in tank wastes and spectra from T-107 real and BY-104 simulant materials. The results of investigating Raman for determining moisture content in tank materials are also presented. A description of software algorithms developed to process Raman spectra from a dispersive grating spectrometer system and an in initial design for a data base to support qualitative and quantitative application of remote Raman sensing with tank wastes.

  11. Detection of cancerous kidney tissue areas by means of infrared spectroscopy of intercellular fluid (United States)

    Urboniene, V.; Jankevicius, F.; Zelvys, A.; Steiner, G.; Sablinskas, V.


    In this work the infrared absorption spectra of intercellular fluid of normal and tumor kidney tissue were recorded and analyzed. The samples were prepared by stamping freshly resected tissue onto a CaF2 substrate. FT-IR spectra obtained from intracellular fluid of tumor tissue exhibit stronger absorption bands in the spectral region from 1000-1200 cm-1 and around 1750 cm-1 than those obtained from normal tissue. It is likely the spectra of extracellular matrix of kidney tumor tissue with large increases in the intensities of these bands represent a higher concentration of fatty acids and glycerol. Amide I and amide II bands are stronger in spectra of normal tissue indicating a higher level of proteins. The results demonstrate that FT-IR spectroscopy of intercellular fluids is a novel approach for a quick diagnosis during surgical resection, which can improve the therapy of kidney tumors.

  12. Detection of regulated herbs and plants in plant food supplements and traditional medicines using infrared spectroscopy. (United States)

    Deconinck, E; Djiogo, C A Sokeng; Bothy, J L; Courselle, P


    The identification of a specific toxic or regulated plant in herbal preparations or plant food supplements is a real challenge, since they are often powdered, mixed with other herbal or synthetic powders and compressed into tablets or capsules. The classical identification approaches based on micro- and macroscopy are therefore not possible anymore. In this paper infrared spectroscopy, combined with attenuated total reflectance was evaluated for the screening of plant based preparations for nine specific plants (five regulated and four common plants for herbal supplements). IR and NIR spectra were recorded for a series of self-made triturations of the targeted plants. After pretreatment of the spectral data chemometric classification techniques were applied to both data sets (IR and NIR) separately and the combination of both. The results show that the screening of herbal preparations or plant food supplements for specific plants, using infrared spectroscopy, is feasible. The best model was obtained with the Mid-IR data, using SIMCA as modelling technique. During validation of the model, using an external test set, 21 of 25 were correctly classified and six of the nine targeted plants showed no misclassifications for the selected test set. For the other three a success rate of 50% was obtained. Mid-IR combined with SIMCA can therefore be applied as a first step in the screening of unknown samples, before applying more sophisticated fingerprint approaches or identification tests described in several national and international pharmacopoeia. As a proof of concept five real suspicious samples were successfully screened for the targeted regulated plants. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Detection and characterization of atherosclerotic plaques by Raman probe spectroscopy and optical coherence tomography (Conference Presentation) (United States)

    Matthäus, Christian; Dochow, Sebastian; Egodage, Kokila D.; Schie, Iwan; Romeike, Bernd F.; Brehm, Bernhard R.; Popp, Jürgen


    Visualization and characterization of inner arterial plaque depositions is of vital diagnostic interest. Established intravascular imaging techniques provide valuable morphological information, but cannot deliver information about the chemical composition of individual plaques. Probe based Raman spectroscopy offers the possibility for a biochemical characterization of atherosclerotic plaque formations during an intravascular intervention. From post mortem studies it is well known that the severity of a plaque and its stability are strongly correlated with its biochemical composition. Especially the identification of vulnerable plaques remains one of the most important and challenging aspects in cardiology. Thus, specific information about the composition of a plaque would greatly improve the risk assessment and management. Furthermore, knowledge about the composition can offer new therapeutic and medication strategies. Plaque calcifications as well as major lipid components such as cholesterol, cholesterol esters and triglycerides can be spectroscopically easily differentiated. Intravascular optical coherence tomography (OCT) is currently a prominent catheter based imaging technique for the localization and visualization of atherosclerotic plaque depositions. The high resolution of OCT with 10 to 15 µm allows for very detailed characterization of morphological features such as different plaque formations, thin fibrous caps and accurate measurements of lesion lengths. In combination with OCT imaging the obtained spectral information can provide substantial information supporting on on-site diagnosis of various plaque types and therefor an improved risk assessment. The potential and feasibility of combining OCT with Raman spectroscopy is demonstrated on excised plaque samples, as well as under in vivo conditions. Acknowledgements: Financial support from the Carl Zeiss Foundation is greatly acknowledged.

  14. Inconsistent detection of changes in cerebral blood volume by near infrared spectroscopy in standard clinical tests. (United States)

    Canova, D; Roatta, S; Bosone, D; Micieli, G


    The attractive possibility of near infrared spectroscopy (NIRS) to noninvasively assess cerebral blood volume and oxygenation is challenged by the possible interference from extracranial tissues. However, to what extent this may affect cerebral NIRS monitoring during standard clinical tests is ignored. To address this issue, 29 healthy subjects underwent a randomized sequence of three maneuvers that differently affect intra- and extracranial circulation: Valsalva maneuver (VM), hyperventilation (HV), and head-up tilt (HUT). Putative intracranial ("i") and extracranial ("e") NIRS signals were collected from the forehead and from the cheek, respectively, and acquired together with cutaneous plethysmography at the forehead (PPG), cerebral blood velocity from the middle cerebral artery, and arterial blood pressure. Extracranial contribution to cerebral NIRS monitoring was investigated by comparing Beer-Lambert (BL) and spatially resolved spectroscopy (SRS) blood volume indicators [the total hemoglobin concentration (tHb) and the total hemoglobin index, (THI)] and by correlating their changes with changes in extracranial circulation. While THIe and tHbe generally provided concordant indications, tHbi and THIi exhibited opposite-sign changes in a high percentage of cases (VM: 46%; HV: 31%; HUT: 40%). Moreover, tHbi was correlated with THIi only during HV (P < 0.05), not during VM and HUT, while it correlated with PPG in all three maneuvers (P < 0.01). These results evidence that extracranial circulation may markedly affect BL parameters in a high percentage of cases, even during standard clinical tests. Surface plethysmography at the forehead is suggested as complementary monitoring helpful in the interpretation of cerebral NIRS parameters.

  15. Exploring the capability of wireless near infrared spectroscopy as a portable seizure detection device for epilepsy patients. (United States)

    Jeppesen, Jesper; Beniczky, Sándor; Johansen, Peter; Sidenius, Per; Fuglsang-Frederiksen, Anders


    Near infrared spectroscopy (NIRS) has proved useful in measuring significant hemodynamic changes in the brain during epileptic seizures. The advance of NIRS-technology into wireless and portable devices raises the possibility of using the NIRS-technology for portable seizure detection. This study used NIRS to measure changes in oxygenated (HbO), deoxygenated (HbR), and total hemoglobin (HbT) at left and right side of the frontal lobe in 33 patients with epilepsy undergoing long-term video-EEG monitoring. Fifteen patients had 34 focal seizures (20 temporal-, 11 frontal-, 2 parietal-lobe, one unspecific) recorded and analyzed with NIRS. Twelve parameters consisting of maximum increase and decrease changes of HbO, HbR and HbT during seizures (1 min before- to 3 min after seizure-onset) for left and right side, were compared with the patients' own non-seizure periods (a 2-h period and a 30-min exercise-period). In both non-seizure periods 4 min moving windows with maximum overlapping were applied to find non-seizure maxima of the 12 parameters. Detection was defined as positive when seizure maximum change exceeded non-seizure maximum change. When analyzing the 12 parameters separately the positive seizure detection was in the range of 6-24%. The increase in hemodynamics was in general better at detecting seizures (15-24%) than the decrease in hemodynamics (6-18%) (P=0.02). NIRS did not seem to be a suitable technology for generic seizure detection given the device, settings, and methods used in this study. There are still several challenges to overcome before the NIRS-technology can be used as a home-monitoring seizure detection device. Copyright © 2015 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.

  16. Detection of protein deposition within latent fingerprints by surface-enhanced Raman spectroscopy imaging. (United States)

    Song, Wei; Mao, Zhu; Liu, Xiaojuan; Lu, Yong; Li, Zhishi; Zhao, Bing; Lu, Lehui


    The detection of metabolites is very important for the estimation of the health of human beings. Latent fingerprint contains many constituents and specific contaminants, which give much information of the individual, such as health status, drug abuse etc. For a long time, many efforts have been focused on visualizing latent fingerprints, but little attention has been paid to the detection of such substances at the same time. In this article, we have devised a versatile approach for the ultra-sensitive detection and identification of specific biomolecules deposited within fingerprints via a large-area SERS imaging technique. The antibody bound to the Raman probe modified silver nanoparticles enables the binding to specific proteins within the fingerprints to afford high-definition SERS images of the fingerprint pattern. The SERS spectra and images of Raman probes indirectly provide chemical information regarding the given proteins. By taking advantage of the high sensitivity and the capability of SERS technique to obtain abundant vibrational signatures of biomolecules, we have successfully detected minute quantities of protein present within a latent fingerprint. This technique provides a versatile and effective model to detect biomarkers within fingerprints for medical diagnostics, criminal investigation and other fields. This journal is © The Royal Society of Chemistry 2012

  17. LSDCat: Detection and cataloguing of emission-line sources in integral-field spectroscopy datacubes (United States)

    Herenz, Edmund Christian; Wisotzki, Lutz


    We present a robust, efficient, and user-friendly algorithm for detecting faint emission-line sources in large integral-field spectroscopic datacubes together with the public release of the software package Line Source Detection and Cataloguing (LSDCat). LSDCat uses a three-dimensional matched filter approach, combined with thresholding in signal-to-noise, to build a catalogue of individual line detections. In a second pass, the detected lines are grouped into distinct objects, and positions, spatial extents, and fluxes of the detected lines are determined. LSDCat requires only a small number of input parameters, and we provide guidelines for choosing appropriate values. The software is coded in Python and capable of processing very large datacubes in a short time. We verify the implementation with a source insertion and recovery experiment utilising a real datacube taken with the MUSE instrument at the ESO Very Large Telescope. The LSDCat software is available for download at and via the Astrophysics Source Code Library at

  18. Rapid and sensitive detection of rotavirus molecular signatures using surface enhanced Raman spectroscopy.

    Directory of Open Access Journals (Sweden)

    Jeremy D Driskell

    Full Text Available Human enteric virus infections range from gastroenteritis to life threatening diseases such as myocarditis and aseptic meningitis. Rotavirus is one of the most common enteric agents and mortality associated with infection can be very significant in developing countries. Most enteric viruses produce diseases that are not distinct from other pathogens, and current diagnostics is limited in breadth and sensitivity required to advance virus detection schemes for disease intervention strategies. A spectroscopic assay based on surface enhanced