Comparative study of analytical methods by direct and first-derivative UV spectrophotometry for evaluation of losartan potassium in capsules

Directory of Open Access Journals (Sweden)

Rudy Bonfilio

2010-03-01

Full Text Available Losartan potassium is an antihypertensive non-peptide agent, which exerts its action by specific blockade of angiotensin II receptors. The aim of the present study was the validation and application of analytical methods for the quality control of losartan potassium 50 mg in pharmaceutical capsules, using direct and first-derivative UV spectrophotometry. Based on losartan potassium spectrophotometric characteristics, a signal at 205 nm of the zero-order spectrum and a signal at 234 nm of the first-derivative spectrum, were found adequate for quantification. The results were used to compare these instrumental techniques. The linearity between the signals and concentrations of losartan potassium in the ranges of 3.0-7.0 mg L-1 and 6.0-14.0 mg L-1 for direct and first-derivative spectrophotometry in aqueous solutions, respectively, presented a correlation coefficient (r of 0.9999 in both cases. The methods were applied for losartan potassium in capsule dosage obtained from local pharmacies, and were shown to be efficient, easy to apply and low cost. These methods do not use polluting reagents and require relatively inexpensive equipment.O losartano potássico é um agente anti-hipertensivo não peptídico, que exerce sua ação por bloqueio específico dos receptores da angiotensina II. Este trabalho propôs a validação e aplicação de métodos analíticos orientados ao controle de qualidade de losartano potássico 50 mg na forma farmacêutica cápsula, utilizando a espectrofotometria direta e derivada de primeira ordem na região do UV. Baseado nas características espectrofotométricas de losartano potássico, um sinal a 205 nm do espectro de ordem zero e um sinal a 234 nm do espectro de primeira derivada foram adequados para a quantificação. Os resultados foram usados para comparar essas duas técnicas instrumentais. O coeficiente de correlação entre as respostas e as concentrações de losartano potássico na faixa de 3,0-7,0 mg L-1 e 6

UV spectrophotometry of the Metronidazole

Directory of Open Access Journals (Sweden)

O. I. Panasenko

2013-10-01

Full Text Available Objective. The purpose of this research was to study the UV spectrum of Metronidazole in different polarity solvents (water, 95 % ethanol, 0,1 M sodium hydroxide, 0,1 M hydrochloric acid and 5 M sulfuric acid solution, to establish the relationship between chemical structure of the analyzed compounds and the nature of their electronic spectrum. In addition, a detailed study of the ultraviolet spectra of Metronidazole in different solutions enables to select the optimal wavelength and a thinner design for Metronidazole in substance and dosage forms. Materials and methods. Spectrophotometer SPECORD 200-222U214 has been used for study of the UV spectra of Metronidazole, the quantitative methods were used. Measuring of the absorption of Metronidazole solutions has been carried out in quartz cuvettes with a layer thickness of 10 mm. Due to the fact that the test material shows selective absorption in the ultraviolet spectra, model compounds were studied at a concentration of 1 mg%. Study of electronic spectra was performed in the range of 200 to 400 nm, and the curve has been constructed in coordinates A = f (λ. It has been used water, 95% ethanol, 0,1 M NaOH, 0,1 M HCl and 5 M H2SO4 as solvents. The content of Metronidazole in substance and dosage forms calculated with the equations according to SPU. The results. Study of the UV spectra of Metronidazole and its model compounds showed that in short-wave part of spectrum due to absorption and excitation electrons of imidazole ring were transferred, and in long-wave – conjugation chromophore imidazole cycle and nitro group as electron acceptor occurred. Analysis of the UV spectra of Metronidazole enables to determine a maximum of the analytical quantification of the medicine. Conclusions. Metronidazole UV spectra in water, 95% ethanol, 0,1 M solution of NaOH, 0,1 M solution of HCl and 5 M solution of H2SO4 have been studied. Metronidazole UV spectra are characterized by two absorption bands in the

Photochemical reaction monitoring by ultra-violet spectrophotometry.

Science.gov (United States)

Roig, B; Touraud, E; Thomas, O

2002-11-01

Within the framework of the monitoring of the trichloroacetylchloride (TCAC) photosynthesis, ultra-violet (UV) spectrophotometry is proposed as a simple and rapid tool allowing, in real time, the control of the process efficiency. A good correlation has been obtained between the results acquired by this alternative method and the standard gas chromatography.

Spectrophotometry (by Barbara Sawrey and Gabriele Wienhausen)

Science.gov (United States)

Pringle, David L.

1998-08-01

Science Media: San Diego, 1997. 1-10 copies, 99 each; 11-20 copies, 69 each; 21+ copies, $49 each. (Note: CD operates with both Mac and PC.) Spectrophotometry is an interactive CD-ROM which introduces the basics of UV-visible spectrophotometry with some mention of infrared and other forms of spectrophotometry. A Macintosh System 7.5 or higher, CPU 68040 or Power PC processor, 6 megabytes of free RAM, 2.6 megabytes of free disk space, and 4X CD-ROM or faster are required.

A simple and cost-effective method, as an appropriate alternative for visible spectrophotometry: development of a dopamine biosensor.

Science.gov (United States)

Abbaspour, Abdolkarim; Khajehzadeh, Abdolreza; Ghaffarinejad, Ali

2009-08-01

In this study, a new, simple, fast and inexpensive method as an alternative to visible spectrophotometry is developed. In this method the cells containing the sample solution were scanned with a scanner, then the color of each cell was analyzed with software written in visual basic (VB 6) media to red, green and blue values. The cells were built by creating holes in the Plexiglas sheet. The dimensions of identical cells were examined by Cr (III) solution with known concentrations. The validity of this new method was studied by determination of dopamine (DA) without using any other reagent. The parameters which affect the system were optimized. The comparison between the current and traditional UV-Vis spectrophotometry methods was studied and the results revealed similar trends in both methods. The developed method was successfully applied to the determination of dopamine in serum and urine without using any pretreatment. Finally comparing the results obtained in the developed method showed that microwave irradiation of the solution can decrease the experimental time, increase sensitivity and improve the limit of detection.

Chemometrics-assisted spectrophotometry method for the determination of chemical oxygen demand in pulping effluent.

Science.gov (United States)

Chen, Honglei; Chen, Yuancai; Zhan, Huaiyu; Fu, Shiyu

2011-04-01

A new method has been developed for the determination of chemical oxygen demand (COD) in pulping effluent using chemometrics-assisted spectrophotometry. Two calibration models were established by inducing UV-visible spectroscopy (model 1) and derivative spectroscopy (model 2), combined with the chemometrics software Smica-P. Correlation coefficients of the two models are 0.9954 (model 1) and 0.9963 (model 2) when COD of samples is in the range of 0 to 405 mg/L. Sensitivities of the two models are 0.0061 (model 1) and 0.0056 (model 2) and method detection limits are 2.02-2.45 mg/L (model 1) and 2.13-2.51 mg/L (model 2). Validation experiment showed that the average standard deviation of model 2 was 1.11 and that of model 1 was 1.54. Similarly, average relative error of model 2 (4.25%) was lower than model 1 (5.00%), which indicated that the predictability of model 2 was better than that of model 1. Chemometrics-assisted spectrophotometry method did not need chemical reagents and digestion which were required in the conventional methods, and the testing time of the new method was significantly shorter than the conventional ones. The proposed method can be used to measure COD in pulping effluent as an environmentally friendly approach with satisfactory results.

Quality control of test iodine in urine by spectrophotometry UV-Vis

Science.gov (United States)

Huda, Thorikul; Nafisah, Durotun; Kumorowulan, Suryati; Lestari, Sri

2017-12-01

A quality control of iodine test in with UV-Vis spectrophotometry has been done. The purpose of this research is to find out whether the test results of samples conducted by Clinical Office of Research and Development Of GAKI (BP2GAKI) laboratory are still controlled, feasible and reliable, and still consistent over time, as indicated by the control chart. Quality control parameters are linearity, precision, accuracy, limit of detection, and limit of quantification. Based on the quality control that has been done, obtained linearity (r)= -0.9974, the detection limit and the limit of quantitation are respectively 2.26 µg/L and 7.54 µg/L, while the accuracy is calculated by %recovery and precision with value % RSD are 97.4161% and 1.7136% respectively. The quality control of iodine test in urine using the control chart shows excellent or stable results for 30 days and no variation of the results is very different for each day.

Relative bioavailability studies on a locally manufactured aspirin tablets using UV spectrophotometry and HPLC

International Nuclear Information System (INIS)

Kwadzo, Ameko David

2005-11-01

Modern trends in drug analysis require use of less time consuming, efficient, cost effective, fast, reproducible, simple and convenient methods. Two analytical methods were employed for the determination, the UV spectrophotometry and the HPLC. Aspirin, which is rapidly deacetylated to salicylic acid after absorption into the plasma, is excreted in the urine. In determining the salicylic acid concentration in the urine, the absorbance was quantitated by a spectrometer at a wavelength of 540nm. Aspirin formed an amber coloured complex with ferric ions (Trinder’s reagent). The complex, which formed instantaneously at room temperature, was stable. The solution of the complex obeyed Beer’s law at 540nm, the wavelength of maximum absorption of radiation (λmax). Phenol—induced absorbance is quenched by acidifying the reaction mixture with phosphoric acid. An HPLC analytical method was used in determining the free salicylate excreted in the urine. The mobile phase employed is a validated method from the USP- XXII (1990) which consists of water, methanol and glacial acetic acid in the ratio 69: 28: 3 respectively. The chromatographic conditions involved a flow rate of 1.0ml/rnin, wavelength of maximum absorption of 236nrn, stationary phase Spherisorb S5 ODS 1 phase sep column with standard dimensions of 25.0 cm length and 4.6cm diameter and chart recorder speed of 5mm/min. The quality of the reference and the test tablets were assessed by a number of standard tests, which include uniformity of weight, friability, hardness and dissolution that fall within the BP 2000 specification. The observation from the study reveals that the relative bioavailability of aspirin (w.r.t. salicylic acid) were 103.39% and 94.93% for HPLC and UV respectively. The mean cumulative percentage of the drug excreted in both cases were ii .05% and 10.69% for test and reference respectively for HPLC and 76.45% and 80.53% for test and reference respectively for UV analysis. The cumulative amount

Diagnosis of soils polluted by aromatic hydrocarbons; Diagnostic de sols pollues par des hydrocarbures aromatiques polycycliques (HAP) a l'aide de la spectrophotometrie UV

Energy Technology Data Exchange (ETDEWEB)

Crone, M

2000-01-28

Polycyclic aromatic hydrocarbons (PAHs) were produced by many pyrolytic or combustion processes. They were found in soils, often in high concentrations. Remediation of industrial sites contaminated by PAHs requires an initial diagnosis of the pollution. In this perspective, an analytical procedure based on UV spectrophotometry was developed and validated with about 80 soil samples. Different exploitation methods of the samples UV spectra enable to develop simple and rapid characterisation tools. A PAH UV index is proposed for the estimation of global PAH concentration. A more accurate exploitation of the spectra gives an indication on the presence or the absence of some individual PAH like benzo[a]pyrene. A maturity index based on a two wavelength approach constitutes an indicator of the potential evolution of soil contamination in natural conditions. Laboratory methodology was adapted to field analyses and a test kit was designed for this purpose. The test duration is 20 minutes. (author)

Spectrophotometry of Artemisia tridentata to quantitatively determine subspecies

Science.gov (United States)

Richardson, Bryce; Boyd, Alicia; Tobiasson, Tanner; Germino, Matthew

2018-01-01

Ecological restoration is predicated on our abilities to discern plant taxa. Taxonomic identification is a first step in ensuring that plants are appropriately adapted to the site. An example of the need to identify taxonomic differences comes from big sagebrush (Artemisia tridentata). This species is composed of three predominant subspecies occupying distinct environmental niches, but overlap and hybridization are common in ecotones. Restoration of A. tridentata largely occurs using wildland collected seed, but there is uncertainty in the identification of subspecies or mix of subspecies from seed collections. Laboratory techniques that can determine subspecies composition would be desirable to ensure that subspecies match the restoration site environment. In this study, we use spectrophotometry to quantify chemical differences in the water-soluble compound, coumarin. Ultraviolet (UV) absorbance of A. tridentata subsp. vaseyana showed distinct differences among A.t. tridentata and wyomingensis. No UV absorbance differences were detected between A.t. tridentata and wyomingensis. Analyses of samples from > 600 plants growing in two common gardens showed that UV absorbance was unaffected by environment. Moreover, plant tissues (leaves and seed chaff) explained only a small amount of the variance. UV fluorescence of water-eluted plant tissue has been used for many years to indicate A.t. vaseyana; however, interpretation has been subjective. Use of spectrophotometry to acquire UV absorbance provides empirical results that can be used in seed testing laboratories using the seed chaff present with the seed to certify A. tridentata subspecies composition. On the basis of our methods, UV absorbance values 3.1 would indicate either A.t. tridentata or wyomingensis. UV absorbance values between 2.7 and 3.1 would indicate a mixture of A.t. vaseyana and the other two subspecies.

The UV-VIS spectrophotometry applied to color and stability study in colored mortars

Directory of Open Access Journals (Sweden)

Alejandre, F. J.

1999-06-01

Full Text Available In the field of methodologies for color studying, a research of it has been done on colored mortars by applying uv-vis spectrophotometry, instrumental technique which can be used for solid materials works, and previously applied to building materials study. Results obtained show that the mentioned technique permits to evaluate quantitatively and qualitatively colors in an easy and objective way, besides nowadays advantages of the instrumental analysis: digital color register, computerized data processing, and precision and exactness increment in chromatic comparisons.

Dentro de las metodologías existentes para el estudio del color, se ha realizado una investigación del mismo en morteros coloreados por medio de la espectrofotometría UV-VIS, técnica instrumental que es adaptable al trabajo con materiales sólidos, y que ha sido aplicada anteriormente en el estudio de diversos materiales de construcción. Los resultados obtenidos muestran cómo la citada técnica permite además de evaluar cualitativamente y cuantitativamente los colores de forma sencilla y objetiva, el disponer de las ventajas que conlleva actualmente el análisis instrumental: registro digital del color, tratamiento informatizado de datos y aumento de precisión y exactitud en las comparaciones cromáticas.

Diagnosis of soils polluted by aromatic hydrocarbons; Diagnostic de sols pollues par des hydrocarbures aromatiques polycycliques (HAP) a l'aide de la spectrophotometrie UV

Energy Technology Data Exchange (ETDEWEB)

Crone, M.

2000-01-28

Polycyclic aromatic hydrocarbons (PAHs) were produced by many pyrolytic or combustion processes. They were found in soils, often in high concentrations. Remediation of industrial sites contaminated by PAHs requires an initial diagnosis of the pollution. In this perspective, an analytical procedure based on UV spectrophotometry was developed and validated with about 80 soil samples. Different exploitation methods of the samples UV spectra enable to develop simple and rapid characterisation tools. A PAH UV index is proposed for the estimation of global PAH concentration. A more accurate exploitation of the spectra gives an indication on the presence or the absence of some individual PAH like benzo[a]pyrene. A maturity index based on a two wavelength approach constitutes an indicator of the potential evolution of soil contamination in natural conditions. Laboratory methodology was adapted to field analyses and a test kit was designed for this purpose. The test duration is 20 minutes. (author)

Headspace single-drop microextraction coupled to microvolume UV-vis spectrophotometry for iodine determination

International Nuclear Information System (INIS)

Pena-Pereira, Francisco; Lavilla, Isela; Bendicho, Carlos

2009-01-01

Headspace single-drop microextraction has been combined with microvolume UV-vis spectrophotometry for iodine determination. Matrix separation and preconcentration of iodide following in situ volatile iodine generation and extraction into a microdrop of N,N'-dimethylformamide is performed. An exhaustive characterization of the microextraction system and the experimental variables affecting iodine generation from iodide was carried out. The procedure employed consisted of exposing 2.5 μL of N,N'-dimethylformamide to the headspace of a 10 mL acidic (H 2 SO 4 2 mol L -1 ) aqueous solution containing 1.7 mol L -1 Na 2 SO 4 for 7 min. Addition of 1 mL of H 2 O 2 1 mol L -1 for in situ iodine generation was performed. The limit of detection was determined as 0.69 μg L -1 . The repeatability, expressed as relative standard deviation, was 4.7% (n = 6). The calibration working range was from 5 to 200 μg L -1 (r 2 = 0.9991). The large preconcentration factor obtained, ca. 623 in only 7 min, compensate for the 10-fold loss in sensitivity caused by the decreased optical path, which results in improved detection limits as compared to spectrophotometric measurements carried out with conventional sample cells. The method was successfully applied to the determination of iodine in water, pharmaceutical and food samples

Antioxidant study of quercetin and their metal complex and determination of stability constant by spectrophotometry method.

Science.gov (United States)

Ravichandran, R; Rajendran, M; Devapiriam, D

2014-03-01

Quercetin found chelate cadmium ions, scavenge free radicals produced by cadmium. Hence new complex, quercetin with cadmium was synthesised, and the synthesised complex structures were determined by UV-vis spectrophotometry, infrared spectroscopy, thermogravimetry and differential thermal analysis techniques (UV-vis, IR, TGA and DTA). The equilibrium stability constants of quercetin-cadmium complex were determined by Job's method. The determined stability constant value of quercetin-cadminum complex at pH 4.4 is 2.27×10(6) and at pH 7.4 is 7.80×10(6). It was found that the quercetin and cadmium ion form 1:1 complex in both pH 4.4 and pH 7.4. The structure of the compounds was elucidated on the basis of obtained results. Furthermore, the antioxidant activity of the free quercetin and quercetin-cadmium complexes were determined by DPPH and ABTS assays. Copyright © 2013 Elsevier Ltd. All rights reserved.

Evolution of Instrumentation for UV-Visible Spectrophotometry. Part I.

Science.gov (United States)

Altemose, Ines R.

1986-01-01

Traces the development of instruments used in spectrophotometry. Discusses how spectrophotometric measurements are made. Describes the color comparator, the filter photometer, and the spectrophotometer. Outlines the evolution of optical systems, including light sources, the monochromator, the photodetector, double-beam optics, and split-beam…

Atomic-fluorescence spectrophotometry

International Nuclear Information System (INIS)

Bakhturova, N.F.; Yudelevich, I.G.

1975-01-01

Atomic-fluorescence spectrophotometry, a comparatively new method for the analysis of trace quantities, has developed rapidly in the past ten years. Theoretical and experimental studies by many workers have shown that atomic-fluorescence spectrophotometry (AFS) is capable of achieving a better limit than atomic absorption for a large number of elements. The present review examines briefly the principles of atomic-fluorescence spectrophotometry and the types of fluorescent transition. The excitation sources, flame and nonflame atomizers, used in AFS are described. The limits of detection achieved up to the present, using flame and nonflame methods of atomization are given

Monitoring Pb in Aqueous Samples by Using Low Density Solvent on Air-Assisted Dispersive Liquid-Liquid Microextraction Coupled with UV-Vis Spectrophotometry.

Science.gov (United States)

Nejad, Mina Ghasemi; Faraji, Hakim; Moghimi, Ali

2017-04-01

In this study, AA-DLLME combined with UV-Vis spectrophotometry was developed for pre-concentration, microextraction and determination of lead in aqueous samples. Optimization of the independent variables was carried out according to chemometric methods in three steps. According to the screening and optimization study, 86 μL of 1-undecanol (extracting solvent), 12 times syringe pumps, pH 2.0, 0.00% of salt and 0.1% DDTP (chelating agent) were chosen as the optimum independent variables for microextraction and determination of lead. Under the optimized conditions, R = 0.9994, and linearity range was 0.01-100 µg mL -1 . LOD and LOQ were 3.4 and 11.6 ng mL -1 , respectively. The method was applied for analysis of real water samples, such as tap, mineral, river and waste water.

Preparation of Dry Extract of Mikania glomerata Sprengel (Guaco and Determination of Its Coumarin Levels by Spectrophotometry and HPLC-UV

Directory of Open Access Journals (Sweden)

Maria da Penha Henriques do Amaral

2012-08-01

Full Text Available Guaco (Mikania glomerata Sprengel syrup is one of the most popular herbal medicines used to treat the symptoms of asthmatic bronchitis, cough and hoarseness. The coumarin 2H-1-benzopyran-2-one, is one of the major constituents of Guaco and contributes to its pharmacological effects. The pharmaceutical capsule form of dry extract of Guaco is recommended by the Brazilian Program of Medicinal Plants and Herbal Medicines and used in primary health care. In order to identify a new protocol to obtain the raw material for Guaco capsule production we evaluated two methods, including a freeze-drying process (lyophilization and the spray-dryer technique, as well as the use of two adjuvants, Maltodextrins and Aerosil^®, in different concentrations. The coumarin levels of the dried extracts were analyzed by UV-spectrophotometry and HPLC-UV/DAD. The adjuvant Aerosil^® 8% showed better dry powder physical appearance. Lyophilization was observed to be the best process to obtain the dry extract of Guaco based on the measured coumarin levels.

Ionic Liquid Dispersive Liquid-Liquid Microextraction Method for the Determination of Irinotecan, an Anticancer Drug, in Water and Urine Samples Using UV-Vis Spectrophotometry.

Science.gov (United States)

Uysal, Deniz; Karadaş, Cennet; Kara, Derya

2017-05-01

A new, simple, efficient, and environmentally friendly ionic liquid dispersive liquid-liquid microextraction method was developed for the determination of irinotecan, an anticancer drug, in water and urine samples using UV-Vis spectrophotometry. The ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate was used as the extraction solvent, and ethanol was used as the disperser solvent. The main parameters affecting the extraction efficiency, including sample pH, volume of the ionic liquid, choice of the dispersive solvent and its volume, concentration of NaCl, and extraction and centrifugation times, were investigated and optimized. The effect of interfering species on the recovery of irinotecan was also examined. Under optimal conditions, the LOD (3σ) was 48.7 μg/L without any preconcentration. Because the urine sample was diluted 10-fold, the LOD for urine would be 487 μg/L. However, this could be improved 16-fold if preconcentration using a 40 mL aliquot of the sample is used. The proposed method was successfully applied to the determination of irinotecan in tap water, river water, and urine samples spiked with 10.20 mg/L for the water samples and 8.32 mg/L for the urine sample. The average recovery values of irinotecan determined were 99.1% for tap water, 109.4% for river water, and 96.1% for urine.

Free radicals in irradiated unstabilized polypropylene, as seen by diffuse reflection absorption-spectrophotometry

International Nuclear Information System (INIS)

Zagorski, Z.P.; Rafalski, A.

1998-01-01

The introduction of UV-Vis absorption spectrophotometry to the study of radiation chemistry of polymers has opened the possibility to investigate even very opaque samples. The virgin powder polypropylene, as obtained from the industrial production line, shows after irradiation unstable products of radiolysis. Until now they were investigated mainly by EPR method. Optical absorption spectra (by diffuse reflection spectrophotometry) contribute to better identification and study of changes in time, temperature and diffusion of reactive gases. Studying the formation of stable compounds, which do not produce EPR signal, we are able to examine these species on the basis of their electronic spectra. The most important results concern the peroxides in irradiated polypropylene

Contribution to Casein Determination by UV Spectrophotometry

Directory of Open Access Journals (Sweden)

Stefanescu Raluca

2017-12-01

Full Text Available In the present paper, the interaction between copper ions and proteins is presented, in order to elaborate a simple and rapid spectrophotometric assay of casein in milk. Under alkaline conditions, copper ions form the biuret complex with the proteins, which can be used in protein determination. Although very specific, the biuret method is less sensitive. Using insoluble copper phosphate, casein is able to extract copper ions, with which it forms the biuret complex, while either the complex or copper ions could be determined in the ultraviolet range. Indeed, an increased absorbance of biuret complex at 215 nm was found. Nevertheless, copper ions can be determined in UV as well, their concentration being proportional to that of casein. When used tetraglycine instead casein, mass spectrometric measurements at pH higher than 11 revealed the formation of complexes with many copper ions bound to each peptide bond-containing molecule. Nevertheless, on diluting the biuret solution the complex may dissociate leading to very complex UV spectra that should be further studied.

UV-visible scanning spectrophotometry and chemometric analysis as tools for carotenoids analysis in cassava genotypes (Manihot esculenta Crantz).

Science.gov (United States)

Moresco, Rodolfo; Uarrota, Virgílio G; Pereira, Aline; Tomazzoli, Maíra; Nunes, Eduardo da C; Martins Peruch, Luiz Augusto; Gazzola, Jussara; Costa, Christopher; Rocha, Miguel; Maraschin, Marcelo

2015-12-01

In this study, the metabolomics characterization focusing on the carotenoid composition of ten cassava (Manihot esculenta) genotypes cultivated in southern Brazil by UV-visible scanning spectrophotometry and reverse phase-high performance liquid chromatography was performed. Cassava roots rich in β-carotene are an important staple food for populations with risk of vitamin A deficiency. Cassava genotypes with high pro-vitamin A activity have been identified as a strategy to reduce the prevalence of deficiency of this vitamin. The data set was used for the construction of a descriptive model by chemometric analysis. The genotypes of yellow-fleshed roots were clustered by the higher concentrations of cis- β-carotene and lutein. Inversely, cream-fleshed roots genotypes were grouped precisely due to their lower concentrations of these pigments, as samples rich in lycopene (redfleshed) differed among the studied genotypes. The analytical approach (UV-Vis, HPLC, and chemometrics) used showed to be efficient for understanding the chemodiversity of cassava genotypes, allowing to classify them according to important features for human health and nutrition.

Study of kinetics of the tetroxane thermolysis by UV spectrophotometry

International Nuclear Information System (INIS)

Jorge, N.L.; Leiva, L.C.; Castellanos, M.G.; Cafferata, L.F.R.; Gomez V, M.E.

2002-01-01

The 3,3,6,6-tetramethyl-1,2,4,5-tetroxane (ACDP) in methanol solution shows an absorbance peak at low wave length in UV spectrum and follows the Lambert Beer law until 10-2 M concentration at 209 nm. The ACDP thermal decomposition have been studied by the UV spectroscopy like an alternative method to find out the kinetic parameters from the thermolysis of these compounds. The rate constants at the temperatures and initial concentration ranges of 130-166 and 0,003-0,013 mol / L, respectively, and the activation parameters were similar to the corresponding values found by other methodology, verifying this analytic technique. Acetone produced during reaction no interference in ACDP quantification by UV analysis. (Author)

Estratégias para aumento de sensibilidade em espectrofotometria UV-VIS Strategies to increase sensitivity in UV-VIS spectrophotometry

Directory of Open Access Journals (Sweden)

Fábio R. P. Rocha

2004-10-01

Full Text Available Spectrophotometry is one of the most widespread analytical techniques due to its simplicity, reliability, and low-cost instrumentation for both direct measurements and coupled to other techniques or processes such as chromatography, electrophoresis and flow analysis. However, the application is often limited by sensitivity. This article describes some advances that greatly improve the performance of spectrophotometric measurements, especially in order to increase sensitivity, including the employment of liquid-core waveguides and solid-phase spectrophotometry.

Determination of piroxicam in pharmaceutical preparations by ultraviolet direct spectrophotometry, ultraviolet difference spectrophotometry and high performance liquid chromatography

Energy Technology Data Exchange (ETDEWEB)

Hackmann, E.R.M.; Santos Gianotto, E.A. dos; Miritello Santoro, M.I.R. (Universidade de Sao Paulo (Brazil))

1993-02-01

Piroxicam in pharmaceutical preparations (capsules (C), tablets (T), oral drops (OD), suppositories (S) and simulated sample (SS)) was determined by UV direct spectrophotometry (UVS) at 333 nm, by UV difference spectrophotometry (UVDS) at 327 nm, and in C and T, by high performance liquid chromatography (HPLC). For UVS, Beer's law was obeyed in the range 3.0-8.5 [mu]g/mL. The coefficient of correlation (CC), absolute precision (AP) and relative precision (RP) were 0.9999, 0.02 and 0.33%, respectively. The coefficient of variation (CV) for C, T, OD, S and SS were 0.48%, 0.35%, 0.48% and 0.19%, respectively. The recovery average (RA) was 100.22%. For UVDS, Beer's law was obeyed in the range 5.0-15.0 [mu]g/mL. The CC, AP and RP were respectively 0.9999, 0.05 and 0.47%. The CV for C, T, OD, S and SS were 0.64%, 0.84%, 0.62%, 0.54% and 0.15%, respectively. The RA was 99.02%. In HPLC determination, a LiChrospher[reg sign] 100 RP-18 (5 [mu]m) in LiChroCART[reg sign] 125-4 column at ambient temperature with a mobile phase consisting of methanol: (buffer solution citric acid-dibasic sodium phosphate pH 3.0) (55:45) and UV detection at 254 nm enabled the determination of piroxicam in C and T. The response peak area versus concentration presented linearity in the range 10.0-100.0 [mu]g/mL. The CC, AP and RP were 0.9997, 0.45 and 0.90%, respectively. The CV was 0.51%-0.82% and the RA, 97.13%. 14 refs., 1 fig., 5 tabs.

Simple spectrophotometry method for the determination of sulfur dioxide in an alcohol-thionyl chloride reaction

Energy Technology Data Exchange (ETDEWEB)

Zheng, Jinjian, E-mail: jinjian.zheng@merck.com; Tan, Feng; Hartman, Robert

2015-09-03

Thionyl chloride is often used to convert alcohols into more reactive alkyl chloride, which can be easily converted to many compounds that are not possible from alcohols directly. One important reaction of alkyl chloride is nucleophilic substitution, which is typically conducted under basic conditions. Sulfur dioxide, the by-product from alcohol-thionyl chloride reactions, often reacts with alkyl chloride to form a sulfonyl acid impurity, resulting in yield loss. Therefore, the alkyl chloride is typically isolated to remove the by-products including sulfur dioxide. However, in our laboratory, the alkyl chloride formed from alcohol and thionyl chloride was found to be a potential mutagenic impurity, and isolation of this compound would require extensive safety measures. As a result, a flow-through process was developed, and the sulfur dioxide was purged using a combination of vacuum degassing and nitrogen gas sweeping. An analytical method that can quickly and accurately quantitate residual levels of sulfur dioxide in the reaction mixture is desired for in-process monitoring. We report here a simple ultraviolet (UV) spectrophotometry method for this measurement. This method takes advantage of the dramatic change in the UV absorbance of sulfur dioxide with respect to pH, which allows for accurate quantitation of sulfur dioxide in the presence of the strong UV-absorbing matrix. Each sample solution was prepared using 2 different diluents: 1) 50 mM ammonium acetate in methanol +1% v/v hydrochloric acid, pH 1.3, and 2) 50 mM ammonium acetate in methanol +1% glacial acetic acid, pH 4.0. The buffer solutions were carefully selected so that the UV absorbance of the sample matrix (excluding sulfur dioxide) at 276 nm remains constant. In the pH 1.3 buffer system, sulfur dioxide shows strong UV absorbance at 276 nm. Therefore, the UV absorbance of sample solution is the sum of sulfur dioxide and sample matrix. While in the pH 4.0 buffer system, sulfur dioxide has

Flare activity on UV CETI: visible and IUE observations

International Nuclear Information System (INIS)

Phillips, K.J.H.; Bromage, G.E.; Dufton, P.L.; Keenan, F.P.; Kingston, A.E.

1988-06-01

Simultaneous far-ultraviolet (IUE) spectroscopy and optical photometry and spectrophotometry of a flare on UV Ceti are reported. The flare reached ΔU = 2sup(m) but showed only modest enhancements in the IUE spectra. The optical spectrophotometry indicated broadened Balmer line profiles during the flare, with Hβ and Hγ clearly showing red wings. The results are compared with other IUE and optical observations of UV Ceti, and their solar analogues. (author)

Flare activity on UV Ceti: visible and IUE observations

International Nuclear Information System (INIS)

Phillips, K.J.H.; Bromage, G.E.; Dufton, P.L.; Keenan, F.P.; Kingston, A.E.

1988-01-01

Simultaneous far-ultraviolet (IUE) spectroscopy and optical photometry and spectrophotometry of a flare on UV Ceti are reported. The flare reached ΔU=2 mag but showed only modest enhancements in the IUE spectra. The optical spectrophotometry indicated broadened Balmer line profiles during the flare, with Hβ and Hγ clearly showing red wings (∼ 100 km s -1 ). The results are compared with other IUE and optical observations of UV Ceti, and their solar analogues. (author)

Simultaneous determination of polysaccharides and 21 nucleosides and amino acids in different tissues of Salvia miltiorrhiza from different areas by UV-visible spectrophotometry and UHPLC with triple quadrupole MS/MS.

Science.gov (United States)

Xiang, Xiang; Sha, Xiuxiu; Su, Shulan; Zhu, Zhenhua; Guo, Sheng; Yan, Hui; Qian, Dawei; Duan, Jin-Ao

2018-03-01

Salvia miltiorrhiza, a traditional Chinese medicine, is a widely used herbal medicine to treat cardiovascular and cerebrovascular diseases. In this study, ultraviolet (UV)-visible spectrophotometry and ultra-high performance liquid chromatography with triple quadrupole tandem mass spectrometry analytical methods were used for rapid quantification of polysaccharides and 21 nucleosides and amino acids in S. miltiorrhiza to determine 17 samples of different tissues from different areas. Based on the total contents, hierarchical clustering analysis and principal components analysis were performed to classify these samples. The established methods were validated with good linearity, precision, repeatability, stability, and recovery. Chemical analysis revealed a higher content of total analytes in the sample of inflorescence from Nanjing (34.17 mg/g), sample of root and rhizome from Shaanxi (34.13 mg/g) and sample of stem and leaf from Nanjing (31.14 mg/g), respectively, indicating that root and rhizome from Shaanxi and the aerial parts from Nanjing exhibited the highest quality due to their highest content. In addition, contents of nucleosides and amino acids in the aerial parts (14.67 mg/g) were much higher than that in roots and rhizomes (9.17 mg/g). This study suggested that UV-visible spectrophotometry and ultra-high performance liquid chromatography with triple quadrupole tandem mass spectrometry are effective techniques to analyze polysaccharides, nucleosides, and amino acids in plants, and they provided valuable information for the development and utilization value of the aerial parts of S. miltiorrhiza. This analysis would also provide useful information for the quality control of S. miltiorrhiza. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Application of UV-Vis spectrophotometric and chemiluminescent methods for the evaluation of the antioxidant action of curcumin

Czech Academy of Sciences Publication Activity Database

Stanchev, Stancho; Pencheva, I.; Konstantinov, S.; Obreshkova, D.; Hadjimitova, V.

2012-01-01

Roč. 77, č. 8 (2012), s. 1063-1069 ISSN 0352-5139 Institutional research plan: CEZ:AV0Z40550506 Keywords : curcumin * antioxidant * UV-Vis spectrophotometry * DNA complexation * chemiluminescence Subject RIV: CC - Organic Chemistry Impact factor: 0.912, year: 2012

Quantification of naphazoline nitrate by UV-spectrophoto-metry

Directory of Open Access Journals (Sweden)

O. I. Panasenko

2013-12-01

Full Text Available One of the main tasks of pharmaceutical chemistry – medical drugs study. Spectrophotometry is widely used in studying of the structure and composition (complexes, dyes, analytical reagents, etc. of various compounds. It widely used for qualitative and quantitative determination of substances (determination of elements traces in metals, alloys, technical facilities. The dependence between substance structure and its electronic spectrum is being studied by many researchers till nowadays. The aim of this work was to highlight the issues of naphazoline quantify definition techniques by the UV-spectrophotometry. According to the existing methods of quality control (MQC, naphazoline nitrate is a substance quantitatively determined by acid-base titration among a mixture of anhydrous acetic acid and acetic anhydride. Titration is carried out with a solution of 0,1 M perchloric acid (indicator - crystal violet. To check the quality of nasal drops nafazoline nitrate MQC is recommended UV-spectrophotometry: drug is dissolved in boric acid solution (20 g/l as the reference solution used solution pharmacopoeia standard sample substance nafazoline nitrate. The character of UV-spectra of the nafazoline nitrate in solvents of different polarity (water, 95% ethanol, 0,1 M NaOH, 0,1 M HCl, 5M H2SO4, was defined and studied. Standard sample of nafazoline nitrate was obtained from the State Enterprise "Scientific and Expert Pharmacopoeia Centre Ukraine". In order to study UV-spectra nafazoline nitrate spectrophotometer SPECORD 200-222U214 (Germany was used. UV-spectrum of nafazoline nitrate in water and 95% ethanol are characterized by two maxima at 270 and 280 nm. Absorption band of nafazoline nitrate in 0, 1 M sodium hydroxide has two maxima at 271 and 280 nm, and in 0, 1 M solution of hydrochloric acid and 5 M solution of sulfuric acid maxima coincide with the maxima spectrum of the drug in water, 95% ethanol. In order to avoid errors associated with

UV/VIS spektrofotometrie a možnosti jejího využití v rámci vzdělávání učitelů chemie

OpenAIRE

Hejsková, Veronika

2016-01-01

This master's thesis discusses the use of UV/VIS spectrophotometry in chemistry teacher education. Optical methods principles are described in theoretical part of the thesis, and. the main part is dedicated to UV-VIS spectrophotometry. Tasks for quantifying and qualifying substances determination are described in experimental part. Educational tasks are described in a way so that chemistry teachers could use for instructions.

All-Optical Method to Assess Stromal Concentration of Riboflavin in Conventional and Accelerated UV-A Irradiation of the Human Cornea.

Science.gov (United States)

Lombardo, Giuseppe; Micali, Norberto Liborio; Villari, Valentina; Serrao, Sebastiano; Lombardo, Marco

2016-02-01

We investigated the concentration of riboflavin in human donor corneas during corneal cross-linking using two-photon optical microscopy and spectrophotometry. Eight corneal tissues were de-epithelialized and soaked with 20% dextran-enriched 0.1% riboflavin solution for 30 minutes. After stromal soaking, three tissues were irradiated using a 3 mW/cm2 UV-A device for 30 minutes and three tissues irradiated using a 10 mW/cm2 device for 9 minutes. Two additional tissues were used as positive controls. A Ti:sapphire laser at 810 nm was used to perform two-photon emission fluorescence (TPEF) and second harmonic generation axial scanning measurements in all specimens before and after stromal soaking and after UV-A irradiation. In addition, spectrophotometry was used to collect the absorbance spectra of each tissue at the same time intervals. Analysis of the absorbance spectra and TPEF signals provided measures of the concentration depth profile of riboflavin in corneal stroma. After stromal soaking, the average peak concentration of riboflavin (0.020% ± 0.001%) was found between a stromal depth of 100 and 250 μm; the concentration of riboflavin was almost constant up to 320 ± 53 μm depth, then decreased toward the endothelium, though riboflavin was still enriched in the posterior stroma (0.016%% ± 0.001%). After conventional and accelerated UV-A irradiation, the concentration of riboflavin decreased uniformly 87% ± 2% and 67% ± 3% (P riboflavin in corneal stroma. The method can assist with the assessment of novel riboflavin formulations and different UV-A irradiation protocols.

Application of response surface methodology for determination of methyl red in water samples by spectrophotometry method.

Science.gov (United States)

Khodadoust, Saeid; Ghaedi, Mehrorang

2014-12-10

In this study a rapid and effective method (dispersive liquid-liquid microextraction (DLLME)) was developed for extraction of methyl red (MR) prior to its determination by UV-Vis spectrophotometry. Influence variables on DLLME such as volume of chloroform (as extractant solvent) and methanol (as dispersive solvent), pH and ionic strength and extraction time were investigated. Then significant variables were optimized by using a Box-Behnken design (BBD) and desirability function (DF). The optimized conditions (100μL of chloroform, 1.3mL of ethanol, pH 4 and 4% (w/v) NaCl) resulted in a linear calibration graph in the range of 0.015-10.0mgmL(-1) of MR in initial solution with R(2)=0.995 (n=5). The limits of detection (LOD) and limit of quantification (LOQ) were 0.005 and 0.015mgmL(-1), respectively. Finally, the DLLME method was applied for determination of MR in different water samples with relative standard deviation (RSD) less than 5% (n=5). Copyright © 2014 Elsevier B.V. All rights reserved.

Application of response surface methodology for determination of methyl red in water samples by spectrophotometry method

Science.gov (United States)

Khodadoust, Saeid; Ghaedi, Mehrorang

2014-12-01

In this study a rapid and effective method (dispersive liquid-liquid microextraction (DLLME) was developed for extraction of methyl red (MR) prior to its determination by UV-Vis spectrophotometry. Influence variables on DLLME such as volume of chloroform (as extractant solvent) and methanol (as dispersive solvent), pH and ionic strength and extraction time were investigated. Then significant variables were optimized by using a Box-Behnken design (BBD) and desirability function (DF). The optimized conditions (100 μL of chloroform, 1.3 mL of ethanol, pH 4 and 4% (w/v) NaCl) resulted in a linear calibration graph in the range of 0.015-10.0 mg mL-1 of MR in initial solution with R2 = 0.995 (n = 5). The limits of detection (LOD) and limit of quantification (LOQ) were 0.005 and 0.015 mg mL-1, respectively. Finally, the DLLME method was applied for determination of MR in different water samples with relative standard deviation (RSD) less than 5% (n = 5).

Determination of gadolinium by the method of derivative spectrophotometry

International Nuclear Information System (INIS)

Aleksandrova, N.N.; Mishchenko, V.T.; Poluehktov, N.S.; Mukomel', V.L.

1988-01-01

Technique for gadolinium determination at the presence of interfering rare earth elements, which is based on the derivative spectrophotometry method, is suggested. The technique is of increased selectivity and allows to determine gadolinium in the mixtures with elements, which presence in solution makes impossible to determine gadolinium directly. At binary mixtures analysis Sr relative standard deviation does not exceed 0.03, while at the analysis of more complex mixtures Sr increases up to 0.06

ANALISA FLAVONOID DARI EKSTRAK ETANOL 96% KULIT BUAH OKRA MERAH (Abelmoschus esculentus L. Moench SECARA KROMATOGRAFI LAPIS TIPIS DAN SPEKTROFOTOMETRI UV-VIS

Directory of Open Access Journals (Sweden)

Nia Lisnawati

2016-03-01

Full Text Available Has done research on flavonoids Analysis of Ethanol Extract 96% Fruit Leather Red Okra In Thin Layer Chromatography and Spectrophotometer UV-Vis. The purpose of this study was to analyze the content of the fruit skin red okra (Abelmoschus esculentus L. Moench by using the method of thin layer chromatography (TLC under UV light and spectrophotometry UV-Vis. Reference standards used in this study is the Standard Solution Routine Quercetin. The results of the research that has been done by the method of thin layer chromatography obtained Rf values of 0.81 and produces the color orange. And the results of research conducted by spectrophotometry UV-Vis method obtained 333,117 mg.L-1 or 421,629 mg.kg-1 or 0,84339 %. The conclusion from this study is that the 96% ethanol extract of the fruit leather red okra (Abelmoschus esculentus L. Moench positive (+ contains flavonoids with levels of 0,84339 %.

Evaluation of clinoptilolite for removal of ammoniacal nitrogen produced in aquaculture by Neutron activation analysis and UV-VIS spectrophotometry

International Nuclear Information System (INIS)

Bibiano C, L.; Iturbe G, J.L.; Lopez M, B.E.; Martinez M, V.

1997-01-01

In fish culture system, ammonia is excreted in the water as a metabolic by-product. In this work, sorption properties of clinoptilolite were determined and it was applied in culture of the rainbow trout Oncorhynchus mykiss for the removal of the ammoniacal nitrogen. The original clinoptilolite was treated with 1N NaCl solution from 24 to 192 h, for exchange NH 4 ions produced in fish culture. The content of Na in the clinoptilolite was determined by neutron activation analysis. The ammonium ion content in the exchange was analysed by UV-VIS spectrophotometry. Maximum uptake of sodium was reached between 24 and 48 hours at neutral pH with granules of the clinoptilolite from 14 to 24 mesh size. The adsorption capacity was from 3.28 to 6.8 mg of ammonium per gram of clinoptilolite. (Author)

Hydride generation coupled to microfunnel-assisted headspace liquid-phase microextraction for the determination of arsenic with UV-Vis spectrophotometry.

Science.gov (United States)

Hashemniaye-Torshizi, Reihaneh; Ashraf, Narges; Arbab-Zavar, Mohammad Hossein

2014-12-01

In this research, a microfunnel-assisted headspace liquid-phase microextraction technique has been used in combination with hydride generation to determine arsenic (As) by UV-Vis spectrophotometry. The method is based on the reduction of As to arsine (AsH3) in acidic media by sodium tetrahydroborate (NaBH4) followed by its subsequent reaction with silver diethyldithiocarbamate (AgDDC) to give an absorbing complex at 510 nm. The complexing reagent (AgDDC) has been dissolved in a 1:1 (by the volume ratio) mixture of chloroform/chlorobenzene microdroplet and exposed to the generated gaseous arsine via a reversed microfunnel in the headspace of the sample solution. Several operating parameters affecting the performance of the method have been examined and optimized. Acetonitrile solvent has been added to the working samples as a sensitivity enhancement agent. Under the optimized operating conditions, the detection limit has been measured to be 0.2 ng mL(-1) (based on 3sb/m criterion, n b = 8), and the calibration curve was linear in the range of 0.5-12 ng mL(-1). The relative standard deviation for eight replicate measurements was 1.9 %. Also, the effects of several potential interferences have been studied. The accuracy of the method was validated through the analysis of JR-1 geological standard reference material. The method has been successfully applied for the determination of arsenic in raw and spiked soft drink and water samples with the recoveries that ranged from 91 to 106 %.

Analysis of nifedipine content in transdermal drug delivery system using non-destructive visible spectrophotometry technique

International Nuclear Information System (INIS)

Normaizira Hamidi; Normaizira Hamidi; Normaizira Hamidi; Mohd Nasir Taib; Mohd Nasir Taib; Wui, Wong Tin; Wui, Wong Tin

2008-01-01

The applicability of visible spectrophotometry technique as a tool to determine the drug content of polymeric film for use as a transdermal drug delivery system was investigated. Hydroxypropylmethycellulose (HPMC) was selected as the matrix polymer and nifedipine as the model drug. Blank and nifedipine-loaded HPMC films were prepared using the solvent evaporation method. The absorbance spectra of these films under the visible wavelengths between 400 and 800 nm were assessed and compared against the drug content values obtained by means of the conventional destructive UV- spectrophotometry technique. The latter required the use of a solvent system which contained methanol, a harmful organic component in pharmaceutical applications. The results indicated that the absorbance values, attributed to nifedipine, at the wavelengths of 545, 585, 638 and 755nm were significantly correlated to the drug content values obtained using the chemical assay method (Pearson correlation value: r = 0.990 and p < 0.01). The visible spectrophotometry technique is potentially suitable for use to determine the nifedipine content of films owing to its nature of characterization of transdermal drug delivery system which does not require sample destruction during the process of measurement. The samples are recoverable from test and analysis of the entire batch of samples is possible without the need of solvents and chemical reagents. (author)

Derivative spectrophotometry of cobalt alloys

International Nuclear Information System (INIS)

Spitsyn, P.K.

1985-01-01

The method of derivative spectrophotometry is briefly described, and derivative absorption spectra are presented for samarium, cobalt, and commercial Sm-Co alloys. It is shown that the use of derivative spectrophotometry not only improves the accuracy and selectivity of element determinations but also simplifies the analysis of alloys. Results of a statistical evaluation of the metrological characteristics of the analytical procedure described here are presented. 8 references

Determination of losartan potassium, quinapril hydrochloride and hydrochlorothiazide in pharmaceutical preparations using derivative spectrophotometry and chromatographic-densitometric method.

Science.gov (United States)

Stolarczyk, Mariusz; Maślanka, Anna; Apola, Anna; Krzek, Jan

2013-01-01

Two methods, spectrophotometric and chromatographic-densitometric ones, were developed for determination of losartan potassium, quinapril hydrochloride and hydrochlorothiazide in pharmaceutical preparations. Spectrophotometric method involved derivative spectrophotometry and zero order spectrophotometry. The measurements were carried out at lambda = 224.0 nm for quinapril, lambda = 261.0 nm for hydrochlorothiazide and lambda = 270.0 nm for losartan when the derivative spectrophotometry was applied and lambda = 317.0 nm when zero order spectrophotometry was applied for the determination of hydrochlorothiazide. In chromatographic-densitometric studies high performance thin layer chromatography (HPTLC) plates were used as stationary phase and a mixture of solvents n-butanol : acetic acid : water (15 : 5 : 1, v/v/v) as mobile phase. Under the established conditions good resolution of examined constituents was obtained. Retardation factor for quinapril hydrochloride was R(f) - 0.70, for losartan potassium R(f) - 0.85 and for hydrochlorothiazide R(f) - 0.78. The developed methods are characterized by high sensitivity and accuracy. For quantitative analysis, densitometric measurements were carried out at lambda = 218.0 nm for quinapril, lambda = 275.0 nm for hydrochlorothiazide and = 232.0 nm for losartan.

UV-irradiation effects on polyester nuclear track detector

International Nuclear Information System (INIS)

Agarwal, Chhavi; Kalsi, P.C.

2010-01-01

The effects of UV irradiation (λ=254 nm) on polyester nuclear track detector have been investigated employing bulk-etch technique, UV-visible spectrophotometry and infra-red spectrometry (FTIR). The activation energy values for bulk-etching were found to decrease with the UV-irradiation time indicating the scission of the polymer. Not much shift in the absorption edge due to UV irradiation was seen in the UV-visible spectra. FTIR studies also indicate the scission of the chemical bonds, thereby further validating the bulk-etch rate results.

Simultaneous quantitative determination of paracetamol and tramadol in tablet formulation using UV spectrophotometry and chemometric methods

Science.gov (United States)

Glavanović, Siniša; Glavanović, Marija; Tomišić, Vladislav

2016-03-01

The UV spectrophotometric methods for simultaneous quantitative determination of paracetamol and tramadol in paracetamol-tramadol tablets were developed. The spectrophotometric data obtained were processed by means of partial least squares (PLS) and genetic algorithm coupled with PLS (GA-PLS) methods in order to determine the content of active substances in the tablets. The results gained by chemometric processing of the spectroscopic data were statistically compared with those obtained by means of validated ultra-high performance liquid chromatographic (UHPLC) method. The accuracy and precision of data obtained by the developed chemometric models were verified by analysing the synthetic mixture of drugs, and by calculating recovery as well as relative standard error (RSE). A statistically good agreement was found between the amounts of paracetamol determined using PLS and GA-PLS algorithms, and that obtained by UHPLC analysis, whereas for tramadol GA-PLS results were proven to be more reliable compared to those of PLS. The simplest and the most accurate and precise models were constructed by using the PLS method for paracetamol (mean recovery 99.5%, RSE 0.89%) and the GA-PLS method for tramadol (mean recovery 99.4%, RSE 1.69%).

A fast determination of nitrate in rain and surface waters by means of UV spectrophotometry

International Nuclear Information System (INIS)

Slanina, J.; Lingerak, W.A.; Bergman, L.

1976-01-01

Organic substances are the main interference in the direct U.V. spectrophotometric determination of nitrate at 210 nm. An active carbon filter (Filopur) is therefore proposed which adsorbs all organic interferences. With this filter the U.V. spectrophotometric method gives the same results as the Na-salicylate method. The reproducibility is generally better than 5%. One determination takes 50 s. (orig.) [de

Effect of fungal mycelia on the HPLC-UV and UV-vis spectrophotometric assessment of mycelium-bound epoxide hydrolase using glycidyl phenyl ether.

Science.gov (United States)

Dolcet, Marta M; Torres, Mercè; Canela, Ramon

2016-06-25

The use of mycelia as biocatalysts has technical and economic advantages. However, there are several difficulties in obtaining accurate results in mycelium-catalysed reactions. Firstly, sample extraction, indispensable because of the presence of mycelia, can bring into the extract components with a similar structure to that of the analyte of interest; secondly, mycelia can influence the recovery of the analyte. We prepared calibration standards of 3-phenoxy-1,2-propanediol (PPD) in the pure solvent and in the presence of mycelia (spiked before or after extraction) from five fungi (Aspergillus niger, Aspergillus tubingensis, Penicillium aurantiogriseum, Penicillium sp. and Aspergillus terreus). The quantification of PPD was carried out by HPLC-UV and UV-vis spectrophotometry. The manuscript shows that the last method is as accurate as the HPLC method. However, the colorimetric method led to a higher data throughput, which allowed the study of more samples in a shorter time. Matrix effects were evaluated visually from the plotted calibration data and statistically by simultaneously comparing the intercept and slope of calibration curves performed with solvent, post-extraction spiked standards and pre-extraction spiked standards. Significant differences were found between the post- and pre-extraction spiked matrix-matched functions. Pre-extraction spiked matrix-matched functions based on A. tubingensis mycelia, selected as the reference, were validated and used to compensate for low recoveries. These validated functions were successfully applied to the quantification of PPD achieved during the hydrolysis of glycidyl phenyl ether by mycelium-bound epoxide hydrolases and equivalent hydrolysis yields were determined by HPLC-UV and UV-vis spectrophotometry. This study may serve as starting point to implement matrix effects evaluation when mycelium-bound epoxide hydrolases are studied. Copyright © 2016 Elsevier B.V. All rights reserved.

Studies of selected transuranium and lanthanide tri-iodides under pressure using absorption spectrophotometry

International Nuclear Information System (INIS)

Haire, R.G.; Young, J.P.; Peterson, J.R.; Tennessee Univ., Knoxville; Benedict, U.

1987-01-01

The anhydrous tri-iodides of plutonium, americium and curium under pressure have been investigated using absorption spectrophotometry. These initial studies on plutonium and curium tri-iodides together with the published data for americium tri-iodide show that the rhombohedral form of these compounds (BiI 3 -type structure) can be converted to the orthorhombic form (PuBr 3 -type structure) by applying pressure at room temperature. Absorption spectrophotometry can often differentiate between two crystallographic forms of a material and has been used in the present high-pressure studies to monitor the effects of pressure on the tri-iodides. A complication in these studies of the tri-iodides is a significant shift of their absorption edges with pressure from the near UV to the visible spectral region. With curium tri-iodide this shift causes interference with the major f-f absorption peaks and precludes identification by absorption spectrophotometry of the high pressure phase of CmI 3 . (orig.)

A Spectrophotometric Method for the Determination of Ramipril in ...

African Journals Online (AJOL)

HP

Purpose: To develop a simple and cost effective spectrophotometer method for the determination of. ACE inhibitor ramipril in dosage forms. Methods: UV spectrophotometry was used to develop and validate a simple method .... 2003 software.

Ultraviolet Spectrophotometry of VV Cephei

Directory of Open Access Journals (Sweden)

Young Woon Kang

1992-06-01

Full Text Available The IUE archival spectra of VV Cephei were collected to investigate the eclipse nature in the ultraviolet. The temperature of the B star has been determined, as approximately 30000K, based on the flux distributions during egress. Light curves of VV Cephei were reduced from the spectrophotometry of the IUE archival spectra. Three light curves at the center wavelengths of 3250 Å, 2550 Å and 2850 Å have been analyzed by the modified Wilson and Devinney light curve program. The radii of the B star and M star were deduced to 0.05 and 0.22 of unit separation, respectively. The UV light curves show an evidence that the light was attenuated by the highly opaque atomsphere of the M star.

Spectrophotometry of Symbiotic Stars (Abstract)

Science.gov (United States)

Boyd, D.

2017-12-01

(Abstract only) Symbiotic stars are fascinating objects - complex binary systems comprising a cool red giant star and a small hot object, often a white dwarf, both embedded in a nebula formed by a wind from the giant star. UV radiation from the hot star ionizes the nebula, producing a range of emission lines. These objects have composite spectra with contributions from both stars plus the nebula and these spectra can change on many timescales. Being moderately bright, they lend themselves well to amateur spectroscopy. This paper describes the symbiotic star phenomenon, shows how spectrophotometry can be used to extract astrophysically useful information about the nature of these systems, and gives results for three symbiotic stars based on the author's observations.

Method for rapidly determining a pulp kappa number using spectrophotometry

Science.gov (United States)

Chai, Xin-Sheng; Zhu, Jun Yong

2002-01-01

A system and method for rapidly determining the pulp kappa number through direct measurement of the potassium permanganate concentration in a pulp-permanganate solution using spectrophotometry. Specifically, the present invention uses strong acidification to carry out the pulp-permanganate oxidation reaction in the pulp-permanganate solution to prevent the precipitation of manganese dioxide (MnO.sub.2). Consequently, spectral interference from the precipitated MnO.sub.2 is eliminated and the oxidation reaction becomes dominant. The spectral intensity of the oxidation reaction is then analyzed to determine the pulp kappa number.

Comparative studies of method for determining total mercury in fish. Dithizone and flameless atomic absorption spectrophotometry techniques

International Nuclear Information System (INIS)

Protasowicki, M.; Ociepa, A.; Chodyniecki, A.

1977-01-01

Two methods for determining total mercury in fish were compared: the dithizone and flameless atomic absorption spectrophotometry techniques. The studies involved determination of recovery when 1μg of mercury as solutions of HgCl 2 or CH 3 HgC were added to each sample of herring flesh. Mean recoveries in the dithizone method were found to be 91.4+-7.47% and 90.25+-4.73% for the two solutions respectively, while the recoveries obtained with the flameless atomic absorption spectrophotometry were 95.00+-9.13% and 98.70+-7.14%, respectively. Both techniques were used to determine the mercury content in the same herring flesh sample. The first technique showed the content of 0.050+-0.018μg Hg g -1 while the result obtained with the other one was 0.062+-0.013μg Hg g -1 . The statistical treatment of the results obtained showed no difference between the two techniques, the significance level being α=0.05. Therefore, the results obtained with the dithizone method are comparable with those obtained with the flameless atomic absorption spectrophotometry for mercury contents of the magnitude order of 0.050 ug.g -1 . (author)

Investigation of Drug–Polymer Compatibility Using Chemometric-Assisted UV-Spectrophotometry

Directory of Open Access Journals (Sweden)

Amir Ibrahim Mohamed

2017-01-01

Full Text Available A simple chemometric-assisted UV-spectrophotometric method was used to study the compatibility of clindamycin hydrochloride (HC1 with two commonly used natural controlled-release polymers, alginate (Ag and chitosan (Ch. Standard mixtures containing 1:1, 1:2, and 1:0.5 w/w drug–polymer ratios were prepared and UV scanned. A calibration model was developed with partial least square (PLS regression analysis for each polymer separately. Then, test mixtures containing 1:1 w/w drug–polymer ratios with different sets of drug concentrations were prepared. These were UV scanned initially and after three and seven days of storage at 25 °C. Using the calibration model, the drug recovery percent was estimated and a decrease in concentration of 10% or more from initial concentration was considered to indicate instability. PLS models with PC3 (for Ag and PC2 (for Ch showed a good correlation between actual and found values with root mean square error of cross validation (RMSECV of 0.00284 and 0.01228, and calibration coefficient (R2 values of 0.996 and 0.942, respectively. The average drug recovery percent after three and seven days was 98.1 ± 2.9 and 95.4 ± 4.0 (for Ag, and 97.3 ± 2.1 and 91.4 ± 3.8 (for Ch, which suggests more drug compatibility with an Ag than a Ch polymer. Conventional techniques including DSC, XRD, FTIR, and in vitro minimum inhibitory concentration (MIC for (1:1 drug–polymer mixtures were also performed to confirm clindamycin compatibility with Ag and Ch polymers.

Evaluation of the acidity constants of the 4-hidroxy-5-6salicylideneamino9-2-7-naphthalenedisulfonic acid (Azomethine-H) using UV?vis spectrophotometry

Science.gov (United States)

Alarcón-Angeles, G.; Corona-Avendaño, S.; Rojas-Hernández, A.; Romero-Romo, M. A.; Ramírez-Silva, M. T.

2005-01-01

The time stability of the azomethine-H species was determined not to be better than 10 min in the absence of oxygen and light, however under phosphate buffered conditions the azomethine-H species remained stable for longer periods, as indicated by the spectrophotometric behaviour. Nevertheless, the analysis time still exceeded the stability allowance. Therefore, the determination of the acidity constants of the Azomethine-H species was studied by means of UV-vis spectrophotometry in buffered media by means of the point-by-point analysis and data processing with SQUAD to refine the resulting constants, which were: p Ka1=3.39, p Ka2 7.36 and p Ka3 8.73. The latter were associated to the corresponding acid-base equilibria of the amine and hydroxy groups constituting the molecule.

UV-Vis spectrophotometry of quinone flow battery electrolyte for in situ monitoring and improved electrochemical modeling of potential and quinhydrone formation.

Science.gov (United States)

Tong, Liuchuan; Chen, Qing; Wong, Andrew A; Gómez-Bombarelli, Rafael; Aspuru-Guzik, Alán; Gordon, Roy G; Aziz, Michael J

2017-12-06

Quinone-based aqueous flow batteries provide a potential opportunity for large-scale, low-cost energy storage due to their composition from earth abundant elements, high aqueous solubility, reversible redox kinetics and their chemical tunability such as reduction potential. In an operating flow battery utilizing 9,10-anthraquinone-2,7-disulfonic acid, the aggregation of an oxidized quinone and a reduced hydroquinone to form a quinhydrone dimer causes significant variations from ideal solution behavior and of optical absorption from the Beer-Lambert law. We utilize in situ UV-Vis spectrophotometry to establish (a), quinone, hydroquinone and quinhydrone molar attenuation profiles and (b), an equilibrium constant for formation of the quinhydrone dimer (K QHQ ) ∼ 80 M -1 . We use the molar optical attenuation profiles to identify the total molecular concentration and state of charge at arbitrary mixtures of quinone and hydroquinone. We report density functional theory calculations to support the quinhydrone UV-Vis measurements and to provide insight into the dimerization conformations. We instrument a quinone-bromine flow battery with a Pd-H reference electrode in order to demonstrate how complexation in both the negative (quinone) and positive (bromine) electrolytes directly impacts measured half-cell and full-cell voltages. This work shows how accounting for electrolyte complexation improves the accuracy of electrochemical modeling of flow battery electrolytes.

Derivative spectrophotometry applied to solutions of complex composition

International Nuclear Information System (INIS)

Perfil'ev, V.A.

1986-01-01

The authors consider not only the basic principles of derivative spectrophotometry but also survey the data on its use in research on the properties of materials, the compositions of compounds, and the structures of complex chemical systems. Recording methods by which derivative spectra can be generated include descriptions of electronic differentiation, computer spectrum differentiation, wavelength modulation, and the two-way derivative method. A section on the advantages of derivative spectrophotometry presents a discussion on features enabling one to determine various substances from their characteristic absorption spectra without performing complicated operations to isolate or separate the components. Other topics include research on the structures of substances and metal-ion complexing in solutions, derivative spectrophotometry in gas analysis, gas determination, and determining organic and compounds

Ion-exchanger ultraviolet spectrophotometry for uranium(VI)

International Nuclear Information System (INIS)

Waki, H.; Korkisch, J.

1983-01-01

A sensitive method based on solid-phase spectrophotometry has been developed for the microdetermination of uranium(VI) in water samples. Uranium is sorbed on the anion-exchanger QAE-Sephadex from thiocyanate solution and the absorbance of the exchanger is measured at 300 nm. This method is about 30 times more sensitive than solution spectrophotometry. Absorption spectra of various metals in the anion-exchanger phase are presented and their interferences discussed. A procedure for the cation-exchange separation of uranium from accompanying elements before spectral measurement of uranium is proposed. (author)

Ionic liquid-based single-drop microextraction followed by liquid chromatography-ultraviolet spectrophotometry detection to determine typical UV filters in surface water samples.

Science.gov (United States)

Vidal, Lorena; Chisvert, Alberto; Canals, Antonio; Salvador, Amparo

2010-04-15

A user-friendly and inexpensive ionic liquid-based single-drop microextraction (IL-SDME) procedure has been developed to preconcentrate trace amounts of six typical UV filters extensively used in cosmetic products (i.e., 2-hydroxy-4-methoxybenzophenone, isoamyl 4-methoxycinnamate, 3-(4'-methylbenzylidene)camphor, 2-ethylhexyl 2-cyano-3,3-diphenylacrylate, 2-ethylhexyl 4-dimethylaminobenzoate and 2-ethylhexyl 4-methoxycinnamate) from surface water samples prior to analysis by liquid chromatography-ultraviolet spectrophotometry detection (LC-UV). A two-stage multivariate optimization approach was developed by means of a Plackett-Burman design for screening and selecting the significant variables involved in the SDME procedure, which were later optimized by means of a circumscribed central composite design. The studied variables were drop volume, sample volume, agitation speed, ionic strength, extraction time and ethanol quantity. Owing to particularities, ionic liquid type and pH of the sample were optimized separately. Under optimized experimental conditions (i.e., 10 microL of 1-hexyl-3-methylimidazolium hexafluorophosphate, 20 mL of sample containing 1% (v/v) ethanol and NaCl free adjusted to pH 2, 37 min extraction time and 1300 rpm agitation speed) enrichment factors up to ca. 100-fold were obtained depending on the target analyte. The method gave good levels of repeatability with relative standard deviations varying between 2.8 and 8.8% (n=6). Limits of detection were found in the low microg L(-1) range, varying between 0.06 and 3.0 microg L(-1) depending on the target analyte. Recovery studies from different types of surface water samples collected during the winter period, which were analysed and confirmed free of all target analytes, ranged between 92 and 115%, showing that the matrix had a negligible effect upon extraction. Finally, the proposed method was applied to the analysis of different water samples (taken from two beaches, two swimming pools and a

PHOTODEGRADATION OF ALIZARIN S DYE USING TiO2-ZEOLITE AND UV RADIATION

Directory of Open Access Journals (Sweden)

Karna Wijaya

2010-06-01

Full Text Available An investigation of Alizarin S photodegradation using TiO2-zeolite and UV radiation was performed. TiO2-zeolite was prepared by dispersing oligocations of titanium into suspension of zeolite. The suspension was stirred and then filtered to separate the solid phase from the filtrate. the solid phase was calcined by microwave oven at 800 Watt for 5 minutes to convert the oligocations into its oxide forms. The calcined product and unmodified zeolite were characterized using x-ray diffractometry, FT-IR spectrophotometry, X-ray fluorescence and gas sorption analysis methods to determine their physicochemical properties. Photocatalytic activity of TiO2-zeolite was tested on Alizarin S solution using following method: 50 mg of zeolite was dispersed into 25 mL of 10-4 M Alizarin S. The dispersion was irradiated using 365 nm UV light at room temperature on various irradiation times, i.e. 10, 20, 30, 40 and 60 minutes. At certain irradiation time, the dispersion was filtered and the filtrate was then analyzed its concentration using UV-Vis spectrophotometry method. Characterization results exhibited that the formation of TiO2 on internal as well as external surfaces of zeolite could not be detected  with x-ray diffractometry and FT-IR spectrophotometry, however determination of titanium using x-ray fluorescence analysis on the calcined product showed that the concentration of titanium was much higher than zeolite (0.22% on zeolite and 12.08% on TiO2-zeolite. Gas sorption analysis result indicated that the the calcination  resulted in the increase of specific surface area (16,31 m2/g on zeolite and 100.96 m2/g on TiO2-zeolite as well as total pore volume of calcined product (13.34 mL/Å/g on zeolite and 57.54 mL/Å/g on TiO2-zeolite. The result of photocatalytic activitiy study showed that ca 99 % of Alizarin S was degraded by TiO2-zeolite after UV irradiation for 60 min.   Keywords: TiO2-zeolite, photocatalytic, Alizarin S.

Development and Validation of Analytical Method for Losartan ...

African Journals Online (AJOL)

Development and Validation of Analytical Method for Losartan-Copper Complex Using UV-Vis Spectrophotometry. ... Tropical Journal of Pharmaceutical Research ... Purpose: To develop a new spectrophotometric method for the analysis of losartan potassium in pharmaceutical formulations by making its complex with ...

Novel and validated titrimetric method for determination of selected angiotensin-II-receptor antagonists in pharmaceutical preparations and its comparison with UV spectrophotometric determination

Directory of Open Access Journals (Sweden)

Shrikant H. Patil

2012-12-01

Full Text Available A novel and simple titrimetric method for determination of commonly used angiotensin-II-receptor antagonists (ARA-IIs is developed and validated. The direct acid base titration of four ARA-IIs, namely eprosartan mesylate, irbesartan, telmisartan and valsartan, was carried out in the mixture of ethanol:water (1:1 as solvent using standardized sodium hydroxide aqueous solution as titrant, either visually using phenolphthalein as an indicator or potentiometrically using combined pH electrode. The method was found to be accurate and precise, having relative standard deviation of less than 2% for all ARA-IIs studied. Also, it was shown that the method could be successfully applied to the assay of commercial pharmaceuticals containing the above-mentioned ARA-IIs. The validity of the method was tested by the recovery studies of standard addition to pharmaceuticals and the results were found to be satisfactory. Results obtained by this method were found to be in good agreement with those obtained by UV spectrophotometric method. For UV spectrophotometric analysis ethanol was used as a solvent and wavelength of 233 nm, 246 nm, 296 nm, and 250 nm was selected for determination of eprosartan mesylate, irbesartan, telmisartan, and valsartan respectively. The proposed titrimetric method is simple, rapid, convenient and sufficiently precise for quality control purposes. Keywords: Angiotensin-II-receptor antagonists, Titrimetric assay, UV spectrophotometry, Validation

Serum paraquat concentration detected by spectrophotometry in patients with paraquat poisoning

Science.gov (United States)

Li, Chang-bin; Li, Xin-hua; Wang, Zhen; Jiang, Cheng-hua; Peng, Ai

2011-01-01

BACKGROUND: Paraquat (PQ) is a world-wide used herbicide and also a type of common poison for suicide and accidental poisoning. Numerous studies have proved that the concentration of serum PQ plays an important role in prognosis. Spectrophotometry, including common spectrophotometry and second-derivative spectrophotometry, is commonly used for PQ detection in primary hospitals. So far, lack of systematic research on the reliability of the method and the correlation between clinical features of patients with PQ poisoning and the test results has restricted the clinical use of spectrophotometry. This study aimed to evaluate the reliability and value of spectrophotometry in detecting the concentration of serum PQ. METHODS: The wavelengths for detecting the concentration of serum PQ by common and second-derivative spectrophotometry were determined. Second-derivative spectrophotometry was applied to detect the concentration of serum PQ. The linear range and precision for detection of PQ concentration by this method were confirmed. The concentration of serum PQ shown by second-derivative spectrophotometry and HPLC were compared in 8 patients with PQ poisoning. Altogether 21 patients with acute poisoning 4 hours after PQ ingestion treated in the period of October 2008 to September 2010 were retrospectively reviewed. The patients were divided into higher and lower than 1.8 μg/mL groups based on their concentrations of serum PQ measured by second-derivative spectrophotometry on admission. The severity of clinical manifestations between the two groups were analyzed with Student's t test or Fisher's exact test. RESULTS: The absorption peak of 257 nm could not be found when common spectrophotometry was used to detect the PQ concentration in serum. The calibration curve in the 0.4–8.0 μg/mL range for PQ concentration shown by second-derivative spectrophotometry obeyed Beer's law with r=0.996. The average recovery rates of PQ were within a range of 95.0% to 99.5%, relative

Improvement of precision method of spectrophotometry with inner standardization and its use in plutonium solutions analysis

International Nuclear Information System (INIS)

Stepanov, A.V.; Stepanov, D.A.; Nikitina, S.A.; Gogoleva, T.D.; Grigor'eva, M.G.; Bulyanitsa, L.S.; Panteleev, Yu.A.; Pevtsova, E.V.; Domkin, V.D.; Pen'kin, M.V.

2006-01-01

Precision method of spectrophotometry with inner standardization is used for analysis of pure Pu solutions. Improvement of the spectrophotometer and spectrophotometric method of analysis is done to decrease accidental constituent of relative error of the method. Influence of U, Np impurities and corrosion products on systematic constituent of error of the method, and effect of fluoride-ion on completeness of Pu oxidation in sample preparation are studied [ru

The effect of different propolis harvest methods on its lead contents determined by ET AAS and UV-visS

Energy Technology Data Exchange (ETDEWEB)

Sales, A. [Department of Analytical Chemistry, Faculty of Biochemistry, Chemistry and Pharmacy, National University of Tucuman, Ayacucho 471, 4000 Tucuman (Argentina)]. E-mail: amsales@fbqf.unt.edu.ar; Alvarez, A. [National Institute of Agricultural Technology (INTA), Experimental Station Famailla, Ruta 301, Km 32, Famailla, Tucuman (Argentina); Areal, M. Rodriguez [Department of Analytical Chemistry, Faculty of Biochemistry, Chemistry and Pharmacy, National University of Tucuman, Ayacucho 471, 4000 Tucuman (Argentina); Maldonado, L. [National Institute of Agricultural Technology (INTA), Experimental Station Famailla, Ruta 301, Km 32, Famailla, Tucuman (Argentina); Marchisio, P. [Department of Analytical Chemistry, Faculty of Biochemistry, Chemistry and Pharmacy, National University of Tucuman, Ayacucho 471, 4000 Tucuman (Argentina); Rodriguez, M. [Department of Analytical Chemistry, Faculty of Biochemistry, Chemistry and Pharmacy, National University of Tucuman, Ayacucho 471, 4000 Tucuman (Argentina); Bedascarrasbure, E. [National Institute of Agricultural Technology (INTA), Experimental Station Famailla, Ruta 301, Km 32, Famailla, Tucuman (Argentina)

2006-10-11

Argentinean propolis is exported to different countries, specially Japan. The market demands propolis quality control according to international standards. The analytical determination of some metals, as lead in food, is very important for their high toxicity even in low concentrations and because of their harmful effects on health. Flavonoids, the main bioactive compounds of propolis, tend to chelate metals as lead, which becomes one of the main polluting agents of propolis. The lead found in propolis may come from the atmosphere or it may be incorporated in the harvest, extraction and processing methods. The aim of this work is to evaluate lead level on Argentinean propolis determined by electrothermal atomic absorption spectrometry (ET AAS) and UV-vis spectrophotometry (UV-visS) methods, as well as the effect of harvest methods on those contents. A randomized test with three different treatments of collection was made to evaluate the effect of harvest methods. These procedures were: separating wedges (traditional), netting plastic meshes and stamping out plastic meshes. By means of the analysis of variance technique for multiple comparisons (ANOVA) it was possible to conclude that there are significant differences between scraped and mesh methods (stamped out and mosquito netting meshes). The results obtained in the present test would allow us to conclude that mesh methods are more advisable than scraped ones in order to obtain innocuous and safe propolis with minor lead contents. A statistical comparison of lead determination by both, ET AAS and UV-visS methods, demonstrated that there is not a significant difference in the results achieved with the two analytical techniques employed.

Evaluation of Biologically Active Compounds from Calendula officinalis Flowers using Spectrophotometry

Directory of Open Access Journals (Sweden)

Butnariu Monica

2012-04-01

Full Text Available Abstract Background This study aimed to quantify the active biological compounds in C. officinalis flowers. Based on the active principles and biological properties of marigolds flowers reported in the literature, we sought to obtain and characterize the molecular composition of extracts prepared using different solvents. The antioxidant capacities of extracts were assessed by using spectrophotometry to measure both absorbance of the colorimetric free radical scavenger 2,2-diphenyl-1-picrylhydrazyl (DPPH as well as the total antioxidant potential, using the ferric reducing power (FRAP assay. Results Spectrophotometric assays in the ultraviolet-visible (UV-VIS region enabled identification and characterization of the full range of phenolic and flavonoids acids, and high-performance liquid chromatography (HPLC was used to identify and quantify phenolic compounds (depending on the method of extraction. Methanol ensured more efficient extraction of flavonoids than the other solvents tested. Antioxidant activity in methanolic extracts was correlated with the polyphenol content. Conclusions The UV-VIS spectra of assimilator pigments (e.g. chlorophylls, polyphenols and flavonoids extracted from the C. officinalis flowers consisted in quantitative evaluation of compounds which absorb to wavelengths broader than 360 nm.

Ultrasensitive, simple and solvent-free micro-assay for determining sulphite preservatives (E220-228) in foods by HS-SDME and UV-vis micro-spectrophotometry.

Science.gov (United States)

Gómez-Otero, E; Costas, M; Lavilla, I; Bendicho, C

2014-03-01

A new method based on headspace single-drop microextraction in combination with UV-vis micro-spectrophotometry has been developed for the ultrasensitive determination of banned sulphite preservatives (E220-228) in fruits and vegetables. Sample acidification was used for SO2 generation, which is collected onto a 5,5'-dithiobis-(2-nitrobenzoic acid) microdrop for spectrophotometric measurement. A careful study of this reaction was necessary, including conditions for SO2 generation from different sulphating salts, drop pH, 5,5'-dithiobis-(2-nitrobenzoic acid) concentration and potential interference effects. Variables influencing mass transfer (stirring, sample volume and addition of salt) and microextraction time were also studied. A simple sulphite extraction was carried out, and problems caused by oxidation during the extraction process were addressed. A high enrichment factor (380) allows the determination of low levels of free SO2 in fruits and vegetables (limit of detection 0.06 μg g(-1), limit of quantification 0.2 μg g(-1)) with an adequate precision (repeatability, relative standard deviation 5 %). In addition, the sulphiting process was studied through the monitoring of residual SO2 in a vegetal sample, thus showing the importance of a sensitive tool for SO2 detection at low levels.

Ensaio de dissolução de cápsulas de fluconazol: problemas encontrados na determinação por espectrofotometria na região do UV

Directory of Open Access Journals (Sweden)

D.M. Oliveira

2010-11-01

Full Text Available

Entre as classes terapêuticas analisadas no Programa Nacional de Verificação da Qualidade de Medicamentos (PROVEME, o antifúngico fluconazol constava na apresentação de cápsulas de diferentes procedências. Na realização dos ensaios de dissolução conforme as técnicas dos fabricantes, constatou-se que os valores obtidos por espectrofotometria-UV foram superiores aos obtidos nos ensaios de teor e uniformidade de conteúdo, cuja determinação foi por CLAE-UV. Considerando este fato, foi objetivo deste trabalho realizar o ensaio de dissolução destas amostras pelos respectivos métodos dos fabricantes e o quantitativo do ensaio por espectrofotometria no UV e por CLAE-UV, a fim de avaliar as possíveis interferências dos excipientes nestas determinações. Os valores obtidos por espectrofotometria foram superiores aos obtidos por CLAE, confirmando a interferência dos excipientes. Concluiu-se que a metodologia a ser empregada na análise de fármacos deve ser criteriosamente selecionada, a fim de evitar resultados não condizentes com a real formulação do produto. Palavras-chave: cápsulas de fluconazol, CLAE, dissolução, espectrofotometria. ABSTRACT Among the therapeutic classes analyzed in the Programa Nacional de Verificação da Qualidade de Medicamentos (PROVEME consisted the antifungal fluconazole in the dosage form of capsules from different origins. In dissolution tests, according to manufacturers techniques, it was found that the values obtained by UV-spectrophotometry were higher than those obtained from tests of content and content uniformity, whose determination was by HPLC-UV. Considering this fact, the objective of this study was to perform the dissolution test of these samples by the respective manufacturers methods and the quantitative assay by UV-spectrophotometry and HPLC-UV, to evaluate possible interferences of excipients in these determinations. The values obtained by spectrophotometry were

Atomic absorption spectrophotometry in perspective

International Nuclear Information System (INIS)

Soffiantini, V.

1981-01-01

Atomic absorption spectrophotometry is essentially an analytical technique used for quantitative trace metal analysis in a variety of materials. The speed and specificity of the technique is its greatest advantage over other analytical techniques. What atomic absorption spectrophotometry can and cannot do and its advantages and disadvantages are discussed, a summary of operating instructions are given, as well as a summary of analytical interferences. The applications of atomic absorption spectrophotometry are also shortly discussed

A Spectrophotometric Method for the Determination of Ramipril in ...

African Journals Online (AJOL)

A Spectrophotometric Method for the Determination of Ramipril in Solid Dosage Forms. ... Tropical Journal of Pharmaceutical Research ... Methods: UV spectrophotometry was used to develop and validate a simple method for the assay of ramipril in solid dosage form at λmax of 210 nm, as per International Conference on ...

Využití UV/VIS spektrofotometrie pro stanovení diklofenaku

Czech Academy of Sciences Publication Activity Database

Čapka, Lukáš; Zlámalová Gargošová, H.; Vávrová, M.; Urbánková, L.

2013-01-01

Roč. 107, č. 7 (2013), s. 550-554 ISSN 0009-2770 Institutional support: RVO:68081715 Keywords : diclofenac * UV-VIS spectrophotometry * environment * fate * pharmaceutical residues Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 0.196, year: 2013

Real-time dissolution behavior of furosemide in biorelevant media as determined by UV imaging

DEFF Research Database (Denmark)

Gordon, Sarah; Naelapää, Kaisa; Rantanen, Jukka

2013-01-01

M bile salt/phospholipid, pH 6.5) together with corresponding blank buffer were employed. Dissolution rates as a function of flow rate (0.2-1.0 mL/min) were determined directly from UV images, and by analysis of collected effluent using UV spectrophotometry. A good agreement in dissolution rates...

Application of spectrophotometry for determination of analytes in high percentage levels

International Nuclear Information System (INIS)

Koteswara Rao, M.; Ram Mohan, Vijaya; Yadav, R.B.

2009-01-01

This paper describes the application of differential Spectrophotometry for the determination of analytes in high concentration levels unlike the conventional photometric methods that are useful for measuring concentration at trace levels. Differential spectrophotometry is based on measuring the absorbance of the test solution against a standard of accurately known concentration instead of a reagent blank or pure solvent. In this way, the error in measurement is confined to the difference in the two concentrations and is minimized. Thus the error is much smaller than in conventional Spectrophotometry, which therefore allows its application for determining analytes in major concentration. This method was applied for the assay of Niobium and Titanium used as strategic materials in various field. (author)

The Comparison Of Silicon Analysis For The Uranium Silicide Fuel Using Spectrophotometrical And Gravimetrical Methods

International Nuclear Information System (INIS)

Putro, P. K.; Suripto, A.; Putra, S.; Gunanjar

1996-01-01

The analysis of silicon content in the uranium silicide fuel spectro-photometrical and gravimetrical method have been performed. The nitrous oxide-acetylene was used in the atomic absorption spectrophotometry (AAS) on the wave length of 251.6 nm, and the mixture of ammonium hepta molybdate complexes and SnC1 2 as reductor were applied during analysis by UV-VIS spectrophotometry (UV-VIS) on the wave length of 757.5 mm. The reagent of HCLO 4 and HNO 3 were used for determining Si content by gravimetrical methods. The results of this comparison is as follows: the accuracy result is around 96.37 % + 0.24 % for the Si concentration up to 300 ppm (the AAS), is 138.60 % = 0.43 % for the Si concentration range between 0.1-1.5 ppm (UV-VIS), and is 51.13 % + 0.8 % for 1 gram of Si (gravimetry). The results also show that the lowest analytical error is obtained by AAS method

Impurities determination of uranium metal flame spectrophotometry and atomic absorption spectrophotometry

International Nuclear Information System (INIS)

Rukihati.

1978-01-01

The atomic absorption flame spectrophotometry has been applied to the determination of chromium, copper, iron, lead, manganese and nickel in the metal of uranium. The first step to be done is to dissolve the uranium sample in nitric acid and then the uranium is extracted by a tributylphosphate-carbon tetrachloride solution. The aqueous phase which contains the chromium, copper, iron, lead, manganese and nickel is aspirated into an airacetylene flame. The results of this method are compared with the results of emission spectrographic method. It is found that this technique is competative to other methods in the sense that it is quite fast and accurate. (author)

Use of Dispersive Liquid-Liquid Microextraction and UV-Vis Spectrophotometry for the Determination of Cadmium in Water Samples

Directory of Open Access Journals (Sweden)

J. Pérez-Outeiral

2014-01-01

Full Text Available A simple and inexpensive method for cadmium determination in water using dispersive liquid-liquid microextraction and ultraviolet-visible spectrophotometry was developed. In order to obtain the best experimental conditions, experimental design was applied. Calibration was made in the range of 10–100 μg/L, obtaining good linearity (R2 = 0.9947. The obtained limit of detection based on calibration curve was 8.5 μg/L. Intra- and interday repeatability were checked at two levels, obtaining relative standard deviation values from 9.0 to 13.3%. The enrichment factor had a value of 73. Metal interferences were also checked and tolerable limits were evaluated. Finally, the method was applied to cadmium determination in real spiked water samples. Therefore, the method showed potential applicability for cadmium determination in highly contaminated liquid samples.

Redox equilibrium of U4+/U3+ in molten NaCl-2CsCl by UV-Vis spectrophotometry and cyclic voltammetry

International Nuclear Information System (INIS)

Nagai, Takayuki; Uehara, Akihiro; Fujii, Toshiyuki; Shirai, Osamu; Yamana, Hajimu; Sato, Nobuaki

2005-01-01

In order to investigate the redox equilibrium of uranium ions in molten NaCl-2CsCl, UV-Vis absorption spectro-photometry measurements were performed for U 4+ and U 3+ in molten NaCl-2CsCl at 923 K under simultaneous electrolytic control of their ratio. Prominent absorption bands at 480 and 570 nm were assigned to U 3+ , and their molar absorptivities were determined to be 1,260±42 and 963±32 mol -1 ·l·cm -1 respectively. From the dependence of the rest potential of the melt on the spectrophotometrically determined ratio of [U 4+ ]/[U 3+ ], the standard redox potential of the couple U 4+ /U 3+ at 923 K was determined to be -1.481±0.004 V vs. Cl 2 /Cl - . Cyclic voltammetry measurements were carried out for the couple U 4+ /U 3+ , and the results agreed well with this standard redox potential value. By the results of cyclic voltammetry, a temperature dependence of the standard redox potential was found to be -2.094+6.639 x 10 -4 T (T=823-923K). (author)

Determination of Oxytetracycline from Salmon Muscle and Skin by Derivative Spectrophotometry.

Science.gov (United States)

Toral, M Inés; Sabay, Tamara; Orellana, Sandra L; Richter, Pablo

2015-01-01

A method was developed for the identification and quantification of oxytetracycline residues present in salmon muscle and skin using UV-Vis derivative spectrophotometry. With this method, it was possible to reduce the number of steps in the procedure typically required for instrumental analysis of a sample. The spectral variables, order of the derivative, scale factor, smoothing factor, and analytical wavelength were optimized using standard solutions of oxytetracycline dissolved in 900 mg/L oxalic acid in methanol. The matrix effect was significant; therefore, quantification for oxytetracycline residues was carried out using drug-free salmon muscle and skin samples fortified with oxytetracycline. The LOD and LOQ were found to be 271 and 903 μg/kg, respectively. The precision and accuracy of the method were validated using drug-free salmon muscle and skin tissues fortified at three different concentrations (8, 16, and 32 mg/kg) on 3 different days. The recoveries at all fortified concentrations were between 90 and 105%, and RSDs in all cases were less than 6.5%. This method can be used to screen out compliant samples and thereby reduce the number of suspect positive samples that will require further confirmatory analysis.

Transmission of UV-irradiance into nectarine fruit

International Nuclear Information System (INIS)

Blanke, M.M.

1996-01-01

With the global depletion of the ozone layer, leaves and fruits are increasingly exposed to UV-irradiance on the tree. Some fruits are additionally exposed postharvest to artificial germicidal W-irradiance, leading to a cumulative effect. This paper examines the transmission of UV-light (200-400 nm) by the peel of ripe nectarine fruit using UV/VIS spectrophotometry to aid understanding of UV-effects and assess the sensitivity of the peel to UV wavelengths. Yellow peel of nectarine fruit transmitted less than 0.1 % in the UV-C range of 220 to 280 nm. With longer wavelenghts, UV-light transmission increased slowly from 0.4 % at 284 nm to 1.6 % at 320 nm and, in the UV-A region, progressively from 1.9 % at 330 nm to a maximum of 13 % of incident irradiance at 400 nm. Red peel of nectarine fruit transmitted less than 0.1 % of UV-C and UV-B light, but up to 0.9 % of incident UV-A light at 400 nm. Conversely, UV-absorption of nectarine peel decreased with longer wavelengths. Hence, fruit parenchyma is more affected by UV-irradiance at wavelengths above ca. 280 nm and underneath yellow than underneath red peel

Lead Quantification in Urine Samples of Athletes by Coupling DLLME with UV-Vis Spectrophotometry.

Science.gov (United States)

Faraji, Hakim; Helalizadeh, Masoumeh

2017-04-01

Urine lead level is one of the most employed measures of lead exposure and risk. The urine samples used in this study were obtained from ten healthy male cyclists. Dispersive liquid-liquid microextraction combined with ultraviolet and visible spectrophotometry was utilized for preconcentration, extraction, and determination of lead in urine samples. Optimization of the independent variables was carried out based on chemometric methods in three steps. According to the screening and optimization study, 133 μL of CCl 4 (extracting solvent), 1.34 mL ethanol (dispersing solvent), pH 2.0, 0.00 % of salt, and 0.1 % O,O-diethyl dithiophosphoric (chelating agent) were used as the optimum independent variables for microextraction and determination of lead. Under the optimized conditions, R 2 was 0.9991, and linearity range was 0.01-100 μg L -1 . Precision was evaluated in terms of repeatability and intermediate precision, with relative standard deviations being <9.1 and <15.3 %, respectively. The accuracy was estimated using urine samples of cyclists as real samples and it was confirmed. The relative error of ≤5 % was considered significant in the method specificity study. The lead concentration mean for the cyclists was 3.79 μg L -1 in urine samples. As a result, the proposed method is a robust technique to quantify lead concentrations higher than 11.6 ng L -1 in urine samples.

Determination of astaxanthin in Haematococcus pluvialis by first-order derivative spectrophotometry.

Science.gov (United States)

Liu, Xiao Juan; Juan, Liu Xiao; Wu, Ying Hua; Hua, Wu Ying; Zhao, Li Chao; Chao, Zhao Li; Xiao, Su Yao; Yao, Xiao Su; Zhou, Ai Mei; Mei, Zhou Ai; Liu, Xin; Xin, Liu

2011-01-01

A highly selective, convenient, and precise method, first-order derivative spectrophotometry, was applied for the determination of astaxanthin in Haematococcus pluvialis. Ethyl acetate and ethanol (1:1, v/v) were found to be the best extraction solvent tested due to their high efficiency and low toxicity compared with nine other organic solvents. Astaxanthin coexisting with chlorophyll and beta-carotene was analyzed by first-order derivative spectrophotometry in order to optimize the conditions for the determination of astaxanthin. The results show that when detected at 432 nm, the interfering substances could be eliminated. The dynamic linear range was 2.0-8.0 microg/mL, with a correlation coefficient of 0.9916. The detection threshold was 0.41 microg/mL. The RSD for the determination of astaxanthin was in the range of 0.01-0.06%; the results of recovery test were 98.1-108.0%. The statistical analysis between first-order derivative spectrophotometry and HPLC by T-testing did not exceed their critical values, revealing no significant differences between these two methods. It was proved that first-order derivative spectrophotometry is a rapid and convenient method for the determination of astaxanthin in H. pluvialis that can eliminate the negative effect resulting from the coexistence of astaxanthin with chlorophyll and beta-carotene.

A Research on Determination of Lecithin in Eggs by Applying Microwave Digestion Techniques and Spectrophotometry

International Nuclear Information System (INIS)

Wu, M.; Ge, Q.L.; Gao, Y. Sh.; Chen, K. W.

2012-01-01

A method to quick detect concentration of lecithin in eggs, namely microwave digestion spectrophotometry, was established in this research. The homogenate of eggs was treated with absolute ethanol to eliminate phosphate protein in eggs which could possibly affect concentration of lecithin examined. A sample then received a new way of pre-treatment, called microwave digestion, before UV-Vis spectrometry was applied to examine the concentration of phosphate at 400 nm. The linear equation was A = 0.08628X (μg), the corresponding coefficient of correlation was 0.9998, the detection limit of phosphorous was 0.2μg (n=11). The content of lecithin in eggs was then obtained. According to the result, the recovery of 90% was secured; therefore the conclusion of high degree of accuracy was reached.

[Microwave assisted UV electrodeless discharge lamp photochemical degradation of 4-chlorophenol in aquatic solutions].

Science.gov (United States)

Ai, Zhi-hui; Jiang, Jun-qing; Yang, Peng; Zhou, Tao; Lu, Xiao-hua

2004-07-01

A microwave assisted UV electrodeless discharge lamp system (MW/UV) was used for photo-degradation of 4CP simulated wastewater. In order to evaluate the degradation efficiency of 4CP, UV spectrophotometry and ion chromatography were used for determination of 4CP and Cl- respectively. The degradation rate in MW/UV system was higher than that in the UV system within 120min, which were 52.40% and 21.56% respectively. The degradation efficiency was improved by increasing pH value of the solution, aerating O2 gas, enhancing light intensity, or adding H2O2 oxidant. The degradation of 4CP under MW/UV accords with the first order kinetics equation.

Assessment of cosmetic ingredients in the in vitro reconstructed human epidermis test method EpiSkin™ using HPLC/UPLC-spectrophotometry in the MTT-reduction assay.

Science.gov (United States)

Alépée, N; Hibatallah, J; Klaric, M; Mewes, K R; Pfannenbecker, U; McNamee, P

2016-06-01

Cosmetics Europe recently established HPLC/UPLC-spectrophotometry as a suitable alternative endpoint detection system for measurement of formazan in the MTT-reduction assay of reconstructed human tissue test methods irrespective of the test system involved. This addressed a known limitation for such test methods that use optical density for measurement of formazan and may be incompatible for evaluation of strong MTT reducer and/or coloured chemicals. To build on the original project, Cosmetics Europe has undertaken a second study that focuses on evaluation of chemicals with functionalities relevant to cosmetic products. Such chemicals were primarily identified from the Scientific Committee on Consumer Safety (SCCS) 2010 memorandum (addendum) on the in vitro test EpiSkin™ for skin irritation testing. Fifty test items were evaluated in which both standard photometry and HPLC/UPLC-spectrophotometry were used for endpoint detection. The results obtained in this study: 1) provide further support for Within Laboratory Reproducibility of HPLC-UPLC-spectrophotometry for measurement of formazan; 2) demonstrate, through use a case study with Basazol C Blue pr. 8056, that HPLC/UPLC-spectrophotometry enables determination of an in vitro classification even when this is not possible using standard photometry and 3) addresses the question raised by SCCS in their 2010 memorandum (addendum) to consider an endpoint detection system not involving optical density quantification in in vitro reconstructed human epidermis skin irritation test methods. Copyright © 2016 Elsevier Ltd. All rights reserved.

Comparative determination of phenytoin by spectrophotometry, gas chromatography, liquid chromatography, enzyme immunoassay, and radioimmunoassay

International Nuclear Information System (INIS)

Castro, A.; Ibanez, J.; DiCesare, J.L.; Adams, R.F.; Malkus, H.

1978-01-01

Sera from patients being treated with phenytoin were analyzed for the drug by spectrophotometry, gas chromatography, radioimmunoasay, enzyme immunoassay, and liquid chromatography. The assay values obtained were intercompared statistically. Enzyme immunoassay and liquid chromatography appear to be attractive alternatives to the more traditional methods of spectrophotometry and gas chromatography. Our radioimmunoassay data correlated poorly with results by the four other methods

Computer tomography of the brain and spectrophotometry of the CSF in cerebral concussion and contusion

International Nuclear Information System (INIS)

Bergvall, U.; Kjellin, K.G.; Levander, B.; Svendsen, P.; Soederstroem, C.E.

1978-01-01

Computer tomography (CT) and spectrophotometry of CSF were performed in 30 patients with the clinical diagnosis of cerebral concussion or contusion. The patients with concussion all had normal CT-findings. Spectrophotometry of CSF was sometimes positive for cerebral contusion with normal CT-findings, but the two methods were complementary so that the extent of the lesion was determined by CT and spectrophotometry of CSF indicated the cause. (Auth.)

On image tube spectrophotometry of weak emission lines

International Nuclear Information System (INIS)

Duflot, R.

1979-01-01

The usual precision of image tube spectrophotometry measures relative to low intensity lines can be improved by the 'method of two lines'. This operating process tested on H II galactic regions leads to a precision of 13%. (Auth.)

Defects in UV-vis-NIR reflectance spectra as method for forgery detections in writing documents

Energy Technology Data Exchange (ETDEWEB)

Somma, F; Aloe, P; Schirripa Spagnolo, G

2010-11-01

Documents have taken up a very important place in our society. Frauds committed in connection with documents are not at all uncommon, and, in fact, represent a very large domain of the forensic science called 'questioned documents'. In the field of forensic examination of questioned documents, the legitimacy of an ink entry is often an essential question. A common type of forgery consists in materially altering an existing writing or adding a new writing. These changes can be characterized by means of optical spectroscopy. The aim of this work is to perform the UV-vis-NIR reflectance spectrophotometry to analyze a range of blue and black commercial ballpoint pens, in order to investigate the discriminating abilities of the different inks found on the same document.

Microwave Synthesized ZnO Nanorod Arrays for UV Sensors: A Seed Layer Annealing Temperature Study.

Science.gov (United States)

Pimentel, Ana; Ferreira, Sofia Henriques; Nunes, Daniela; Calmeiro, Tomas; Martins, Rodrigo; Fortunato, Elvira

2016-04-20

The present work reports the influence of zinc oxide (ZnO) seed layer annealing temperature on structural, optical and electrical properties of ZnO nanorod arrays, synthesized by hydrothermal method assisted by microwave radiation, to be used as UV sensors. The ZnO seed layer was produced using the spin-coating method and several annealing temperatures, ranging from 100 to 500 °C, have been tested. X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and spectrophotometry measurements have been used to investigate the structure, morphology, and optical properties variations of the produced ZnO nanorod arrays regarding the seed layer annealing temperatures employed. After the growth of ZnO nanorod arrays, the whole structure was tested as UV sensors, showing an increase in the sensitivity with the increase of seed layer annealing temperature. The UV sensor response of ZnO nanorod arrays produced with the seed layer annealed temperature of 500 °C was 50 times superior to the ones produced with a seed layer annealed at 100 °C.

UV Spectrophotometry of the Galilean Satellites, Saturnian Satellites & Selected Asteroids

Science.gov (United States)

Nelson, Robert M.

We propose a series of ultraviolet spectral observations of solid surfaces of selected solar system objects, specifically the Galilean satellites of Jupiter, several atmosphereless satellites of Saturn, and the asteroids, 5 Astraea, 18 Melpomene, 532 Herculina, 68 Leto, 31 Euphmsyne, 80 Sappho, 3 Juno, and 39 Laetitia. Historically such spectral observations have allowed for the Identification of spectrally active solid state materials on planetary surfaces. Furthermore, because the rotational properties are known for all the objects proposed for study, this technique will provide a longitude map of such materials on the objects' surfaces. The study of asteroid surface mineralogy is an important method of constraining solar system formation models. The asteroid spectra we have previously acquired with IUE have created unique subdivisions within the existent asteroid types. The new spectra will provide more sophisticated mineralogical characterizations of asteroid surface materials. Our other accomplishments with IUE include mapping of the distribution of condensed S02 on Io, identification of a longitudinal asymmetry on Europa associated with magnetospheric particle bombardment of the surface, and establishing the ultraviolet geometric albedo variation as a function of longitude for all the Galilean satellites. Because Io is the most volcanically active body In the solar system, and short tern variations in selected regions of the Jovian magnetosphere are known to occur, it is important to periodically check for temporal variations in the spectra of the Galilean satellites that may be due to variations n Io tectonic/volcanic activity, or magnetosphere changes. These proposed UV observations are critical to the design and operation of several instruments on Project Galileo, NASA's Jupiter Orbiter and Probe Mission. Spectra of Iapetus, Rhea and Dione have been acquired during the previous year; however, only at orbital locations near elongation. In addition, the dark

Use of HPLC/UPLC-spectrophotometry for detection of formazan in in vitro Reconstructed human Tissue (RhT)-based test methods employing the MTT-reduction assay to expand their applicability to strongly coloured test chemicals.

Science.gov (United States)

Alépée, N; Barroso, J; De Smedt, A; De Wever, B; Hibatallah, J; Klaric, M; Mewes, K R; Millet, M; Pfannenbecker, U; Tailhardat, M; Templier, M; McNamee, P

2015-06-01

A number of in vitro test methods using Reconstructed human Tissues (RhT) are regulatory accepted for evaluation of skin corrosion/irritation. In such methods, test chemical corrosion/irritation potential is determined by measuring tissue viability using the photometric MTT-reduction assay. A known limitation of this assay is possible interference of strongly coloured test chemicals with measurement of formazan by absorbance (OD). To address this, Cosmetics Europe evaluated use of HPLC/UPLC-spectrophotometry as an alternative formazan measurement system. Using the approach recommended by the FDA guidance for validation of bio-analytical methods, three independent laboratories established and qualified their HPLC/UPLC-spectrophotometry systems to reproducibly measure formazan from tissue extracts. Up to 26 chemicals were then tested in RhT test systems for eye/skin irritation and skin corrosion. Results support that: (1) HPLC/UPLC-spectrophotometry formazan measurement is highly reproducible; (2) formazan measurement by HPLC/UPLC-spectrophotometry and OD gave almost identical tissue viabilities for test chemicals not exhibiting colour interference nor direct MTT reduction; (3) independent of the test system used, HPLC/UPLC-spectrophotometry can measure formazan for strongly coloured test chemicals when this is not possible by absorbance only. It is therefore recommended that HPLC/UPLC-spectrophotometry to measure formazan be included in the procedures of in vitro RhT-based test methods, irrespective of the test system used and the toxicity endpoint evaluated to extend the applicability of these test methods to strongly coloured chemicals. Copyright © 2015 Elsevier Ltd. All rights reserved.

Zirconium determination in rocks by solid-phase spectrophotometry

International Nuclear Information System (INIS)

Brykina, G.D.; Lebedeva, G.G.; Agapova, G.F.; AN SSSR, Moscow

1990-01-01

A method was developed for determination of zirconium in rocks by solid-phase spectrophotometry using AV-17x8-Cl anion exchanger modified with xylenol orange. Relative standard deviation at the level of (2-4.9)x10 -3 % ZrO 2 was about 0.245

Enhanced Sensitivity to Detection Nanomolar Level of Cu2 + Compared to Spectrophotometry Method by Functionalized Gold Nanoparticles: Design of Sensor Assisted by Exploiting First-order Data with Chemometrics

Science.gov (United States)

Rasouli, Zolaikha; Ghavami, Raouf

2018-02-01

A simple, sensitive and efficient colorimetric assay platform for the determination of Cu2 + was proposed with the aim of developing sensitive detection based on the aggregation of AuNPs in presence of a histamine H2-receptor antagonist (famotidine, FAM) as recognition site. This study is the first to demonstrate that the molar extinction coefficients of the complexes formed by FAM and Cu2 + are very low (by analyzing the chemometrics methods on the first order data arising from different metal to ligand ratio method), leading to the undesirable sensitivity of FAM-based assays. To resolve the problem of low sensitivity, the colorimetry method based on the Cu2 +-induced aggregation of AuNPs functionalized with FAM was introduced. This procedure is accompanied by a color change from bright red to blue which can be observed with the naked eyes. Detection sensitivity obtained by the developed method increased about 100 fold compared with the spectrophotometry method. This sensor exhibited a good linear relation between the absorbance ratios at 670 to 520 nm (A670/520) and the concentration in the range 2-110 nM with LOD = 0.76 nM. The satisfactory analytical performance of the proposed sensor facilitates the development of simple and affordable UV-Vis chemosensors for environmental applications.

Determination of Tetracycline in Pharmaceutical Preparation by Molecular and Atomic Absorption Spectrophotometry and High Performance Liquid Chromatography via Complex Formation with Au(III) and Hg(II) Ions in Solutions

Science.gov (United States)

Abdulghani, Ahlam Jameel; Jasim, Hadi Hassan; Hassan, Abbas Shebeeb

2013-01-01

UV-visible and atomic spectrophotometry and HPLC techniques were applied for the determination of tetracycline (TC) in pharmaceutical preparations via complexation of the drug with Au(III) and Hg(II) ions in solutions. The mole ratio of TC to metal ions was 1 : 1. Maximum peak absorption at λ 425 and 320 nm for the two ions, respectively, was optimized at heating temperature 75°C for 15 minutes at pH = 4 followed by the extraction with ethyl acetate. The percentage of extraction and stability constants for the two complexes was 95.247, 95.335% and 2.518 × 104, 1.162 × 105 M−1, respectively. HPLC method was applied without extraction process. The analytical data obtained from direct calibration curves of UV-visible absorption, FAAS, and HPLC for Au(III) complexes were recovery (100.78, 104.85, and 101.777%, resp.); detection limits (0.7403, 0.0997, and 2.647 μg/ml, resp.); linearity (5–70, 5–30, and 10–150 μg/ml, resp.), and correlation coefficient (0.9991, 0.9967, and 0.9986, resp.). The analytical data obtained from direct calibration curves for Hg(II) complexes by UV-visible spectrophotometry and HPLC were recovery (100.95 and 102.000%, resp.); detection limits (0.5867 and 2.532 μg/ml, resp.); linearity (5–70 and 10–150 μg/ml, resp.); and correlation coefficients (0.9989 and 0.9997, resp.). PMID:23853607

Spectrophotometry of RR Telescopii

International Nuclear Information System (INIS)

Walker, A.R.

1977-01-01

The strongest emission lines in the nova-like variable RR Telescopii were measured during late 1974 using a spectrum scanner. The wavelength range 3350 to 7700 A was scanned with a resolution of 50 A. The results are compared with published spectrophotometry covering the period 1961 to 72, with the conclusion that few changes have taken place in the last 6 yr. No evidence was found that suggested the existence of a cool star, nor was there any indication of night-to-night changes in the emission line intensities. The spectrophotometry of the past 15 yr is consistent with an expanding shell, the emission from this shell being caused by high-energy radiation from an underlying star. (author)

Analytical application of derivative spectrophotometry

Directory of Open Access Journals (Sweden)

VIOLETA M. STEFANOVIC

2000-07-01

Full Text Available 1. Introduction 2. Basic characteristics of derivative spectrophotometry 2.1. Increase of spectra resolution 2.2. Elimination of the influence of baseline shift and matrix interferences 2.3. Enhancement of the detectability of minor spectral features 2.4. Precise determination of the positions of absorption maxima 2.5. Signal-to-noise ratio (SNR 2.6. Quantitative analysis 3. Analytical applications 3.1. Inorganic analysis 3.2. Organic and pharmaceutical analysis 3.3. Analysis of food and water 3.4. Application of derivative spectrophotometry for the determination of equilibrium constants

In situ, rapid, and temporally resolved measurements of cellulase adsorption onto lignocellulosic substrates by UV-vis spectrophotometry

Science.gov (United States)

Hao Liu; J. Y. Zhu; X. S. Chai

2011-01-01

This study demonstrated two in situ UV-vis spectrophotometric methods for rapid and temporally resolved measurements of cellulase adsorption onto cellulosic and lignocellulosic substrates during enzymatic hydrolysis. The cellulase protein absorption peak at 280 nm was used for quantification. The spectral interferences from light scattering by small fibers (fines) and...

Four Brazilian Maytenus salicifolia Reissek (Celastraceae groups studied by TLC and UV/Vis spectrophotometry

Directory of Open Access Journals (Sweden)

Frederico N. Valladão

Full Text Available The great variety of angiosperms shows the need to development of botanical classification systems supported by phytochemistry, biochemistry and others. Recently, techniques of analysis used for the isolation and characterization of secondary metabolites have been employed as auxiliary quick and efficient methods for the identification and classification of plant species. M. salicifolia is popularly known in Brazil, as "small coffee" and decoct obtained from its fresh leaves is topically used to alleviate itches and other skins allergic symptoms. This work presents the use of TLC and UV/Vis spectrophotomety processes to be applied like an auxiliary method in botanical taxonomy. The results demonstrate that this process can be used in differentiation of the same genera species, and in the selection of chemical variations between individuals of the same species.

Review of recent applications of flow injection spectrophotometry to pharmaceutical analysis

International Nuclear Information System (INIS)

Tzanavaras, Paraskevas D.; Themelis, Demetrius G.

2007-01-01

Pharmaceutical analysis is one of the most important fields in analytical chemistry. The discovery of new drugs and the on-going update of international regulations for the safety and efficacy of pharmaceutical formulations demand the continuous development of new analytical methods. Inevitably, automation plays an important role, especially when a lot of samples have to be analyzed in the minimum of time. The present study reviews the applications of flow injection (FI) spectrophotometry to the determination of active pharmaceutical ingredients (APIs) in their respective formulations. However, the topic covered in this study is important not only to pharmaceutical analytical scientists. The principles, figures of merit and 'chemistry' of the presented methods can be of interest to bio-analytical and clinical chemists as well for the analysis of biological samples, to environmental analysts that study the up-to-date demand of the determination of the fate of pharmaceuticals in the environment and even to toxicologists and forensic scientists. This review covers scientific contributions published later than 2000. A variety of FI procedures based on homogeneous (direct UV measurements, colour-forming reactions, metal-drug interactions) and heterogeneous (optical sensors and solid-phase reactors) systems are discussed. A third section covers on-line sample pretreatment (solid-phase extraction, liquid-liquid extraction, on-line digestion, etc.)

Determination of tantalum in standard steels by INAA and absorption spectrophotometry

Energy Technology Data Exchange (ETDEWEB)

Obrusnik, I; Posta, S [Ustav Jaderneho Vyzkumu, Rez (Czechoslovakia)

1978-02-14

Two analytical methods, instrumental neutron activation analysis (INAA) and absorption spectrophotometry with malachite green, have been used for the determination of tantalum in standard steels produced by the Research Institute of CKD Prague - steels No. 167 and No. 169 with expected concentrations of Ta 0.01% and 0.03%, respectively. INAA method consisted of irradiation of steel samples (chips) in a nuclear reactor and Ge(Li) ..gamma..-ray spectrometry after a cooling period of one month. A spectrophotometric determination is based on the extraction of ionic associate of TaF/sub 6//sup -/ with malachite green into Oenzene from a solution of diluted sulphuric acid and hydrofluoric acid. The results obtained by the two methods are in a good agreement. However, INAA method is more sensitive and precise then spectrophotometry for the determination of tantalum in steels in the above-mentioned concentration ranges.

Determination of tantalum in standard steels by INAA and absorption spectrophotometry

International Nuclear Information System (INIS)

Obrusnik, I.; Posta, S.

1978-01-01

Two analytical methods, instrumental neutron activation analysis (INAA) and absorption spectrophotometry with malachite green, have been used for the determination of tantalum in standard steels produced by the Research Institute of CKD Prague - steels No. 167 and No. 169 with expected concentrations of Ta 0.01% and 0.03%, respectively. INAA method consisted of irradiation of steel samples (chips) in a nuclear reactor and Ge(Li) γ-ray spectrometry after a cooling period of one month. A spectrophotometric determination is based on the extraction of ionic associate of TaF 6 - with malachite green into Oenzene from a solution of diluted sulphuric acid and hydrofluoric acid. The results obtained by the two methods are in a good agreement. However, INAA method is more sensitive and precise then spectrophotometry for the determination of tantalum in steels in the above-mentioned concentration ranges. (author)

Indirect determination of uranium by atomic-absorption spectrophotometry using an air-acetylene flame

International Nuclear Information System (INIS)

Alder, J.F.; Das, B.C.

1977-01-01

An indirect method has been developed for the determination of uranium by atomic-absorption spectrophotometry using an air-acetylene flame. Use is made of the reduction of copper(II) by uranium(IV) followed by complex formation of the copper(I) ions so produced with neocuproine (2,9-dimethyl-1,10-phenanthroline) and finally the determination of copper in this complex by atomic-absorption spectrophotometry. The results show that the method can be recommended, provided that care is taken to ensure the complete reduction of uranium(VI) to uranium(IV). The sensitivity of the method is 4.9 μg of uranium and the upper limit 500 μg without dilution. (author)

A Critical Comparison of Methods for the Analysis of Indigo in Dyeing Liquors and Effluents

Directory of Open Access Journals (Sweden)

Valentina Buscio

2014-08-01

Full Text Available Indigo is one of the most important dyes in the textile industry. The control of the indigo concentration in dyeing liquors and effluents is an important tool to ensure the reproducibility of the dyed fabrics and also to establish the efficiency of the wastewater treatment. In this work, three analytical methods were studied and validated with the aim to select a reliable, fast and automated method for the indigo dye determination. The first method is based on the extraction of the dye, with chloroform, in its oxidized form. The organic solution is measured by Ultraviolet (UV-visible spectrophotometry at 604 nm. The second method determines the concentration of indigo in its leuco form in aqueous medium by UV-visible spectrophotometry at 407 nm. Finally, in the last method, the concentration of indigo is determined by redox titration with potassium hexacyanoferrate (K3(Fe(CN6. The results indicated that the three methods that we studied met the established acceptance criteria regarding accuracy and precision. However, the third method was considered the most adequate for application on an industrial scale due to its wider work range, which provides a significant advantage over the others.

UV-durable superhydrophobic textiles with UV-shielding properties by coating fibers with ZnO/SiO2 core/shell particles

Science.gov (United States)

Xue, Chao-Hua; Yin, Wei; Jia, Shun-Tian; Ma, Jian-Zhong

2011-10-01

ZnO/SiO2 core/shell particles were fabricated by successive coating of multilayer polyelectrolytes and then a SiO2 shell onto ZnO particles. The as-prepared ZnO/SiO2 core/shell particles were coated on poly(ethylene terephthalate) (PET) textiles, followed by hydrophobization with hexadecyltrimethoxysilane, to fabricate superhydrophobic surfaces with UV-shielding properties. Transmission electron microscopy and ζ potential analysis were employed to evidence the fabrication of ZnO/SiO2 core/shell particles. Scanning electron microscopy and thermal gravimetric analysis were conducted to investigate the surface morphologies of the textile and the coating of the fibers. Ultraviolet-visible spectrophotometry and contact angle measurement indicated that the incorporation of ZnO onto fibers imparted UV-blocking properties to the textile surface, while the coating of SiO2 shell on ZnO prohibited the photocatalytic degradation of hexadecyltrimethoxysilane by ZnO, making the as-treated PET textile surface show stable superhydrophobicity with good UV-shielding properties.

A general approach to quantification of hydroxycinnamic acid derivatives and flavones, flavonols, and their glycosides by UV spectrophotometry

Science.gov (United States)

A general method was developed for the quantification of hydroxycinnamic acid derivatives and flavones, flavonols, and their glycosides based on the UV molar relative response factors (MRRF) of the standards. Each of these phenolic compounds contains a cinnamoyl structure and has a maximum absorban...

Absolute spectrophotometry of Nova Cygni 1975

International Nuclear Information System (INIS)

Kontizas, E.; Kontizas, M.; Smyth, M.J.

1976-01-01

Radiometric photoelectric spectrophotometry of Nova Cygni 1975 was carried out on 1975 August 31, September 2, 3. α Lyr was used as reference star and its absolute spectral energy distribution was used to reduce the spectrophotometry of the nova to absolute units. Emission strengths of Hα, Hβ, Hγ (in W cm -2 ) were derived. The Balmer decrement Hα:Hβ:Hγ was compared with theory, and found to deviate less than had been reported for an earlier nova. (author)

Europium determination in oxide and oxysulfide luminophors and their wastes by the method of direct and derivative spectrophotometry

International Nuclear Information System (INIS)

Mishchenko, V.T.; Aleksandrova, N.N.

1989-01-01

Spectrophotometric methods for europium determination in luminophors are proposed. Application of standard and derivative spectrophotometry allows one to determine europium in oxide and oxysulfide luminophors, their wastes and raffinates produced during waste reprocessing quite accurately and reliably. When determining Eu 2 O 3 (Eu 2 O 2 S) mass shares within 4-8 % limits absolute deviation from the mean result makes up to more than ± 0.2 %, relative standard deviation does not exceed 0.02

Desenvolvimento e validação de um método analítico por espectrofotometria UV para quantificação de carvedilol

Directory of Open Access Journals (Sweden)

Paola Aline Amarante Borba

2013-01-01

Full Text Available This paper reports the development and validation of a new analytical method using UV spectrophotometry to quantify carvedilol (CRV in hydrophilic matrices and raw material. This method was shown to be linear, accurate, precise, robust and to have adequate limits of quantification and detection (LQ and LD, respectively, allowing its use in the dissolution test of hydrophilic matrices. The content of CRV determined through this method was compared with two previously validated methods based on the reference techniques of High Performance Liquid Chromatography (HPLC and Potentiometric Titrations (PT. ANOVA confirmed the equivalence of these methods, showing no significant differences.

Objective-prism spectrophotometry of quasars

International Nuclear Information System (INIS)

Clowes, R.G.

1980-01-01

A procedure is derived for obtaining low-resolution spectrophotometry of quasars directly from the objective-prism plates on which they were discovered. Measurements with a PDS microdensitometer of approximately 130 quasar candidates in approximately the central 19 square degrees of the UK Schmidt prism plate UJ3682P were used in the application of the procedure. The success of the objective-prism spectrophotometry is demonstrated in a comparison with 12 slit spectra. Redshifts and equivalent widths can be determined with typical discrepancies of 1% and 40% respectively. This work on objective-prism spectrophotometry leads to a quantification of the selection effects that operate in the searches for emission-line objects on objective-prism plates. The quantification successfully explains an apparent discrepancy in the detection efficiencies of the CTIO-4m and Curtis Schmidt surveys for quasars. Spectra of quasars that were observed with the Image Photon Counting System on the Anglo-Australian Telescope are presented. The observations of quasars with broad absorption troughs indicate the ejection of matter with velocities up to approximately 22000kms -1 and with velocity dispersions up to approximately 11000kms -1 . Data on the wavelength dependences of the contrast γ and the grain response function g of the Kodak emulsion IIIaJ are presented. (author)

Analysis of N-nitrosodiethylamine by ion chromatography coupled with UV photolysis pretreatment

Directory of Open Access Journals (Sweden)

Xueli Li

2016-04-01

Full Text Available Nitrosamines such as N-nitrosodiethylamine (NDEA are commonly detected by spectrophotometry after photolysis and Griess reaction (PG in food industries for lower cost. Results of this research indicate that NDEA decays rapidly under UV irradiation, and concentrations of the generated NO2− and NO3− ions vary with photolysis conditions. Thus, the measurement of the PG method may be inconsistent because it is based on the amount of photoproduced NO2−. In addition, more errors may be present in the PG method since NO3− cannot be measured colorimetrically using Griess reagent. In this work, the sum of the concentrations of photoproduced NO2− and NO3− was found to be equivalent to the initial NDEA before photolysis, and a photolysis–ion chromatography method was validated, which may serve as a feasible and accurate method to determine nitrosamines.

Improving the submicro determination of vanadium in natural water using primary-secondary wavelength spectrophotometry

International Nuclear Information System (INIS)

Khongven Gao

1999-01-01

In acidic solution and in the presence of ammonium persulfate, the conventional reaction of vanadium(5) with gallic acid to form an orange complex has been used for the improvement of the determination of trace amounts of vanadium in water by the updated method named primary-secondary wavelength spectrophotometry. The results show that the analytical precision and accuracy were improved and gave higher determination sensitivity than ordinary spectrophotometry. The relative standard deviations were less than 5.6 % [ru

A new dyed ECE track identification method for nuclear particle detection

International Nuclear Information System (INIS)

Sohrabi, M.; Bojd, S.S.

1990-01-01

A new procedure for obtaining highly contrasted red-dyed electrochemically etched recoil tracks in polymers such as polycarbonate (PC) and CR-39 has been successfully developed for spectrophotometry as applied to neutron dosimetry. The principal rationale in this method has been the provision of highly contrasted, photon-absorbing, large, dyed recoil tracks in an unaffected bulk material. The method consists of: (a) exposing the polymer to charged particles or neutrons; (b) electrochemical etching of the tracks; (c) acid sensitization; (d) dyeing with an appropriate dye. By investigation of the type, concentration, duration and temperature of the acid and the dye, optimized values of 20% by weight acrylic acid at 75 0 C for 3.5 h for sensitization, and 3% by weight eosin bluish dye at 95 0 C for 4 h for dyeing, provided a nearly 100% dyed-track efficiency. Spectrophotometry by UV and infrared radiation track counting, and optical densitometry were applied to the dyed samples. The results have shown some promise for UV absorbance measurements in routine large-scale applications. In this paper, the results of optimization studies and preliminary application of the technique to neutron dosimetry are presented and discussed. (author)

A simple and efficient ultrasonic-assisted extraction procedure combined with UV-Vis spectrophotometry for the pre-concentration and determination of folic acid (vitamin B9) in various sample matrices.

Science.gov (United States)

Gürkan, Ramazan; Altunay, Nail

2016-07-01

A simple and efficient ultrasonic-assisted extraction (UAE) procedure has been proposed for the pre-concentration of (2S)-2-[(4-{[(2-amino-4-hydroxypteridin-yl)methyl]amino}phenyl)formamido]pentanedioic acid (folic acid) in vegetables, pharmaceuticals and foods prior to determination at 540 nm using UV-Vis spectrophotometry. The method is based on hydrophobic ternary complex formation of folic acid with silver ions in the presence of cetyltrimethylammonium bromide (CTAB) as a sensitivity enhancer counter ion at pH 7.0, and then extraction into a micellar phase of polyethylene glycol monoalkyl ether (Genapol X-080). The impacts on the extraction efficiency and complex formation of analytical parameters such as sample pH, concentration of silver, concentration of surfactants and extraction time, ultrasonic time and sample volume, were investigated and optimised in detail. The matrix effect on the pre-concentration and determination of folic acid was investigated, and it was observed that the proposed method was highly selective against possible matrix co-extractives. Under optimised conditions, a good linear relationship between the analytical signal and folic acid concentration was obtained in the range of 0.6-180 μg l(-1) with a detection limit of 0.19 μg l(-1) and quantification limit of 0.63 μg l(-1). The applicability was evaluated using samples fortified at different concentration levels, and recoveries higher than 94.1% were obtained. The precision as the percent relative standard deviation (RSD%) was in range of 2.5-3.8% (10 and 40 μg l(-1), n = 5). The proposed method was validated by analysis of two standard reference materials (SRMs) and various real samples, and satisfactory results were obtained.

Extraction of phenolic compounds from extra virgin olive oil by a natural deep eutectic solvent: Data on UV absorption of the extracts

Directory of Open Access Journals (Sweden)

Vito Michele Paradiso

2016-09-01

Full Text Available This data article refers to the paper “Towards green analysis of virgin olive oil phenolic compounds: extraction by a natural deep eutectic solvent and direct spectrophotometric detection” [1]. A deep eutectic solvent (DES based on lactic acid and glucose was used as green solvent for phenolic compounds. Eight standard phenolic compounds were solubilized in the DES. Then, a set of extra virgin olive oil (EVOO samples (n=65 were submitted to liquid–liquid extraction by the DES. The standard solutions and the extracts were analyzed by UV spectrophotometry. This article reports the spectral data of both the standard solutions and the 65 extracts, as well as the total phenolic content of the corresponding oils, assessed by the Folin–Ciocalteu assay. Keywords: Natural deep eutectic solvents, Extra virgin olive oil, Phenolic compounds, UV spectrophotometry

Measurement of uranium concentration by molecular absorption spectrophotometry by means optical fibers

International Nuclear Information System (INIS)

Gauna, Alberto C.; Pascale, Ariel A.

1996-01-01

An on-line method for measuring the concentration of uranium in uranyl nitrate-nitric acid aqueous solutions is described. The method is based on molecular absorption spectrophotometry with transmission of light by means of optical fibers. It is ideally suited for control and processes development applications. (author)

Synthesis of Graphene-CdSe Composite by a Simple Hydrothermal Method and Its Photocatalytic Degradation of Organic Dyes

Institute of Scientific and Technical Information of China (English)

OH Won-Chun; CHEN Mingliang; CHO Kwangyoun; KIM Cheolkyu; MENG Zeda; ZHULei

2011-01-01

A graphene-CdSe composite was synthesized by a facile hydrothermal method,and characterized by X-ray diffiraction,scanning electron microscopy with energy dispersive X-ray analysis,transmission electron microscopy and UV-vis diffuse reflectance spectrophotometry.The graphene-CdSe composite efficiently catalyzed the photodegradation of methylene blue (MB),methyl orange (MO) and rhodamine B (Rh.B) in aqueous solution under UV or visible light irradiation.The graphene-CdSe composite exhibited a higher photocatalytic activity for the MB solution.

[Noninvasive total hemoglobin monitoring based on multiwave spectrophotometry in obstetrics and gynecology].

Science.gov (United States)

Pyregov, A V; Ovechkin, A Iu; Petrov, S V

2012-01-01

Results of prospective randomized comparative research of 2 total hemoglobin estimation methods are presented. There were laboratory tests and continuous noninvasive technique with multiwave spectrophotometry on the Masimo Rainbow SET. Research was carried out in two stages. At the 1st stage (gynecology)--67 patients were included and in second stage (obstetrics)--44 patients during and after Cesarean section. The standard deviation of noninvasive total hemoglobin estimation from absolute values (invasive) was 7.2 and 4.1%, an standard deviation in a sample--5.2 and 2.7 % in gynecologic operations and surgical delivery respectively, that confirms lack of reliable indicators differences. The method of continuous noninvasive total hemoglobin estimation with multiwave spectrophotometry on the Masimo Rainbow SET technology can be recommended for use in obstetrics and gynecology.

Biosythesis of Silver Nanoparticles using Putri Malu (Mimosa pudica Leaves Extract and Microwave Irradiation Method

Directory of Open Access Journals (Sweden)

Is Fatimah

2016-11-01

Full Text Available In this paper, the biosynthesis of silver nanoparticles (AgNPs using Mimosa pudica extract is discussed. Mimosa pudica leaves extract using water as solvent was used as bio-reductor to an aqueous solution of silver nitrate (AgNO3 and in order to accelerate the reduction, microwave irradiation method was applied. The AgNPs obtained were characterized using UV-Vis spectrophotometry, FTIR spectrophotometry, XRD, SEM-EDX, and particle size analysis based on dynamic scattering method. Effect of preparation method to the formation of AgNPs is also evaluated in antibacterial activity towards E.coli and P. aeruginosa. Rapid and ecofriendly biosynthesis of stable silver nanoparticles was observed in this study. The characterization results and antibacterial assay indicated the uniform and smaller particle size of AgNPs obtained by using microwave method and positively enhance the antibacterial activity against tested bacteria.

Water contentwater of determination of cationic polystyrene sulfonate resins by infrared spectrophotometry

International Nuclear Information System (INIS)

Noki, V.

1987-01-01

A method of the determination of water content in polystyrene sulfonate ion-exchange resins in the presence of alkaline earth counter-ions by I.R. spectrophotometry is proposed. This method does not hold in the case of transition metal due to the formation of coordinated complexes with water molecules.

Micro-lightguide spectrophotometry for tissue perfusion in ischemic limbs

DEFF Research Database (Denmark)

Jørgensen, Lise Pyndt; Schroeder, Torben V

2012-01-01

To validate micro-lightguide spectrophotometry (O2C) in patients with lower limb ischemia and to compare results with those obtained from toe blood pressure.......To validate micro-lightguide spectrophotometry (O2C) in patients with lower limb ischemia and to compare results with those obtained from toe blood pressure....

UV-induced changes of structural and functional properties of blood lactatedehydrogenase isoenzymes in free sate and in the presence of serotonin

International Nuclear Information System (INIS)

Nakvasina, M.A.; Artyukhov, V.G.; Agisheva, N.V.

1999-01-01

Photoinduced changes in structural and functional properties of lactatedehydrogenase isoenzymes from human erythrocytes in free state and in the presence of serotonin have been studied by means of gel chromatography, electrophoresis, IR-spectrophotometry and by the method of definition of catalytic activity. UV radiation exposure induces photoinactivation of erythrocytes lactatedehydrogenase, while its inhibitory effect intensifies with the increase of radiation dose. Pronounced photoprotective effect of serotonin towards the molecules of erythrocytic lactatedehydrogenase isoenzymes has been discovered. It seems to be caused by formation of enzyme - biogenic amine complex affecting the secondary protein structure [ru

Simultaneous estimation of etodolac and thiocolchicoside in bulk and in tablet formulation by UV-spectrophotometry

Directory of Open Access Journals (Sweden)

Pandey Ramchandra

2014-01-01

Full Text Available Two simple, rapid and reproducible simultaneous equation and Q-Analysis UV-Spectrophotometric methods have been developed for simultaneous estimation of Etodolac (ETO and Thiocolchicoside (THC in combined tablet dosage form. The methods involved solving simultaneous equations and Q-value Analysis based on measurement of absorbance at wavelengths, 223 (λmax of ETO, 259.4 nm (λmax of THC and 236 nm (Iso-absorptive point. Linearity was found in the concentration range of 1-6 μg/mL and 4 - 24 μg/mL for ETO & THC respectively with coefficient correlation 0.9998 & 0.9992. The amount of drugs estimated by proposed methods are in excellent agreement with label claimed. Further-more, the methods were applied for the determination of ETO and THC in spiked human urine. The degradation behavior of ETO and THC was investigated under acid hydrolysis, alkali hydrolysis, photo and oxidative degradation. The samples subsequently generated were used for degradation studies using the developed method. Thiocolchicoside was found to degrade extensively under alkali hydrolysis and unaffected by other stress conditions while ETO was found to be stable in all stress conditions. The methods were validated according to ICH guidelines. The method, suitable for routine quality control, has been successfully applied to the determination of both drugs in commercial brands of tablets.

Single-laboratory evaluation of SW-846 Methods 7090/7091 determination of beryllium by flame and furnace atomic absorption spectrophotometry. Summary report January-August 1987

International Nuclear Information System (INIS)

Hodge, V.F.; Darby, D.A.; Thompson, W.E.; Jones, C.L.

1988-02-01

The results of a single-laboratory study of the Determination of Beryllium by Flame and Furnace Atomic Absorption Spectrophotometry, are described. The study examined the application of these two powerful beryllium detection methods to the analysis of selected liquid and solid samples after digestion by appropriate SW-846 methods. Method performance data including detection limits, optimum concentration ranges (linearity), spike recoveries, interferences, precision, accuracy, and optimum operating parameters are presented and discussed

Simultaneous determination of sulphaquinoxaline and amprolium in veterinary mixture by HPLC and first derivative ultraviolet spectrophotometry

International Nuclear Information System (INIS)

El-Sattar, Osama Abd

2002-01-01

Two simple and reliable methods are described for the determination of sulphaquinoxaline (SQX) and amprolium (AMP) combined in veterinary powder. The first method depends on high performance liquid chromatography on a reversed phase column (Bondapak-C18) using mobile phase consisting of acetonitrile-methanol-water-phosphoric acid (30: 5: 55: 0.7, by volumes) at a flow rate of 1 ml min with UV detection at 254 nm. The detection limits were 0.2 ug ml and 0.35 ug ml and linearity ranges were 2-20 ug ml and 4-40ug ml for SQX and AMP, respectively. The second one deals with the first derivative (D) spectrophotometry with zero-crossing measurement at 253 nm and 226 nm for SQX and AMP respectively. The detection limits were 0.3 ug ml and linearity ranges were 1-18 ug ml and 4-32 ug-ml for SQX and AMP respectively. The proposed procedures were successfully applied to the determination of these drugs in laboratory prepared mixtures with mean percentage recovery ranged from 98.50 to 99.75 and in commercial preparation ranged from 103.85 to 104.85. (author)

A method for evaluation of UV and biologically effective exposures to plants

International Nuclear Information System (INIS)

Paris, A.V.; Southern Queensland Univ., Toowoomba, QLD; Wong, J.C.F.; Galea, V.

1996-01-01

This paper presents a method for evaluating the UV and biologically effective exposures to a plant canopy during the irradiation of soybean with supplemental levels of UV radiation in a greenhouse study. The method employs four materials as dosimeters that allow evaluation of the UV spectra. The exposures evaluated at three growth stages were less by factors of 0.44, 0.49 and 0.56 compared to the ambient exposures. At the end of the irradiation period, the ambient biologically effective exposure for generalized plant response was higher by 180% compared to that calculated over the canopy. This is the magnitude of the error in UV studies that provide the ambient exposure as a measure of the UV incident on the plant. Additionally, the difference between the ambient and canopy exposures varied during the growth stages. These results indicate that the dosimetric technique applied to evaluating the UV exposures over a plant canopy is a more accurate representation of the UV exposure incidence on a plant than any obtained by measuring the ambient exposures only. (Author)

Spectrophotometry of cerebrospinal fluid in subacute and chronic subdural haematomas

Science.gov (United States)

Kjellin, K. G.; Steiner, L.

1974-01-01

Spectrophotometric examinations were performed on cerebrospinal and subdural fluids in subacute (five patients) and chronic (20 patients) subdural haematomas, with special reference to the diagnostic aid of CSF spectrophotometry. Spectrophotometric xanthochromia of haemorrhagic origin was found in all CSFs examined, while definite visible xanthochromia was observed in only 28% and the CSF was judged as colourless in 52% of those cases. Characteristic bleeding patterns were found spectrophotometrically in all the 20 CSFs examined within 24 hours after lumbar puncture, haematoma patterns being detected in 90-95% of the cases. In many cases the electrophoretically separated protein fractions of CSF and subdural fluids were spectrophotometrically examined. In conclusion, CSF spectrophotometry is a simple, fast, and extremely sensitive method, which in our opinion should be used routinely in the diagnosis of suspected subdural haematomas, if lumbar puncture is not contraindicated. PMID:4140892

An Overview of Analytical Determination of Diltiazem, Cimetidine, Ranitidine, and Famotidine by UV Spectrophotometry and HPLC Technique

Directory of Open Access Journals (Sweden)

Nighat Shafi

2013-01-01

Full Text Available This review article recapitulates the analytical methods for the quantitative determinations of diltiazem and three H2 receptor antagonists (cimetidine, ranitidine, and famotidine by one of the spectroscopic technique (UV spectrophotometery and separation technique such as high-performance liquid chromatography (HPLC. The clinical and pharmaceutical analysis of these drugs requires effective analytical procedures for quality control, pharmaceutical dosage formulations, and biological fluids. An extensive survey of the literature published in various analytical and pharmaceutical chemistry-related journals has been compiled in its review. A synopsis of reported spectrophotometric and high-performance liquid chromatographic methods for individual drug is integrated. This appraisal illustrates that majority of the HPLC methods reviewed are based on the quantitative analysis of drugs in biological fluids, and they are appropriate for therapeutic drug monitoring purpose.

UV-Visible Absorption Spectroscopy Enhanced X-ray Crystallography at Synchrotron and X-ray Free Electron Laser Sources.

Science.gov (United States)

Cohen, Aina E; Doukov, Tzanko; Soltis, Michael S

2016-01-01

This review describes the use of single crystal UV-Visible Absorption micro-Spectrophotometry (UV-Vis AS) to enhance the design and execution of X-ray crystallography experiments for structural investigations of reaction intermediates of redox active and photosensitive proteins. Considerations for UV-Vis AS measurements at the synchrotron and associated instrumentation are described. UV-Vis AS is useful to verify the intermediate state of an enzyme and to monitor the progression of reactions within crystals. Radiation induced redox changes within protein crystals may be monitored to devise effective diffraction data collection strategies. An overview of the specific effects of radiation damage on macromolecular crystals is presented along with data collection strategies that minimize these effects by combining data from multiple crystals used at the synchrotron and with the X-ray free electron laser.

Isolation of uv-sensitive variants of human FL cells by a viral suicide method

International Nuclear Information System (INIS)

Shiomi, T.; Sato, K.

1979-01-01

A new method (viral suicide method) for the isolation of uv-sensitive mutants is described. Colonies of mutagenized human FL cells were infected with uv-irradiated Herpes simplex viruses and surviving ones which seemed to be deficient in host cell reactivation (HCR) were examined for their uv sensitivity. Nineteen of 238 clones examined were sensitive to uv irradiation at the time of the isolation. After recloning, four of these clones have been studied and two (UVS-1 and UVS-2) of them are stable in their uv sensitivity for 4 months in culture. uv sensitivity of UVS-1, UVS-2, and the parental FL cells are as follows: the extrapolation numbers (n) are 2.2, 2.1, and 1.8 and mean lethal doses (DO) are 2.9, 3.7, and 7.8 J/m 2 for UVS-1, UVS-2, and the parental FL cells, respectively. They are no more sensitive than FL cells to x-irradiation. The ability of HCR in UVS-2 cells is apparently lower than that in FL cells, whereas UVS-1 cells are the same as FL cells in the ability

Spectrophotometry of nova Cygni 1975

International Nuclear Information System (INIS)

Panek, R.J.

1977-01-01

Low-resolution spectrophotometry of nova Cygni 1975 is presented for eight nights in September 1975. Representative spectrum scans from 3600 A to 4500 A (10 A bandpass) and from 6350 A to 6750 A (20 A bandpass) also are shown

An application of micelle solubilization spectrophotometry in the determination of thorium

International Nuclear Information System (INIS)

Peng Changhai; Zeng Xiaoming

1988-01-01

In this review article the characteristics of the analytical method of Th by means of micelle solubilization spectrophotometry are described and the mechanism of the solubilization and chemical reactions involved is discussed. Also the various color-developing reagents that have been used for this determination are described and compared

A comparison of hair colour measurement by digital image analysis with reflective spectrophotometry.

Science.gov (United States)

Vaughn, Michelle R; van Oorschot, Roland A H; Baindur-Hudson, Swati

2009-01-10

While reflective spectrophotometry is an established method for measuring macroscopic hair colour, it can be cumbersome to use on a large number of individuals and not all reflective spectrophotometry instruments are easily portable. This study investigates the use of digital photographs to measure hair colour and compares its use to reflective spectrophotometry. An understanding of the accuracy of colour determination by these methods is of relevance when undertaking specific investigations, such as those on the genetics of hair colour. Measurements of hair colour may also be of assistance in cases where a photograph is the only evidence of hair colour available (e.g. surveillance). Using the CIE L(*)a(*)b(*) colour space, the hair colour of 134 individuals of European ancestry was measured by both reflective spectrophotometry and by digital image analysis (in V++). A moderate correlation was found along all three colour axes, with Pearson correlation coefficients of 0.625, 0.593 and 0.513 for L(*), a(*) and b(*) respectively (p-values=0.000), with means being significantly overestimated by digital image analysis for all three colour components (by an average of 33.42, 3.38 and 8.00 for L(*), a(*) and b(*) respectively). When using digital image data to group individuals into clusters previously determined by reflective spectrophotometric analysis using a discriminant analysis, individuals were classified into the correct clusters 85.8% of the time when there were two clusters. The percentage of cases correctly classified decreases as the number of clusters increases. It is concluded that, although more convenient, hair colour measurement from digital images has limited use in situations requiring accurate and consistent measurements.

Fully-differential spectrophotometry determination of trace thorium in uranium-containing waste water separated by CL-TBP levextrel resin

International Nuclear Information System (INIS)

You Jiannan

2000-01-01

A method for separation by CL-TBP levextrel resin and determination of trace thorium in uranium-containing waste water by fully-differential spectrophotometry is developed. In 4 mol/L HNO 3 medium, in presence of tartaric acid, CL-TBP levextrel resin is used for adsorption of thorium and separating from other elements. The thorium on the resin is stripped by 4 mol/L HCl, with oxalic acid and urea as screening agent, thorium forms red complex with arsenazo III. The maximum absorption of the complex is at 668 nm, and the molar absorptivity is 1.27 x 10 5 L/(mol·cm) . The complex can be steady for 2.5 h. By regulating micro-current of differential spectrophotometry, the method can realize determination with high precision. Sensitivity of this method increase 10 times than usual spectrophotometry. The relative standard deviation is better than +- 5% and recovery of thorium is 99%-107%

Development of a molecular method for testing the effectiveness of UV systems on-site.

Science.gov (United States)

Nizri, Limor; Vaizel-Ohayon, Dalit; Ben-Amram, Hila; Sharaby, Yehonatan; Halpern, Malka; Mamane, Hadas

2017-12-15

We established a molecular method for quantifying ultraviolet (UV) disinfection efficacy using total bacterial DNA in a water sample. To evaluate UV damage to the DNA, we developed the "DNA damage" factor, which is a novel cultivation-independent approach that reveals UV-exposure efficiency by applying a simple PCR amplification method. The study's goal was to prove the feasibility of this method for demonstrating the efficiency of UV systems in the field using flow-through UV reactors. In laboratory-based experiments using seeded bacteria, the DNA damage tests demonstrated a good correlation between PCR products and UV dose. In the field, natural groundwater sampled before and after being subjected to the full-scale UV reactors was filtered, and the DNA extracted from the filtrate was subjected to PCR amplification for a 900-bp fragment of the 16S rRNA gene with initial DNA concentrations of 0.1 and 1 ng/μL. In both cases, the UV dose predicted and explained a significant proportion of the variance in the log inactivation ratio and DNA damage factor. Log inactivation ratio was very low, as expected in groundwater due to low initial bacterial counts, whereas the DNA damage factor was within the range of values obtained in the laboratory-based experiments. Consequently, the DNA damage factor reflected the true performance of the full-scale UV system during operational water flow by using the indigenous bacterial array present in a water sample. By applying this method, we were able to predict with high confidence, the UV reactor inactivation potential. For method validation, laboratory and field iterations are required to create a practical field calibration curve that can be used to determine the expected efficiency of the full-scale UV system in the field under actual operation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Comparison of two novel in-syringe dispersive liquid-liquid microextraction techniques for the determination of iodide in water samples using spectrophotometry.

Science.gov (United States)

Kaykhaii, Massoud; Sargazi, Mona

2014-01-01

Two new, rapid methodologies have been developed and applied successfully for the determination of trace levels of iodide in real water samples. Both techniques are based on a combination of in-syringe dispersive liquid-liquid microextraction (IS-DLLME) and micro-volume UV-Vis spectrophotometry. In the first technique, iodide is oxidized with nitrous acid to the colorless anion of ICl2(-) at high concentration of hydrochloric acid. Rhodamine B is added and by means of one step IS-DLLME, the ion-pair formed was extracted into toluene and measured spectrophotometrically. Acetone is used as dispersive solvent. The second method is based on the IS-DLLME microextraction of iodide as iodide/1, 10-phenanthroline-iron((II)) chelate cation ion-pair (colored) into nitrobenzene. Methanol was selected as dispersive solvent. Optimal conditions for iodide extraction were determined for both approaches. Methods are compared in terms of analytical parameters such as precision, accuracy, speed and limit of detection. Both methods were successfully applied to determining iodide in tap and river water samples. Copyright © 2013 Elsevier B.V. All rights reserved.

Comparison of gas chromotography, spectrophotometry and near infrared spectroscopy to quantify prussic acid potential in forages.

Science.gov (United States)

Goff, Ben M; Moore, Kenneth J; Fales, Steven L; Pedersen, Jeffery F

2011-06-01

Sorghum [Sorghum bicolor (L.) Moench] has been shown to contain the cyanogenic glycoside dhurrin, which is responsible for the disorder known as prussic acid poisoning in livestock. The current standard method for estimating hydrogen cyanide (HCN) uses spectrophotometry to measure the aglycone, p-hydroxybenzaldehyde (p-HB), after hydrolysis. Errors may occur due to the inability of this method to solely estimate the absorbance of p-HB at a given wavelength. The objective of this study was to compare the use of gas chromatography (GC) and near infrared spectroscopy (NIRS) methods, along with a spectrophotometry method to estimate the potential for prussic acid (HCNp) of sorghum and sudangrasses over three stages maturities. It was shown that the GC produced higher HCNp estimates than the spectrophotometer for the grain sorghums, but lower concentrations for the sudangrass. Based on what is known about the analytical process of each method, the GC data is likely closer to the true HCNp concentrations of the forages. Both the GC and spectrophotometry methods yielded robust equations with the NIRS method; however, using GC as the calibration method resulted in more accurate and repeatable estimates. The HCNp values obtained from using the GC quantification method are believed to be closer to the actual values of the forage, and that use of this method will provide a more accurate and easily automated means of quantifying prussic acid. Copyright © 2011 Society of Chemical Industry.

Method development and validation of potent pyrimidine derivative by UV-VIS spectrophotometer.

Science.gov (United States)

Chaudhary, Anshu; Singh, Anoop; Verma, Prabhakar Kumar

2014-12-01

A rapid and sensitive ultraviolet-visible (UV-VIS) spectroscopic method was developed for the estimation of pyrimidine derivative 6-Bromo-3-(6-(2,6-dichlorophenyl)-2-(morpolinomethylamino) pyrimidine4-yl) -2H-chromen-2-one (BT10M) in bulk form. Pyrimidine derivative was monitored at 275 nm with UV detection, and there is no interference of diluents at 275 nm. The method was found to be linear in the range of 50 to 150 μg/ml. The accuracy and precision were determined and validated statistically. The method was validated as a guideline. The results showed that the proposed method is suitable for the accurate, precise, and rapid determination of pyrimidine derivative. Graphical Abstract Method development and validation of potent pyrimidine derivative by UV spectroscopy.

Ultraviolet spectrophotometry of comet Giacobini-Zinner during the ICE encounter. [International Cometary Explorer (ICE)

Science.gov (United States)

Ahearn, Michael F.; Mcfadden, Lucy A.; Feldman, Paul D.; Boehnhardt, Hermann; Rahe, Juergen; Festou, Michael; Brandt, John C.; Maran, Stephen P.; Niedner, Malcom B.; Smith, Andrew M.

1986-01-01

The IUE spectrophotometry of Comet P/Giacobini-Zinner was acquired in support of the International Cometary Explorer (ICE) mission. The abundances (or upper limits) of UV-active species were calculated. During the ICE encounter the H2O production rate was 3 times 10 to the 28th power/sec, + or - 50%, consistent with values derived from the ICE experiments. Comparison of the abundance of CO2(+) ions with the total electron density measured by the plasma electron experiment on ICE indicates a deficiency of ions relative to electrons indicating a population of ions not detected by remote sensing. The absence of detectable Mg(+) rules out this species as a possible ion of M/Q = 24 detected by the Ion Composition Instrument, part of the ICE complement of instruments.

Net Analyte Signal Standard Additions Method for Simultaneous Determination of Sulfamethoxazole and Trimethoprim in Pharmaceutical Formulations and Biological Fluids

OpenAIRE

Givianrad, M. H.; Mohagheghian, M.

2012-01-01

The applicability of a novel net analyte signal standard addition method (NASSAM) to the resolving of overlapping spectra corresponding to the sulfamethoxazole and trimethoprim was verified by UV-visible spectrophotometry. The results confirmed that the net analyte signal standard additions method with simultaneous addition of both analytes is suitable for the simultaneous determination of sulfamethoxazole and trimethoprim in aqueous media. Moreover, applying the net analyte signal standard a...

The determination of copper in biological materials by flame spectrophotometry

Science.gov (United States)

Newman, G. E.; Ryan, M.

1962-01-01

A method for the determination of the copper content of biological materials by flame spectrophotometry is described. The effects of interference by ions such as sodium and phosphate were eliminated by isolating copper as the dithizonate in CCl4. Results obtained for the urinary excretion of copper by a patient with Wilson's disease before and after treatment with penicillamine are reported. PMID:14479334

Solid-phase spectrophotometry

International Nuclear Information System (INIS)

Brykina, G.D.; Marchenko, D.Yu.; Shpigun, O.A.

1995-01-01

Solid-phase spectrophotometry (SPS), which is based on the direct measurement of light absorption of an ion exchanger containing a substance of interest, was reviewed. Since 1976, it has been known that aborbance of an ion exchanger is directly proportional to the concentration of a particular ion in solution. A similar dependence can also be followed for other sorbents, as well as for foams, membranes, films, etc., which do not exhibit ion exchange properties. One can use absorption, diffuse reflection, and luminescence spectra parameters as an analytical signal. Thus, SPS of ion exchangers is among the analytical techniques that combine the sorption concentration and surface determination of the substance of interest. This review summarizes the advancements in SPS over the last six years and demonstrates the prospects for its development. Special attention is paid to experimental methods for measuring solid-phase absorption and to the basic procedures of sample preparation, including new ones. These two facets are of great importance for obtaining precise results and extending the capabilities of SPS

The analysis of coal-and coke ashes by atomic absorption spectrophotometry

International Nuclear Information System (INIS)

Coutinho, C.A.; Prates, H.T.; Pereira, C.P.

1977-01-01

In order to provide better conditions for the control of the chemical composition of the load in the USIMINAS blast furnaces, a method of analysis for sodium, potassium, iron, aluminium, calcium, magnesium and maganese in coal-and coke ash by atomic absorption spectrophotometry was developed. The precision of the calibration curves and the reproducibility of the results are given, together with an estimate of the speed compared with conventional methods of chemical analysis [pt

Spectrophotometry of transuranium elements in reprocessing

International Nuclear Information System (INIS)

Cauchetier, P.; Guichard, C.; Wagner, J.F.

1985-06-01

Quantitative determination of U, Pu and Np at different oxidation degrees by spectrophotometry and problems encountered for industrial applications and automation are reviewed. Work in progress includes memorization of reference spectra, simplification of preliminary treatments of solutions [fr

Spectrophotometry or visual inspection to most reliably detect xanthochromia in subarachnoid hemorrhage: systematic review.

Science.gov (United States)

Chu, Kevin; Hann, Angus; Greenslade, Jaimi; Williams, Julian; Brown, Anthony

2014-09-01

We assess the sensitivity and specificity of xanthochromia as adjudicated by visual inspection and spectrophotometry at predicting the presence of cerebral aneurysm in patients with suspected subarachnoid hemorrhage who have a normal computed tomography (CT) head scan result. A systematic review was performed. MEDLINE and EMBASE databases were searched. Relevant studies with clinical data on the diagnostic accuracy of visual inspection or spectrophotometry were considered. Patients who had a normal CT head scan result followed by a lumbar puncture were included in this review. Sensitivities, specificities, and heterogeneity (I(2)) were calculated. Subgroup analyses were performed to explore reasons for the heterogeneity. There were major methodological limitations in the studies found. Twenty-two relevant articles were heterogeneous in regard to time to lumbar puncture, spectrophotometry methods, and follow-up of patients not undergoing cerebral angiography. Twelve of the 22 studies selected patients on the basis of a cerebral aneurysm or subarachnoid hemorrhage on imaging, or a positive lumbar puncture result. These studies were excluded from our initial analysis, which included only patients with clinically suspected subarachnoid hemorrhage. In this initial analysis, pooled estimates of sensitivity and specificity for spectrophotometry were 87% (95% confidence interval [CI] 71% to 96%; I(2)=26%) and 86% (95% CI 84% to 88%; I(2)=96%), respectively. For visual inspection, pooled sensitivity and specificity were 83% (95% CI 59% to 96%; I(2)=52%) and 96% (95% CI 93% to 97%; I(2)=76%), respectively. Sensitivity estimates are difficult to interpret without knowing time to lumbar puncture. The heterogeneity in the underlying studies, combined with significant overlap in pooled confidence limits, makes it impossible to provide a definite conclusion about the diagnostic accuracy of spectrophotometry versus visual inspection. Copyright © 2014 American College of Emergency

Monitoring of monosaccharides, oligosaccharides, ethanol and glycerol during wort fermentation by biosensors, HPLC and spectrophotometry.

Science.gov (United States)

Monošík, Rastislav; Magdolen, Peter; Stredanský, Miroslav; Šturdík, Ernest

2013-05-01

The aim of the present study was to analyze sugar levels (namely maltose, maltotriose, glucose and fructose) and alcohols (ethanol and glycerol) during the fermentation process in wort samples by amperometric enzymatic biosensors developed by our research group for industrial application, HPLC and spectrophotometry, and to compare the suitability of the presented methods for determination of individual analytes. We can conclude that for the specific monitoring of maltose or maltotriose only the HPLC method was suitable. On the other hand, biosensors and spectrophotometry reflected a decrease in total sugar concentration better and were able to detect both glucose and fructose in the later stages of fermentation, while HPLC was not. This can be attributed to the low detection limits and good sensitivity of the proposed methods. For the ethanol and glycerol analysis all methods proved to be suitable. However, concerning the cost expenses and time analysis, biosensors represented the best option. Copyright © 2012 Elsevier Ltd. All rights reserved.

Polarization control method for UV writing of advanced bragg gratings

DEFF Research Database (Denmark)

Deyerl, Hans-Jürgen; Plougmann, Nikolai; Jensen, Jesper Bo Damm

2002-01-01

We report the application of the polarization control method for the UV writing of advanced fiber Bragg gratings (FBG). We demonstrate the strength of the new method for different apodization profiles, including the Sinc-profile and two designs for dispersion-free square filters. The method has...

On a variant of the first derivative technique in spectrophotometry

International Nuclear Information System (INIS)

Kvaratskheli, Yu.K.; Pchelkin, V.A.; Demin, Yu.V.; Kukushkin, G.R.

1981-01-01

A variant of the first derivative technique in spectrophotometry is suggested which is based on continuous sinusoidal sweep of the wavelength within a narrow spectral region. A spectrophotometer has been designed which records the first derivative (dA/dlambda). A method has been developed of determining uranium (6) with arsenazo 3 in the presence of 20 times its amounts of zirconium thorium or iron (3). The method can be used for spectrophotometric determination of some other elements with different reagents, particularly in the analysis of elements with overlapped absorption spectra [ru

A near-UV-converted LiMgBO3:Dy3+ nanophosphor: Surface and spectral investigations

International Nuclear Information System (INIS)

Bedyal, A.K.; Kumar, Vinay; Prakash, Ram; Ntwaeaborwa, O.M.; Swart, H.C.

2015-01-01

Graphical abstract: - Highlights: • Combustion method was employed to synthesize LiMgBO 3 :Dy 3+ nanophosphors. • The phosphor can be efficiently excited by near-UV chips. • XPS was done to investigate the chemical constitution and chemical bonding state of elements in the LiMgBO 3 : Dy 3+ nanophosphor. • The calculated CIE coordinates (0.45, 0.46) were found to be in the white spectrum region. - Abstract: A near-ultra violet (UV) converted LiMgBO 3 :Dy 3+ nanophosphors have been synthesized by the combustion method. The structural, spectral and optical properties were examined by powder X-ray diffraction, fluorescent spectrophotometry and UV–vis spectroscopy. The excitation spectra of the phosphors contain sharp peaks at 294, 323, 348 and 385 nm due to the 4f–4f transition of the Dy 3+ ion. The phosphor is efficiently excited by near-UV chips. Upon near-UV excitation the phosphor emits intense blue and yellow with a weak red band centered at 484, 573 and 669 nm respectively, ascribed to the transition of Dy 3+ ion from 4 F 9/2 → 6 H 15/2 , 6 H 13/2 , 6 H 11/2 . The diffuse reflectance spectra of the phosphors were consistent with the excitation spectra and were used to calculate the band gap of the material, approximated to be 5.4 eV. The calculated CIE coordinates (0.45, 0.46) under 348 nm excitation were found to be in the white spectrum region. For surface investigation, X-ray photoelectron spectroscopy was used which confirms the presence of all the elements on the surface of the material

METHODS ELABORATION ON DETECTION OF SOME ATYPICAL NEUROLYTIC AGENTS FOR CHEMICAL AND TOXICOLOGICAL ANALYSIS

Directory of Open Access Journals (Sweden)

I. P. Remezova

2014-01-01

Full Text Available It is necessary to elaborate methods of atypical neuroleptic agents detection as individual substances and in different combinations as well for diagnosis of poisoning by some of them: clozapine, risperidone, sertindole, olanzapine, aripiprazole. The purpose of this work is methods elaboration of detection of clozapine, risperidone, sertindole, olanzapine, aripiprazole, haloperidol, oxazepam, carbamazapine using TLC, HPLC and UV spectrophotometry methods. During this work we used tablet forms of clozapine, risperidone, sertindole, olanzapine, aripiprazole. It is possible to use solution systems like ethanol-water-25% ammonia solution (8:1:1, toluolacetone-ethanol-25% ammonia solution (45:45:7.5:2.5, dioxan-chloroform-acetone-25% ammonia solution (47.5:45:5:2.5 for preliminary examination of atypical neuroleptic agents under study in combination with typical neuroleptics and tranquilizers with undirected analysis (general screening. System of solvents ethyl-acetate-chloroform-25% ammonia solution (85:10:5 is recommended to use for individual screening of risperidone, sertindole, olanzapine, haloperidol, benzol-ethanol-25% ammonia solution (50:10:0.5 system to use for clozapine, sertindole, olanzapine. Ethanol-25% ammonia solution (100:1.5 system is reasonable to use for chromatographic clearance of extracts from biological substances under study. We recommend using HPLC method and UV spectrophotometry for carrying out of a principal examination of clozapine, risperidone, sertindole, olanzapine and aripiprazole in case one of the substances under study is determined in the object.

evaluation of atomic absorption spectrophotometry (ashing, non ...

African Journals Online (AJOL)

cistvr

1Department of Agricultural and Food Science and 2Department of ... used techniques, namely atomic absorption spectrophotometry (AAS-Ashing and ..... fact that more preparation steps were involved in the Ashing procedure and thus.

Simultaneous Preconcentration and Determination of Brilliant Blue and Sunset Yellow in Foodstuffs by Solid-Phase Extraction Combined UV-Vis Spectrophotometry.

Science.gov (United States)

Bişgin, Abdullah Taner

2018-05-29

Background: Brilliant Blue and Sunset Yellow, two highly water-soluble synthetic food dyes, are the most popular food dyes used and consumed. Although they are not highly toxic, some health problems can be observed when excessive amounts of food products containing these dyes are consumed. Objectives: The aim of the study was to develop a simultaneous UV-Vis combined solid-phase extraction method, based on the adsorption onto Amberlite XAD-8 resin, for determination of Brilliant Blue and Sunset Yellow dyes. Methods: Sample solution was poured into the reservoir of the column and permitted to gravitationally pass through the column at 2 mL/min flow rate. Adsorbed dyes were eluted to 5 mL of final volume with 1 mol/L HNO₃ in ethanol solution by applying a 2 mL/min flow rate. Dye concentrations of the solution were determined at 483 and 630 nm for Sunset Yellow and Brilliant Blue, respectively. Results: The detection limits of the method for Brilliant Blue and Sunset Yellow were determined as 0.13 and 0.66 ng/mL, respectively. Preconcentration factor was 80. Brilliant Blue contents of real food samples were found to be between 11 and 240 μg/g. Sunset Yellow concentrations of foodstuffs were determined to be between 19 and 331 μg/g. Conclusions: Economical, effective, and simple simultaneous determination of Brilliant Blue and Sunset Yellow was achieved by using a solid-phase extraction combined UV-Vis spectrometry method. Highlights: The method is applicable and suitable for routine analysis in quality control laboratories without the need for expert personnel and high operational costs because the instrumentation is simple and inexpensive.

Validation of ultraviolet method to determine serum phosphorus level

International Nuclear Information System (INIS)

Garcia Borges, Lisandra; Perez Prieto, Teresa Maria; Valdes Diez, Lilliam

2009-01-01

Validation of a spectrophotometry method applicable in clinic labs was proposed to analytical assessment of serum phosphates using a kit UV-phosphorus of domestic production from 'Carlos J. Finlay' Biologics Production Enterprise (Havana, Cuba). Analysis method was based on phosphorus reaction to ammonium molybdenum to acid pH to creating a measurable complex to 340 nm. Specificity and precision were measured considering the method strength, linearity, accuracy and sensitivity. Analytical method was linear up to 4,8 mmol/L, precise (CV 30 .999) during clinical interest concentration interval where there were not interferences by matrix. Detection limit values were of 0.037 mmol/L and of quantification of 0.13 mmol/L both were satisfactory for product use

Multi-filter spectrophotometry simulations

Science.gov (United States)

Callaghan, Kim A. S.; Gibson, Brad K.; Hickson, Paul

1993-01-01

To complement both the multi-filter observations of quasar environments described in these proceedings, as well as the proposed UBC 2.7 m Liquid Mirror Telescope (LMT) redshift survey, we have initiated a program of simulated multi-filter spectrophotometry. The goal of this work, still very much in progress, is a better quantitative assessment of the multiband technique as a viable mechanism for obtaining useful redshift and morphological class information from large scale multi-filter surveys.

A new method for estimating UV fluxes at ground level in cloud-free conditions

Science.gov (United States)

Wandji Nyamsi, William; Pitkänen, Mikko R. A.; Aoun, Youva; Blanc, Philippe; Heikkilä, Anu; Lakkala, Kaisa; Bernhard, Germar; Koskela, Tapani; Lindfors, Anders V.; Arola, Antti; Wald, Lucien

2017-12-01

A new method has been developed to estimate the global and direct solar irradiance in the UV-A and UV-B at ground level in cloud-free conditions. It is based on a resampling technique applied to the results of the k-distribution method and the correlated-k approximation of Kato et al. (1999) over the UV band. Its inputs are the aerosol properties and total column ozone that are produced by the Copernicus Atmosphere Monitoring Service (CAMS). The estimates from this new method have been compared to instantaneous measurements of global UV irradiances made in cloud-free conditions at five stations at high latitudes in various climates. For the UV-A irradiance, the bias ranges between -0.8 W m-2 (-3 % of the mean of all data) and -0.2 W m-2 (-1 %). The root mean square error (RMSE) ranges from 1.1 W m-2 (6 %) to 1.9 W m-2 (9 %). The coefficient of determination R2 is greater than 0.98. The bias for UV-B is between -0.04 W m-2 (-4 %) and 0.08 W m-2 (+13 %) and the RMSE is 0.1 W m-2 (between 12 and 18 %). R2 ranges between 0.97 and 0.99. This work demonstrates the quality of the proposed method combined with the CAMS products. Improvements, especially in the modeling of the reflectivity of the Earth's surface in the UV region, are necessary prior to its inclusion into an operational tool.

Thermoluminescent properties of polycrystalline carbon doped LaAlO3/La(OH)3 crystals synthesized by solid state reaction for application in UV dosimetry

International Nuclear Information System (INIS)

Alves, N.; Oliveira de F, L.; Barbosa F, W.

2017-10-01

It is well known that UV radiation can induce certain deleterious effects, such as erythema, painful inflammation of the membrane of the eye and skin cancer. Therefore, it has been pushing the research for producing new and high performance UV sensitive Tl materials. There is an increasing interest in the development of new Tl materials for ultraviolet (UV) dosimetry purposes, owing to simplicity of the sample readout compared to other techniques. In this paper, thermoluminescence and dosimetric characteristics of pure and carbon doped lanthanum aluminate and hydroxide lanthanum crystals, irradiated with different UV doses, were studied and discussed. All samples studied were produced by solid state reaction method with different mixing methodologies. Characterization of sintered powders by X-ray diffraction, UV-Vis spectrophotometry and Ftir spectroscopy were performed. XRD data confirmed the LaAlO 3 and La(OH) 3 crystalline phases. The thermoluminescent study revealed that all compositions presented high UV sensibility. The sample which was grown by first sintering La 2 O 3 together carbon atoms and then sintering again in order to obtain La 2 O 3 :C together Al 2 O 3 , presented the best linear dose response over UV doses ranging from 0.042 to 0.63 mJ/cm 2 , with correlation coefficients equal to 0.99931. The synthesis methodology used was very efficient to obtain crystals with high Tl output intensities for low exposure rate UV R fields. (Author)

Feasibility of Using Fluorescence Spectrophotometry to Develop a Sensitive Dye Immersion Method for Container Closure Integrity Testing of Prefilled Syringes.

Science.gov (United States)

Lu, Xujin; Lloyd, David K; Klohr, Steven E

2016-01-01

A feasibility study was conducted for a sensitive and robust dye immersion method for the measurement of container closure integrity of unopened prefilled syringes using fluorescence spectrophotometry as the detection method. A Varian Cary Eclipse spectrofluorometer was used with a custom-made sample holder to position the intact syringe in the sample compartment for fluorescence measurements. Methylene blue solution was initially evaluated as the fluorophore in a syringe with excitation at 607 nm and emission at 682 nm, which generated a limit of detection of 0.05 μg/mL. Further studies were conducted using rhodamine 123, a dye with stronger fluorescence. Using 480 nm excitation and 525 nm emission, the dye in the syringe could be easily detected at levels as low as 0.001 μg/mL. The relative standard deviation for 10 measurements of a sample of 0.005 μg/mL (with repositioning of the syringe after each measurement) was less than 1.1%. A number of operational parameters were optimized, including the photomultiplier tube voltage, excitation, and emission slit widths. The specificity of the testing was challenged by using marketed drug products and a protein sample, which showed no interference to the rhodamine detection. Results obtained from this study demonstrated that using rhodamine 123 for container closure integrity testing with in-situ (in-syringe) fluorescence measurements significantly enhanced the sensitivity and robustness of the testing and effectively overcame limitations of the traditional methylene blue method with visual or UV-visible absorption detection. Ensuring container closure integrity of injectable pharmaceutical products is necessary to maintain quality throughout the shelf life of a sterile drug product. Container closure integrity testing has routinely been used to evaluate closure integrity during product development and production line qualification of prefilled syringes, vials, and devices. However, container closure integrity testing

Collection/concentration of trace uranium for spectrophotometric detection using activated carbon and first-derivative spectrophotometry

International Nuclear Information System (INIS)

El-Sayed, A.A.; Hamed, M.M.; El-Reefy, S.; Hmmad, H.A.

2007-01-01

The need exists for preconcentration of trace and ultratrace amounts of uranium from environmental, geological and biological samples. The adsorption of uranium on various solids is important from the purification, environmental, and radioactivity waste disposal points of view. A method is described for the determination of traces of uranium using first-derivative spectrophotometry after adsorptive preconcentration of uranium on activated carbon. Various parameters that influence the adsorptive preconcentration of uranium on activated carbon, viz., pH, amounts of activated carbon and time of stirring and interference of metals have been studied. First-derivative spectrophotometry in conjunction with adsorptive preconcentration of uranium on activated carbon is used for determining uranium at concentration levels down to 20 ppb (w/v). (orig.)

A method for UV-bonding in the fabrication of glass electrophoretic microchips.

Science.gov (United States)

Huang, Z; Sanders, J C; Dunsmor, C; Ahmadzadeh, H; Landers, J P

2001-10-01

This paper presents an approach for the development of methodologies amenable to simple and inexpensive microchip fabrication, potentially applicable to dissimilar materials bonding and chip integration. The method involves a UV-curable glue that can be used for glass microchip fabrication bonding at room temperature. This involves nothing more than fabrication of glue "guide channels" into the microchip architecture that upon exposure to the appropriate UV light source, bonds the etched plate and cover plate together. The microchip performance was verified by capillary zone electrophoresis (CZE) of small fluorescent molecules with no microchannel surface modification carried out, as well as with a DNA fragment separation following surface modification. The performance of these UV-bonded electrophoretic microchips indicates that this method may provide an alternative to high temperature bonding.

Spectrophotometry of VV Cephei-type systems

International Nuclear Information System (INIS)

Piccirillo, J.

1974-01-01

Photoelectric spectrophotometry of four VV Cephei-type systems and two related objects is analyzed to derive the visual magnitude differences of the binary components. The results are in good agreement with previous photometric determinations. An extension of the present technique to other types of binary systems is briefly discussed. (U.S.)

Near-simultaneous optical and infrared spectrophotometry of active galaxies

International Nuclear Information System (INIS)

Yates, M.G.; Garden, R.P.

1989-01-01

We present optical and infrared spectrophotometry for a sample of eight optically bright quasars, and the broad-line radio galaxy (BLRG) 3C 120. The optical and infrared spectrophotometry is separated by only five weeks, thus we have been able to minimize uncertainties due to variations in the objects. We compare our observed Paα/Hα and Hα/Hβ ratios with a large number of current photoionization models. We find that none of these models are able to reproduce our observed values of Paα/Hα in any of the active galaxies except the quasars 3C 273 and 0736+017. (author)

Thermoluminescent properties of polycrystalline carbon doped LaAlO{sub 3}/La(OH){sub 3} crystals synthesized by solid state reaction for application in UV dosimetry

Energy Technology Data Exchange (ETDEWEB)

Alves, N.; Oliveira de F, L. [Federal University of the State of Minas Gerais, Department of Nuclear Engineering, Av. Pres. Antonio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais (Brazil); Barbosa F, W., E-mail: neire.radiologia@yahoo.com.br [Nuclear Technology Development Center, 941, 30161-970 Belo Horizonte, Minas Gerais (Brazil)

2017-10-15

It is well known that UV radiation can induce certain deleterious effects, such as erythema, painful inflammation of the membrane of the eye and skin cancer. Therefore, it has been pushing the research for producing new and high performance UV sensitive Tl materials. There is an increasing interest in the development of new Tl materials for ultraviolet (UV) dosimetry purposes, owing to simplicity of the sample readout compared to other techniques. In this paper, thermoluminescence and dosimetric characteristics of pure and carbon doped lanthanum aluminate and hydroxide lanthanum crystals, irradiated with different UV doses, were studied and discussed. All samples studied were produced by solid state reaction method with different mixing methodologies. Characterization of sintered powders by X-ray diffraction, UV-Vis spectrophotometry and Ftir spectroscopy were performed. XRD data confirmed the LaAlO{sub 3} and La(OH){sub 3} crystalline phases. The thermoluminescent study revealed that all compositions presented high UV sensibility. The sample which was grown by first sintering La{sub 2}O{sub 3} together carbon atoms and then sintering again in order to obtain La{sub 2}O{sub 3}:C together Al{sub 2}O{sub 3}, presented the best linear dose response over UV doses ranging from 0.042 to 0.63 mJ/cm{sup 2}, with correlation coefficients equal to 0.99931. The synthesis methodology used was very efficient to obtain crystals with high Tl output intensities for low exposure rate UV R fields. (Author)

Quantitation of heparosan with heparin lyase III and spectrophotometry.

Science.gov (United States)

Huang, Haichan; Zhao, Yingying; Lv, Shencong; Zhong, Weihong; Zhang, Fuming; Linhardt, Robert J

2014-02-15

Heparosan is Escherichia coli K5 capsule polysaccharide, which is the key precursor for preparing bioengineered heparin. A rapid and effective quantitative method for detecting heparosan is important in the large-scale production of heparosan. Heparin lyase III (Hep III) effectively catalyzes the heparosan depolymerization, forming unsaturated disaccharides that are measurable using a spectrophotometer at 232 nm. We report a new method for the quantitative detection of heparosan with heparin lyase III and spectrophotometry that is safer and more specific than the traditional carbazole assay. In an optimized detection system, heparosan at a minimum concentration of 0.60 g/L in fermentation broth can be detected. Copyright © 2013 Elsevier Inc. All rights reserved.

Development of the H-point standard additions method for coupled liquid-chromatography and UV-visible spectrophotometry

Energy Technology Data Exchange (ETDEWEB)

Campins-Falco, Pilar; Bosch-Reig, Francisco; Herraez-Hernandez, Rosa; Sevillano-Cabeza, Adela (Universidad de Valencia (Spain). Facultad de Quimica, Departamento de Quimica Analitica)

1992-02-10

This work establishes the fundamentals of the H-point standard additions method for liquid chromatography for the simultaneous analysis of binary mixtures with overlapped chromatographic peaks. The method was compared with the deconvolution method of peak suppression and the second derivative of elution profiles. Different mixtures of diuretics were satisfactorily resolved. (author). 21 refs.; 9 figs.; 2 tabs.

Determination of Alkaloid Contents in Various Tissues of Coptis Chinensis Franch. by Reversed Phase-High Performance Liquid Chromatography and Ultraviolet Spectrophotometry.

Science.gov (United States)

Yang, Yanfang; Peng, Jingling; Li, Fangping; Liu, Xin; Deng, Meng; Wu, Hezhen

2017-05-01

A simple and intuitive method for optimizing the chemical constituents of Coptis Chinensis Franch. is important to assess its quality and clinical efficacy. An high performance liquid chromatography and ultraviolet spectrophotometry method was developed for the determination of berberine hydrochloride, palmatine chloride, jatrorrhizine hydrochloride, epiberberine, coptisine, columbamine and magnoflorine in various tissues (i.e., phloem, xylem and medulla) and rizhome of C. Chinensis Franch. The transection of rhizome from outside-in includes cork layer, cortex, phloem, cambium, xylem and medulla. Cork layer consists of dead cells, and therefore is not of any research significance. Cortex, phloem and cambium were almost impossible to separate, therefore they were studied as a whole in our experiments. They were collectively referred to as "phloem". The analytes were separated on a Gemini-NX C18 (250 mm × 4.6 mm, 5 μm) reversed phase column using a gradient elution of acetonitrile-0.03 mol/L ammonium acetate solution (containing 0.1% triethylamine and 0.6% ammonium hydroxide) as the mobile phase at a flow rate of 1.0 mL/min and UV detection at 270 nm. The method allowing the simultaneous quantification of seven major active constituents was optimized and validated for linearity, precision, accuracy, limits of detection (LOD) and quantification. The LOD ranged from 0.102 to 0.651 mg/mL (r ≥ 0.9993). Accuracy, precision and recovery were all within the required limits. The average recovery was between 100.14% and 102.75% and the relative standard deviations were spectrophotometry at 345 nm wavelength. Based on contents of the seven constituents and clustering result, this investigation suggests that there are significant differences in the distribution of seven alkaloids in the tissues examined. Furthermore, the total alkaloid content in xylem is relatively lower than that in phloem, medulla and rhizome. © The Author 2017. Published by Oxford University Press. All

Inter-laboratory verification of European pharmacopoeia monograph on derivative spectrophotometry method and its application for chitosan hydrochloride.

Science.gov (United States)

Marković, Bojan; Ignjatović, Janko; Vujadinović, Mirjana; Savić, Vedrana; Vladimirov, Sote; Karljiković-Rajić, Katarina

2015-01-01

Inter-laboratory verification of European pharmacopoeia (EP) monograph on derivative spectrophotometry (DS) method and its application for chitosan hydrochloride was carried out on two generation of instruments (earlier GBC Cintra 20 and current technology TS Evolution 300). Instruments operate with different versions of Savitzky-Golay algorithm and modes of generating digital derivative spectra. For resolution power parameter, defined as the amplitude ratio A/B in DS method EP monograph, comparable results were obtained only with algorithm's parameters smoothing points (SP) 7 and the 2nd degree polynomial and those provided corresponding data with other two modes on TS Evolution 300 Medium digital indirect and Medium digital direct. Using quoted algorithm's parameters, the differences in percentages between the amplitude ratio A/B averages, were within accepted criteria (±3%) for assay of drug product for method transfer. The deviation of 1.76% for the degree of deacetylation assessment of chitosan hydrochloride, determined on two instruments, (amplitude (1)D202; the 2nd degree polynomial and SP 9 in Savitzky-Golay algorithm), was acceptable, since it was within allowed criteria (±2%) for assay deviation of drug substance, for method transfer in pharmaceutical analyses. Copyright © 2015 Elsevier B.V. All rights reserved.

Selective determination of thorium in water using dual-wavelength β-correction spectrophotometry and the reagent 4-(2-pyridylazo)-resorcinol

International Nuclear Information System (INIS)

Kadi, M.W.; El-Shahawi, M.S.

2011-01-01

A simple, fast, low cost, and precise direct β-correction spectrophotometric method was developed for thorium determination in water. The method is based on the reaction of Th(IV) with 4-(2-pyridylazo)-resorcinol (PAR) in aqueous solution of pH 5-6 and measuring the absorbance of the resulting red-colored complex at λ max 497 nm. The effective molar absorptivity of the Th(IV)-PAR complex was 2.52 x 10 4 L mol -1 cm -1 . Beer's law and Ringbom plots were obeyed in the concentration range 0.04-2.0 and 0.07-1.2 μg mL -1 of thorium ions using β-correction spectrophotometry, respectively. The limits of detection and quantification of Th(IV) were 0.02 and 0.066 μg mL -1 , respectively. The developed method was applied for the analysis of thorium in certified reference material (IAEA-soil-7), tap-, underground- and Red-sea water samples. The validation of the method was also tested by comparison with data obtained by ICP-MS. The method is convenient, less sensitive to common interfering species and less laborious than most of published methods. The statistical treatment of data in terms of Student t-tests and variance ratio f-tests has revealed no significance differences. The structure of the Th(IV)-PAR complex was determined with the aid of spectroscopic measurements (UV-Visible and Fourier Transform Infrared Spectroscopy). (author)

Determination of macro nickel, vanadium and iron in crude oil and residues by derivative spectrophotometry

International Nuclear Information System (INIS)

Liu, W.; Wang, L.; Li, X.

1992-01-01

In this paper, a new method with derivative spectrophotometry and 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol as the chromogenic reagent in buffer solution of different pH developed for determining micro amounts of nickel. Vanadium and iron in crude oil and residues is reported. Forth-, Second- and Third-, Fourth-order derivative spectrophotometry were applied to determine nickel, nickel and vanadium, nickel and iron in crude oil and residues, respectively. The derivative maximums chosen for the measurement were at 556 nm for nickel, 540 nm and 643 nm for nickel and vanadium, 524 nm and 604 nm for nickel and iron. Beer's law is valid for the range 1.0 x 10 -6 to 2.5 x 10 -5 M

Determination of mercury, lead and cadmium in water by the CRA-atomic absorption spectrophotometry with solvent extraction

International Nuclear Information System (INIS)

Shim, Y.B.; Won, M.S.; Kim, C.J.

1980-01-01

The method of CRA-atomic absorption spectrophotometer with solvent extraction for the determination of mercury, lead and cadmium in water was studied. The optimum extracting conditions for CRA-atomic absorption spectrophotometry were the following: the complexes of mercury, lead and cadmium with dithizone were separated from the aqueous solution and concentrated into the 10 ml chloroform solution. Back extraction was performed; the concentrated mercury, lead and cadmium was extracted from the chloroform solution into the 10 ml 6-normal aqueous hydrochloric acid solution. In this case, recovery ratios were the following: mercury was 94.7%, lead 97.7% and cadmium 103.6%. The optimum operating conditions for the determination of mercury, lead and cadmium by the CRA-atomic absorption spectrophotometry also were investigated to test the dry step, ash step and atomization step for each metal. The experimental results of standard addition method were the following: the determination limit of each metal within 6% relative deviation was that lead was 0.04 ppb, and cadmium 0.01 ppb. Especially, mercury has been known impossible to determine by CRA-atomic absorption spectrophotometry until now. But in this study, mercury can be determined with CRA-atomic absorption spectrophotometer. Its determination limit was 4 ppb within 8% relative deviation. (author)

An important improvement in Ferron-timed spectrophotometry

NARCIS (Netherlands)

Zhang, Jing; Chang, Fang; Ren, Yijin; Shi, Qiuyi

Ferron dosage ([Ferron]) is key to ferron-timed spectrophotometry (ferron assay). In order to clarify some important questions, the following studies were conducted: (1) The effect of [Ferron] on the sensitivity of total aluminum (AlT) determination was experimentally investigated and ²⁷Al nuclear

The quantification of spermatozoa by real-time quantitative PCR, spectrophotometry, and spermatophore cap size.

Science.gov (United States)

Doyle, Jacqueline M; McCormick, Cory R; DeWoody, J Andrew

2011-01-01

Many animals, such as crustaceans, insects, and salamanders, package their sperm into spermatophores, and the number of spermatozoa contained in a spermatophore is relevant to studies of sexual selection and sperm competition. We used two molecular methods, real-time quantitative polymerase chain reaction (RT-qPCR) and spectrophotometry, to estimate sperm numbers from spermatophores. First, we designed gene-specific primers that produced a single amplicon in four species of ambystomatid salamanders. A standard curve generated from cloned amplicons revealed a strong positive relationship between template DNA quantity and cycle threshold, suggesting that RT-qPCR could be used to quantify sperm in a given sample. We then extracted DNA from multiple Ambystoma maculatum spermatophores, performed RT-qPCR on each sample, and estimated template copy numbers (i.e. sperm number) using the standard curve. Second, we used spectrophotometry to determine the number of sperm per spermatophore by measuring DNA concentration relative to the genome size. We documented a significant positive relationship between the estimates of sperm number based on RT-qPCR and those based on spectrophotometry. When these molecular estimates were compared to spermatophore cap size, which in principle could predict the number of sperm contained in the spermatophore, we also found a significant positive relationship between sperm number and spermatophore cap size. This linear model allows estimates of sperm number strictly from cap size, an approach which could greatly simplify the estimation of sperm number in future studies. These methods may help explain variation in fertilization success where sperm competition is mediated by sperm quantity. © 2010 Blackwell Publishing Ltd.

A Study on the Application of UV Sterilization Method in HVAC System

International Nuclear Information System (INIS)

Cho, S. W.; Park, J. S.; Seo, I. W.; Lim, K. R.; An, W. S.; Oh, S. H.; Lee, K. W.; Kim, J. G.; Kwon, S. J.

2005-04-01

The objective of this report is to study on the application of UV sterilization method on HVAC system in building. One type of commercial UV lamp was utilized during this research. It was 1,050 mm length, 24.5 mm diameter, 65 w lamp output, single ended lamp intended for insertion into al frame from inside. Twenty six lamps were mounted and operated in cross flow. They were allowed to operate for at least 30 minutes prior to beginning each test. The test rig was operated at 2.5 m/s and 20 .deg. C, and the relatively humidity 21.6 %RH. The effect of UV sterilization are investigated that as the general virus about 94 %, the mold microbe about 64 % and the bacillus about 86 %, respectively. Following this report will be used important data for the design and manufacture of the UV

A Study on the Application of UV Sterilization Method in HVAC System

Energy Technology Data Exchange (ETDEWEB)

Cho, S. W.; Park, J. S.; Seo, I. W.; Lim, K. R.; An, W. S.; Oh, S. H.; Lee, K. W.; Kim, J. G.; Kwon, S. J

2005-04-15

The objective of this report is to study on the application of UV sterilization method on HVAC system in building. One type of commercial UV lamp was utilized during this research. It was 1,050 mm length, 24.5 mm diameter, 65 w lamp output, single ended lamp intended for insertion into al frame from inside. Twenty six lamps were mounted and operated in cross flow. They were allowed to operate for at least 30 minutes prior to beginning each test. The test rig was operated at 2.5 m/s and 20 .deg. C, and the relatively humidity 21.6 %RH. The effect of UV sterilization are investigated that as the general virus about 94 %, the mold microbe about 64 % and the bacillus about 86 %, respectively. Following this report will be used important data for the design and manufacture of the UV.

Practical application of solid phase spectrophotometry in analysis of materials and goods of mining and metallurgy

International Nuclear Information System (INIS)

Duan Qunzhang

1999-01-01

The author reviewed recent development and practical application of solid phase spectrophotometry in analysis of materials and goods of mining-metallurgy. Separation and preconcentration and conditions of coloring determination, sensitivity and range of detection, as well as interference of corresponding method are discussed

A novel and simple fabrication method of embedded SU-8 micro channels by direct UV lithography

International Nuclear Information System (INIS)

Fu, C; Hung, C; Huang, H

2006-01-01

In this paper, we presents a novel and simple method to fabricate embedded micro channels. The method based on different light absorption properties of the SU-8 thick photoresist under different incident UV wavelengths. The channel structures are defined by the ordinary I-line, while the cover layer is patterned by the deep UV. Because the deep UV is obtained directly on the same aligner with a set of filter mirrors, the embedded channel can be easily produced without other rare facilities. Besides, the relationship between the thickness of the top layer and the exposure dose of the deep UV has been measured by an ingeniously designed experiment. The specific thickness of the top layer of the embedded micro channel can then be secured by the specific deep-UV exposure dose. Further more, many meaningful mechanical structures have been realized by this method, the material property of the top layer are also measured

Selenium determination in biological material by atomic absorption spectrophotometry in graphite furnace and using vapor generation

International Nuclear Information System (INIS)

Carvalho Vidal, M. de F. de.

1984-01-01

The applicability of the atomic absorption spectrophotometry to the determination of selenium in biological material using vapor generation and electrothermal atomization in the graphite furnace was investigated. Instrumental parameters and the analytical conditions of the methods were studied. Decomposition methods for the samples were tested, and the combustion in the Wickbold apparatus was chosen. (author) [pt

Indonesian palm civet coffee discrimination using UV-visible spectroscopy and several chemometrics methods

International Nuclear Information System (INIS)

Yulia, M; Suhandy, D

2017-01-01

Indonesian palm civet coffee or kopi luwak (Indonesian words for coffee and palm civet) is well known as the world’s priciest and rarest coffee. To protect the authenticity of luwak coffee and protect consumer from luwak coffee adulteration, it is very important to develop a simple and inexpensive method to discriminate between civet and non-civet coffee. The discrimination between civet and non-civet coffee in ground roasted (powder) samples is very challenging since it is very difficult to distinguish between the two by using conventional method. In this research, the use of UV-Visible spectra combined with two chemometric methods, SIMCA and PLS-DA, was evaluated to discriminate civet and non-civet ground coffee samples. The spectral data of civet and non-civet coffee were acquired using UV-Vis spectrometer (Genesys™ 10S UV-Vis, Thermo Scientific, USA). The result shows that using both supervised discrimination methods: SIMCA and PLS-DA, all samples were correctly classified into their corresponding classes with 100% rate for accuracy, sensitivity and specificity, respectively. (paper)

Study of PVDF/Graphene oxide nanocomposites by UV-Vis analysis

International Nuclear Information System (INIS)

Pereira, Juliana V.

2013-01-01

In this work we have prepared nanocomposites made by mixing Poly (vinylidene fluoride) [PVDF] and grapheme oxide nanosheets (GO) aiming to find dosimetric properties for applications in high dose dosimetry. Graphene Oxides (GO) nanosheets were synthesized by the Hummers method, using graphite supplied by Aldrich as the starting material. Nanocomposites were produced by mixing solved PDVF in DMAc with GO dispersed in an aqueous solution by sonication. The samples were irradiated with a Co-60 source at constant dose rate (12 kGy/h), with doses ranging from 50 to 1,000 kGy. The UV-Vis and spectrophotometry have been used to monitor the appearing of C=C conjugated bonds and radio-oxidation of carbon (C=O). The PVDF/OG nanocomposites prepared with 1.88 at.% of OG presented the best dosimetric properties. In this material, UVVis spectrometry has revealed that the absorbance intensities at 250 nm can be used for high dosimetry purposes for gamma doses ranging from 100 to 750 kGy. In this range, it is possible to observe a linear relationship between Abs and Dose. (author)

Validated UV-Spectrophotometric Methods for Determination of Gemifloxacin Mesylate in Pharmaceutical Tablet Dosage Forms

Directory of Open Access Journals (Sweden)

R. Rote Ambadas

2010-01-01

Full Text Available Two simple, economic and accurate UV spectrophotometric methods have been developed for determination of gemifloxacin mesylate in pharmaceutical tablet formulation. The first UV-spectrophotometric method depends upon the measurement of absorption at the wavelength 263.8 nm. In second area under curve method the wavelength range for detection was selected from 268.5-258.5 nm. Beer’s law was obeyed in the range of 2 to 12 μgmL-1 for both the methods. The proposed methods was validated statistically and applied successfully to determination of gemifloxacin mesylate in pharmaceutical formulation.

Simple and fast method for iron determination in white and red wines using dispersive liquid-liquid microextraction and ultraviolet-visible spectrophotometry.

Science.gov (United States)

Maciel, Juliana V; Soares, Bruno M; Mandlate, Jaime S; Picoloto, Rochele S; Bizzi, Cezar A; Flores, Erico M M; Duarte, Fabio A

2014-08-20

This work reports the development of a method for Fe extraction in white and red wines using dispersive liquid-liquid microextraction (DLLME) and determination by ultraviolet-visible spectrophotometry. For optimization of the DLLME method, the following parameters were evaluated: type and volume of dispersive (1300 μL of acetonitrile) and extraction (80 μL of C(2)Cl(4)) solvents, pH (3.0), concentration of ammonium pyrrolidinedithiocarbamate (APDC, 500 μL of 1% m/v APDC solution), NaCl concentration (not added), and extraction time. The calibration curve was performed using the analyte addition method, and the limit of detection and relative standard deviation were 0.2 mg L(-1) and below 7%, respectively. The accuracy was evaluated by comparison of results obtained after Fe determination by graphite furnace atomic absorption spectrometry, with agreement ranging from 94 to 105%. The proposed method was applied for Fe determination in white and red wines with concentrations ranging from 1.3 to 4.7 mg L(-1).

A Computer-aided Learning Exercise in Spectrophotometry.

Science.gov (United States)

Pamula, Frederick

1994-01-01

Discusses the use of a computer simulation program in teaching the concepts of spectrophotometry. Introduces several parts of the program and program usage. Presents an assessment activity to evaluate students' mastery of material. Concludes with the advantages of this approach to the student and to the assessor. (ASK)

Evaluation of atomic absorption Spectrophotometry (ashing, non ...

African Journals Online (AJOL)

Three commonly used techniques, namely atomic absorption spectrophotometry (AAS-Ashing and AAS-Non Ashing) and titrimetry (potassium permanganate titration) have been evaluated in this study to determine the calcium content in six food samples whose calcium levels ranged from 0 to more than 250mg/100g ...

FORMULA ESTABLISHMENT OF COLORLESS Pb(II COMPLEX WITH N-BENZOYL-N-PHENYL HYDROXYLAMINE (BPA USING ATOMIC ABSORPTION SPECTROSCOPY

Directory of Open Access Journals (Sweden)

Dhananjay B Sarode

2012-02-01

Full Text Available A new method for determination of stoichiometry of colorless complexes by using atomic absorption spectrophotometric technique in continuous variation method and slope ratio method was described here. This method can be used in same manner as that of mole ratio method and slope ratio method. In this method atomic absorption spectroscopy was used instead of UV-Vis spectrophotometry. Atomic absorption spectrophotometric technique is superior to UV-Vis spectrophotometry as it can be applied to colorless soluble complexes. Pb(II and n-benzoyl-n-phenyl hydroxylamine react to form colorless complex at pH 6.5, which can be easily determined by this method. It was found that Pb(II forms 1:2 complex with n-benzoyl-n-phenyl hydroxylamine and is quantitatively extracted back to aqueous solution for AAS analysis.

Operator care and eco-concerned development of a fast, facile and economical assay for basic nitrogenous drugs based on simplified ion-pair mini-scale extraction using safer solvent combined with drop-based spectrophotometry.

Science.gov (United States)

Plianwong, Samarwadee; Sripattanaporn, Areerut; Waewsa-nga, Kwanrutai; Buacheen, Parin; Opanasopit, Praneet; Ngawhirunpat, Tanasait; Rojanarata, Theerasak

2012-08-30

A fast, facile, and economical assay for basic nitrogenous drugs has been developed based on the mini-scale extraction of the drug-dye ion pair complex combined with the use of safe-for-analyst and eco-friendlier organic extractant and drop-based micro-spectrophotometry. Instead of using large volume devices, the extraction was simply carried out in typical 1.5 mL microcentrifuge tubes along with the use of micropipettes for accurate transfer of liquids, vortex mixer for efficient partitioning of solutes and benchtop centrifuge for rapid phase separation. In the last step, back-extraction was performed by using the microvolume of acidic solution in order to concentrate the colored species into a confined aqueous microdrop and to keep the analyst away from unwanted contact and inhalation of organic solvents during the quantitation step which was achieved by using cuvetteless UV-vis micro-spectrophotometry without any prior dilutions. Using chlorpheniramine maleate as a representative analyte and n-butyl acetate as a less toxic and non-ozone depleting extractant, the miniaturized method was less laborious and much faster. It was accurate, precise and insensitive to the interferences from common excipients. Notably, it gave the assay results of drug in tablets and oral solution comparable to the large-scale pharmacopeial method while the consumption of organic solvents and the release of wastes were lowered by 200-400 folds. Copyright © 2012 Elsevier B.V. All rights reserved.

Protection against UV-induced toxicity and lack of mutagenicity of Antarctic Sanionia uncinata

International Nuclear Information System (INIS)

Fernandes, A.S; Mazzei, J.L; Oliveira, C.G; Evangelista, H.; Marques, M.R.C.; Ferraz, E.R.A.; Felzenszwalb, I.

2017-01-01

Antarctica moss Sanionia uncinata (Hedw.) Loeske is exposed in situ to damaging levels of ultraviolet (UV) radiation. This moss has the ability to respond to UV radiation exposure producing secondary metabolites such as flavonoids, and has been recommended as a potential source of photoprotective compounds and antioxidants. The aim of the present paper was to investigate the free-radical scavenging activity and mutagenic and photomutagenic properties of methanolic (ME), hydroethanolic (HE) and ethanolic (EE) extracts of S. uncinata. The phenolic contents were evaluated by high-performance liquid chromatography (HPLC) and spectrophotometry. The findings showed that ME and EE presented the highest phenolic contents and inhibited free radical-scavenging activity against 2,2′-diphenyl-1 picrylhydrazyl (DPPH) and the HPLC analysis indicated several classes of phenolic acids and flavonoids. The sun protection factors (SPF) were determined by an in vitro method and the results showed significant values. The SPF values of BZ-3 at 50 μg/mL increased significantly in association with ME, HE and EE. The extracts did not induce mutagenicity in auxotrophic Salmonella typhimurium histidine and photomutagenicity was not detected in the TA102 and TA104 strains after exposure to UV-A at doses of up to 6.5 J/cm 2 for the TA102 strain and up to 0.24 J/cm 2 for the TA104 strain. In addition, with the exception of ME, all the extracts induced photoprotective effects in the presence of the TA104 strain at 0.04 J/cm 2 . The present results suggest that S. uncinata extracts did not induce photomutation and showed promise for photoprotection against the photobiological and ROS-inducing effects of the UV-A radiation.

Spectrophotometric Determination of Cilostazol in Tablet Dosage Form

African Journals Online (AJOL)

Erah

Purpose: To develop simple, rapid and selective spectrophotometric methods for ... Conclusion: These validated methods may be useful for routine analysis of cilostazol ... Keywords: Cilostazol tablets, UV spectrophotometry, Linear regression ...

Isolation of UV-sensitive mutants of mouse L5178Y cells by a cell suspension spotting method

International Nuclear Information System (INIS)

Shiomi, T.; Hieda-Shiomi, N.; Sato, K.

1982-01-01

We have isolated 56 UV-sensitive mutant clones from a mouse L51 T/t line of L5178Y cells by a cell suspension spotting method. Five mutants have also been isolated from L51 T/t and L5178Y cells by the method reported by Thompson and coworkers. We divided the mutants into two groups, highly sensitive and moderately sensitive mutants, according to their sensitivity to UV irradiation. Fifty-eight mutants were highly sensitive and three were moderately sensitive to UV. The reconstruction experiments indicate that more than 90% of highly sensitive mutants were recovered by the cell suspension spotting method. Frequencies of recovered mutants highly sensitive to UV increased with increasing dose of mutagens. Recovered mutant frequency reached 10(-2) after treatment with 1.5 micrograms/ml of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) (survival 0.2%). Eight UV-sensitive mutants were divided into four complementation groups. These mutants were 2-6 times more sensitive to UV than parental L51 T/t cells in terms of D37 (dose required to reduce survival to 37%). Four representative UV-sensitive mutants which are classified into different complementation groups were examined for their sensitivity to killing by UV, 4-nitroquinoline-1-oxide (4NQO), mitomycin C (MMC), X-rays, and MNNG. All four classes of mutants were found to be cross-sensitive to UV, 4NQO, and MMC, but not sensitive to X-rays and MNNG

Natural organic UV-absorbent coatings based on cellulose and lignin: designed effects on spectroscopic properties.

Science.gov (United States)

Hambardzumyan, Arayik; Foulon, Laurence; Chabbert, Brigitte; Aguié-Béghin, Véronique

2012-12-10

Novel nanocomposite coatings composed of cellulose nanocrystals (CNCs) and lignin (either synthetic or fractionated from spruce and corn stalks) were prepared without chemical modification or functionalization (via covalent attachment) of one of the two biopolymers. The spectroscopic properties of these coatings were investigated by UV-visible spectrophotometry and spectroscopic ellipsometry. When using the appropriate weight ratio of CNC/lignin (R), these nanocomposite systems exhibited high-performance optical properties, high transmittance in the visible spectrum, and high blocking in the UV spectrum. Atomic force microscopy analysis demonstrated that these coatings were smooth and homogeneous, with visible dispersed lignin nodules in a cellulosic matrix. It was also demonstrated that the introduction of nanoparticles into the medium increases the weight ratio and the CNC-specific surface area, which allows better dispersion of the lignin molecules throughout the solid film. Consequently, the larger molecular expansion of these aromatic polymers on the surface of the cellulosic nanoparticles dislocates the π-π aromatic aggregates, which increases the extinction coefficient and decreases the transmittance in the UV region. These nanocomposite coatings were optically transparent at visible wavelengths.

Implementation of the method for the determination of lactulose (4-O-β-D-Galactopyranosyl-D-Fructofuranose) and HMF (5-hydroxymethyl-2-furaldehyde) in ultra-pasteurized milk (UHT) ultraviolet-visible spectrophotometry

International Nuclear Information System (INIS)

Cardenas Miranda, Jeisson Alberto

2015-01-01

Measurement methods of HMF concentrations and lactulose is implemented and evaluated in low-fat milk (2% fat), subjected to ultra pasteurization process in order to establish indicators of nutritional quality. A protocol is developed for the management of equipment and methodology of the analytical method. The determination methods of HMF and lactulose are validated by ultraviolet visible spectrophotometry. The content of HMF and lactulose is determined in different production batches for 4 months of storage at a temperature of 24 Celsius degrees [es

Derivative spectrophotometry for the determination of faropenem in the presence of degradation products: an application for kinetic studies.

Science.gov (United States)

Cielecka-Piontek, Judyta

2013-07-01

A simple and selective derivative spectrophotometric method was developed for the quantitative determination of faropenem in pure form and in pharmaceutical dosage. The method is based on the zero-crossing effect of first-derivative spectrophotometry (λ = 324 nm), which eliminates the overlapping effect caused by the excipients present in the pharmaceutical preparation, as well as degradation products, formed during hydrolysis, oxidation, photolysis, and thermolysis. The method was linear in the concentration range 2.5-300 μg/mL (r = 0.9989) at λ = 341 nm; the limits of detection and quantitation were 0.16 and 0.46 μg/mL, respectively. The method had good precision (relative standard deviation from 0.68 to 2.13%). Recovery of faropenem ranged from 97.9 to 101.3%. The first-order rate constants of the degradation of faropenem in pure form and in pharmaceutical dosage were determined by using first-derivative spectrophotometry. A statistical comparison of the validation results and the observed rate constants for faropenem degradation with these obtained with the high-performance liquid chromatography method demonstrated that both were compatible.

PRECISION SPECTROPHOTOMETRY AT THE LEVEL OF 0.1%

International Nuclear Information System (INIS)

Yan Renbin

2011-01-01

Accurate relative spectrophotometry is critical for many science applications. Small wavelength-scale residuals in the flux calibration can significantly impact the measurements of weak emission and absorption features in the spectra. Using Sloan Digital Sky Survey data, we demonstrate that the average spectra of carefully selected red-sequence galaxies can be used as a spectroscopic standard to improve the relative spectrophotometry precision to 0.1% on small wavelength scales (from a few to hundreds of Angstroms). We achieve this precision by comparing stacked spectra across tiny redshift intervals. The redshift intervals must be small enough that any systematic stellar population evolution is minimized and is less than the spectrophotometric uncertainty. This purely empirical technique does not require any theoretical knowledge of true galaxy spectra. It can be applied to all large spectroscopic galaxy redshift surveys that sample a large number of galaxies in a uniform population.

Spectrophotometry of the QSO NRAO 530

International Nuclear Information System (INIS)

Junkkarinen, V.

1984-01-01

Spectrophotometry of the QSO NRAO 530 with the KPNO Cryogenic Camera is reported. A redshift of 0.902 is determined from the H-beta, H-gamma, and 3727 A forbidden O II emission lines, confirming a redshift that had been based on a single line, the 2798 A Mg II. The H-beta equivalent is smaller than in normal QSOs, which may be characteristic of optically variable QSOs. 16 references

Automation of plutonium spectrophotometry

International Nuclear Information System (INIS)

Perez, J.J.; Boisde, G.; Goujon de Beauvivier, M.; Chevalier, G.; Isaac, M.

1980-01-01

Instrumentation was designed and constructed for automatic control of plutonium by molecular absorption spectrophotometry, on behalf of the reprocessing facilities, to meet two objectives: on-line measurement, of the valency state of plutonium, on by-pass, with the measured concentration covering the process concentration range up to a few mg.l -1 ; laboratory measurement of plutonium adjusted to valency VI, with operation carried out using a preparative system meeting the required containment specifications. For this two objectives, the photometer, optical cell connections are made by optical fibers resistant to β, γ radiation. Except this characteristic the devices are different according to the quality required for result [fr

Determination of Lead in Blood by Atomic Absorption Spectrophotometry1

Science.gov (United States)

Selander, Stig; Cramér, Kim

1968-01-01

Lead in blood was determined by atomic absorption spectrophotometry, using a wet ashing procedure and a procedure in which the proteins were precipitated with trichloroacetic acid. In both methods the lead was extracted into isobutylmethylketone before measurement, using ammonium pyrrolidine dithiocarbamate as chelator. The simpler precipitation procedure was shown to give results identical with those obtained with the ashing technique. In addition, blood specimens were examined by the precipitation method and by spectral analysis, which method includes wet ashing of the samples, with good agreement. All analyses were done on blood samples from `normal' persons or from lead-exposed workers, and no additions of inorganic lead were made. The relatively simple protein precipitation technique gave accurate results and is suitable for the large-scale control of lead-exposed workers. PMID:5663425

KAJIAN ADSORPSI ION LOGAM Cr(VI OLEH ADSORBEN KOMBINASI ARANG AKTIF SEKAM PADI DAN ZEOLIT MENGGUNAKAN METODE SOLID-PHASE SPECTROPHOTOMETRY (SPS

Directory of Open Access Journals (Sweden)

Sulistyo Saputro

2016-10-01

  This study aims to study the use of activated rice husk charcoal and zeolite as combination adsorbents to adsorb Cr(VI metal ions; the effect of the combination adsorbents of activated rice husk charcoal and zeolite’s compositions to adsorb Cr(VI metal ions; and the sensitivity of solid-phase spectrophotometry (SPS as a method to determine the reduced levels of Cr(VI metal ions in the level of 15μ"> g/L. The activated rice husk charcoal used were obtained through the activation process by soaking in a solution of ZnCl2 10% while the zeolite with a solution of H2SO4 10%. The contacting process of the adsorbents with Cr(VI metal ions was done by varying the compositions of the activated rice husk charcoal and zeolite adsorbent, 1:1, 1:2, 1:3, and 2:1. The data analysis of the Cr(VI level used solid-phase spectrophotometry (SPS method. Characterization of activated rice husk charcoal and zeolite used FTIR. The results showed that: (1 a combination of activated rice husk charcoal and zeolite can be used as adsorbent to adsorb Cr(VI metal ions with the adsorption capacity was 0,28 15μ"> g/g; (2 the optimum composition of adsorbents was 1:2 with the percentage of absorption was 40,99%; (3 solid-phase spectrophotometry (SPS is a sensitive method to determine the reduced levels of Cr(VI in the level of 15μ"> g/L with the limit of detection (LOD was 0,021 15μ"> g/L.   Keywords: adsorption, Cr(VI,  activated  rice husk charcoal,  zeolite, solid-phase spectrophotometry

UV-C radiation based methods for aqueous metoprolol elimination

Energy Technology Data Exchange (ETDEWEB)

Rivas, F.J., E-mail: fjrivas@unex.es [Departamento de Ingenieria Quimica y Quimica Fisica, Universidad de Extremadura, Facultad de Ciencias, Edificio Jose Luis Sotelo, Avenida de Elvas S/N, 06071 Badajoz (Spain); Gimeno, O.; Borralho, T.; Carbajo, M. [Departamento de Ingenieria Quimica y Quimica Fisica, Universidad de Extremadura, Facultad de Ciencias, Edificio Jose Luis Sotelo, Avenida de Elvas S/N, 06071 Badajoz (Spain)

2010-07-15

The endocrine disruptor metoprolol has been oxidised in aqueous solution by means of the systems UV-C, UV-C/H{sub 2}O{sub 2}, UV-C/percarbonate, UV-C/monopersulfate, UV-C/TiO{sub 2}, UV-C/H{sub 2}O{sub 2}/TiO{sub 2} and photo-Fenton. From simple photolysis experiments the quantum yield of metoprolol has been calculated (roughly 5 x 10{sup -3} mol Einstein{sup -1} at circumneutral pH). Addition of free radicals promoters significantly enhanced the metoprolol depletion rate. Mineralization degree was negligible when no promoter was added, while low values were achieved in the presence of either inorganic peroxides or titanium dioxide. The combination of radiation, hydrogen peroxide and TiO{sub 2} increased the mineralization level up to values in the proximity of 45-50% under the best conditions investigated. The photo-Fenton process was the best system in terms of total oxidation (mineralization degree 70%) when optimum conditions were applied.

UV-C radiation based methods for aqueous metoprolol elimination

International Nuclear Information System (INIS)

Rivas, F.J.; Gimeno, O.; Borralho, T.; Carbajo, M.

2010-01-01

The endocrine disruptor metoprolol has been oxidised in aqueous solution by means of the systems UV-C, UV-C/H 2 O 2 , UV-C/percarbonate, UV-C/monopersulfate, UV-C/TiO 2 , UV-C/H 2 O 2 /TiO 2 and photo-Fenton. From simple photolysis experiments the quantum yield of metoprolol has been calculated (roughly 5 x 10 -3 mol Einstein -1 at circumneutral pH). Addition of free radicals promoters significantly enhanced the metoprolol depletion rate. Mineralization degree was negligible when no promoter was added, while low values were achieved in the presence of either inorganic peroxides or titanium dioxide. The combination of radiation, hydrogen peroxide and TiO 2 increased the mineralization level up to values in the proximity of 45-50% under the best conditions investigated. The photo-Fenton process was the best system in terms of total oxidation (mineralization degree 70%) when optimum conditions were applied.

Fourier transform infrared spectrophotometry and X-ray powder ...

African Journals Online (AJOL)

This study aimed at demonstrating complementary roles offered by both Fourier transform infrared (FTIR) spectrophotometry and x-ray powder diffraction (XRPD) techniques in characterizing clay size fraction of kaolins. The clay size fraction of kaolin samples obtained from Kgwakgwe, Makoro, Lobatse and Serule kaolin ...

Process for neptunium analysis by absorption spectrophotometry

International Nuclear Information System (INIS)

Wagner, J.F.

1987-01-01

An aqueous solution of a neptunium compounds is treated by a reagent, preferentially a vanadyl sulfate oxidized by cerium IV ions, to obtain neptunium V by oxidation of neptunium IV and reduction of neptunium VI. The reagent is chosen for a negligible absorption at the wavelength used for neptunium V absorption spectrophotometry for instance 981 nm [fr

Quantitative analysis of trivalent uranium and lanthanides in a molten chloride by absorption spectrophotometry

International Nuclear Information System (INIS)

Toshiyuki Fujii; Akihiro Uehara; Hajimu Yamana

2013-01-01

As an analytical application for pyrochemical reprocessing using molten salts, quantitative analysis of uranium and lanthanides by UV/Vis/NIR absorption spectrophotometry was performed. Electronic absorption spectra of LiCl-KCl eutectic at 773 K including trivalent uranium and eight rare earth elements (Y, La, Ce, Pr, Nd, Sm, Eu, and Gd as fission product elements) were measured in the wavenumber region of 4,500-33,000 cm -1 . The composition of the solutes was simulated for a reductive extraction condition in a pyroreprocessing process for spent nuclear fuels, that is, about 2 wt% U and 0.1-2 wt% rare earth elements. Since U(III) possesses strong absorption bands due to f-d transitions, an optical quartz cell with short light path length of 1 mm was adopted in the analysis. The quantitative analysis of trivalent U, Nd, Pr, and Sm was possible with their f-f transition intensities in the NIR region. The analytical results agree with the prepared concentrations within 2σ experimental uncertainties. (author)

Absolute spectrophotometry of the β Lyr

International Nuclear Information System (INIS)

Burnashev, V.I.; Skul'skij, M.Yu.

1978-01-01

In 1974 an absolute spectrophotometry of β Lyr was performed with the scanning spectrophotometer in the 3300-7400 A range. The energy distribution in the β Lyr spectrum is obtained. The β Lyr model is proposed. It is shown, that the continuous spectrum of the β Lyr radiation can be presented by the total radiation of the B8 3 and A5 3 two stars and of the gaseous envelope with Te =20000 K

Diseño y validación de un método espectrofotométrico para el control de calidad del piroxicam jalea 0,5 % Design and validation of a spectrophotometry method used in quality control of a 0,5 % Piroxican jelly

Directory of Open Access Journals (Sweden)

Yania Suárez Pérez

2009-12-01

Full Text Available La jalea de piroxicam al 0,5 % es un nuevo producto en fase de desarrollo de la Empresa Laboratorio "Roberto Escudero Díaz". En el presente trabajo se diseñó un método por espectrofotometría UV, para lo cual se empleó ácido clorhídrico etanólico como disolvente y 328 nm como longitud de onda de máxima absorción. Se estableció un procedimiento simple y rápido para procesar la muestra previa al análisis. Posteriormente se aplicó la validación de este según exigencias regulatorias actuales. El método resultó suficientemente específico, lineal, preciso y exacto en el rango de 3,125 a 9,375 µg/mL. Se aplicó a la cuantificación del principio activo en 3 lotes de la formulación desarrollada, con resultados satisfactorios sin diferencias estadísticamente significativas según el procesamiento aplicado.The 0.5 % jelly Piroxican is a new product in developing phase from "Roberto Escudero Díaz" Laboratory Enterprise. In present paper a UV spectrophotometry method was designed using ethanol chloride acid as solvent and 328 nm as maximal absorption wave length. A simple and fast procedure was established to processing the sample previous to analysis. Subsequently, we applied the validation of it according current regulatory demands. Method was enough specific, linear, precise and exact at the 3.125 to 9.375 µg/mL. Active principle quantification was applied in three batches of developed formula achieving satisfactory results without statistically significant differences according the applied procedure.

Magnetic resonance cell-tracking studies: spectrophotometry-based method for the quantification of cellular iron content after loading with superparamagnetic iron oxide nanoparticles.

Science.gov (United States)

Böhm, Ingrid

2011-08-01

The purpose of this article is to present a user-friendly tool for quantifying the iron content of superparamagnetic labeled cells before cell tracking by magnetic resonance imaging (MRI). Iron quantification was evaluated by using Prussian blue staining and spectrophotometry. White blood cells were labeled with superparamagnetic iron oxide (SPIO) nanoparticles. Labeling was confirmed by light microscopy. Subsequently, the cells were embedded in a phantom and scanned on a 3 T magnetic resonance tomography (MRT) whole-body system. Mean peak wavelengths λ(peak) was determined at A(720 nm) (range 719-722 nm). Linearity was proven for the measuring range 0.5 to 10 μg Fe/mL (r  =  .9958; p  =  2.2 × 10(-12)). The limit of detection was 0.01 μg Fe/mL (0.1785 mM), and the limit of quantification was 0.04 μg Fe/mL (0.714 mM). Accuracy was demonstrated by comparison with atomic absorption spectrometry. Precision and robustness were also proven. On T(2)-weighted images, signal intensity varied according to the iron concentration of SPIO-labeled cells. Absorption spectrophotometry is both a highly sensitive and user-friendly technique that is feasible for quantifying the iron content of magnetically labeled cells. The presented data suggest that spectrophotometry is a promising tool for promoting the implementation of magnetic resonance-based cell tracking in routine clinical applications (from bench to bedside).

Magnetic Resonance Cell-Tracking Studies: Spectrophotometry-Based Method for the Quantification of Cellular Iron Content after Loading with Superparamagnetic Iron Oxide Nanoparticles

Directory of Open Access Journals (Sweden)

Ingrid Böhm

2011-07-01

Full Text Available The purpose of this article is to present a user-friendly tool for quantifying the iron content of superparamagnetic labeled cells before cell tracking by magnetic resonance imaging (MRI. Iron quantification was evaluated by using Prussian blue staining and spectrophotometry. White blood cells were labeled with superparamagnetic iron oxide (SPIO nanoparticles. Labeling was confirmed by light microscopy. Subsequently, the cells were embedded in a phantom and scanned on a 3 T magnetic resonance tomography (MRT whole-body system. Mean peak wavelengths Λpeak was determined at A720nm (range 719–722 nm. Linearity was proven for the measuring range 0.5 to 10 μg Fe/mL (r = .9958; p = 2.2 × 10−12. The limit of detection was 0.01 μg Fe/mL (0.1785 mM, and the limit of quantification was 0.04 μg Fe/mL (0.714 mM. Accuracy was demonstrated by comparison with atomic absorption spectrometry. Precision and robustness were also proven. On T2-weighted images, signal intensity varied according to the iron concentration of SPIO-labeled cells. Absorption spectrophotometry is both a highly sensitive and user-friendly technique that is feasible for quantifying the iron content of magnetically labeled cells. The presented data suggest that spectrophotometry is a promising tool for promoting the implementation of magnetic resonance-based cell tracking in routine clinical applications (from bench to bedside.

Two-dimensional spectrophotometry of planetary nebulae by CCD imaging

International Nuclear Information System (INIS)

Jacoby, G.H.; Africano, J.L.; Quigley, R.J.; Western Washington Univ., Bellingham, WA)

1987-01-01

The spatial distribution of the electron temperature and density and the ionic abundances of O(+), O(2+), N(+), and S(+) have been derived from CCD images of the planetary nebulae NGC 40 and NGC 6826 taken in the important emission lines of forbidden O II, forbidden O III, H-beta, forbidden N II, and forbidden S II. The steps required in the derivation of the absolute fluxes, line, ratios, and ionic abundances are outlined and then discussed in greater detail. The results show that the CCD imaging technique for two-dimensional spectrophotometry can effectively compete with classical spectrophotometry, providing the added benefits of complete spatial coverage at seeing-disk spatial resolution. The multiplexing in the spatial dimension, however, results in a loss of spectral information, since only one emission line is observed at any one time. 37 references

Development and Validation of a Stability-Indicating LC-UV Method ...

African Journals Online (AJOL)

Development and Validation of a Stability-Indicating LC-UV Method for Simultaneous Determination of Ketotifen and Cetirizine in Pharmaceutical Dosage Forms. ... 5 μm) using an isocratic mobile phase that consisted of acetonitrile and 10 mM disodium hydrogen phosphate buffer (pH 6.5) in a ratio of 45:55 % v/v at a flow ...

Determination of serum albumin with tribromoarsenazo by spectrophotometry

Directory of Open Access Journals (Sweden)

Qing-Zhou Zhai

2007-08-01

Full Text Available The reaction of tribromoarsenazo(TB-ASA with serum albumin in the presence of emulgent OP was studied by spectrophotometry. In a Britton-Robinson buffer solution at pH 2.9, tribromoarsenazo and bovine serum albumin can immediately form a red compound in the presence of emulgent OP with a maximum absorption wavelength at 354 nm. The presence of emulgent OP can increase the reaction sensitivity and the compound stability. The molar absorptivity of the compound is ε354 nm = 6.13 x 105 M-1•cm-1. Beer's law is obeyed over the range of 5.0-75.0 mg•L-1 for bovine serum albumin. The present method was applied to the determination of the total proteins in human serums with satisfactory results.

Spectrophotometry of the Seyfert galaxy NGC 4593

International Nuclear Information System (INIS)

MacAlpine, G.M.; Williams, G.A.; Lewis, D.W.

1979-01-01

Spectrophotometry of the bright class 1 Seyfert galaxy NGC 4593 is presented. The emission-line characteristics are briefly discussed and compared with those of other Seyfert galaxies. The measured hydrogen Balmer-line ratios are reasonably consistent with expected recombination values, and the emission intensities of Fe II, He I 5876, and forbidden O III 4363 relative to other lines are stronger than average in NGC 4593

Determination of micro amounts of praseodymium by analogue derivative spectrophotometry

International Nuclear Information System (INIS)

Ishii, Hajime; Satoh, Katsuhiko.

1986-01-01

Derivative spectrophotometry using the analogue differentiation circuit was applied to the determination of praseodymium at the ppm level. By the proposed method, in which the second or fourth derivative spectrum of the characteristic absorption band of praseodymium(III) at 444 nm is measured, as little as 3 ppm of praseodymium can be determined directly and easily even in the presence of large amounts of other rare earths without any prior separation. Interferences from neodymium, samarium, dysprosium, holmium and erbium ions which have characteristic absorption bands around 444 nm can easily be removed by utilizing the isosbestic point in the derivative spectra of praseodymium(III) and the interfering rare earth(III). (author)

Analysis of impurities in silver matrix by atomic absorption spectrophotometry

International Nuclear Information System (INIS)

Hussain, R.; Ishaque, M.; Mohammad, D.

1999-01-01

A procedure for the analysis of aluminium, chromium, copper, lead, mercury, nickel and zinc mainly using flame lens atomic absorption spectrophotometry has been described. The results depict that the presence of silver does not introduce any significant interference, when standards are prepared in matching silver matrix solutions. The calibration curves obey the straight-line equations passing through the origin. Thus the separation of silver matrix from the analyte solutions is not necessary. The method has successfully been applied for the analysis of silver foils, wires, battery grade silver oxides and silver nitrate samples containing analyte elements in the concentration range 2 to 40 ppm. (author)

Spectrophotometry of four galaxies of high surface brightness

International Nuclear Information System (INIS)

Arakelyan, M.A.; Magtesyan, A.P.

1982-01-01

Spectrophotometry has been performed for the emission lines in the nuclei of Arakelyan galaxies Nos. 428, 449, 454, 532. In the first two objects, H II clouds occur roughly-equal2 kpc out from the nucleus. No. 449 may contain another cloud moving at roughly-equal1500 km/sec radial velocity. radial

Formaldehyde in Alcoholic Beverages: Large Chemical Survey Using Purpald Screening Followed by Chromotropic Acid Spectrophotometry with Multivariate Curve Resolution

Directory of Open Access Journals (Sweden)

Julien A. Jendral

2011-01-01

Full Text Available A strategy for analyzing formaldehyde in beer, wine, spirits, and unrecorded alcohol was developed, and 508 samples from worldwide origin were analyzed. In the first step, samples are qualitatively screened using a simple colorimetric test with the purpald reagent, which is extremely sensitive for formaldehyde (detection limit 0.1 mg/L. 210 samples (41% gave a positive purpald reaction. In the second step, formaldehyde in positive samples is confirmed by quantitative spectrophotometry of the chromotropic acid-formaldehyde derivative combined with Multivariate Curve Resolution-Alternating Least Squares (MCR-ALS. Calculation of UV-VIS and 13C NMR spectra confirmed the monocationic dibenzoxanthylium structure as the product of the reaction and disproved the widely cited para,para-quinoidal structure. Method validation for the spectrophotometric procedure showed a detection limit of 0.09 mg/L and a precision of 4.2–8.2% CV. In total, 132 samples (26% contained formaldehyde with an average of 0.27 mg/L (range 0–14.4 mg/L. The highest incidence occurred in tequila (83%, Asian spirits (59%, grape marc (54%, and brandy (50%. Our survey showed that only 9 samples (1.8% had formaldehyde levels above the WHO IPCS tolerable concentration of 2.6 mg/L.

Formaldehyde in alcoholic beverages: large chemical survey using purpald screening followed by chromotropic Acid spectrophotometry with multivariate curve resolution.

Science.gov (United States)

Jendral, Julien A; Monakhova, Yulia B; Lachenmeier, Dirk W

2011-01-01

A strategy for analyzing formaldehyde in beer, wine, spirits, and unrecorded alcohol was developed, and 508 samples from worldwide origin were analyzed. In the first step, samples are qualitatively screened using a simple colorimetric test with the purpald reagent, which is extremely sensitive for formaldehyde (detection limit 0.1 mg/L). 210 samples (41%) gave a positive purpald reaction. In the second step, formaldehyde in positive samples is confirmed by quantitative spectrophotometry of the chromotropic acid-formaldehyde derivative combined with Multivariate Curve Resolution-Alternating Least Squares (MCR-ALS). Calculation of UV-VIS and (13)C NMR spectra confirmed the monocationic dibenzoxanthylium structure as the product of the reaction and disproved the widely cited para,para-quinoidal structure. Method validation for the spectrophotometric procedure showed a detection limit of 0.09 mg/L and a precision of 4.2-8.2% CV. In total, 132 samples (26%) contained formaldehyde with an average of 0.27 mg/L (range 0-14.4 mg/L). The highest incidence occurred in tequila (83%), Asian spirits (59%), grape marc (54%), and brandy (50%). Our survey showed that only 9 samples (1.8%) had formaldehyde levels above the WHO IPCS tolerable concentration of 2.6 mg/L.

DETERMINAÇÃO DE ENXOFRE EM SHAMPOO POR ESPECTROFOTOMETRIA UV-VIS: AVALIAÇÃO DE MÉTODOS DE PREPARO DE AMOSTRAS

Directory of Open Access Journals (Sweden)

Natalia J. Bielemann

Full Text Available Dry ashing, dissolution in aqueous medium or wet digestion methods were evaluated for sample preparation of shampoo for the subsequent indirect determination of sulfur by UV-Vis spectrophotometry. Among the sample preparation methods evaluated, microwave-assisted wet digestion using 7 mol L-1 HNO3 was the most suitable method for this purpose. Accuracy of the proposed method was evaluated by recovery test using standard solution, and the recovery was about 96%. Moreover, for comparison of results, S (as SO42- was also determined by ion chromatography, after microwave-assisted wet digestion using concentrated HNO3, and no significant difference was observed between the obtained results (according to the t-test for a 95% confidence level, p = 0.288. Relative standard deviations were always lower than 10% and the limit of detection was 0.007% w/v. Finally, the proposed method was applied for analysis of sixteen shampoos used to many types of hair, from different brands produced in Brazil, and the concentration of S ranged from 0.78 to 2.82% w/v.

Classification of Argentinean Sauvignon blanc wines by UV spectroscopy and chemometric methods.

Science.gov (United States)

Azcarate, Silvana Mariela; Cantarelli, Miguel Ángel; Pellerano, Roberto Gerardo; Marchevsky, Eduardo Jorge; Camiña, José Manuel

2013-03-01

Argentina is an important worldwide wine producer. In this country, there are several recognizable provinces that produce Sauvignon blanc wines: Neuquén, Río Negro, Mendoza, and San Juan. The analysis of the provenance of these white wines is complex and requires the use of expensive and time-consuming techniques. For this reason, this work discusses the determination of the provenance of Argentinean Sauvignon blanc wines by the use of UV spectroscopy and chemometric methods, such as principal component analysis (PCA), cluster analysis (CA), linear discriminant analysis (LDA), and partial least square discriminant analysis (PLS-DA). The proposed method requires low-cost equipment and short-time analysis in comparison with other techniques. The results are in very good agreement with results based on the geographical origin of Sauvignon blanc wines. This manuscript describes a method to determine the geographical origin of Sauvignon wines from Argentina. The main advantage of this method is the use of nonexpensive techniques, such as UV-Vis spectroscopy. © 2013 Institute of Food Technologists®

Use of reflectance spectrophotometry and colorimetry in a general linear model for the determination of the age of bruises.

Science.gov (United States)

Hughes, Vanessa K; Langlois, Neil E I

2010-12-01

Bruises can have medicolegal significance such that the age of a bruise may be an important issue. This study sought to determine if colorimetry or reflectance spectrophotometry could be employed to objectively estimate the age of bruises. Based on a previously described method, reflectance spectrophotometric scans were obtained from bruises using a Cary 100 Bio spectrophotometer fitted with a fibre-optic reflectance probe. Measurements were taken from the bruise and a control area. Software was used to calculate the first derivative at 490 and 480 nm; the proportion of oxygenated hemoglobin was calculated using an isobestic point method and a software application converted the scan data into colorimetry data. In addition, data on factors that might be associated with the determination of the age of a bruise: subject age, subject sex, degree of trauma, bruise size, skin color, body build, and depth of bruise were recorded. From 147 subjects, 233 reflectance spectrophotometry scans were obtained for analysis. The age of the bruises ranged from 0.5 to 231.5 h. A General Linear Model analysis method was used. This revealed that colorimetric measurement of the yellowness of a bruise accounted for 13% of the bruise age. By incorporation of the other recorded data (as above), yellowness could predict up to 32% of the age of a bruise-implying that 68% of the variation was dependent on other factors. However, critical appraisal of the model revealed that the colorimetry method of determining the age of a bruise was affected by skin tone and required a measure of the proportion of oxygenated hemoglobin, which is obtained by spectrophotometric methods. Using spectrophotometry, the first derivative at 490 nm alone accounted for 18% of the bruise age estimate. When additional factors (subject sex, bruise depth and oxygenation of hemoglobin) were included in the General Linear Model this increased to 31%-implying that 69% of the variation was dependent on other factors. This

SEM/EDX and vis spectrophotometry study of the stability of resin-bound mortars used for casting replicas and filling missing parts of historic stone fountains.

Science.gov (United States)

Roig-Salom, José-Luis; Doménech-Carbó, María-Teresa; de la Cruz-Cañizares, Juana; Bolívar-Galiano, Fernando; Pelufo-Carbonell, María-José; Peraza-Zurita, Yaiza

2003-04-01

A study by SEM/EDX and spectrophotometry in the visible region attempting to assess the stability of new resin-bound mortars used for casting replicas of marble historic fountains is presented in this paper. Different accelerating tests such as thermal ageing, UV light ageing, ageing in an SO(2) pollutant chamber, freezing cycles ageing, salt crystallisation ageing, natural ageing and biological attack have been applied to a series of test specimens prepared with polyester-, epoxy- and gel-coat-bound mortars. Examination of morphology, measurement of chemical composition and chromatic coordinates before and after ageing treatments establish the higher stability and resistance properties of these resin-bound mortars by comparison to those from the natural marbles.

UV-VIS spectrophotometry method for the determination of titanium and aluminum in zirconyl chloride

International Nuclear Information System (INIS)

Purwanto A; Farida Emawati

2013-01-01

Analysis of Ti and Al in zirconyl chloride (ZrOCI 2 .8 H 2 0) with a spectrophotometric method has been studied. Analysis of Ti based on the formation of a yellow complex from the reaction of Ti (IV) with H 2 O 2 in sulfuric acid solution. Studied the influence of zirconium, the determination of detection limits, precision and accuracy test. Spectrophotometric analysis of Ti obtained optimum conditions: wavelength (A) 400 nm, while the stability of complexes is 5-15 minutes, the concentration of complexing H 2 O 2 is 0.3%, sulfuric acid concentrations is 1.0 M, the detection limit is 0.103 µg/mL. Standard curve was linear in the range of concentrations from 1.0 to 30.0 µ/mL with r = 0.999. Zirconium with 20 times concentration of Ti is interference. Content of Ti in ZrOCl 2 . 8 H 2 O obtained average 0.0048 ± 0.0002%. Testing precision of Ti with coefficient variation is 4.8% and accuracy is 91.4%. Analysis of AI obtained optimum conditions are : λ 536 nm, stable complexes is 7-10 minutes, the concentration of eriokrom cyanine is 3,73.10-5 M, ascorbic acid 0.02%. Standard curve AI with the range concentrations of 10-50 ng/mL is linear with r = 0.999. Zirconium with a concentration of 10 time is not interference. Samples solution in 0.5 M H 2 SO 4 , extracted with 30% trioctylamine-kerosene, water phase was analyzed. Contents of AI in ZrOCI 2 . 8 H 2 0 local products obtained average 0.0030 ± 0.0001%. The precision is 2.48% and accuracy is 89.3%. (author)

The determination of zirconium by atomic absorption spectrophotometry

International Nuclear Information System (INIS)

Rodriguez, E.R.; Cunha, M.T.C. da

1975-01-01

The interference of iron in the determination of zirconium by atomic absorption spectrophotometry was studied. Attempts were made to emininate this interference by complexing the iron with EDTA, ascorbic acid and hydrazine; also by the addition of ammonium fluoride to the solution. Some experiments were carried out in order to explain the results obtained [pt

Development of new analytical methods for the determination of caffeine content in aqueous solution of green coffee beans.

Science.gov (United States)

Weldegebreal, Blen; Redi-Abshiro, Mesfin; Chandravanshi, Bhagwan Singh

2017-12-05

This study was conducted to develop fast and cost effective methods for the determination of caffeine in green coffee beans. In the present work direct determination of caffeine in aqueous solution of green coffee bean was performed using FT-IR-ATR and fluorescence spectrophotometry. Caffeine was also directly determined in dimethylformamide solution using NIR spectroscopy with univariate calibration technique. The percentage of caffeine for the same sample of green coffee beans was determined using the three newly developed methods. The caffeine content of the green coffee beans was found to be 1.52 ± 0.09 (% w/w) using FT-IR-ATR, 1.50 ± 0.14 (% w/w) using NIR and 1.50 ± 0.05 (% w/w) using fluorescence spectroscopy. The means of the three methods were compared by applying one way analysis of variance and at p = 0.05 significance level the means were not significantly different. The percentage of caffeine in the same sample of green coffee bean was also determined by using the literature reported UV/Vis spectrophotometric method for comparison and found to be 1.40 ± 0.02 (% w/w). New simple, rapid and inexpensive methods were developed for direct determination of caffeine content in aqueous solution of green coffee beans using FT-IR-ATR and fluorescence spectrophotometries. NIR spectrophotometry can also be used as alternative choice of caffeine determination using reduced amount of organic solvent (dimethylformamide) and univariate calibration technique. These analytical methods may therefore, be recommended for the rapid, simple, safe and cost effective determination of caffeine in green coffee beans.

Rapid and Sensitive Determination of Lipid Oxidation Using the Reagent Kit Based on Spectrophotometry (FOODLABfat System

Directory of Open Access Journals (Sweden)

Chang Woo Kwon

2016-01-01

Full Text Available The reliability and availability of FOODLABfat system for determining acid value (AV and peroxide value (POV were assessed during the hydrolytic rancidification and lipid oxidation of edible oils. This reagent kit based on spectrophotometry was compared to the official methods (ISO 660 and 3960 protocols based on manual titration employing the standard mixture for the simulated oxidation models and edible oils during the thermally induced oxidation at 180°C. The linear regression line of standard mixture and the significant difference of thermally oxidized time course study determined between them showed high correlations (R2=0.998 and p<0.05 in both AVs and POVs. Considering ISO protocols with a probability of human error in manual titration, the rapidness and simplicity of the reagent kit based on spectrophotometry make it a promising alternative to monitor the lipid oxidation of edible oils and lipid-containing foods.

Determination of micro amounts of samarium and europium by analogue derivative spectrophotometry

International Nuclear Information System (INIS)

Ishii, H.; Satoh, K.

1982-01-01

Derivative spectrophotometry using the analogue differentiation circuit was applied to the determination of samarium and europium at ppm levels. By measuring the second or the fourth derivative spectra of the characteristic absorption bands of both the rare earth ions around 400 nm, they can be determined directly and selectively in the presence of large amounts of most other rare earths without any prior separation. Further, aptly selecting conditions for the measurement of the derivative spectra, the simultaneous determination of both the rare earth elements was feasible. The principle and the characteristics of analogue derivative spectrophotometry are also described. (orig.) [de

Spectrophotometry of CRL 2688 from 2 to 24 microns

International Nuclear Information System (INIS)

Forrest, W.J.; Merrill, K.M.; Russell, R.W.; Soifer, B.T.

1975-01-01

Medium-resolution spectrophotometry (Δlambda/lambdaapprox. =0.01) of CRL 2688 from 2 μ to 24 μ are reported. No significant features are found from 3 μ to 24 μ, although the spectral flux distribution is broader than that of a single-temperature blackbody

8-13μm spectrophotometry of galaxies

International Nuclear Information System (INIS)

Roche, P.F.; Aitken, D.K.; Whitmore, B.

1983-01-01

Spectrophotometry at 8-13 μm of Mkn 231 confirms that the 10 μm minimum is due to large columns of silicate dust in the line-of-sight to the nucleus. Fits to the detailed spectral shape demonstrate that the cool absorbing grains are at the emission (z=0.042) rather than the absorption (z approx.= 0.025) redshift and are located within the nuclear region. (author)

Robotic UV-Vis apparatus for long-term characterization of drug release from nanochannels

International Nuclear Information System (INIS)

Geninatti, T; Grattoni, A; Small, E

2014-01-01

Reliable monitoring of the kinetics of molecular release from drug delivery devices is crucial for their therapeutic success. Commercially available UV-Vis spectrophotometers provide reliable quantification of analyte concentrations directly correlated to the absorbance of fluids. However, they are not suitable for long-term measurements requiring high frequency of sampling from a large number of replicates and continuous fluid mixing, all of which are necessary for evaluation of drug delivery devices. To address this need, we developed a novel robotic apparatus serially connected to a commercial UV-Vis spectrophotometer. The robotic apparatus enables us to automatically and reliably acquire long-term data for up to 48 samples with high frequency of measurements and independent magnetic stirring. We equipped the robotic apparatus with independent connectors that allowed us to apply an electric potential to each sample for electrokinetic studies. The apparatus repeatability and accuracy was demonstrated in comparison to a commercial UV-Vis spectrophotometer. The system was successfully employed to characterize the diffusion kinetics of acetone and doxorubicin through nanochannel membranes (nDS) designed for long-term drug delivery. Dendritic fullerene 1 was used to show that the robotic apparatus routes the electric potential to nanochannel membranes enabling us to investigate the actively controlled release of molecules. Our results demonstrate that the robotic apparatus could widely broaden the range of applications of UV-Vis spectrophotometry, especially in the case of large sample processing and for long-term diffusive and electrokinetic studies in drug delivery. (technical design note)

Optical properties of orthodontic aligners?spectrophotometry analysis of three types before and after aging

OpenAIRE

Lombardo, Luca; Arreghini, Angela; Maccarrone, Roberta; Bianchi, Anna; Scalia, Santo; Siciliani, Giuseppe

2015-01-01

Background The aim was to assess and compare absorbance and transmittance values of three types of clear orthodontic aligners before and after two cycles of in vitro aging. Methods Nine samples of orthodontic aligners from three different manufacturers (Invisalign, Align Technology, Santa Clara, CA, USA; All-In, Micerium, Avegno, GE, Italy; F22 Aligner, Sweden & Martina, Due Carrare, PD, Italy) were selected, and each sample was subjected to spectrophotometry analysis of both its transmittanc...

Determination of silica in silicates by differential spectrophotometry as α-molybdosilicic acid

International Nuclear Information System (INIS)

Ohlweiler, O.A.; Meditsch, J.O.; Silva, S.

1980-01-01

A method for determining silica in silicates by differential spectrophotometry, using β-molybdosilic acid, is described. The sample is attacked by a mixture of boron trioxide and lithium carbonate (10:1). α-molydbosilicic acid is developed in a buffered solution (pH approximatelly 3.9) containing acetic acid and sodium acetate. The analytical procedure involves a series of preliminary steps which were previously elaborated for the gravimetric determination of silica as oxine molybdosilicate and which account for the removal of phosphorus, titanium and zirconium through ion exchange resins. (C.L.B.) [pt

Comparison of Ho and Y complexation data obtained by electromigration methods, potentiometry and spectrophotometry

International Nuclear Information System (INIS)

Vinsova, H.; Koudelkova, M.; Ernestova, M.; Jedinakova-Krizova, V.

2003-01-01

Many of holmium and yttrium complex compounds of both organic and inorganic origin have been studied recently from the point of view of their radiopharmaceutical behavior. Complexes with Ho-166 and Y-90 can be either directly used as pharmaceutical preparations or they can be applied in a conjugate form with selected monoclonal antibody. Appropriate bifunctional chelation agents are necessary in the latter case for indirect binding of monoclonal antibody and selected radionuclide. Our present study has been focused on the characterization of radionuclide (metal) - ligand interaction using various analytical methods. Electromigration methods (capillary electrophoresis, capillary isotachophoresis), potentiometric titration and spectrophotometry have been tested from the point of view of their potential to determine conditional stability constants of holmium and yttrium complexes. A principle of an isotachophoretic determination of stability constants is based on the linear relation between logarithms of stability constant and a reduction of a zone of complex. For the calculation of thermodynamic constants using potentiometry it was necessary at first to determine the protonation constants of acid. Those were calculated using the computer program LETAGROP Etitr from data obtained by potentiometric acid-base titration. Consequently, the titration curves of holmium and yttrium with studied ligands and protonation constants of corresponding acid were applied for the calculation of metal-ligand stability constants. Spectrophotometric determination of stability constants of selected systems was based on the titration of holmium and yttrium nitrate solutions by Arsenazo III following by the titration of metal-Arsenazo III complex by selected ligand. Data obtained have been evaluated using the computation program OPIUM. Results obtained by all analytical methods tested in this study have been compared. It was found that direct potentiometric titration technique could not be

The Classification of Ground Roasted Decaffeinated Coffee Using UV-VIS Spectroscopy and SIMCA Method

Science.gov (United States)

Yulia, M.; Asnaning, A. R.; Suhandy, D.

2018-05-01

In this work, an investigation on the classification between decaffeinated and non- decaffeinated coffee samples using UV-VIS spectroscopy and SIMCA method was investigated. Total 200 samples of ground roasted coffee were used (100 samples for decaffeinated coffee and 100 samples for non-decaffeinated coffee). After extraction and dilution, the spectra of coffee samples solution were acquired using a UV-VIS spectrometer (Genesys™ 10S UV-VIS, Thermo Scientific, USA) in the range of 190-1100 nm. The multivariate analyses of the spectra were performed using principal component analysis (PCA) and soft independent modeling of class analogy (SIMCA). The SIMCA model showed that the classification between decaffeinated and non-decaffeinated coffee samples was detected with 100% sensitivity and specificity.

Studies on antioxidant properties before and after UV- and γ-IR radiation of Bulgarian lavender essential oil isolated from Lavandula Angostifolia Mill

International Nuclear Information System (INIS)

Karamalakova, Yanka; Nikolova, Galina; Gadjeva, Veselina; Zheleva, Antoaneta; Sharma, Jyoti; Stanev, Stanko; Arora, Rajesh

2013-01-01

At present there is not enough data about different types of radiation on Bulgarian essential oils isolated from medicinal plants. Here we report for the first time our studies on the effects of UV-radiation (290 nm to 320 nm) and γ-radiation (doses of 5 Gy, 10 Gy, 20 Gy and 30 Gy) on Bulgarian lavender essential oil isolated from Lavandulla angustifolia Mill. A spectrophotometry method was used for evaluation of the changes in the reducing power of the Bulgarian lavender oil before and after radiation. The electron donation potential of non-irradiated oil was found to be lower (0.268 ± 0.0244) than those of both, UV-irradiated (0.336 ± 0.0121) and γ-irradiated, oil samples (0.427 ± 0.0251 at 5 Gy radiation, 0.341 ± 0.0371 at 10 Gy; 0.328± 0.0173 at 20 Gy). By direct electron paramagnetic resonance (EPR) spectroscopy, single almost symmetrical EPR signals with different values of the g-factor were registered in non-irradiated (g = 2.0047 ± 0.0002), UV-irradiated (g = 2.01050 ± 0.00005) and γ-irradiated oil samples (g = 2.0017 ± 0.0002), respectively. EPR spectroscopy was used for assessment of the radical scavenging capacity of the non-irradiated and UV- and γ-irradiated samples of the Bulgarian lavender oil towards the stable free radical 1,1-diphenyl- 2-picrylhydrazyl (DPPH). Excellent DPPH radical scavenging capacities were found for UV- and 30 Gy-irradiated lavender oil samples. Based on these preliminary results, we consider that, after proper UV- or γ-radiation treatment, Bulgarian lavender oil might find application as a good radioprotector and antioxidant in cosmetics and medicine

A laboratory manual for the determination of metals in water and wastewater by atomic absorption spectrophotometry

International Nuclear Information System (INIS)

Smith, R.

1983-01-01

This guide presents, in addition to a brief discussion of the basic principles and practical aspects of atomic absorption spectrophotometry, a scheme of analysis for the determination of 19 metals in water and wastewater, 16 by flame atomic absorption and 3 by vapour generation techniques. Simplicity, speed and accuracy were the main criteria considered in the selection of the various methods

UV-vis, IR and 1H NMR spectroscopic studies and characterization of ionic-pair crystal violet-oxytetracycline

Science.gov (United States)

Orellana, Sandra; Soto, César; Toral, M. Inés

2010-01-01

The present study shows the formation and characterization of the ionic-pair between the antibiotic oxytetracycline and the dye crystal violet in ammonia solution pH 9.0 ± 0.2 extracted into chloroform. The characterization was demonstrated using UV-vis spectrophotometry, 1H NMR, measurement of relaxation times T1 and IR spectroscopy, using a comparison between the signals of individual pure compounds with the signals with the mixture CV-OTC in different alkaline media. The formation of ionic-pair was also corroborated by new signals and chemical shifts. (2D) NMR spectroscopy experiments show that the interaction is electrostatic.

Stability indicating HPLC-UV method for detection of curcumin in Curcuma longa extract and emulsion formulation.

Science.gov (United States)

Syed, Haroon Khalid; Liew, Kai Bin; Loh, Gabriel Onn Kit; Peh, Kok Khiang

2015-03-01

A stability-indicating HPLC-UV method for the determination of curcumin in Curcuma longa extract and emulsion was developed. The system suitability parameters, theoretical plates (N), tailing factor (T), capacity factor (K'), height equivalent of a theoretical plate (H) and resolution (Rs) were calculated. Stress degradation studies (acid, base, oxidation, heat and UV light) of curcumin were performed in emulsion. It was found that N>6500, Tcurcumin were ⩽0.87% and ⩽2.0%, while the inter-day precision and accuracy values were ⩽2.1% and ⩽-1.92. Curcumin degraded in emulsion under acid, alkali and UV light. In conclusion, the stability-indicating method could be employed to determine curcumin in bulk and emulsions. Copyright © 2014 Elsevier Ltd. All rights reserved.

Indium sulfide buffer layers deposited by dry and wet methods

International Nuclear Information System (INIS)

Asenjo, B.; Sanz, C.; Guillen, C.; Chaparro, A.M.; Gutierrez, M.T.; Herrero, J.

2007-01-01

Indium sulfide (In 2 S 3 ) thin films have been deposited on amorphous glass, glass coated by tin oxide (TCO) and crystalline silicon substrates by two different methods: modulated flux deposition (MFD) and chemical bath deposition (CBD). Composition, morphology and optical characterization have been carried out with Scanning Electron Microscopy (SEM), IR-visible-UV Spectrophotometry, X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectrometer. Different properties of the films have been obtained depending on the preparation techniques. With MFD, In 2 S 3 films present more compact and homogeneous surface than with CBD. Films deposited by CBD present also indium oxide in their composition and higher absorption edge values when deposited on glass

A rapid and accurate method for determining protein content in dairy products based on asynchronous-injection alternating merging zone flow-injection spectrophotometry.

Science.gov (United States)

Liang, Qin-Qin; Li, Yong-Sheng

2013-12-01

An accurate and rapid method and a system to determine protein content using asynchronous-injection alternating merging zone flow-injection spectrophotometry based on reaction between coomassie brilliant blue G250 (CBBG) and protein was established. Main merit of our approach is that it can avoid interferences of other nitric-compounds in samples, such as melamine and urea. Optimized conditions are as follows: Concentrations of CBBG, polyvinyl alcohol (PVA), NaCl and HCl are 150 mg/l, 30 mg/l, 0.1 mol/l and 1.0% (v/v), respectively; volumes of the sample and reagent are 150 μl and 30 μl, respectively; length of a reaction coil is 200 cm; total flow rate is 2.65 ml/min. The linear range of the method is 0.5-15 mg/l (BSA), its detection limit is 0.05 mg/l, relative standard deviation is less than 1.87% (n=11), and analytical speed is 60 samples per hour. Copyright © 2013 Elsevier Ltd. All rights reserved.

Synthesis of polyaniline nanotubes through UV light catalytic method

Directory of Open Access Journals (Sweden)

Chuanyu Sun

2015-03-01

Full Text Available In this study, nitrocellulose (NC fiber blanket prepared by electrostatic spinning method has been used as a template, and copper nitrate (Cu(NO32 as an oxidant to synthesise polyaniline nanotubes doped with heteropolyacid (H4SiW12O40, SiW12 using UV light catalytic method. Infrared spectroscopy (IR, X-ray powder diffraction (XRD, scanning electron microscopy (SEM and transmission electron microscopy (TEM technologies were applied to characterize the prepared samples of polyaniline nanotubes. The results show that the external diameter of the tube is about 200 nm, and the internal diameter about 170 nm. We also give a reasonable speculation and explanation about the formation mechanism of the nanotubes.

Effect of UV irradiation on Cu2ZnSnS4 thin films prepared by the sol–gel sulfurization method

International Nuclear Information System (INIS)

Miyazawa, Hayato; Tanaka, Kunihiko; Uchiki, Hisao

2015-01-01

Cu 2 ZnSnS 4 (CZTS) thin films were fabricated on Mo-coated soda lime glass substrates by the sol–gel sulfurization method, which is a non-vacuum process. UV irradiation was introduced to the drying process, resulting in a significant increase in the grain size and density as well as a remarkable improvement in the crystallinity of the CZTS films. In addition, sulfurization of the Mo substrate was suppressed due to the increased density. We confirmed that the carbon/metal ratio in the precursor increased as a result of the UV irradiation. - Graphical abstract: Surface and cross sectional SEM images of the (a) CZTS prepared without UV irradiation and (b) CZTS prepared with UV irradiation. - Highlights: • CZTS thin film was prepared by sol–gel sulfurization method. • UV irradiation was introduced during the drying process. • Density and crystallinity of the CZTS films were improved by the UV irradiation. • Sulfurization of Mo substrates was suppressed by the UV irradiation.

Liquid-phase microextraction and fibre-optics-based cuvetteless CCD-array micro-spectrophotometry for trace analysis

International Nuclear Information System (INIS)

Sharma, Nisha; Pillai, Aradhana K.K.V.; Pathak, Neeraj; Jain, Archana; Verma, Krishna K.

2009-01-01

Liquid-phase microextraction (LPME) has been investigated for trace analysis in the present work in conjunction with fibre-optic-based micro-spectrophotometry which accommodates sample volume of 1 μL placed between the two ends of optical fibres. Methods have been evolved for the determination of (i) 1-100 μM and 0.5-20 μM of thiols by single drop microextraction (SDME) and LPME in 25 μL of the organic solvent, respectively, involving their reaction with the Ellman reagent and ion pair microextraction of thiolate ion formed; (ii) 70 μg to 7 mg L -1 of chlorine/chlorine dioxide by headspace in-drop reaction with alternative reagents, viz., mixed phenylhydrazine-4-sulphonic acid and N-(1-naphthyl)ethylenediamine dihydrochloride, o-dianisidine, o-tolidine, and N,N-diethyl-p-phenylenediamine; (iii) 0.2-4 mg L -1 of ammonia by reaction with 2,4-dinitro-1-fluorobenzene to give 2,4-dinitroaniline which was diazotized and coupled with 1-naphthylamine, the resulting dye was subjected to preconcentration by solid-phase extraction and LPME; and (iv) 25-750 μg L -1 of iodide/total iodine by oxidation of iodide by 2-iodosobenzoate, microextraction of iodine in organic solvent, and re-extraction into aqueous starch-iodide reagent drop held in the organic phase. LPME using 25-30 μL of organic solvent was found to produce more sensitive results than SDME. The cuvetteless spectrophotometry as used in combination with sample handling techniques produced limits of detection of analytes which were better than obtained by previously reported spectrophotometry.

Determination of traces of silver in waters by anion exchange and atomic absorption spectrophotometry

Science.gov (United States)

Chao, T.T.; Fishman, M. J.; Ball, J.W.

1969-01-01

A method has been developed for the accurate determination of 0.1-1 ??g of silver per liter of water. The method permits stabilization of silver in water without loss to container walls. Optimum conditions have been established for the complete recovery of silver from water with an anion-exchange column, for quantitative elution of silver from the resin, and for measurement of silver by atomic absorption spectrophotometry after chelation with ammonium pyrrolidine dithiocarbamate and extraction of the chelate with MIBK. Silver in the 1-10 ??g 1 range can be determined by extraction without pre-concentration on an ion-exchange resin. ?? 1969.

Facile method for liquid-exfoliated graphene size prediction by UV-visible spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Ismail, Zulhelmi, E-mail: helmie83@hotmail.com [Faculty of Manufacturing Engineering, Universiti Malaysia Pahang, 26600 Pekan, Pahang (Malaysia); Yusoh, Kamal, E-mail: kamal@ump.edu.my [Faculty of Chemical Engineering and Natural Resources, Universiti Malaysia Pahang, Lebuhraya Tun Razak, 26300 Kuantan, Pahang (Malaysia)

2016-07-19

In this work, an application of UV spectroscopy for facile prediction of liquid –exfoliated graphene size is discussed. Dynamic light scattering method was used to estimate the graphene flake size ( whilst UV spectroscopy measurement was carried out for extinction coefficient value (ε) determination. It was found that the value of (ε) decreased gradually as the graphene size was further reduced after intense sonication time (7h). This observation showed the influence of sonication time on electronic structure of graphene. A mathematical equation was derived from log-log graph for correlation between () and (ε) value. Both values can be expressed in a single equation as ( = (3.4 × 10{sup −2}) ε{sup 1.2}).

Surface composition of Mercury from reflectance spectrophotometry

Science.gov (United States)

Vilas, Faith

1988-01-01

The controversies surrounding the existing spectra of Mercury are discussed together with the various implications for interpretations of Mercury's surface composition. Special attention is given to the basic procedure used for reducing reflectance spectrophotometry data, the factors that must be accounted for in the reduction of these data, and the methodology for defining the portion of the surface contributing the greatest amount of light to an individual spectrum. The application of these methodologies to Mercury's spectra is presented.

UV Spectrophotometric Method for theEstimation of Itopride Hydrochloride in Pharmaceutical Formulation

OpenAIRE

K. R. Gupta; R. R. Joshi; R. B. Chawla; S. G. Wadodkar

2010-01-01

Three simple, precise and economical UV methods have been developed for the estimation of itopride hydrochloride in pharmaceutical formulations. Itopride hydrochloride in distilled water shows the maximum absorbance at 258.0 nm (Method A) and in first order derivative spectra of the same shows sharp peak at 247.0 nm, when n = 1 (Method B). Method C utilises area under curve (AUC) in the wavelength range from 262.0-254.0 nm for analysis of itopride hydrochloride. The drug was found to obey Bee...

A high-throughput screening strategy for nitrile-hydrolyzing enzymes based on ferric hydroxamate spectrophotometry.

Science.gov (United States)

He, Yu-Cai; Ma, Cui-Luan; Xu, Jian-He; Zhou, Li

2011-02-01

Nitrile-hydrolyzing enzymes (nitrilase or nitrile hydratase/amidase) have been widely used in the pharmaceutical industry for the production of carboxylic acids and their derivatives, and it is important to build a method for screening for nitrile-hydrolyzing enzymes. In this paper, a simple, rapid, and high-throughput screening method based on the ferric hydroxamate spectrophotometry has been proposed. To validate the accuracy of this screening strategy, the nitrilases from Rhodococcus erythropolis CGMCC 1.2362 and Alcaligenes sp. ECU0401 were used for evaluating the method. As a result, the accuracy for assaying aliphatic and aromatic carboxylic acids was as high as the HPLC-based method. Therefore, the method may be potentially used in the selection of microorganisms or engineered proteins with nitrile-hydrolyzing enzymes.

Spectrophotometric Determination of Cilostazol in Tablet Dosage Form

African Journals Online (AJOL)

Purpose: To develop simple, rapid and selective spectrophotometric methods for the determination of cilostazol in tablet dosage form. Methods: Cilostazol was dissolved in 50 % methanol and its absorbance was scanned by ultraviolet (UV) spectrophotometry. Both linear regression equation and standard absorptivity were ...

Dynamic range broadening for photomultipliers in kinetic spectrophotometry

International Nuclear Information System (INIS)

Rumas, V.K.

1983-01-01

The circuit of switching on a photomultiplier with prestage modulation developed for kinetic spectrophotometry purposes is described. Distinguishing features of the scheme are wide range of control pulse duration (40 nc - 2.5 mc) and direct transistor photostart by laser light pulse. In the case of PM prestage modulation for the second dynode modulation depth attains 400 while PM opening time constitutes 40 nc

Characteristics and performance of the Sunna high dose dosemeter using green photoluminescence and UV absorption readout methods

Energy Technology Data Exchange (ETDEWEB)

Miller, S.D.; Murphy, M.K.; Tinker, M.R.; Kovacs, A.; McLaughlin, W

2002-07-01

Growth in the use of ionising radiation for medical sterilisation and the potential for wide-scale international food irradiation have created the need for robust, mass-producible, inexpensive, and highly accurate radiation dosemeters. The Sunna dosemeter, lithium fluoride injection-moulded in a polyethylene matrix, can be read out using either green photoluminescence or ultraviolet (UV) absorption. The Sunna dosemeter can be mass-produced inexpensively with high precision. Both the photoluminescent and the UV absorption reader are simple and inexpensive. Both methods of analysis display negligible humidity effects, minimal dose rate dependence, acceptable post-irradiation effects, and permit measurements with a precision of nearly 1% 1s. The UV method shows negligible irradiation temperature effects from -30 deg. C to +60 deg. C. The photoluminescence method shows negligible irradiation temperature effects above room temperature for sterilisation dose levels and above. The dosimetry characteristics of these two readout methods are presented along with performance data in commercial sterilisation facilities. (author)

LINEARIZATION OF THE BRADFORD PROTEIN ASSAY TO APPLICATION IN COW MILK PROTEINS QUANTIFICATION BY UV-Vis SPECTROPHOTOMETRY METHOD

Directory of Open Access Journals (Sweden)

Alessa Siqueira de Oliveira dos Santos

2015-01-01

Full Text Available Reliable methods for determination and quantification of total protein in food are essential information to ensure quality and safety of food trade. The objective of this study was to evaluate the linearity of calibration curves obtained from different proteins (blood serum albumin-BSA, α-LA, β-LG, caseins (CN: αs, β and κ-CAS with the reagent of Bradford. Comercial UHT skimmed bovine milk was analyzed for the determination of total protein using the Bradford method by reading at 595 nm. The determination of the concentrations of total milk protein was achieved by linear regression. The Bradford method showed a high sensitivity for the determination of total proteins in bovine milk dilution 1:25 to values closer to those obtained by the Kjeldahl method. The results showed that the calibration curve of standard proteins β-CN and BSA obtained better linearity with less variation in the absorbance measurements for the determination of total protein of milk.

The analysis, by atomic-absorption spectrophotometry, of matte-leach residues

International Nuclear Information System (INIS)

Mallett, R.C.; Ring, E.J.; Middleton, H.R.; Dubois, M.

1973-01-01

Alternative methods for the analysis of matte-leach residues by atomic-absorption spectrophotometry were investigated. For the determination of the platinum-group metals, gold, and certain of the base metals, a fusion with sodium peroxide, followed by the separation of gold by reverse-phase chromatography and of the platinum-group metals by ion-exchange, is proposed. The noble metals are then determined in a solution that is free of most base metals including the sodium present as a result of the fusion. Copper, nickel, iron, calcium, magnesium, and aluminium can be determined after they have been removed from the ion-exchange column. Arsenic, selenium, tellurium, bismuth, tin, silver, lead, manganese, zinc, and cobalt can be determined in a separate sample after dissolution by a sealed-tube method. This is also an alternative method for the determination of copper, nickel, and iron. Chromium is determined separately after fusion with sodium peroxide, and silver can also be determined in this way. The laboratory method for these procedures is given as an appendix [af

Acid-Base Properties of Azo Dyes in Solution Studied Using Spectrophotometry and Colorimetry

Science.gov (United States)

Snigur, D. V.; Chebotarev, A. N.; Bevziuk, K. V.

2018-03-01

Colorimetry and spectrophotometry with chemometric data processing were used to study the acid-base properties of azo dyes in aqueous solution. The capabilities of both methods were compared. Ionization constants of all the functional groups of the azo compounds studied could be determined relative to the change in the specific color difference depending on the acidity of the medium. The colorimetric functions of ion-molecular forms of azo compounds used as an analytical signal allow us to obtain complete information on the acid-base equilibrium in a wide acidity range.

Flow analysis methods for the direct ultra-violet spectrophotometric measurement of nitrate and total nitrogen in freshwaters

Energy Technology Data Exchange (ETDEWEB)

Gentle, Brady S.; Ellis, Peter S.; Grace, Michael R. [Water Studies Centre, School of Chemistry, Monash University, Victoria 3800 (Australia); McKelvie, Ian D., E-mail: iandm@unimelb.edu.au [School of Chemistry, University of Melbourne, Victoria 3010 (Australia); School of Geography, Earth and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom)

2011-10-17

Highlights: {yields} Second derivative UV spectrophotometry has been used to determine nitrate and total N using flow analysis techniques. {yields} A simple flow system with a single-reflection flow-through cell was used for the UV measurement of nitrate. {yields} Total N was determined after on-line UV photooxidation with alkaline peroxodisulfate. {yields} Analyses carried out using the developed flow systems show a high degree of agreement with comparative analyses. {yields} This method requires no colorimetric reagents and eliminates the requirement for a toxic cadmium reduction column. - Abstract: Second derivative ultra-violet spectrophotometric methods are described for the measurement of nitrate and total nitrogen in freshwaters using flow analysis techniques. A simple flow system consisting of a peristaltic pump and a single-reflection flow-through cell was used for the measurement of nitrate. Quantification of total nitrogen using alkaline peroxodisulfate photo-digestion was achieved by incorporating an ultra-violet photo-reactor, a hollow-fibre filter and a debubbler into the flow system. The nitrate system featured a limit of detection of 0.04 mg N L{sup -1}, 0.4%RSD (1 mg N L{sup -1} as nitrate, n = 10), a coefficient of determination (R{sup 2}) of 0.9995 over the calibration range 0.0-2.0 mg N L{sup -1}, and a data acquisition time of 1.5 s per spectrum. The total nitrogen system featured a limit of detection of 0.05 mg N L{sup -1}, 1%RSD (1 mg N L{sup -1} as ammonium chloride, n = 10), a coefficient of determination of 0.9989 over the calibration range 0.0-2.0 mg N L{sup -1}, and a throughput of 5 sample h{sup -1} measured in triplicate. Digestions of five model nitrogen compounds returned recoveries of >88%. Determinations carried out using the developed systems show a high degree of agreement with data obtained using reference methods. These methods require no colorimetric reagents and eliminate the requirement for a toxic cadmium reduction column

Flow analysis methods for the direct ultra-violet spectrophotometric measurement of nitrate and total nitrogen in freshwaters

International Nuclear Information System (INIS)

Gentle, Brady S.; Ellis, Peter S.; Grace, Michael R.; McKelvie, Ian D.

2011-01-01

Highlights: → Second derivative UV spectrophotometry has been used to determine nitrate and total N using flow analysis techniques. → A simple flow system with a single-reflection flow-through cell was used for the UV measurement of nitrate. → Total N was determined after on-line UV photooxidation with alkaline peroxodisulfate. → Analyses carried out using the developed flow systems show a high degree of agreement with comparative analyses. → This method requires no colorimetric reagents and eliminates the requirement for a toxic cadmium reduction column. - Abstract: Second derivative ultra-violet spectrophotometric methods are described for the measurement of nitrate and total nitrogen in freshwaters using flow analysis techniques. A simple flow system consisting of a peristaltic pump and a single-reflection flow-through cell was used for the measurement of nitrate. Quantification of total nitrogen using alkaline peroxodisulfate photo-digestion was achieved by incorporating an ultra-violet photo-reactor, a hollow-fibre filter and a debubbler into the flow system. The nitrate system featured a limit of detection of 0.04 mg N L -1 , 0.4%RSD (1 mg N L -1 as nitrate, n = 10), a coefficient of determination (R 2 ) of 0.9995 over the calibration range 0.0-2.0 mg N L -1 , and a data acquisition time of 1.5 s per spectrum. The total nitrogen system featured a limit of detection of 0.05 mg N L -1 , 1%RSD (1 mg N L -1 as ammonium chloride, n = 10), a coefficient of determination of 0.9989 over the calibration range 0.0-2.0 mg N L -1 , and a throughput of 5 sample h -1 measured in triplicate. Digestions of five model nitrogen compounds returned recoveries of >88%. Determinations carried out using the developed systems show a high degree of agreement with data obtained using reference methods. These methods require no colorimetric reagents and eliminate the requirement for a toxic cadmium reduction column. The overlap of chloride and nitrate spectra in seawater is

Assessing Pearl Quality Using Reflectance UV-Vis Spectroscopy: Does the Same Donor Produce Consistent Pearl Quality?

Directory of Open Access Journals (Sweden)

Paul C. Southgate

2010-09-01

with UV-Vis spectrophotometry. Nevertheless, this technique could have a role to play in developing less subjective methods of assessing pearl quality and in further studies of the relationships between pearl quality and that of the donor and recipient oysters.

Preparation of flower-like CuS by solvothermal method and its photodegradation and UV protection

Energy Technology Data Exchange (ETDEWEB)

Hu, Xiao-Sai; Shen, Yong, E-mail: shenyong@sues.edu.cn; Xu, Li-Hui; Wang, Li-Ming; Xing, Ya-Jun

2016-07-25

The flower-like CuS with hierarchical structures were synthesized by a solvothermal method. X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, UV–vis optical absorption spectroscopy and thermogravimetric analysis (TGA) and ultraviolet transmittance analyzer labsphere were used to characterize the as-prepared products. The results of photocatalytic degradation of Methylene blue (MB) demonstrated that the as-prepared flower-like CuS possessed high photocatalytic performance in UV and visible range and its band gap was 1.45 eV. The degradation rate of MB by CuS with the absence of H{sub 2}O{sub 2} was 98.23% and 100% under xenon lamp and Mercury tungsten blended lamp for 30 min, respectively. And a new approach for ultraviolet (UV) protection of cotton fabrics treated by flower-like CuS microspheres was innovatively investigated and the results showed that flower-like CuS was a good UV resistant material. - Highlights: • The flower-like CuS was prepared via solvothermal method. • The as-prepared CuS showed better photodegradation of MB solution under visible region. • The cotton fabric treated by the obtained flower-like CuS was proved to have a potential application in anti-UV field.

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

MPTQ) with DNA was studied by UV-Vis and fluorescenc'e spectrophotometry as well as by hydrodynamic methods. On binding to DNA, the absorption spectrum underwent bathochromic and hypochromic shifts and the fluorescence was ...

Development and validation of a FIA/UV-vis method for pK(a) determination of oxime based acetylcholinesterase reactivators.

Science.gov (United States)

Musil, Karel; Florianova, Veronika; Bucek, Pavel; Dohnal, Vlastimil; Kuca, Kamil; Musilek, Kamil

2016-01-05

Acetylcholinesterase reactivators (oximes) are compounds used for antidotal treatment in case of organophosphorus poisoning. The dissociation constants (pK(a1)) of ten standard or promising acetylcholinesterase reactivators were determined by ultraviolet absorption spectrometry. Two methods of spectra measurement (UV-vis spectrometry, FIA/UV-vis) were applied and compared. The soft and hard models for calculation of pK(a1) values were performed. The pK(a1) values were recommended in the range 7.00-8.35, where at least 10% of oximate anion is available for organophosphate reactivation. All tested oximes were found to have pK(a1) in this range. The FIA/UV-vis method provided rapid sample throughput, low sample consumption, high sensitivity and precision compared to standard UV-vis method. The hard calculation model was proposed as more accurate for pK(a1) calculation. Copyright © 2015 Elsevier B.V. All rights reserved.

DARPA Antibody Technology Program Standardized Test Bed for Antibody Characterization: Characterization of an MS2 ScFv Antibody

Science.gov (United States)

2016-03-01

2 2.2 UV –Visible Spectrophotometry...3 M phosphoric acid or 3 M sodium hydroxide [Sigma-Aldrich] as necessary), and overhead pressure of 1 psi. When the OD inside the 100 L fermentor...chromatography media (GE Healthcare). 2.2 UV –Visible Spectrophotometry A NanoDrop ND-1000 spectrophotometer (Thermo Scientific; Waltham, MA

Validation of analytical method for quality control of B12 Vitamin-10 000 injection

International Nuclear Information System (INIS)

Botet Garcia, Martha; Garcia Penna, Caridad Margarita; Troche Concepcion, Yenilen; Cannizares Arencibia, Yanara; Moreno Correoso, Barbara

2009-01-01

Analytical method reported by USA Pharmacopeia was validated for quality control of injectable B 1 2 Vitamin (10 000 U) by UV spectrophotometry because this is a simpler and low-cost method allowing quality control of finished product. Calibration curve was graphed at 60 to 140% interval, where it was linear with a correlation coefficient similar to 0, 9999; statistical test for interception and slope was considered non-significant. There was a recovery of 99.7 % in study concentrations interval where the Cochran (G) and Student(t) test were not significant too. Variation coefficient in repetition study was similar to 0.59 % for the 6 assayed replies, whereas in intermediate precision analysis, the Fisher and Student tests were not significant. Analytical method was linear, precise, specific and exact in study concentrations interval

Advances in analytical methods and occurrence of organic UV-filters in the environment--A review.

Science.gov (United States)

Ramos, Sara; Homem, Vera; Alves, Arminda; Santos, Lúcia

2015-09-01

UV-filters are a group of compounds designed mainly to protect skin against UVA and UVB radiation, but they are also included in plastics, furniture, etc., to protect products from light damage. Their massive use in sunscreens for skin protection has been increasing due to the awareness of the chronic and acute effects of UV radiation. Some organic UV-filters have raised significant concerns in the past few years for their continuous usage, persistent input and potential threat to ecological environment and human health. UV-filters end up in wastewater and because wastewater treatment plants are not efficient in removing them, lipophilic compounds tend to sorb onto sludge and hydrophilics end up in river water, contaminating the existing biota. To better understand the risk associated with UV-filters in the environment a thorough review regarding their physicochemical properties, toxicity and environmental degradation, analytical methods and their occurrence was conducted. Higher UV-filter concentrations were found in rivers, reaching 0.3mg/L for the most studied family, the benzophenone derivatives. Concentrations in the ng to μg/L range were also detected for the p-aminobenzoic acid, cinnamate, crylene and benzoyl methane derivatives in lake and sea water. Although at lower levels (few ng/L), UV-filters were also found in tap and groundwater. Swimming pool water is also a sink for UV-filters and its chlorine by-products, at the μg/L range, highlighting the benzophenone and benzimidazole derivatives. Soils and sediments are not frequently studied, but concentrations in the μg/L range have already been found especially for the benzophenone and crylene derivatives. Aquatic biota is frequently studied and UV-filters are found in the ng/g-dw range with higher values for fish and mussels. It has been concluded that more information regarding UV-filter degradation studies both in water and sediments is necessary and environmental occurrences should be monitored more

Zero crossing and ratio spectra derivative spectrophotometry for the dissolution tests of amlodipine and perindopril in their fixed dose formulations

Directory of Open Access Journals (Sweden)

Maczka Paulina

2014-06-01

Full Text Available Dissolution tests of amlodipine and perindopril from their fixed dose formulations were performed in 900 mL of phosphate buffer of pH 5.5 at 37°C using the paddle apparatus. Then, two simple and rapid derivative spectrophotometric methods were used for the quantitative measurements of amlodipine and perindopril. The first method was zero crossing first derivative spectrophotometry in which measuring of amplitudes at 253 nm for amlodipine and 229 nm for perindopril were used. The second method was ratio derivative spectrophotometry in which spectra of amlodipine over the linearity range were divided by one selected standard spectrum of perindopril and then amplitudes at 242 nm were measured. Similarly, spectra of perindopril were divided by one selected standard spectrum of amlodipine and then amplitudes at 298 nm were measured. Both of the methods were validated to meet official requirements and were demonstrated to be selective, precise and accurate. Since there is no official monograph for these drugs in binary formulations, the dissolution tests and quantification procedure presented here can be used as a quality control test for amlodipine and perindopril in respective dosage forms.

[Fe₃O₄-β-Cyclodextrin Polymer Nano Composites Solid-Phase Extraction-UV-Vis Spectrophotometry for Separation Analysis Malachite Green].

Science.gov (United States)

Feng, Gang; Ping, Wen-hui; Zhu, Xia-shi

2016-02-01

In this paper, carboxymethyl-hydroxypropyl-β-cyclodextrin polymer modified magnetic particles Fe₃O₄ (CM-HP-β-CD- CP-MNPs) were prepared and applied to magnetic solid phase extraction of malachite green combined with UV-Visible spectrom- etry detection. The synthesized magnetic particles were characterized by element analysis, Fourier transform infrared spectra and transmission electron microscopy. Several variables affecting the extraction and desorption of malachite green such as pH, the amount of adsorbent, the type and volume of eluent, extraction and desorption time, and temperature were investigated. Under the optimum conditions, malachite green could be adsorbed by CM-HP-β-CDCP-MNPs (RE% = 92), and elution by C₂H₅OH (EE% = 90). the preconcentration factor of the proposed method was approximately 7.5, the CM-HP-β-CDCP-MNPs could be used repeatedly for 5 times and offered better recovery. The linear range and detection limit (DL) were found to be 0.08~8.00 µg · mL⁻¹ and 5.6 ng · mL⁻¹ respectively. This technique had been successfully applied to the determination of malachite green in real samples. The inclusion interaction of CM-HP--CDCP-MNPs with malachite green was studied through FTIR.

Diagnosis of Smith-Lemli-Opitz syndrome by ultraviolet spectrophotometry

Directory of Open Access Journals (Sweden)

F.B. Scalco

2003-10-01

Full Text Available Smith-Lemli-Opitz syndrome (SLOS is an autosomal recessive disorder due to an inborn error of cholesterol metabolism, characterized by congenital malformations, dysmorphism of multiple organs, mental retardation and delayed neuropsychomotor development resulting from cholesterol biosynthesis deficiency. A defect in 3ß-hydroxysteroid-delta7-reductase (delta7-sterol-reductase, responsible for the conversion of 7-dehydrocholesterol (7-DHC to cholesterol, causes an increase in 7-DHC and frequently reduces plasma cholesterol levels. The clinical diagnosis of SLOS cannot always be conclusive because of the remarkable variability of clinical expression of the disorder. Thus, confirmation by the measurement of plasma 7-DHC levels is needed. In the present study, we used a simple, fast, and selective method based on ultraviolet spectrophotometry to measure 7-DHC in order to diagnose SLOS. 7-DHC was extracted serially from 200 µl plasma with ethanol and n-hexane and the absorbance at 234 and 282 nm was determined. The method was applied to negative control plasma samples from 23 normal individuals and from 6 cases of suspected SLOS. The method was adequate and reliable and 2 SLOS cases were diagnosed.

Linearization of the Bradford protein assay to application in cow milk proteins quantification by UV-Vis spectrophotometry method.

OpenAIRE

SANTOS, A. S. de O. dos; COSTA, F. F.; ESTEVES, W. T.; BRITO, M. A. V. P. e; FURTADO, M. A. M.; MARTINS, M. F.

2015-01-01

Reliable methods for determination and quantification of total protein in food are essential information to ensure quality and safety of food trade. The objective of this study was to evaluate the linearity of calibration curves obtained from different proteins (blood serum albumin-BSA, α-LA, β-LG, αs, β and κ-CAS) with the reagent of Bradford. Comercial UHT skimmed bovine milk was analyzed for the determination of total protein using the Bradford method by reading at 595 nm. The determinatio...

Technical note: comparing von Luschan skin color tiles and modern spectrophotometry for measuring human skin pigmentation.

Science.gov (United States)

Swiatoniowski, Anna K; Quillen, Ellen E; Shriver, Mark D; Jablonski, Nina G

2013-06-01

Prior to the introduction of reflectance spectrophotometry into anthropological field research during the 1950s, human skin color was most commonly classified by visual skin color matching using the von Luschan tiles, a set of 36 standardized, opaque glass tiles arranged in a chromatic scale. Our goal was to establish a conversion formula between the tile-based color matching method and modern reflectance spectrophotometry to make historical and contemporary data comparable. Skin pigmentation measurements were taken on the forehead, inner upper arms, and backs of the hands using both the tiles and a spectrophotometer on 246 participants showing a broad range of skin pigmentation. From these data, a second-order polynomial conversion formula was derived by jackknife analysis to estimate melanin index (M-index) based on tile values. This conversion formula provides a means for comparing modern data to von Luschan tile measurements recorded in historical reports. This is particularly important for populations now extinct, extirpated, or admixed for which tile-based measures of skin pigmentation are the only data available. Copyright © 2013 Wiley Periodicals, Inc.

Spectrophotometry-based detection of carbapenemase producers among Enterobacteriaceae.

Science.gov (United States)

Bernabeu, Sandrine; Poirel, Laurent; Nordmann, Patrice

2012-09-01

Carbapenem-hydrolyzing ß-lactamases are the most powerful ß-lactamases being able to hydrolyse almost all ß-lactams. They are mostly of the KPC, VIM, IMP, NDM, and OXA-48 type. A spectrophotometry technique based on analysis of the imipenem hydrolysis has been developed that differentiated carbapenemase- from noncarbapenemase producers. This inexpensive technique adapted to screening of carbapenemase producers may be implemented in any reference laboratory worldwide. Copyright © 2012 Elsevier Inc. All rights reserved.

Simultaneous Estimation of Ibuprofen and Phenylephrine Hydrochloride in Bulk and Combined Dosage Form by First Derivative UV Spectrophotometry Method

Directory of Open Access Journals (Sweden)

Mehul Patel

2013-01-01

Full Text Available A simple, precise, rapid, and economic method was developed for the simultaneous determination of Ibuprofen and Phenylephrine HCl in bulk and combined dosage form. This method involves first-order derivative spectroscopy using 248 nm and 237 nm as zero crossing points for Ibuprofen and Phenylephrine HCl, respectively. For spectrophotometric method 0.1 N NaOH was used as a solvent. The linearity was established over the concentration range of 12–72 μg/mL and 1.5–22 μg/mL for Ibuprofen and Phenylephrine HCl with correlation coefficient (r2 of 0.9972 and 0.9981, respectively. The mean % recoveries were found to be in the range of 98.88% and 98.54% for Ibuprofen and Phenylephrine HCl, respectively. Interday and intraday studies showed repeatability of the method. The method was found to be specific and robust. The method was successfully applied to pharmaceutical formulation, with no interference from excipients as indicated by the recovery study. Results of analysis were validated statistically and by recovery studies.

Quantitative determination of praesodymium(III)-neodymium(III)-holmium(III)-erbium(III) four-component systems by matrix-fourth derivative spectrophotometry

International Nuclear Information System (INIS)

Wu Yang; Jinzhang Gao; Jingwan Kang; Guangbi Bai; Cunxiong Li

1994-01-01

A new approach is developed through a combination of matrix representation and higher derivative spectrophotometry and can be used to analyse seven four-component mixtures of lanthanide ions, simultaneously, with a recovery of between 92.0 and 107.1%. The method is rapid, sensitive and accurate and is suitable for a large number of samples. (Author)

Capillary electrophoresis method with UV-detection for analysis of free amino acids concentrations in food.

Science.gov (United States)

Omar, Mei Musa Ali; Elbashir, Abdalla Ahmed; Schmitz, Oliver J

2017-01-01

Simple and inexpensive capillary electrophoresis with UV-detection method (CE-UV) was optimized and validated for determination of six amino acids namely (alanine, asparagine, glutamine, proline, serine and valine) for Sudanese food. Amino acids in the samples were derivatized with 4-chloro-7-nitro-2,1,3-benzoxadiazole (NBD-Cl) prior to CE-UV analysis. Labeling reaction conditions (100mM borate buffer at pH 8.5, labeling reaction time 60min, temperature 70°C and NBD-Cl concentration 40mM) were systematically investigated. The optimal conditions for the separation were 100mM borate buffer at pH 9.7 and detected at 475nm. The method was validated in terms of linearity, limit of detection (LOD), limit of quantification (LOQ), precision (repeatability) (RSD%) and accuracy (recovery). Good linearity was achieved for all amino acids (r(2)>0.9981) in the concentration range of 2.5-40mg/L. The LODs in the range of 0.32-0.56mg/L were obtained. Recoveries of amino acids ranging from 85% to 108%, (n=3) were obtained. The validated method was successfully applied for the determination of amino acids for Sudanese food samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

Determination of Lead in Urine by Atomic Absorption Spectrophotometry1

Science.gov (United States)

Selander, Stig; Cramé, Kim

1968-01-01

A method for the determination of lead in urine by means of atomic absorption spectrophotometry (AAS) is described. A combination of wet ashing and extraction with ammonium pyrrolidine dithiocarbamate into isobutylmethylketone was used. The sensitivity was about 0·02 μg./ml. for 1% absorption, and the detection limit was about 0·02 μg./ml. with an instrumental setting convenient for routine analyses of urines. Using the scale expansion technique, the detection limit was below 0·01 μg./ml., but it was found easier to determine urinary lead concentrations below 0·05 μg./ml. by concentrating the lead in the organic solvent by increasing the volume of urine or decreasing that of the solvent. The method was applied to fresh urines, stored urines, and to urines, obtained during treatment with chelating agents, of patients with lead poisoning. Urines with added inorganic lead were not used. The results agreed well with those obtained with a colorimetric dithizone extraction method (r = 0·989). The AAS method is somewhat more simple and allows the determination of smaller lead concentrations. PMID:5647975

Kinetic Spectrophotometric Method for the 1,4-Diionic Organophosphorus Formation in the Presence of Meldrum′s Acid: Stopped-Flow Approach

Directory of Open Access Journals (Sweden)

Fatemeh Ghodsi

2016-11-01

Full Text Available The kinetics of the reaction between triphenylphosphine (TPP and dimethyl acetylenedicarboxylate (DMAD in the presence of Meldrum’s acid (MA for the generation of the 1,4-diionic organophosphorus compound has been investigated using the stopped-flow and UV-VIS spectrophotometry techniques. The first step of the reaction between TPP and DMAD for the generation of (I1 in ethanol was followed by the stopped-flow apparatus. This step was recognized as a fast step. The reaction between the intermediate (I1 and MA showed first-order kinetics, and it was followed by the UV-VIS spectrophotometry technique. The activation parameters for the slow step of the proposed mechanism were determined using two linearized forms of the Eyring equation. From the temperature, concentration and solvent studies, the activation energy (Ea = 20.16 kJ·mol−1 and the related activation parameters (ΔG‡ = 71.17 ± 0.015 kJ·mol−1, ΔS‡ = −185.49 ± 0.026 J·mol−1 and ΔH‡ =17.72 ± 0.007 kJ·mol−1 were calculated. The experimental data indicated that the reaction was zero-order in MA and second-order overall. The proposed mechanism was confirmed with the observed kinetic data obtained from the UV-VIS and stopped-flow techniques.

The determination, by atomic-absorption spectrophotometry, of impurities in manganese dioxide

International Nuclear Information System (INIS)

Balaes, G.E.E.; Robert, R.V.D.

1981-01-01

This report describes various methods for the determination of impurities in electrolytic manganese dioxide by atomic-absorption spectrophotometry (AAS). The sample is dissolved in a mixture of acids, any residue being ignited and retreated with acid. Several AAS methods were applied so that the analysis required to meet the specifications could be attained. These involved conventional flame AAS, AAS with electrothermal atomization (ETA), hydride generation coupled with AAS, and cold-vapour AAS. Of the elements examined, copper, iron, zinc, and lead can be determined direct with confidence with or without corrections based on recoveries obtained from spiked solutions. Nickel can be determined direct by use of the method of standard additions, and copper, nickel, and lead by ETA with the method of standard additions. Arsenic and antimony are determined by hydride generation coupled with AAS, and mercury by cold-vapour AAS. The precision of analysis (relative standard deviation) is generally less than 0,050. Values were obtained for aluminium, molybdenum, magnesium, sodium, copper, chromium, and cadmium, but the accuracy of these determinations has not been fully established

Water and Wastewater Disinfection with Peracetic Acid and UV Radiation and Using Advanced Oxidative Process PAA/UV

Directory of Open Access Journals (Sweden)

Jeanette Beber de Souza

2015-01-01

Full Text Available The individual methods of disinfection peracetic acid (PAA and UV radiation and combined process PAA/UV in water (synthetic and sanitary wastewater were employed to verify the individual and combined action of these advanced oxidative processes on the effectiveness of inactivation of microorganisms indicators of fecal contamination E. coli, total coliforms (in the case of sanitary wastewater, and coliphages (such as virus indicators. Under the experimental conditions investigated, doses of 2, 3, and 4 mg/L of PAA and contact time of 10 minutes and 60 and 90 s exposure to UV radiation, the results indicated that the combined method PAA/UV provided superior efficacy when compared to individual methods of disinfection.

Micro solid phase spectrophotometry in a sequential injection lab-on-valve platform for cadmium, zinc, and copper determination in freshwaters.

Science.gov (United States)

Santos, Inês C; Mesquita, Raquel B R; Rangel, António O S S

2015-09-03

This work describes the development of a solid phase spectrophotometry method in a μSI-LOV system for cadmium, zinc, and copper determination in freshwaters. NTA (Nitrilotriacetic acid) beads with 60-160 μm diameter were packed in the flow cell of the LOV for a μSPE column of 1 cm length. The spectrophotometric determination is based on the colourimetric reaction between dithizone and the target metals, previously retained on NTA resin. The absorbance of the coloured product formed is measured, at 550 nm, on the surface of the NTA resin beads in a solid phase spectrophotometry approach. The developed method presented preconcentration factors in the range of 11-21 for the metal ions. A LOD of 0.23 μg L(-1) for cadmium, 2.39 μg L(-1) for zinc, and 0.11 μg L(-1) for copper and a sampling rate of 12, 13, and 15 h(-1) for cadmium, zinc, and copper were obtained, respectively. The proposed method was successfully applied to freshwater samples. Copyright © 2015 Elsevier B.V. All rights reserved.

A new method of UA_CPE coupled with spectrophotometry for the faster and cost-effective detection of proline in fruit juice, honey, and wine.

Science.gov (United States)

Dağdeviren, Semahat; Altunay, Nail; Sayman, Yasin; Gürkan, Ramazan

2018-07-30

The study developed a new method for proline detection in honey, wine and fruit juice using ultrasound assisted-cloud point extraction (UA-CPE) and spectrophotometry. Initially, a quaternary complex was built, containing proline, histamine, Cu(II), and fluorescein at pH 5.5. Samples were treated with ethanol-water mixture before extraction and preconcentration, using an ultrasonic bath for 10 min at 40 °C (40 kHz, 300 W). After the optimization of variables affecting extraction efficiency, good linearity was obtained between 15 and 600 µg L -1 with sensitivity enhancement factor of 105. The limits of detection and quantification were 5.7 and 19.0 µg L -1 , respectively. The recovery percentage and relative standard deviations (RSD %) were between 95.3 and 103.3%, and 2.5 and 4.2%, respectively. The accuracy of the method was verified by the analysis of a standard reference material (SRM 2389a). Copyright © 2018 Elsevier Ltd. All rights reserved.

Advances in analytical methods and occurrence of organic UV-filters in the environment — A review

International Nuclear Information System (INIS)

Ramos, Sara; Homem, Vera; Alves, Arminda; Santos, Lúcia

2015-01-01

UV-filters are a group of compounds designed mainly to protect skin against UVA and UVB radiation, but they are also included in plastics, furniture, etc., to protect products from light damage. Their massive use in sunscreens for skin protection has been increasing due to the awareness of the chronic and acute effects of UV radiation. Some organic UV-filters have raised significant concerns in the past few years for their continuous usage, persistent input and potential threat to ecological environment and human health. UV-filters end up in wastewater and because wastewater treatment plants are not efficient in removing them, lipophilic compounds tend to sorb onto sludge and hydrophilics end up in river water, contaminating the existing biota. To better understand the risk associated with UV-filters in the environment a thorough review regarding their physicochemical properties, toxicity and environmental degradation, analytical methods and their occurrence was conducted. Higher UV-filter concentrations were found in rivers, reaching 0.3 mg/L for the most studied family, the benzophenone derivatives. Concentrations in the ng to μg/L range were also detected for the p-aminobenzoic acid, cinnamate, crylene and benzoyl methane derivatives in lake and sea water. Although at lower levels (few ng/L), UV-filters were also found in tap and groundwater. Swimming pool water is also a sink for UV-filters and its chlorine by-products, at the μg/L range, highlighting the benzophenone and benzimidazole derivatives. Soils and sediments are not frequently studied, but concentrations in the μg/L range have already been found especially for the benzophenone and crylene derivatives. Aquatic biota is frequently studied and UV-filters are found in the ng/g-dw range with higher values for fish and mussels. It has been concluded that more information regarding UV-filter degradation studies both in water and sediments is necessary and environmental occurrences should be monitored more

Advances in analytical methods and occurrence of organic UV-filters in the environment — A review

Energy Technology Data Exchange (ETDEWEB)

Ramos, Sara; Homem, Vera, E-mail: vhomem@fe.up.pt; Alves, Arminda; Santos, Lúcia

2015-09-01

UV-filters are a group of compounds designed mainly to protect skin against UVA and UVB radiation, but they are also included in plastics, furniture, etc., to protect products from light damage. Their massive use in sunscreens for skin protection has been increasing due to the awareness of the chronic and acute effects of UV radiation. Some organic UV-filters have raised significant concerns in the past few years for their continuous usage, persistent input and potential threat to ecological environment and human health. UV-filters end up in wastewater and because wastewater treatment plants are not efficient in removing them, lipophilic compounds tend to sorb onto sludge and hydrophilics end up in river water, contaminating the existing biota. To better understand the risk associated with UV-filters in the environment a thorough review regarding their physicochemical properties, toxicity and environmental degradation, analytical methods and their occurrence was conducted. Higher UV-filter concentrations were found in rivers, reaching 0.3 mg/L for the most studied family, the benzophenone derivatives. Concentrations in the ng to μg/L range were also detected for the p-aminobenzoic acid, cinnamate, crylene and benzoyl methane derivatives in lake and sea water. Although at lower levels (few ng/L), UV-filters were also found in tap and groundwater. Swimming pool water is also a sink for UV-filters and its chlorine by-products, at the μg/L range, highlighting the benzophenone and benzimidazole derivatives. Soils and sediments are not frequently studied, but concentrations in the μg/L range have already been found especially for the benzophenone and crylene derivatives. Aquatic biota is frequently studied and UV-filters are found in the ng/g-dw range with higher values for fish and mussels. It has been concluded that more information regarding UV-filter degradation studies both in water and sediments is necessary and environmental occurrences should be monitored more

Development and Validation of a UV Spectrophotometric and a RP-HPLC Methods for Moexipril Hydrochloride in Pure Form and Pharmaceutical Dosage Form

International Nuclear Information System (INIS)

Mastiholimath, V.S.; Gupte, P.P.; Mannur, V.S.

2012-01-01

A simple and reliable UV spectrophotometric and high-performance liquid chromatography (HPLC) methods were developed and validated for Moexipril hydrochloride in pure form and pharmaceutical dosage form. The RP-HPLC method was developed on agilant eclipse C 18 , (150 mm x 4.6 mm, 5 μm) with a mobile phase gradient system of 60 % (methanol:acetonitrile (70:30 % v/v)) : 40 % 20 mM ammonium acetate buffer pH 4.5 (v/v) and UV spectrophotometric method was developed in phosphate buffer pH 6.8. The effluent was monitored by SPD-M20A, prominence PDA detector at 210 nm. Calibration curve was linear over the concentration range of 10-35 μg/ml and 1-9 μg/ml for RP-HPLC and UV with a regression coefficient of 0.999. For RP-HPLC method Inter-day and intra-day precision % RSD values were found to be 1.00078 % and 1.49408 % respectively. For UV method 0.73386 % to 1.44111 % for inter day 0.453864 to 1.15542 intra-day precision. Recovery of Moexipril hydrochloride was found to be in the range of 99.8538 % to 101.5614 % and 100.5297586 % to 100.6431587 % for UV and RP-HPLC respectively. The limits of detection (LOD) and quantification (LOQ) for HPLC were 0.98969 and 2.99907 μg/ml, respectively. The developed RP-HPLC and UV spectrophotometric method was successfully applied for the quantitative determination of Moexipril hydrochloride in pharmaceutical dosage. (author)

Alternative set of conditions for molybdenum determination by atomic absorption spectrophotometry

International Nuclear Information System (INIS)

Edgar, R.M.

1975-01-01

In comparing a newly developed procedure with that recommended by Perkin--Elmer, et al., (Analytical Methods for Atomic Absorption Spectrophotometry, Perkin--Elmer Corp., Norwalk, Conn. 1973) two areas were found in which the new procedure appeared more suitable for Mo determination. If Cr is present in concentrations greater than 100 ppM, the recommended procedure results in an enhancement effect on Mo absorption. This erroneously high result is eliminated when the new procedure is followed. In the recommended procedure, when the sample has to be dissolved in hydrofluoric acid and Al is added to help eliminate interferences, the acid combines with the Al to form insoluble aluminum fluoride. The part that Al plays in eliminating interferences is lessened, because it is no longer in solution

Preconcentration of Sn (II) using the methylene blue on the activated carbon and its determination by spectrophotometry method.

Science.gov (United States)

Khodadoust, Saeid; Cham Kouri, Narges

2014-04-05

A simple and accurate spectrophotometric method for determination of trace amounts of Sn (II) ion in soil sample was developed by using the methylene blue (MB) in the presence of activated carbon (AC) as the adsorbent Solid Phase Extraction (SPE) of Sn (II) and then determined by UV-Vis. The Beer's law is obeyed over the concentration range of 1-80ngmL(-1) of Sn (II) with the detection limits of 0.34ngmL(-1). The influence of type and volume of eluent, concentration of MB, pH, and amount of AC on sensitivity of spectrophotometric method were optimized. The method has been successfully applied for Sn (II) ion determination in soil sample. Copyright © 2013 Elsevier B.V. All rights reserved.

Discovery and spectrophotometry of high-redshift quasars

International Nuclear Information System (INIS)

MacAlpine, G.M.; Feldman, F.R.

1982-01-01

We report on the discovery and spectrophotometry of 30 new high-redshift quasars, which were detected using the Curtis Schmidt technique. We also discuss new follow-up spectrophotometry for 23 quasar candidates from University of Michigan Lists I--IV. Our program sample contains eight quasars with z>3, at least five objects exhibiting broad absorption troughs, and a pair of quasars which are 1' apart on the sky and nearly identical in redshift, at z near 2.13. The redshift distribution for the majority of quasars in UM List IV suggests that most of the single-line quasar candidates in the UM List have low to moderate redshifts, with the reported line often being Mg II lambda2798 or C III] lambda1909. For 17 high-redshift quasars where lambda912 at the emission-line redshift could be examined, we did not find any definite Lyman limit cutoffs. Although three objects show a decline of the continuum within 100 A of lambda912, we do not believe them to be unambiguous examples for emission-line clouds situated in the line of sight. When our O I lambda1304 measurements are combined with the data of others to yield a composite spectrum, we obtain O I lambda1304/lambda8446 = 1.35. This suggests reddening with E/sub B/-Vroughly-equal0.23. Finally, our data exhibit a correlation between Lyα emission line velocity widths and redshift. The higher z quasars in the sample tend to have narrower lines, due, at least in part, to bias in the detection technique

Measurement of uranium concentration by molecular absorption spectrophotometry by means optical fibers; Medicion continua de concentracion de uranio por espectrofotometria de absorcion molecular mediante fibras opticas

Energy Technology Data Exchange (ETDEWEB)

Gauna, Alberto C.; Pascale, Ariel A. [Comision Nacional de Energia Atomica, Buenos Aires (Argentina). Centro Atomico Ezeiza. Agencia Minipost

1996-07-01

An on-line method for measuring the concentration of uranium in uranyl nitrate-nitric acid aqueous solutions is described. The method is based on molecular absorption spectrophotometry with transmission of light by means of optical fibers. It is ideally suited for control and processes development applications. (author)

Effects of UV assistance on the properties of al-doped ZnO thin films deposited by sol-gel method

Science.gov (United States)

Tseng, Yung-Kuan; Pai, Feng-Ming; Chen, Yan-Cheng; Wu, Chao-Hsien

2013-11-01

We report here the preparation of aluminum doped zinc oxide transparent conductive thin films by a UV-assisted sol-gel method. It was found that UV irradiation creates ozone, which promotes the conductivity and transparency of the films. Boro-silicate glasses are used as substrates; an PGME is used as a solvent; after spin-coating, the films are dried and radiated with UV and then heated to 400°C for decarburization and 500°C for annealing under air. The surface morphologies of the prepared films are observed by FE-SEM and AFM. It was found that the films irradiated with UV-C are smoother and denser. An XRD analysis shows that the films have a typical wurtzite crystalline structure with a c-axis orientation normal to the surface. The electric resistance values measured with a four-point probe show that the films irradiated with UV have better conductivity (at approximately 3.4 × 10-3Ω-cm) than the films that did not undergo UV irradiation. An analysis by visible light spectrometry indicates that the AZO films irradiated with UV are more transparent than the films without UV-irradiation.

Combined spectrophotometry and tensile measurements of human connective tissues: potentials and limitations.

Science.gov (United States)

Ernstberger, Markus; Sichting, Freddy; Baselt, Tobias; Hartmann, Peter; Aust, Gabriela; Hammer, Niels

2013-06-01

Strain-dependent transmission data of nine iliotibial tract specimens are determined using a custom-built optical setup with a halogen light source and an industrial norm material testing machine. Polarized light microscopy and hematoxylin-eosin staining indicated that lateral contraction of collagen structures is responsible for total intensity variations during a 20-cycle preconditioning and a 5-cycle tensile test. Tensile force progress is opposite to total transmission progress. Due to dehydration, wavelength-specific radiation intensity shifting is determined during the test, primarily noticeable in a water absorption band between 1400 and 1500 nm. The results show the capability of integrating spectrophotometry technology into biomechanics for determining structural alterations of human collagen due to applied strain. Being more sensitive to drying, spectrophotometry may likely serve as a quality control in stress-strain testing of biological structures.

Tunable Diode Laser Heterodyne Spectrophotometry of Ozone

Science.gov (United States)

Fogal, P. F.; McElroy, C. T.; Goldman, A.; Murcray, D. G.

1988-01-01

Tunable diode laser heterodyne spectrophotometry (TDLHS) has been used to make extremely high resolution (less than 0.0005/ cm) solar spectra in the 9.6 micron ozone band. Observations have shown that a signal-to-noise ratio of 95 : 1 (35% of theoretical) for an integration time of 1/8 second can be achieved at a resolution of 0.0005 wavenumbers. The spectral data have been inverted to yield a total column amount of ozone, in good agreement with that. measured at the nearby National Oceanographic and Atmospheric Administration (NOAA) ozone monitoring facility in Boulder, Colorado.

Uranium determination by spectrophotometry, in chloride solutions, using titanium (III) as reducer; Determinacao de uranio por espectrofotometria, em solucoes cloridricas, utilizando titanio (III) como redutor

Energy Technology Data Exchange (ETDEWEB)

Bastos, E T.R.; Bastos, M B.R.

1986-08-01

A simple method for determining uranium in uranium (VI) solutions with the presence of uranium (IV), iron (II), and titanium (IV) in chloridic solution is described. The method comprises in uranium (VI) reduction with titanium (III), acidity adjustment and uranium (IV) spectrophotometry in hydrochloric acid 2 M. (C.G.C.).

PROPOSTA EXPERIMENTAL DIDÁTICA PARA O ENSINO DE ANÁLISE DE COMPONENTES PRINCIPAIS

Directory of Open Access Journals (Sweden)

Leonardo Valderrama

2016-02-01

Full Text Available Principal component analysis (PCA is a chemometric method that allows for the extraction of chemical information that would otherwise be impossible to determine. Teaching chemometrics to undergraduates can contribute to the overall professional development and training of new teachers, whose profiles have been gaining attention due to the current demand for data interpretation. In this study, a didactic experiment involving PCA is proposed. Spectrophotometry was used in the ultraviolet-visible (UV-Vis region to assess the behavior of anthocyanins extracted from red cabbage at different pH values. The results suggest the possible separation of anthocyanin structures into three distinct groups, according to their chemical characteristics displayed in acid, neutral, and basic media. The objective is to develop educational materials targeted to undergraduate courses, which encompass a larger number of concepts and introduce instrumental techniques currently being employed in both academic research and the industrial sector. Specifically, the proposed experiment introduces concepts related to spectrophotometry in the UV-Vis range and the PCA chemometric method. The materials used are easily accessible, and UV-Vis spectroscopy equipment is less expensive in comparison with other spectroscopy methods.

Kombineret laser Doppler flowmetri og spectrophotometri som metode til vurdering af mikrocirculation

DEFF Research Database (Denmark)

Berggren Olsen, Mette; Sørensen, Hanne Birke; Houlind, Kim Christian

Kombineret laser Doppler flowmetri og spectrophotometri som metode til vurdering af mikrocirculation Berggren, MB, reservelæge, Karkirurgisk Afdeling, Kolding, mette.marie.berggren.olsen@slb.regionsyddanmark.dk; Houlind, K, lektor, afdelingslæge, Ph.d., Karkirurgisk afdeling, Kolding, kim...

The Influence of Different Processing Methods on Component Content of Sophora japonica

Science.gov (United States)

Ji, Y. B.; Zhu, H. J.; Xin, G. S.; Wei, C.

2017-12-01

The purpose of this experiment is to understand the effect of different processing methods on the content of active ingredients in Sophora japonica, and to determine the content of rutin and quercetin in Sophora japonica under different processing methods by UV spectrophotometry of the content determination. So as to compare the effect of different processing methods on the active ingredient content of Sophora japonica. Experiments can be seen in the rutin content: Fried Sophora japonica>Vinegar sunburn Sophora> Health products Sophora japonica> Charred sophora flower, Vinegar sunburn Sophora and Fried Sophora japonica difference is not obvious; Quercetin content: Charred sophora flower> Fried Sophora japonica> Vinegar sunburn Sophora>Health products Sophora japonica. It is proved that there are some differences in the content of active ingredients in Sophora japonica in different processing methods. The content of rutin increased with the increase of the processing temperature, but the content decreased after a certain temperature; Quercetin content will increase gradually with time.

UV Spectrophotometric Method for theEstimation of Itopride Hydrochloride in Pharmaceutical Formulation

Directory of Open Access Journals (Sweden)

K. R. Gupta

2010-01-01

Full Text Available Three simple, precise and economical UV methods have been developed for the estimation of itopride hydrochloride in pharmaceutical formulations. Itopride hydrochloride in distilled water shows the maximum absorbance at 258.0 nm (Method A and in first order derivative spectra of the same shows sharp peak at 247.0 nm, when n = 1 (Method B. Method C utilises area under curve (AUC in the wavelength range from 262.0-254.0 nm for analysis of itopride hydrochloride. The drug was found to obey Beer-Lambert’s law in the concentration range of 5-50 μg/mL for all three proposed methods. Results of the analysis were validated statistically and recovery studies were found to be satisfactory.

Study of Biological Pigments by Single Specimen Derivative Spectrophotometry

Science.gov (United States)

Goldstein, Jack M.

1970-01-01

The single specimen derivative (SSD) method provides an absolute absorption spectrum of a substance in the absence of a suitable reference. Both a reference and a measuring monochromatic beam pass through a single sample, and the specimen itself acts as its own reference. The two monochromatic beams maintain a fixed wavelength difference upon scanning, and the difference in absorbance of the two beams is determined. Thus, the resulting spectrum represents the first derivative of the conventional type absorption spectrum. Tissues and cell fractions have been examined at room and liquid N2 temperature and chromophoric molecules such as the mitochondrial cytochromes and blood pigments have been detectable in low concentrations. In the case of isolated cellular components, the observed effects of substrates and inhibitors confirm similar studies by conventional spectrophotometry. The extension of the SSD concept to the microscopic level has permitted the study of the tissue compartmentalization and function of cytochromes and other pigments within layered tissue. PMID:4392452

Rapid measurement of indocyanine green retention by pulse spectrophotometry: a validation study in 70 patients with Child-Pugh A cirrhosis before hepatectomy for hepatocellular carcinoma.

Science.gov (United States)

Cheung, Tan To; Chan, See Ching; Chok, Kenneth S H; Chan, Albert C Y; Yu, Wan Ching; Poon, Ronnie T P; Lo, Chung Mau; Fan, Sheung Tat

2012-06-01

The indocyanine green (ICG) retention test is the most popular liver function test for selecting patients for major hepatectomy. Traditionally, it is done using spectrophotometry with serial blood sampling. The newly-developed pulse spectrophotometry is a faster alternative, but its accuracy on Child-Pugh A cirrhotic patients undergoing hepatectomy for hepatocellular carcinoma has not been well documented. This study aimed to assess the accuracy of the LiMON(®), one of the pulse spectrophotometry systems, in measuring preoperative ICG retention in these patients and to devise an easy formula for conversion of the results so that they can be compared with classical literature records where ICG retention was measured by the traditional method. We measured the liver function of 70 Child-Pugh A cirrhotic patients before hepatectomy for hepatocellular carcinoma from September 2008 to January 2009. ICG retention at 15 minutes measured by traditional spectrophotometry (ICGR15) was compared with ICG retention at 15 minutes measured by the LiMON (ICGR15(L)). The median ICGR15 was 14.7% (5.6%-32%) and the median ICGR15(L) was 10.4% (1.2%-28%). The mean difference between them was -4.3606. There was a strong correlation between ICGR15 and ICGR15(L) (correlation coefficient, 0.844; 95% confidence interval, 0.762-0.899). The following formula was devised: ICGR15=1.16XICGR15(L)+2.73. The LiMON provides a fast and repeatable way to measure ICG retention at 15 minutes, but with constant underestimation of the real value. Therefore, when comparing results obtained by traditional spectrophotometry and the LiMON, adjustment of results from the latter is necessary, and this can be done with a simple mathematical calculation using the above formula.

Effect of UV irradiation on the apoptosis and necrosis of Jurkat cells using UV LEDs

Science.gov (United States)

Inada, Shunko A.; Amano, Hiroshi; Akasaki, Isamu; Morita, Akimichi; Kobayashi, Keiko

2009-02-01

Phototherapy is a very effective method for treating most of the incurable skin diseases. A fluorescent light bulb is used as a conventional UV light source for this type of therapy. However, infrared radiation from the light source sometimes causes serious problems on patient's health. In addition, the normal part of the skin is irradiated when a large fluorescent light bulb is used. Moreover, a conventional UV irradiation system is heavy and has a short lifetime and a high electrical power consumption. Therefore, a new UV light source for solving the problems of phototherapy is required. To realize low-power-consumption, lightweight and long-lifetime systems, group III nitride-based UV-A1 light-emitting diodes (LEDs) were investigated. We examined the UV LED irradiation of Jurkat cell, which is a tumor cell and more sensitive to UV light than a healthy cell. The numbers of apoptotic and necrotic cells were confirmed to be the same using a UV LED and a conventional lamp system. The UV LED showed the possibility of realizing a new UV light source for phototherapy.

Manufacturing and characterization of ceramic pigment Zn1-xFexCr2O4 by synthetic non conventional methods

International Nuclear Information System (INIS)

Nieves, Leidy Johana Jaramillo; Baena, Oscar Jaime Restrepo

2012-01-01

The ceramic pigment with structure Zn 1-x Fe x Cr 2 O 4 (x = 0, 0.5, 1) was synthesized by non conventional methods of coprecipitation assisted by ultrasound and milling of high energy. This pigment was characterized by XRD, XRF, SEM, UV-VIS spectrophotometry and CIELab colorimetry. The aim of this work was studied two alternative methods to the traditional method of synthesis, evaluating the pigment properties, varying the stoichiometry, such as structure, composition, morphology and colorimetric coordinates. The results showed that is possible to obtain the desired crystalline structure at temperatures below 1000 ° C in both cases, also expected hues are obtained according to each stoichiometry, which shows the advantages of using methods non conventional when produce these pigments, since it has a higher controlling the composition, stoichiometry and is obtained at temperatures below compared with traditional ceramic method

Method validation using weighted linear regression models for quantification of UV filters in water samples.

Science.gov (United States)

da Silva, Claudia Pereira; Emídio, Elissandro Soares; de Marchi, Mary Rosa Rodrigues

2015-01-01

This paper describes the validation of a method consisting of solid-phase extraction followed by gas chromatography-tandem mass spectrometry for the analysis of the ultraviolet (UV) filters benzophenone-3, ethylhexyl salicylate, ethylhexyl methoxycinnamate and octocrylene. The method validation criteria included evaluation of selectivity, analytical curve, trueness, precision, limits of detection and limits of quantification. The non-weighted linear regression model has traditionally been used for calibration, but it is not necessarily the optimal model in all cases. Because the assumption of homoscedasticity was not met for the analytical data in this work, a weighted least squares linear regression was used for the calibration method. The evaluated analytical parameters were satisfactory for the analytes and showed recoveries at four fortification levels between 62% and 107%, with relative standard deviations less than 14%. The detection limits ranged from 7.6 to 24.1 ng L(-1). The proposed method was used to determine the amount of UV filters in water samples from water treatment plants in Araraquara and Jau in São Paulo, Brazil. Copyright © 2014 Elsevier B.V. All rights reserved.

UV-LIGA technique for ECF micropumps using back UV exposure and self-alignment

Science.gov (United States)

Han, D.; Xia, Y.; Yokota, S.; Kim, J. W.

2017-12-01

This paper proposes and develops a novel UV-LIGA technique using back UV exposure and self-alignment to realize high aspect ratio micromachining (HARM) in high power density electro-conjugate fluid (ECF) micropumps. ECF is a functional fluid designed to be able to generate strong and active jet flow (ECF jetting) between anode and cathode in ECF when high DC voltage is applied. We have developed high power density ECF micropumps consisting of triangular prism and slit electrode pairs (TPSEs) fabricated by HARM. The traditional UV-LIGA technique for HARM is mainly divided into two approaches: (a) single thick layer and (b) multiple thin layers. Both methods have limitations—deformed molds in the former and misalignment between layers in the latter. Using the finite element method software COMSOL Multiphysics, we demonstrate that the deformed micro-molds critically impair the performance of ECF micropumps. In addition, we experimentally prove that the misalignment would easily trigger electric discharge in the ECF micropumps. To overcome these limitations, we conceive a new concept utilizing the seed electrode layer for electroforming as the UV shield and pattern photoresist (KMPR) by back UV exposure. The seed electrode layer should be composed of a non-transparent conductor (Au/Ti) for patterning and a transparent conductor (ITO) for wiring. Instead of ITO, we propose the concept of transparency-like electrodes comprised of thin metal line patterns. To verify this concept, KMPR layers with thicknesses of 70, 220, and 500 µm are experimentally investigated. In the case of 500 µm KMPR thickness, the concept of transparency-like electrode was partially proved. As a result, TPSEs with a height of 440 µm were successfully fabricated. Characteristic experiments demonstrated that ECF micropumps (367 mW cm-3) fabricated by back UV achieved almost the same output power density as ECF micropumps (391 mW cm-3) fabricated by front UV. This paper proves that the proposed

UV-LIGA technique for ECF micropumps using back UV exposure and self-alignment

International Nuclear Information System (INIS)

Han, D; Xia, Y; Yokota, S; Kim, J W

2017-01-01

This paper proposes and develops a novel UV-LIGA technique using back UV exposure and self-alignment to realize high aspect ratio micromachining (HARM) in high power density electro-conjugate fluid (ECF) micropumps. ECF is a functional fluid designed to be able to generate strong and active jet flow (ECF jetting) between anode and cathode in ECF when high DC voltage is applied. We have developed high power density ECF micropumps consisting of triangular prism and slit electrode pairs (TPSEs) fabricated by HARM. The traditional UV-LIGA technique for HARM is mainly divided into two approaches: (a) single thick layer and (b) multiple thin layers. Both methods have limitations—deformed molds in the former and misalignment between layers in the latter. Using the finite element method software COMSOL Multiphysics, we demonstrate that the deformed micro-molds critically impair the performance of ECF micropumps. In addition, we experimentally prove that the misalignment would easily trigger electric discharge in the ECF micropumps. To overcome these limitations, we conceive a new concept utilizing the seed electrode layer for electroforming as the UV shield and pattern photoresist (KMPR) by back UV exposure. The seed electrode layer should be composed of a non-transparent conductor (Au/Ti) for patterning and a transparent conductor (ITO) for wiring. Instead of ITO, we propose the concept of transparency-like electrodes comprised of thin metal line patterns. To verify this concept, KMPR layers with thicknesses of 70, 220, and 500 µ m are experimentally investigated. In the case of 500 µ m KMPR thickness, the concept of transparency-like electrode was partially proved. As a result, TPSEs with a height of 440 µ m were successfully fabricated. Characteristic experiments demonstrated that ECF micropumps (367 mW cm −3 ) fabricated by back UV achieved almost the same output power density as ECF micropumps (391 mW cm −3 ) fabricated by front UV. This paper proves that the

Role of Glycol Chitosan-incorporated Ursolic Acid Nanoparticles in ...

African Journals Online (AJOL)

Purpose: To investigate the effect of ursolic acid (UA)-incorporated glycol chitosan (GC) nanoparticles on inhibition of human osteosarcoma. Methods: U2OS and Saos-2 osteosarcoma cells were transfected with ursolic acid (UA) incorporated glycol chitosan (GC) nanoparticles. Ultraviolet (UV) spectrophotometry was used ...

Functionalization of biosynthesized gold nanoparticle from aqueous ...

African Journals Online (AJOL)

The biosynthesized nanoparticles and formulated nanodrug were characterized using UV-Vis spectrophotometry, Zetasizer, Scanning and transmission Electron Microscopy (SEM; TEM), Energy Dispersive spectrophotometry (EDAX) and Fourier Transform Infra-red Spectroscopy. Polyethylene glycol and Lincomycin were ...

Method of reinfusion of UV-irradiated autoblood in the treatment of peptic ulcer

International Nuclear Information System (INIS)

Murashko, V.V.; Sklyarova, M.A.; Shakhidul, Kh.; Gilis, R.Ya.; Karandashov, V.I.

1989-01-01

Efficiency of the reinfusion method for autoblood irradiated by UV-rays during the treatment of 40 patients with peptic ulcer of duodenum and 8 patients with peptic ulcer of stomach is studied. It isestablished that the method above promotes the fast improvement of state of health in patients, the normalization of sleep, appetite, the disappearance of asthenias, aches and the reduction of time of ulcer cicatrization up to 14±4 days. It is supposed that high efficiency of the method is caused by the improvement of microcirculation and trophicity of mucous membrane of stomach and duodenum

Validation of HPLC and UV spectrophotometric methods for the determination of meropenem in pharmaceutical dosage form.

Science.gov (United States)

Mendez, Andreas S L; Steppe, Martin; Schapoval, Elfrides E S

2003-12-04

A high-performance liquid chromatographic method and a UV spectrophotometric method for the quantitative determination of meropenem, a highly active carbapenem antibiotic, in powder for injection were developed in present work. The parameters linearity, precision, accuracy, specificity, robustness, limit of detection and limit of quantitation were studied according to International Conference on Harmonization guidelines. Chromatography was carried out by reversed-phase technique on an RP-18 column with a mobile phase composed of 30 mM monobasic phosphate buffer and acetonitrile (90:10; v/v), adjusted to pH 3.0 with orthophosphoric acid. The UV spectrophotometric method was performed at 298 nm. The samples were prepared in water and the stability of meropenem in aqueous solution at 4 and 25 degrees C was studied. The results were satisfactory with good stability after 24 h at 4 degrees C. Statistical analysis by Student's t-test showed no significant difference between the results obtained by the two methods. The proposed methods are highly sensitive, precise and accurate and can be used for the reliable quantitation of meropenem in pharmaceutical dosage form.

UV-LEDs Efficiently Inactivate DNA and RNA Coliphages

Directory of Open Access Journals (Sweden)

Alyaa M. Zyara

2017-01-01

Full Text Available UV-LEDs are a new method of disinfecting drinking water. Some viruses are very resistant to UV and the efficiency of UV-LEDs to disinfect them needs to be studied. Drinking water was disinfected with UV-LEDs after spiking the water with MS2 and four UV- and/or Cl-resistant coliphages belonging to RNA or DNA coliphages isolated from municipal wastewater. UV-LEDs operating at a wavelength of 270 nm for 2 min with 120 mW of irradiation caused 0.93–2.73 Log10-reductions of coliphages tested in a reactor of a 5.2 L volume. Irradiation time of 10 min in the same system increased the Log10-reductions to 4.30–5.16. Traditional mercury UV (Hg-UV lamp at a 254 nm wavelength caused 0.67–4.08 Log10-reductions in 2 min and 4.56–7.21 Log10-reductions in 10 min in 10 mL of water. All coliphages tested except MS2 achieved 4 Log10-reductions with UV-LEDs at a dose that corresponded to 70 mWs/cm2 using Hg-UV. Thus, UV-LEDs are a promising method of disinfecting UV- and/or Cl-resistant viruses.

Impact of Room Location on UV-C Irradiance and UV-C Dosage and Antimicrobial Effect Delivered by a Mobile UV-C Light Device.

Science.gov (United States)

Boyce, John M; Farrel, Patricia A; Towle, Dana; Fekieta, Renee; Aniskiewicz, Michael

2016-06-01

OBJECTIVE To evaluate ultraviolet C (UV-C) irradiance, UV-C dosage, and antimicrobial effect achieved by a mobile continuous UV-C device. DESIGN Prospective observational study. METHODS We used 6 UV light sensors to determine UV-C irradiance (W/cm2) and UV-C dosage (µWsec/cm2) at various distances from and orientations relative to the UV-C device during 5-minute and 15-minute cycles in an ICU room and a surgical ward room. In both rooms, stainless-steel disks inoculated with methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), and Clostridium difficile spores were placed next to sensors, and UV-C dosages and log10 reductions of target organisms achieved during 5-minute and 15-minute cycles were determined. Mean irradiance and dosage readings were compared using ANOVA. RESULTS Mean UV-C irradiance was nearly 1.0E-03 W/cm2 in direct sight at a distance of 1.3 m (4 ft) from the device but was 1.12E-05 W/cm2 on a horizontal surface in a shaded area 3.3 m (10 ft) from the device (P4 to 1-3 for MRSA, >4 to 1-2 for VRE and >4 to 0 log10 for C. difficile spores, depending on the distance from, and orientation relative to, the device with 5-minute and 15-minute cycles. CONCLUSION UV-C irradiance, dosage, and antimicrobial effect received from a mobile UV-C device varied substantially based on location in a room relative to the UV-C device. Infect Control Hosp Epidemiol 2016;37:667-672.

Acceptability criteria for linear dependence in validating UV-spectrophotometric methods of quantitative determination in forensic and toxicological analysis

Directory of Open Access Journals (Sweden)

L. Yu. Klimenko

2014-08-01

Full Text Available Introduction. This article is the result of authors’ research in the field of development of the approaches to validation of quantitative determination methods for purposes of forensic and toxicological analysis and devoted to the problem of acceptability criteria formation for validation parameter «linearity/calibration model». The aim of research. The purpose of this paper is to analyse the present approaches to acceptability estimation of the calibration model chosen for method description according to the requirements of the international guidances, to form the own approaches to acceptability estimation of the linear dependence when carrying out the validation of UV-spectrophotometric methods of quantitative determination for forensic and toxicological analysis. Materials and methods. UV-spectrophotometric method of doxylamine quantitative determination in blood. Results. The approaches to acceptability estimation of calibration models when carrying out the validation of bioanalytical methods is stated in international papers, namely «Guidance for Industry: Bioanalytical method validation» (U.S. FDA, 2001, «Standard Practices for Method Validation in Forensic Toxicology» (SWGTOX, 2012, «Guidance for the Validation of Analytical Methodology and Calibration of Equipment used for Testing of Illicit Drugs in Seized Materials and Biological Specimens» (UNODC, 2009 and «Guideline on validation of bioanalytical methods» (ЕМА, 2011 have been analysed. It has been suggested to be guided by domestic developments in the field of validation of analysis methods for medicines and, particularly, by the approaches to validation methods in the variant of the calibration curve method for forming the acceptability criteria of the obtained linear dependences when carrying out the validation of UV-spectrophotometric methods of quantitative determination for forensic and toxicological analysis. The choice of the method of calibration curve is

Development of a HPLC method for determination of four UV filters in sunscreen and its application to skin penetration studies.

Science.gov (United States)

Souza, Carla; Maia Campos, Patrícia M B G

2017-12-01

This study describes the development, validation and application of a high-performance liquid chromatography (HPLC) method for the simultaneous determination of the in vitro skin penetration profile of four UV filters on porcine skin. Experiments were carried out on a gel-cream formulation containing the following UV filters: diethylamino hydroxybenzoyl hexyl benzoate (DHHB), bis-ethylhexyloxyphenol methoxyphenyl triazine (BEMT), methylene bis-benzotriazolyl tetramethylbutylphenol (MBBT) and ethylhexyl triazone (EHT). The HPLC method demonstrated suitable selectivity, linearity (10.0-50.0 μg/mL), precision, accuracy and recovery from porcine skin and sunscreen formulation. The in vitro skin penetration profile was evaluated using Franz vertical diffusion cells for 24 h after application on porcine ear skin. None of the UV filters penetrated the porcine skin. Most of them stayed on the skin surface (>90%) and only BEMT, EHT and DHHB reached the dermis plus epidermis layer. These results are in agreement with previous results in the literature. Therefore, the analytical method was useful to evaluate the in vitro skin penetration of the UV filters and may help the development of safer and effective sunscreen products. Copyright © 2017 John Wiley & Sons, Ltd.

CUVE - Cubesat UV Experiment: Unveil Venus' UV Absorber with Cubesat UV Mapping Spectrometer

Science.gov (United States)

Cottini, V.; Aslam, S.; D'Aversa, E.; Glaze, L.; Gorius, N.; Hewagama, T.; Ignatiev, N.; Piccioni, G.

2017-09-01

Our Venus mission concept Cubesat UV Experiment (CUVE) is one of ten proposals selected for funding by the NASA PSDS3 Program - Planetary Science Deep Space SmallSat Studies. CUVE concept is to insert a CubeSat spacecraft into a Venusian orbit and perform remote sensing of the UV spectral region using a high spectral resolution point spectrometer to resolve UV molecular bands, observe nightglow, and characterize the unidentified main UV absorber. The UV spectrometer is complemented by an imaging UV camera with multiple bands in the UV absorber main band range for contextual imaging. CUVE Science Objectives are: the nature of the "Unknown" UV-absorber; the abundances and distributions of SO2 and SO at and above Venus's cloud tops and their correlation with the UV absorber; the atmospheric dynamics at the cloud tops, structure of upper clouds and wind measurements from cloud-tracking; the nightglow emissions: NO, CO, O2. This mission will therefore be an excellent platform to study Venus' cloud top atmospheric properties where the UV absorption drives the planet's energy balance. CUVE would complement past, current and future Venus missions with conventional spacecraft, and address critical science questions cost effectively.

Photostability of cosmetic UV filters on mammalian skin under UV exposure.

Science.gov (United States)

Stiefel, Constanze; Schwack, Wolfgang; Nguyen, Yen-Thi Hai

2015-01-01

Previous studies showed that the common UV filter substances benzophenone-3 (BP-3), butyl methoxydibenzoylmethane (BM-DBM), octocrylene (OCR), ethylhexyl methoxycinnamate (EHMC), ethylhexyl salicylate (EHS) and ethylhexyl triazone (EHT) were able to react with amino side chains of different proteins in vitro. To transfer the results to mammalian skin conditions, sunscreen products were applied on both prepared fresh porcine skin and glass plates, followed by UV irradiation and the determination of depletion of the respective UV filters. Significantly lower recoveries of the UV filters extracted from skin samples than from glass plates indicated the additional reaction of the UV filters with skin constituents, when proteins will be the most important reactants. Among the products tested, BP-3 showed the greatest differences in recoveries between glass and skin samples of about 13% and 24% after 2 and 4 h of irradiation, respectively, followed by EHS > BM-DBM > OCR > EHMC > EHT. The obtained results raise the question, whether the common in vitro evaluations of sunscreens, using inert substrate materials like roughened quartz or polymethyl methacrylate (PMMA) plates are really suitable to fully replace in vivo methods, as they cannot include skin-typical reactions. © 2014 The American Society of Photobiology.

uvsI mutants defective in UV mutagenesis define a fourth epistatic group of uvs genes in Aspergillus.

Science.gov (United States)

Chae, S K; Kafer, E

1993-01-01

Three UV-sensitive mutations of A. nidulans, uvsI, uvsJ and uvsA, were tested for epistatic relationships with members of the previously established groups, here called the "UvsF", "UvsC", and "UvsB" groups. uvsI mutants are defective for spontaneous and induced reversion of certain point mutations and differ also for other properties from previously analyzed uvs types. They are very sensitive to the killing effects of UV-light and 4-NQO (4-nitro-quinoline-N-oxide) but not to MMS (methylmethane sulfonate). When double- and single-mutant uvs strains were compared for sensitivity to these three agents, synergistic or additive effects were found for uvsI with all members of the three groups. The uvsI gene may therefore represent a fourth epistatic group, possibly involved in mutagenic repair. On the other hand, uvsJ was clearly epistatic with members of the UvsF group and fitted well into this group also by phenotype. The uvsA gene was tentatively assigned to the UvsC group. uvsA showed epistatic interactions with uvsC in all tests, and like UvsC-group mutants is UV-sensitive mainly in dividing cells. However, the uvsA mutation does not cause the defects in recombination and UV mutagenesis typical for this group.

Novel UV-emitting single crystalline film phosphors grown by LPE method

International Nuclear Information System (INIS)

Zorenko, Y.; Gorbenko, V.; Savchyn, V.; Voznyak, T.; Nikl, M.; Mares, J.A.; Winnacker, A.

2010-01-01

This work reports the development of new types of UV-emitting phosphors based on single crystalline films (SCF) of aluminum garnet and perovskite compounds grown by the liquid phase epitaxy method. We consider peculiarities of the growth and the luminescent and scintillation properties of the following four types of UV SCF phosphors: i) Ce-doped SCF of Y-Lu-Al-perovskites with the Ce 3+ emission in the 300-450 nm range of the decay time of 16-17 ns; ii) Pr-doped SCF of Y-Lu-Al garnets and perovskites with the Pr 3+ emission in the 300-400 nm and 235-330 nm ranges with the decay time of 13-19 and 7-8 ns, respectively; iii) La 3+ or Sc 3+ doped SCF of Y-Lu-Al-garnets, emitting in the 280-400 nm range due to formation of the La Y,Lu , Sc Y,Lu and Sc Al centers with decay time of the order of several hundreds of nanoseconds; iv) Bi 3+ doped SCF of garnets with Bi 3+ emission in 275-350 nm with decay time of about 1.9 μs.

Spectrophotometric and potentiometric study of uranyl hydrolysis in perchlorate medium. Is derivative spectrophotometry suitable for search of the chemical model?

International Nuclear Information System (INIS)

Lubal, P.; Havel, J.

1997-01-01

Uranyl hydrolysis (I = 3.00 mol dm -3 NaClO 4 , T = 298.15 K) was studied by potentiometry and spectrophotometry. Numerical analysis of experimental data yielded the logarithmic values of hydrolytic constants for (UO 2 ) p (OH) q (2p-q) species with (p, q) indices: (2, 2) - 6.24 ± 0.02, (3, 5) - 16.80 ± 0.04, and (3, 4) - 12.8 ± 0.1 (potentiometry) and (2, 2) - 6.13 ± 0.02, (3, 5) - 16.81 ± 0.02, and (32, 4) - 12.57 ± 0.02 (average values obtained by derivative spectrophotometry from the first to the fourth order). The spectra of hydrolytic species were deconvoluted and the use of derivative spectrophotometry in equilibria studies has been discussed. (authors)

Development of a simple, sensitive and inexpensive ion-pairing cloud point extraction approach for the determination of trace inorganic arsenic species in spring water, beverage and rice samples by UV-Vis spectrophotometry.

Science.gov (United States)

Gürkan, Ramazan; Kır, Ufuk; Altunay, Nail

2015-08-01

The determination of inorganic arsenic species in water, beverages and foods become crucial in recent years, because arsenic species are considered carcinogenic and found at high concentrations in the samples. This communication describes a new cloud-point extraction (CPE) method for the determination of low quantity of arsenic species in the samples, purchased from the local market by UV-Visible Spectrophotometer (UV-Vis). The method is based on selective ternary complex of As(V) with acridine orange (AOH(+)) being a versatile fluorescence cationic dye in presence of tartaric acid and polyethylene glycol tert-octylphenyl ether (Triton X-114) at pH 5.0. Under the optimized conditions, a preconcentration factor of 65 and detection limit (3S blank/m) of 1.14 μg L(-1) was obtained from the calibration curve constructed in the range of 4-450 μg L(-1) with a correlation coefficient of 0.9932 for As(V). The method is validated by the analysis of certified reference materials (CRMs). Copyright © 2015 Elsevier Ltd. All rights reserved.

High reflectivity YDH/SiO2 distributed Bragg reflector for UV-C wavelength regime

KAUST Repository

Alias, Mohd Sharizal

2018-02-15

A distributed Bragg reflector (DBR) composed of Y2O3-doped HfO2 (YDH)/SiO2 layers with high reflectivity spectrum centered at a wavelength of ~240 nm is deposited using radio-frequency magnetron sputtering. Before the DBR deposition, optical properties for a single layer of YDH, SiO2, and HfO2 thin films were studied using spectroscopic ellipsometry and spectrophotometry. To investigate the performance of YDH as a material for the high refractive index layer in the DBR, a comparison of its optical properties was made with HfO2 thin films. Due to larger optical bandgap, the YDH thin films demonstrated higher transparency, lower extinction coefficient, and lower absorption coefficient in the UV-C regime (especially for wavelengths below 250 nm) compared to the HfO2 thin films. The deposited YDH/SiO2 DBR consisting of 15 periods achieved a reflectivity higher than 99.9% at the wavelength of ~240 nm with a stopband of ~50 nm. The high reflectivity and broad stopband of YDH/SiO2 DBRs will enable further advancement of various photonic devices such as vertical-cavity surface-emitting lasers, resonant-cavity light-emitting diodes, and resonant-cavity photodetectors operating in the UV-C wavelength regime.

A Simple and Efficient Method to Improve Mechanical Properties of Collagen Scaffolds by UV Irradiation

Directory of Open Access Journals (Sweden)

F. Khayyatan

2010-12-01

Full Text Available Collagen is the major protein component of cartilage, bone, skin and connective tissue and constitutes the major part of the extracellular matrix. Collagen type I has complex structural hierarchy, which consists of treepolypeptide α-chains wound together in a rod-like helical structure. Collagen is an important biomaterial, finding many applications in the field of tissue engineering. It has been processed into various shapes, such as, gel, film, sponge and fiber. It is commonly used as the scaffolding material for tissue engineering due to its many superior properties including low antigenicity and high growth promotion. Unfortunately, poor mechanical properties and rapid degradation rates of collagen scaffolds can cause instability and difficulty in handling. By crosslinking, the structural stability of the collagen and its rate of resorption can be adapted with respect to its demanding requirements. The strength, resorption rate, and biocompatibility of collagenous biomaterials are profoundly influenced by the method and extent of crosslinking. In thisstudy, the effect of UV irradiation on collagen scaffolds has been carried out.Collagen scaffolds were fabricated using freeze drying method with freezing temperature of -80oC, then exposed to UV irradiation. Mean pore size of the scaffolds was obtained as 98.52±14.51 μm using scanning electron microscopy. Collagen scaffolds exposed to UV Irradiation (254 nm for 15 min showed the highest tensile strain (17.37±0.98 %, modulus (1.67±0.15 MPa and maximum load (24.47±2.38 cN values. As partial loss of the native collagen structure may influence attachment, migration, and proliferation of cells on collagen scaffolds, we detected no intact α-chains after SDS-Page chromatography. We demonstrate that UV irradiation is a rapid and easily controlled means of increasing the mechanical strength of collagen scaffolds without any molecular fracture.

An effective method of UV-oxidation of dissolved organic carbon in natural waters for radiocarbon analysis by accelerator mass spectrometry

Science.gov (United States)

Xue, Yuejun; Ge, Tiantian; Wang, Xuchen

2015-12-01

Radiocarbon (14C) measurement of dissolved organic carbon (DOC) is a very powerful tool to study the sources, transformation and cycling of carbon in the ocean. The technique, however, remains great challenges for complete and successful oxidation of sufficient DOC with low blanks for high precision carbon isotopic ratio analysis, largely due to the overwhelming proportion of salts and low DOC concentrations in the ocean. In this paper, we report an effective UV-Oxidation method for oxidizing DOC in natural waters for radiocarbon analysis by accelerator mass spectrometry (AMS). The UV-oxidation system and method show 95%±4% oxidation efficiency and high reproducibility for DOC in both river and seawater samples. The blanks associated with the method was also low (about 3 µg C) that is critical for 14C analysis. As a great advantage of the method, multiple water samples can be oxidized at the same time so it reduces the sample processing time substantially compared with other UV-oxidation method currently being used in other laboratories. We have used the system and method for 14C studies of DOC in rivers, estuaries, and oceanic environments and have received promise results.

A simple gel electrophoresis method for separating polyhedral gold nanoparticles

Science.gov (United States)

Kim, Suhee; Lee, Hye Jin

2015-07-01

In this paper, a simple approach to separate differently shaped and sized polyhedral gold nanoparticles (NPs) within colloidal solutions via gel electrophoresis is described. Gel running parameters for separating efficiently gold NPs including gel composition, added surfactant types and applied voltage were investigated. The plasmonic properties and physical structure of the separated NPs extracted from the gel matrix were then investigated using transmission electron microscopy (TEM) and UV-vis spectrophotometry respectively. Data analysis revealed that gel electrophoresis conditions of a 1.5 % agarose gel with 0.1 % sodium dodecyl sulfate (SDS) surfactant under an applied voltage of 100 V resulted in the selective isolation of ~ 50 nm polyhedral shaped gold nanoparticles. Further efforts are underway to apply the method to purify biomolecule-conjugated polyhedral Au NPs that can be readily used for NP-enhanced biosensing platforms.

Optimization, validation and application of UV-Vis spectrophotometric-colorimetric methods for determination of trimethoprim in different medicinal products

Directory of Open Access Journals (Sweden)

Goran Stojković

2016-03-01

Full Text Available Two simple, sensitive, selective, precise, and accurate methods for determination of trimethoprim in different sulfonamide formulations intended for use in human and veterinary medicine were optimized and validated. The methods are based on the trimethoprim reaction with bromcresol green (BCG and 2,4-dinitro-1-fluorobenzene (DNFB. As extraction solvents we used 10 % N,N-dimethylacetamide in methanol and acetone for both methods, respectively. The colored products are quantified applying visible spectrophotometry at their corresponding absorption maxima. The methods were validated for linearity, sensitivity, accuracy, and precision. We tested the method applicability on four different medicinal products in tablet and powder forms containing sulfametrole and sulfamethoxazole in combination with trimethoprim. The results revealed that both methods are equally accurate with recoveries within the range 95-105 %. The obtained between-day precision for both methods, when applied on four different medicinal products, was within in the range 1.08-3.20 %. By applying the F-statistical test (P<0.05, it was concluded that for three medicinal products tested both methods are applicable with statistically insignificant difference in precision. The optimized and validated BCG and DNFB methods could find application in routine quality control of trimethoprim in various formulation forms, at different concentration levels, and in combination with different sulfonamides.

Spectrophotometry of peculiar B and A stars

International Nuclear Information System (INIS)

Adelman, S.J.

1980-01-01

Spectrophotometry of the optical region lambda lambda 3300-7100 is presented for seven magnetic Ap stars: HD 32650, 84 Ursa Majoris, HD 149822, 19 Lyrae, 4 Cygni, HD 196178, and 108 Aquarii. The energy distributions of all seven stars show definite lambda 4200 and lambda 5200 broad, continuum features as well as other more subtle deviations from the predictions of normal stellar atmospheres. The observations of HD 32650 violate the general rule for the Ap stars that the temperature found by comparing the Balmer jump regions with the predictions of normal stalle atmospheres with log g = 4.0 are systematically greater than those found from fitting the slopes of the Paschen continua. (orig.)

Spectrophotometry of the shell around AG Carinae

Science.gov (United States)

Mitra, P. Mila; Dufour, Reginald J.

1990-01-01

Spatially-resolved long-slit spectrophotometry are presented for two regions of the shell nebula around the P-Cygni variable star AG Carinae. The spectra cover the 3700-6800 A wavelength range. Emission-line diagnostics are used to derive extinction, electron temperatures, and densities for various positions in the nebula. The chemical abundances and ionization structure are calculated and compared with other types of planetary nebulae and shells around other luminous stars. It is found that the N/O and N/S ratios of Ag Car are high compared to solar neighborhood ISM values. The O/H depletion found for the AG Car shell approaches that found in the condensations of the Eta Car system.

Development and validation of alternative methods by non-aqueous acid-base titration and derivative ultraviolet spectrophotometry for quantification of sildenafil in raw material and tablets

Directory of Open Access Journals (Sweden)

Taízia Dutra Silva

2017-04-01

Full Text Available Sildenafil citrate (SILC is a potent phosphodiesterase-5 inhibitor used for erectile dysfunction and pulmonary hypertension. This study shows two simple, fast and alternative analytical methods for SILC determination by non-aqueous titration and by derivative ultraviolet spectrophotometry (DUS in active pharmaceutical ingredient and/or dosage forms. The quantitation method of SILC active pharmaceutical ingredient by non-aqueous acid-base titration was developed using methanol as solvent and 0.1 mol/L of perchloric acid in acetic acid as titrant. The endpoint was potentiometrically detected. The non-aqueous titration method shows satisfactory repeatability and intermediate precision (RSD 0.70-1.09%. The neutralization reaction occurred in the stoichiometric ratio 1:1 in methanol. The determination of SILC active pharmaceutical ingredient or dosage forms by DUS was developed in the linear range from 10 to 40 µg/mL, in 0.01 mol/L HCl, using the first order zero-peak method at λ 256 nm. The DUS method shows selectivity toward tablets excipients, appropriate linearity (R2 0.9996, trueness (recovery range 98.86-99.30%, repeatability and intermediate precision in three concentration levels (RSD 1.17-1.28%; 1.29-1.71%, respectively. Therefore, the methods developed are excellent alternatives to sophisticated instrumental methods and can be easily applied in any pharmaceutical laboratory routine due to simple and fast executions.

Identification and spectrophotometry of faint southern radio galaxies

International Nuclear Information System (INIS)

Spinrad, H.; Kron, R.G.; Hunstead, R.W.

1980-01-01

We have observed a mixed sample of southern radio sources, identified on the Palomar sky survey or on previous direct plates taken with medium-aperture reflectors. At CIO we obtained a few deep 4m photographs and SIT spectrophotometry for redshift and continuum-color measurement. Almost all our sources were faint galaxies; the largest redshift measured was for 3C 275, with z=0.480. The ultraviolet continuum of PKS 0400--643, a ''thermal'' galaxy with z=0.476, closely resembles that of 3C 295 and shows some color evolution in U--B compared to nearby giant ellipticals

Determination of trace impurities in materials

International Nuclear Information System (INIS)

Parashar, D.C.

1991-01-01

Research work done at the National Physical Laboratory to develop new methods which are more specific and/or more sensitive has been reviewed. These methods are based on the use of existing facilities viz. atomic absorption spectrophotometry, uv-visible spectrophotometry, gas chromatography and conventional chemical methods. It is possible to determine impurities like boron at 5ppb level, phosphorus at 100 ppb and oxygen non-stoichiometry in 1:2:3 compounds with higher accuracy. Boron is determined spectrophotometrically by forming a complex with curcumin and phosphorus is determined indirectly by atomic absorption spectrophotometry by forming phosphomolybdate complex with antimony or bismuth which have 1:1 ratio with phosphorus in the complex. Gas chromatographic technique has been used to evaluate the oxygen non-stoichiometry in high temperature superconductors (1:2:3 compound) where the HTc sample is dissolved in dilute nitric acid in helium environment and the oxygen released is determined using thermal conductivity detector. (author). 19 refs., 3 figs., 4 tabs

Modification of the Fitzpatrick system of skin phototype classification for the Indian population, and its correlation with narrowband diffuse reflectance spectrophotometry.

Science.gov (United States)

Sharma, V K; Gupta, V; Jangid, B L; Pathak, M

2018-04-01

The Fitzpatrick classification for skin phototyping is widely used, but its usefulness in dark-skinned populations has been questioned by some researchers. Recently, skin colour measurement has been proposed for phototyping skin colour objectively. To modify the Fitzpatrick system of skin phototyping for the Indian population and to study its correlation with skin colour using narrowband diffuse reflectance spectrophotometry METHODS: Answer choices for three items (eye colour, hair colour, colour of unexposed skin) out of 10 in the original Fitzpatrick questionnaire were modified, followed by self-administration of the original and the modified Fitzpatrick questionnaire by 70 healthy Indian volunteers. Skin colour (melanin and erythema indices) was measured from two photoexposed and two photoprotected sites using a narrowband reflectance spectrophotometer. The mean ± SD scores for the original and modified Fitzpatrick questionnaires were 25.40 ± 4.49 and 23.89 ± 4.82, respectively (r = 0.97, P Spectrophotometry can be a useful objective tool for skin phototyping. © 2018 British Association of Dermatologists.

Studies on Coloration and UV Protective Action of Anar Peel (Pomegranate Rind) as an Effective Natural Colorant for Cotton Khadi Fabric

Science.gov (United States)

Sinnur, H. D.; Samanta, Ashis Kumar; Verma, D. K.; Kaware, Runali

2018-06-01

Besides optimization of conditions of colour extraction from dried anar peel, effect of different single and double mordants, dyeing process variables and UV protective action of anar peels (pomegranate rind i.e. Punica granatum L.) as a natural colourant is studied in this work. Mordants used are potash alum, aluminium sulphate and stannous chloride (as metallic salt mordant) and harda (i.e., myrobolan as natural mordant) from natural source. Relevant results indicate that 50:50 ratio of harda plus potash aluminium sulphate at overall 15% application level offers maximum K/S value and overall good colour fastness than any other combination. After finalizing the mordants, dyeing process variables were studied for standardization of conditions for dyeing cotton khadi fabric with aqueous extract of pomegranate rind. The results indicate that standardized conditions for dyeing are (a) dyeing time : 60 min, (b) dyeing temperature: 80 °C, (c) dye bath MLR : 1:30, (d) dye bath pH : 9.0, (e) max dye concentration : 20% and (f) common salt : 3%. Studies of FTIR, UV scan, Atomic Absorption Spectrophotometry (AAS) and UV Protection Factor (UPF) characters show a medium to good level of ultraviolet protection. Corresponding reaction mechanism amongst mordant/fibre and dye forming giant complex is also reported.

Studies on Coloration and UV Protective Action of Anar Peel (Pomegranate Rind) as an Effective Natural Colorant for Cotton Khadi Fabric

Science.gov (United States)

Sinnur, H. D.; Samanta, Ashis Kumar; Verma, D. K.; Kaware, Runali

2017-10-01

Besides optimization of conditions of colour extraction from dried anar peel, effect of different single and double mordants, dyeing process variables and UV protective action of anar peels (pomegranate rind i.e. Punica granatum L.) as a natural colourant is studied in this work. Mordants used are potash alum, aluminium sulphate and stannous chloride (as metallic salt mordant) and harda (i.e., myrobolan as natural mordant) from natural source. Relevant results indicate that 50:50 ratio of harda plus potash aluminium sulphate at overall 15% application level offers maximum K/S value and overall good colour fastness than any other combination. After finalizing the mordants, dyeing process variables were studied for standardization of conditions for dyeing cotton khadi fabric with aqueous extract of pomegranate rind. The results indicate that standardized conditions for dyeing are (a) dyeing time : 60 min, (b) dyeing temperature: 80 °C, (c) dye bath MLR : 1:30, (d) dye bath pH : 9.0, (e) max dye concentration : 20% and (f) common salt : 3%. Studies of FTIR, UV scan, Atomic Absorption Spectrophotometry (AAS) and UV Protection Factor (UPF) characters show a medium to good level of ultraviolet protection. Corresponding reaction mechanism amongst mordant/fibre and dye forming giant complex is also reported.

Qualitative Aspects of UV-Vis Spectrophotometry of Beta-Carotene and Lycopene.

Science.gov (United States)

Tan, Barrie; Soderstrom, David N.

1989-01-01

Explores the structural behavior of polyenic pi systems such as isomerization and conjugation. Uses the simultaneous spectrophotometric analysis of a beta-carotene and lycopene mixture. Presents an empirical method to determine the number of double bonds in the polyenic carotenoid. (MVL)

Development of a method for the characterization and operation of UV-LED for water treatment.

Science.gov (United States)

Kheyrandish, Ataollah; Mohseni, Madjid; Taghipour, Fariborz

2017-10-01

Tremendous improvements in semiconductor technology have made ultraviolet light-emitting diodes (UV-LEDs) a viable alternative to conventional UV sources for water treatment. A robust and validated experimental protocol for studying the kinetics of microorganism inactivation is key to the further development of UV-LEDs for water treatment. This study proposes a protocol to operate UV-LEDs and control their output as a polychromatic radiation source. In order to systematically develop this protocol, the results of spectral power distribution, radiation profile, and radiant power measurements of a variety of UV-LEDs are presented. A wide range of UV-LEDs was selected for this study, covering various UVA, UVB, and UVC wavelengths, viewing angles from 3.5° to 135°, and a variety of output powers. The effects of operational conditions and measurement techniques were investigated on these UV-LEDs using a specially designed and fabricated setup. Operating conditions, such as the UV-LED electrical current and solder temperature, were found to significantly affect the power and peak wavelength output. The measurement techniques and equipment, including the detector size, detector distance from the UV-LED, and potential reflection from the environment, were shown to influence the results for many of the UV-LEDs. The results obtained from these studies were analyzed and applied to the development of a protocol for UV-LED characterization. This protocol is presented as a guideline that allows the operation and control of UV-LEDs in any structure, as well as accurately measuring the UV-LED output. Such information is essential for performing a reliable UV-LED assessment for the inactivation of microorganisms and for obtaining precise kinetic data. Copyright © 2017 Elsevier Ltd. All rights reserved.

Net Analyte Signal Standard Additions Method for Simultaneous Determination of Sulfamethoxazole and Trimethoprim in Pharmaceutical Formulations and Biological Fluids

Directory of Open Access Journals (Sweden)

M. H. Givianrad

2012-01-01

Full Text Available The applicability of a novel net analyte signal standard addition method (NASSAM to the resolving of overlapping spectra corresponding to the sulfamethoxazole and trimethoprim was verified by UV-visible spectrophotometry. The results confirmed that the net analyte signal standard additions method with simultaneous addition of both analytes is suitable for the simultaneous determination of sulfamethoxazole and trimethoprim in aqueous media. Moreover, applying the net analyte signal standard additions method revealed that the two drugs could be determined simultaneously with the concentration ratios of sulfamethoxazole to trimethoprim varying from 1:35 to 60:1 in the mixed samples. In addition, the limits of detections were 0.26 and 0.23 μmol L-1 for sulfamethoxazole and trimethoprim, respectively. The proposed method has been effectively applied to the simultaneous determination of sulfamethoxazole and trimethoprim in some synthetic, pharmaceutical formulation and biological fluid samples.

UV Deprivation Influences Social UV Preference in Juvenile Sticklebacks

Directory of Open Access Journals (Sweden)

Ricarda Modarressie

2015-05-01

Full Text Available Social aggregations occur in many different animal taxa and mainly result from non-random assortment. Investigating factors that shape and maintain the composition of social aggregations are among others a main topic for understanding ecological speciation processes. Aggregation decisions are mediated by olfactory and visual cues, which in many animals are extended into the UV part of the electromagnetic spectrum. Here, we were interested in developmental plasticity of social preferences with respect to UV radiation in aquatic organisms. Specifically, we tested whether different lighting environments with respect to UV wavelengths during early life stages influence the shoaling preference in juvenile threespine sticklebacks (Gasterosteus aculeatus. Family (full-sibling groups were split and reared under UV-lacking (UV- and UV-present (UV+ lighting conditions. Subsequent shoal choice experiments, in which test fish from both rearing conditions could simultaneously choose between a shoal seen behind a UV-blocking (UV- and a shoal seen behind a UV-transmitting (UV+ filter, revealed a significant effect of lighting condition during rearing on association preference. Test fish that had been deprived of UV spent significantly more time near the UV- shoal compared to the test fish reared under full-spectrum lighting conditions. The results are discussed with respect to plasticity of the visual system and environmental lighting conditions.

[Application of HPLC-UV method for aripiprazole determination in serum].

Science.gov (United States)

Synowiec, Anna; Gomółka, Ewa; Zyss, Tomasz; Zieba, Andrzej; Florek, Ewa; Piekoszewski, Wojciech

2012-01-01

Aripiprazole is a new drug applied in schizophrenia treatment. There are not strict indications for aripiprazole therapeutic drug monitoring. Despite, serum aripiprazole measuring would help control the drug doses effectiveness. The drug monitoring can eliminate overdosing, adverse effects and let control proper drug ingestion. The aim of the paper was to develop a simple method for aripiprazole determination in serum for therapeutic drug monitoring. High performance liquid chromatography with spectrophotometric detection (HPLC-UV) was used. Resolution was performed on LC-8 column; moving phase was solution 0,025M trimethylammonium buffer: acetonitrile (62:38). Isocratic flow was 1,2 ml/min; internal standard (IS) was promazine; monitored wavelength was lambda=214 nm. The validation parameters were: limits of linearity (LOL) 100-800 ng/ml, limit of detection (LOD) 10 ng/ml, limit of quantity (LOQ) 100 ng/ml. Coefficient of variation (CV) describing accuracy and precision didn't cross 10%. The method was useful for therapeutic drug monitoring in serum of patients treated with aripiprazole.

UV Spectrophotometric Method for Determination of Cinitapride in Pure and its Solid Dosage Form

Directory of Open Access Journals (Sweden)

B. Thangabalan

2009-01-01

Full Text Available A new, rapid, precise, accurate and sensitive analytical method was developed for the UV spectrophotometric assay of cinitapride (CTP. The drug obeyed the Beer's law and showed good correlation. It showed absorption maxima at 260 nm in methanol. The linearity was observed between 5-40 µg mL-1. The results of analysis were validated by recovery studies. The recovery was more than 99%. The proposed method is the only method available for spectrophotometric determination of the drug. It is simple, precise, sensitive and reproducible and can be used for the routine quality control testing of the marketed formulations.

The Use of Self-scanned Silicon Photodiode Arrays for Astronomical Spectrophotometry

Science.gov (United States)

Cochran, A. L.

1984-01-01

The use of a Reticon self scanned silicon photodiode array for precision spectrophotometry is discussed. It is shown that internal errors are + or - 0.003 mag. Observations obtained with a photodiode array are compared with observations obtained with other types of detectors with agreement, from 3500 A to 10500 A, of 1%. The photometric properties of self scanned photodiode arrays are discussed. Potential pitfalls are given.

Spectrophotometry of the nucleus of the Sy 2 galaxy Markarian 308

International Nuclear Information System (INIS)

Popov, V.N.; Khachikyan, Eh.E.

1980-01-01

The results of spectrophotometry of the Sy2 galaxy Markarian 308 are presented. The profiles of the emission lines [N II] lambda lambda 6583, 6548 A, Hsub(α), [O III] lambda lambda 5007, 4959 A and Hsub(β) are drawn. The electron density, electron temperature, mass and effective volume of the emitting gas are estimated. Markarian 308 shows now less activity compared with other Sy2 galaxies

Determination of Ca, Cu, Fe and Pb in sugarcane raw spirits by atomic absorption spectrophotometry

International Nuclear Information System (INIS)

Lorenzo, Magdalena; Reyes, Arlyn; Blanco, Idania; Vasallo, Maria C

2010-01-01

The determination of Ca, Cu, Fe and Pb in sugarcane raw spirits by atomic absorption spectrophotometry was carried out. For 20 μL injected sample, calibration within the 0,5-25,0 mg. L -1 Ca; 0,25-5,0 mg. L -1 Cu, Pb and Cu intervals were established using the ratios Cu, Ca, Fe and Pb absorbance versus analyte concentration, respectively. Typical linear correlations of r = 0,999 were obtained. The proposed method was applied for the direct determination of Ca, Cu, Fe and Pb in sugar cane spirits, and in samples. The results obtained were in accordance to those obtained at 95% confidence level

Ultraviolet spectrophotometry from Gemini 11 of stars in Orion

International Nuclear Information System (INIS)

Morgan, T.H.; Spear, G.G.; Kondo, Y.; Henize, K.G.

1975-01-01

Ultraviolet spectrophotometry in the wavelength region 2600--3600 A is reported for the bright early-type stars β, eta, γ, delta, iota, epsilon, sigma, xi, and kappa Ori. The results are in good agreement with other observations, and with the possible exception of the supergiants, are in good agreement with recent line-blanketed model atmospheres. There is evidence that the supergiants possess a small ultraviolet deficiency shortward of 3000 A relative to main-sequence stars of similar spectral type. The most extreme example of this phenomenon is the star kappa Ori

Spectrophotometry of comets Giacobini-Zinner and Halley

International Nuclear Information System (INIS)

Tegler, S.C.; O'dell, C.R.

1987-01-01

Optical window spectrophotometry was performed on comets Giacobini-Zinner and Halley over the interval 300-1000 nm. Band and band-sequence fluxes were obtained for the brightest features of OH, CN, NH, and C2, special care having been given to determinations of extinction, instrumental sensitivities, and corrections for Fraunhofer lines. C2 Swan band-sequence flux ratios were determined with unprecedented accuracy and compared with the predictions of the detailed equilibrium models of Krishna Swamy et al. (1977, 1979, 1981, and 1987). It is found that these band sequences do not agree with the predictions, which calls into question the assumptions made in deriving the model, namely resonance fluorescence statistical equilibrium. Suggestions are made as to how to resolve this discrepancy. 16 references

Spectrophotometry of comets Giacobini-Zinner and Halley

Science.gov (United States)

Tegler, Stephen C.; O'Dell, C. R.

1987-01-01

Optical window spectrophotometry was performed on comets Giacobini-Zinner and Halley over the interval 300-1000 nm. Band and band-sequence fluxes were obtained for the brightest features of OH, CN, NH, and C2, special care having been given to determinations of extinction, instrumental sensitivities, and corrections for Fraunhofer lines. C2 Swan band-sequence flux ratios were determined with unprecedented accuracy and compared with the predictions of the detailed equilibrium models of Krishna Swamy et al. (1977, 1979, 1981, and 1987). It is found that these band sequences do not agree with the predictions, which calls into question the assumptions made in deriving the model, namely resonance fluorescence statistical equilibrium. Suggestions are made as to how to resolve this discrepancy.

The spectroscopic analysis of {gamma}-irradiated glass by colorimetry, ESR and XPS

Energy Technology Data Exchange (ETDEWEB)

Hong, S.I. [College of Life Sciences and Biotechnology, Korea University, 5 ga Anam-dong, Seongbuk-Gu, Seoul 135-701 (Korea, Republic of); Lee, Y.N. [R and D Institute Biscuit Team, 131-1, Namyoung-dong, Youngsan-Gu, Seoul 140-708 (Korea, Republic of); Cho, S.Y. [College of Life Sciences and Biotechnology, Korea University, 5 ga Anam-dong, Seongbuk-Gu, Seoul 135-701 (Korea, Republic of); Whiteside, W.S. [Department of Packaging Science, 226 Poole Agricultural Center, Clemson University, Clemson, SC 29634-0320 (United States); Park, H.J. [College of Life Sciences and Biotechnology, Korea University, 5 ga Anam-dong, Seongbuk-Gu, Seoul 135-701 (Korea, Republic of)], E-mail: hjpark@korea.ac.kr

2008-09-15

The darkening of {gamma}-irradiated glass was related to the binding of Si-O and Sn-O, and the binding of Na-O. The dosimetric range of glass color change was evaluated by colorimetry, UV-Vis spectrophotometry and ESR. Colorimetry and UV-Vis spectrophotometry, revealed linear changes up to 9 kGy. For the calibration curve of {gamma}-irradiation, the signal of g=2.01 observed by ESR responded most sensitively with a linear increase with up to 12 kGy.

The spectroscopic analysis of γ-irradiated glass by colorimetry, ESR and XPS

International Nuclear Information System (INIS)

Hong, S.I.; Lee, Y.N.; Cho, S.Y.; Whiteside, W.S.; Park, H.J.

2008-01-01

The darkening of γ-irradiated glass was related to the binding of Si-O and Sn-O, and the binding of Na-O. The dosimetric range of glass color change was evaluated by colorimetry, UV-Vis spectrophotometry and ESR. Colorimetry and UV-Vis spectrophotometry, revealed linear changes up to 9 kGy. For the calibration curve of γ-irradiation, the signal of g=2.01 observed by ESR responded most sensitively with a linear increase with up to 12 kGy

p Ka determinations of xanthene derivates in aqueous solutions by multivariate analysis applied to UV-Vis spectrophotometric data

Science.gov (United States)

Batistela, Vagner Roberto; Pellosi, Diogo Silva; de Souza, Franciane Dutra; da Costa, Willian Ferreira; de Oliveira Santin, Silvana Maria; de Souza, Vagner Roberto; Caetano, Wilker; de Oliveira, Hueder Paulo Moisés; Scarminio, Ieda Spacino; Hioka, Noboru

2011-09-01

Xanthenes form to an important class of dyes which are widely used. Most of them present three acid-base groups: two phenolic sites and one carboxylic site. Therefore, the p Ka determination and the attribution of each group to the corresponding p Ka value is a very important feature. Attempts to obtain reliable p Ka through the potentiometry titration and the electronic absorption spectrophotometry using the first and second orders derivative failed. Due to the close p Ka values allied to strong UV-Vis spectral overlap, multivariate analysis, a powerful chemometric method, is applied in this work. The determination was performed for eosin Y, erythrosin B, and bengal rose B, and also for other synthesized derivatives such as 2-(3,6-dihydroxy-9-acridinyl) benzoic acid, 2,4,5,7-tetranitrofluorescein, eosin methyl ester, and erythrosin methyl ester in water. These last two compounds (esters) permitted to attribute the p Ka of the phenolic group, which is not easily recognizable for some investigated dyes. Besides the p Ka determination, the chemometry allowed for estimating the electronic spectrum of some prevalent protolytic species and the substituents effects evaluation.

Effect of UV-A and UV-B irradiation on the metabolic profile of aqueous humor in rabbits analyzed by 1H NMR spectroscopy.

Science.gov (United States)

Tessem, May-Britt; Bathen, Tone F; Cejková, Jitka; Midelfart, Anna

2005-03-01

This study was conducted to investigate metabolic changes in aqueous humor from rabbit eyes exposed to either UV-A or -B radiation, by using (1)H nuclear magnetic resonance (NMR) spectroscopy and unsupervised pattern recognition methods. Both eyes of adult albino rabbits were irradiated with UV-A (366 nm, 0.589 J/cm(2)) or UV-B (312 nm, 1.667 J/cm(2)) radiation for 8 minutes, once a day for 5 days. Three days after the last irradiation, samples of aqueous humor were aspirated, and the metabolic profiles analyzed with (1)H NMR spectroscopy. The metabolic concentrations in the exposed and control materials were statistically analyzed and compared, with multivariate methods and one-way ANOVA. UV-B radiation caused statistically significant alterations of betaine, glucose, ascorbate, valine, isoleucine, and formate in the rabbit aqueous humor. By using principal component analysis, the UV-B-irradiated samples were clearly separated from the UV-A-irradiated samples and the control group. No significant metabolic changes were detected in UV-A-irradiated samples. This study demonstrates the potential of using unsupervised pattern recognition methods to extract valuable metabolic information from complex (1)H NMR spectra. UV-B irradiation of rabbit eyes led to significant metabolic changes in the aqueous humor detected 3 days after the last exposure.

Aplicación de la espectrofotometría UV-visible al estudio de la estabilidad térmica de aceites vegetales comestibles

Directory of Open Access Journals (Sweden)

Molero Meneses, M.

2000-12-01

Full Text Available The thermal s tabi l i ty of three ol ive oils of different characteristics, under atmosphere of air, nitrogen and oxygen has been studied, by means of simultaneous thermal analysis (TG-TGDUV-visible spectrophotometry. The specific extinction coefficient values of the oils at 232 and 270 nm were calculated at different temperatures from room temperature to those corresponding to the 10% of the thermogravimetric curve. The results show the negative influence of the temperature and the oxidant atmosphere on the thermal stability of the oils; this is verified by the increase of the coefficients K232 and K270 and by the decreasing of the degradation beginning temperature under such atmospheres, compared with the results obtained under inert atmosphere. On the other hand, in this work is made evident a high correlation between the obtained data from thermal analysis and those obtained from UV-visible spectrophotometry.Se estudia la estabilidad térmica de tres aceites de oliva de distintas características, en atmósfera de aire, oxígeno y nitrógeno, mediante la combinación de las técnicas de análisis térmico (TG-TGD y espectrofotometría UV-visible. Para ello se miden los coeficientes de extinción específico a 232 y 270 nm de los aceites a distintas temperaturas, comprendidas entre la temperatura ambiente y la correspondiente al 10% de la curva termogravimétrica. Los resultados muestran la influencia negativa de la temperatura y de la atmósfera oxidante sobre la estabilidad de los aceites, que se manifiesta por el fuerte incremento de los coeficientes K232 y K270, y por el descenso de la temperatura de comienzo de la degradación en dichas atmósferas, comparado con los resultados obtenidos en atmósfera inerte. Por otra parte, en el trabajo se pone de manifiesto una alta correlación entre los datos obtenidos por análisis térmico y los obtenidos por espectrofotometría UV-visible.

Validation of HPLC method for the simultaneous and quantitative determination of 12 UV-filters in cosmetics.

Science.gov (United States)

Nyeborg, M; Pissavini, M; Lemasson, Y; Doucet, O

2010-02-01

The aim of the study was the validation of a high-performance liquid chromatography (HPLC) method for the simultaneous and quantitative determination of twelve commonly used organic UV-filters (phenylbenzimidazole sulfonic acid, benzophenone-3, isoamyl p-methoxycinnamate, diethylamino hydroxybenzoyl hexyl benzoate, octocrylene, ethylhexyl methoxycinnamate, ethylhexyl salicylate, butyl methoxydibenzoylmethane, diethylhexyl butamido triazone, ethylhexyl triazone, methylene bis-benzotriazolyl tetramethylbutylphenol and bis-ethylhexyloxyphenol methoxyphenyl triazine) contained in suncare products. The separation and quantitative determination was performed in <30 min, using a Symmetry Shield(R) C18 (5 microm) column from Waters and a mobile phase (gradient mode) consisting of ethanol and acidified water. UV measurements were carried out at multi-wavelengths, according to the absorption of the analytes.

Application of neutron activation analysis and spectrophotometry for the determination of copper level in sera and cerebrospinal fluids of schizophrenic patients

International Nuclear Information System (INIS)

Lipcsey, A.; Fekete, J.; Oerdoegh, M.; Szabo, E.

1985-01-01

Neutron activation analysis and spectrophotometry were used for the determination of copper content in sera and cerebrospinal fluids of schizophrenic patients against control persons. Comparison of the results of copper determination by both methods is tabulated. From the data the following conclusions can be drawn: for copper determinations in sera the results of the two methods agree excellently. At small copper concentrations in the cerebrospinal fluids the deviations are rather high. It can also be seen that the copper contents determined from cerebrospinal fluids taken at different times are nearly equal. (author)

Degradation of Iodinated Contrast Media in Aquatic Environment by Means of UV, UV/TiO2 Process, and by Activated Sludge.

Science.gov (United States)

Borowska, Ewa; Felis, Ewa; Żabczyński, Sebastian

Iodinated contrast media (ICM), which are used for radiological visualization of human tissue and cardiovascular system, are poorly biodegradable; hence, new methods of their removal are sought. In this study, the effectiveness of selected X-ray ICM removal by means of UV and UV/TiO 2 pretreatment processes from synthetic hospital wastewater was demonstrated. The following compounds were investigated: iodipamide, iohexol, and diatrizoate. The experiments were as follows: (i) estimated susceptibility of the ICM to decay by UV radiation in different aquatic matrices, (ii) determined an optimal retention time of hospital wastewater in the UV reactor, (iii) determined optimum TiO 2 concentration to improve the effectiveness of the UV pretreatment, and (iv) investigated removal of ICM by combination of the photochemical and biological treatment methods. The quantum yields of selected ICM decay in deionized water (pH = 7.0) were established as 0.006, 0.004, and 0.029 for iohexol, diatrizoate, and iodipamide, respectively. Furthermore, the experiments revealed that diatrizoate and iohexol removal in the UV/TiO 2 process is more efficient than in UV process alone. For diatrizoate, the removal efficiency equaled to 40 and 30 %, respectively, and for iohexol, the efficiency was 38 and 27 %, respectively. No significant increase in iodipamide removal in UV and UV/TiO 2 processes was observed (29 and 28 %, respectively). However, highest removal efficiency was demonstrated in synthetic hospital wastewater with the combined photochemical and biological treatment method. The removal of diatrizoate and iohexol increased to at least 90 %, and for iodipamide, to at least 50 %.

Micro solid phase spectrophotometry in a sequential injection lab-on-valve platform for cadmium, zinc, and copper determination in freshwaters

International Nuclear Information System (INIS)

Santos, Inês C.; Mesquita, Raquel B.R.; Rangel, António O.S.S.

2015-01-01

This work describes the development of a solid phase spectrophotometry method in a μSI-LOV system for cadmium, zinc, and copper determination in freshwaters. NTA (Nitrilotriacetic acid) beads with 60–160 μm diameter were packed in the flow cell of the LOV for a μSPE column of 1 cm length. The spectrophotometric determination is based on the colourimetric reaction between dithizone and the target metals, previously retained on NTA resin. The absorbance of the coloured product formed is measured, at 550 nm, on the surface of the NTA resin beads in a solid phase spectrophotometry approach. The developed method presented preconcentration factors in the range of 11–21 for the metal ions. A LOD of 0.23 μg L"−"1 for cadmium, 2.39 μg L"−"1 for zinc, and 0.11 μg L"−"1 for copper and a sampling rate of 12, 13, and 15 h"−"1 for cadmium, zinc, and copper were obtained, respectively. The proposed method was successfully applied to freshwater samples. - Highlights: • Multi-parametric determination of cadmium, zinc, and copper at the μg L"−"1 level. • In-line metal ions preconcentration using NTA resin. • Minimization of matrix interferences by performing solid phase spectrometry in a SI-LOV platform. • Successful application to metal ions determination in freshwaters.

Micro solid phase spectrophotometry in a sequential injection lab-on-valve platform for cadmium, zinc, and copper determination in freshwaters

Energy Technology Data Exchange (ETDEWEB)

Santos, Inês C. [CBQF–Centro de Biotecnologia e Química Fina – Laboratório Associado, Escola Superior de Biotecnologia, Universidade Católica Portuguesa/Porto, Rua Arquiteto Lobão Vital, Apartado 2511, 4202-401 Porto (Portugal); Mesquita, Raquel B.R. [CBQF–Centro de Biotecnologia e Química Fina – Laboratório Associado, Escola Superior de Biotecnologia, Universidade Católica Portuguesa/Porto, Rua Arquiteto Lobão Vital, Apartado 2511, 4202-401 Porto (Portugal); Laboratório de Hidrobiologia, Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Rua de Jorge Viterbo Ferreira no. 228, 4050-313 Porto (Portugal); Rangel, António O.S.S., E-mail: arangel@porto.ucp.pt [CBQF–Centro de Biotecnologia e Química Fina – Laboratório Associado, Escola Superior de Biotecnologia, Universidade Católica Portuguesa/Porto, Rua Arquiteto Lobão Vital, Apartado 2511, 4202-401 Porto (Portugal)

2015-09-03

This work describes the development of a solid phase spectrophotometry method in a μSI-LOV system for cadmium, zinc, and copper determination in freshwaters. NTA (Nitrilotriacetic acid) beads with 60–160 μm diameter were packed in the flow cell of the LOV for a μSPE column of 1 cm length. The spectrophotometric determination is based on the colourimetric reaction between dithizone and the target metals, previously retained on NTA resin. The absorbance of the coloured product formed is measured, at 550 nm, on the surface of the NTA resin beads in a solid phase spectrophotometry approach. The developed method presented preconcentration factors in the range of 11–21 for the metal ions. A LOD of 0.23 μg L{sup −1} for cadmium, 2.39 μg L{sup −1} for zinc, and 0.11 μg L{sup −1} for copper and a sampling rate of 12, 13, and 15 h{sup −1} for cadmium, zinc, and copper were obtained, respectively. The proposed method was successfully applied to freshwater samples. - Highlights: • Multi-parametric determination of cadmium, zinc, and copper at the μg L{sup −1} level. • In-line metal ions preconcentration using NTA resin. • Minimization of matrix interferences by performing solid phase spectrometry in a SI-LOV platform. • Successful application to metal ions determination in freshwaters.

[Mutual Effect on Determination of Gibberellins and Glyphosate in Groundwater by Spectrophotometry].

Science.gov (United States)

Zhang, Li; Chen, Liang; Liu, Fei

2015-04-01

In the present study, a spectrophotometry method for the simultaneous determination of gibberellins (GA3) and glyphosate in groundwater was established and optimized. In addition, the mutual effect on simultaneous determination of GA3 and glyphosate was studied. Based on the experiment, good linearity (R2 > 0.99) was obtained for GA3 in the range of 0-20 and 0-100 µg and for glyphosate in the range of 0-8 and 5-15 µg. The method's detection limit (MDL) of GA3 and glyphosate was 0.48 and 0.82 µg, respectively; and the recovery rates of 15 to 150 µg GA3 and 3 to 10 µg glyphosate in all samples at a spiked level were 71.3% ± 1.9% and 98.4% ± 8.1%, respectively. No obvious influence of glyphosate (0-100 mg · L(-1)) on the recovery rates of GA3 was observed, but the presence of glyphosate could cause slight determination precision decrease of GA3. Meanwhile, adding 2 mg · L(-1) GA3 can increase the recovery rate of glyphosate.

Ascorbic acid as a free radical scavenger in porcine and bovine aqueous humour.

Science.gov (United States)

Erb, Carl; Nau-Staudt, Kerstin; Flammer, Josef; Nau, Werner

2004-01-01

To study the antioxidant activity, UV absorption, concentration and stability of ascorbic acid (AA) in porcine and bovine aqueous humour (AH). Porcine and bovine AH was taken within 5 min after death and frozen at -70 degrees C. The characteristic UV absorption band of AA and the concentration of AA in AH was determined by UV spectrophotometry. The antioxidant activity of AA to serve as a free radical scavenger in AH has been determined by using a novel fluorescent probe for antioxidants, the azoalkane 2,3-diazabicyclo[2.2.2]oct-2-ene (DBO). The fluorescence lifetime and intensity of this probe reflect the concentration of dissolved antioxidants. The time-resolved fluorescence of DBO (laser excitation at 351 nm) in AH and in a neutral phosphate-buffered saline (PBS) solution containing only the natural amount of AA as an additive were measured. The characteristic UV absorption band of AA has its maximum at 266 nm in AH. The concentration of AA in porcine and bovine AH was found to be 0.547 +/- 0.044 and 1.09 +/- 0.16 mM, respectively, by spectrophotometry. The fluorescence lifetime of the probe DBO was reduced from 320 +/- 5 ns in pure aerated PBS to 205 +/- 5 ns in porcine AH and 165 +/- 3 ns in bovine AH. A detailed kinetic analysis of the lifetime shortening suggests that AA contributes approximately 75 and 85% to the antioxidant activity of porcine and bovine AH, respectively. Our experiments suggest that AA is the major contributor to the antioxidant activity of porcine and bovine AH. The role of AA to serve as an antioxidant in AH is discussed. In addition, UV spectrophotometry is established as an alternative method to determine the concentration of AA in AH. Copyright 2004 S. Karger AG, Basel

SiO2 sol-gel films after ammonia and heat two-step treatments

International Nuclear Information System (INIS)

Zhang Chunlai; Wang Biyi; Tian Dongbin; Yin Wei; Jiang Xiaodong; Yuan Xiaodong; Yan Lianghong; Zhang Hongliang; Zhao Songnan; Lv Haibing

2008-01-01

SiO 2 thin films were deposited using tetraethoxylsilane as precursor, ammonia as catalyst on K9 glass by sol-gel method. These films were post-treated by ammonia and heat. The properties of the coatings were characterized by ellipsometer, UV-vis spectrophotometry, FTIR-spectroscopy, scanning probe microscope and contact angle measurement apparatus. The resuits indicate that the thickness of the films with ammonia and heat treatment tend to decrease. Both the refractive index and water contact angle increase after ammonia treatment. However, they both decrease after heat treatment. The former increases by 0.236 for the first step, then decreases by 0.202 for the second. The latter increases to 58.92 degree, then decreases to 38.07 degree. The transmittance of the coatings turn to be better and continuously shift to short wave by UV-vis spectrophotometry. The surface becomes smoother by AFM after the two-step treatment. (authors)

Blood volume measurement with indocyanine green pulse spectrophotometry: dose and site of dye administration

NARCIS (Netherlands)

Germans, Menno R.; de Witt Hamer, Philip C.; van Boven, Leonard J.; Zwinderman, Koos A. H.; Bouma, Gerrit J.

2010-01-01

(1) To determine the optimal administration site and dose of indocyanine green (ICG) for blood volume measurement using pulse spectrophotometry, (2) to assess the variation in repeated blood volume measurements for patients after subarachnoid hemorrhage and (3) to evaluate the safety and efficacy of

Development and validation of RP-HPLC and UV-spectrophotometric methods for rapid simultaneous estimation of amlodipine and benazepril in pure and fixed dose combination

Directory of Open Access Journals (Sweden)

Abhi Kavathia

2017-05-01

Full Text Available High-performance liquid chromatographic (HPLC and UV spectrophotometric methods were developed and validated for the quantitative determination of amlodipine besylate (AM and benazepril hydrochloride (BZ. Different analytical performance parameters such as linearity, precision, accuracy, specificity, limit of detection (LOD and limit of quantification (LOQ were determined according to International Conference on Harmonization ICH Q2B guidelines. The RP-HPLC method was developed by the isocratic technique on a reversed-phase Shodex C-18 5e column. The retention time for AM and BZ was 4.43 min and 5.70 min respectively. The UV spectrophotometric determinations were performed at 237 nm and 366 nm for AM and at 237 nm for BZ. Correlation between absorbance of AM at 237 nm and 366 nm was established and based on developed correlation equation estimation of BZ at 237 nm was carried out. The linearity of the calibration curves for each analyte in the desired concentration range was good (r2 > 0.999 by both the HPLC and UV methods. The method showed good reproducibility and recovery with percent relative standard deviation less than 5%. Moreover, the accuracy and precision obtained with HPLC co-related well with the UV method which implied that UV spectroscopy can be a cheap, reliable and less time consuming alternative for chromatographic analysis. The proposed methods are highly sensitive, precise and accurate and hence successfully applied for determining the assay and in vitro dissolution of a marketed formulation.

Analytical Methods for the Determination of Rosuvastatin in Pharmaceutical Formulations and Biological Fluids: A Critical Review.

Science.gov (United States)

Ângelo, Marilene Lopes; Moreira, Fernanda de Lima; Morais Ruela, André Luís; Santos, Ana Laura Araújo; Salgado, Hérida Regina Nunes; de Araújo, Magali Benjamim

2018-07-04

Rosuvastatin calcium (ROS), ( Figure 1 ) belongs to the "statins" group, which is the 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor. This drug is indicated for dyslipidemias treatment and can help to decrease the level of "bad cholesterol" and can consequently reduce the development of atherosclerosis and the risk of heart diseases. ROS was developed by Astra-Zeneca and it was approved in 2003 by the FDA in the United States. In 2015, under the trade name Crestor®, it was the fourth largest selling drug in the United States with sales above $5 billion. This study presents a literature review of analytical methods for the quantification of ROS in pharmaceutical preparations and biological fluids. The major analytical methods described in this study for ROS were spectrophotometry, high-performance liquid chromatography (HPLC) coupled to ultraviolet (UV) detection, and tandem mass spectrometry (LC-MS/MS).

Spectrophotometry with optical fibers applied to nuclear product processing

International Nuclear Information System (INIS)

Boisde, G.; Perez, J.J.; Velluet, M.T.; Jeunhomme, L.B.

1988-01-01

Absorption spectrophotometry is widely used in laboratories for composition analysis and quality control of chemical processes. Using optical fibers for transmitting the light between the instrument and the process line allows to improve the safety and productivity of chemical processes, thanks to real time measurements. Such applications have been developed since 1975 in CEA for the monitoring of nuclear products. This has led to the development of fibers, measurement cells, and optical feedthrough sustaining high radiation doses, of fiber/spectrophotometer couplers, and finally of a photodiode array spectrophotometer optimized for being used together with optical fibers [fr

Novel Spectrophotometric Methods for Determination of Salicylamide and Ascorbic acid in their binary mixture

International Nuclear Information System (INIS)

Ali, N.W.; Zaazaa, H.E.S.; Abdelrahman, M.M.

2014-01-01

Simple, selective and precise four spectrophotometric methods were developed and validated for quantitative determination of Salicylamide (SAD) and Ascorbic acid (ASC, Vitamin C) in their binary mixture. Method A is Area under curve spectrophotometry, in which the area under curve in the wavelength ranges 225-245 nm and 265-285 nm were selected for determination of SAD and ASC. Method B is based on dual wavelength spectrophotometry, where ASC can be determined by difference in absorbance at 249.8 and 285.8 nm. On the same way; SAD is measured by difference in absorbance at 240.4 and 286.4 nm. Method C utilizes isoabsorptive point spectrophotometry where total concentration of SAD and ASC was calculated at their isoabsorptive points at 246.4 and 287 nm, while SAD concentration alone can be determined by first derivative spectrophotometry (1D) at 315.4 nm, then ASC concentration can be determined by subtraction. Method D is ratio subtraction spectrophotometry, where ASC can be determined by dividing the spectrum of the mixture by the spectrum of the SAD (as a divisor) followed by subtracting the constant absorbance value of the plateau region, then finally multiplying the obtained spectrum by the spectrum of the divisor. The developed methods have been successfully applied for determination of the studied drugs in different laboratory prepared mixtures and in their pharmaceutical formulation. Statistical comparison between the results obtained by applying the proposed methods and the reported HPLC method was done, and it was found that there was no significant difference between them regarding both accuracy and precision. (author)

Simultaneous Chloramphenicol and Florfenicol Determination by A Validated DLLME-HPLC-UV Method in Pasteurized Milk

OpenAIRE

Karami-Osboo, Rouhollah; Miri, Ramin; Javidnia, Katayoun; Kobarfard, Farzad

2016-01-01

The antibiotic residues in milk are a well-known serious problem and pose several health hazards to consumers. We have described a simple, rapid, and inexpensive DLLME-HPLC/UV technique for the extraction of chloramphenicol and florfenicol residues in milk samples. Under the optimum conditions, linearity of the method was observed over the range 0.02-0.85 ?g/L with correlation coefficients > 0.999. The proposed method has been found to have a good limit of detection (signal to noise ratio = 3...

Validation of an HPLC–UV method for the determination of digoxin residues on the surface of manufacturing equipment

Directory of Open Access Journals (Sweden)

ZORAN B. TODOROVIĆ

2009-09-01

Full Text Available In the pharmaceutical industry, an important step consists in the removal of possible drug residues from the involved equipments and areas. The cleaning procedures must be validated and methods to determine trace amounts of drugs have, therefore, to be considered with special attention. An HPLC–UV method for the determination of digoxin residues on stainless steel surfaces was developed and validated in order to control a cleaning procedure. Cotton swabs, moistened with methanol were used to remove any residues of drugs from stainless steel surfaces, and give recoveries of 85.9, 85.2 and 78.7 % for three concentration levels. The precision of the results, reported as the relative standard deviation (RSD, were below 6.3 %. The method was validated over a concentration range of 0.05–12.5 µg mL-1. Low quantities of drug residues were determined by HPLC–UV using a Symmetry C18 column (150´4.6 mm, 5 µm at 20 °C with an acetonitrile–water (28:72, v/v mobile phase at a flow rate of 1.1 mL min-1, an injection volume of 100 µL and were detected at 220 nm. A simple, selective and sensitive HPLC–UV assay for the determination of digoxin residues on stainless steel was developed, validated and applied.

Reduction of patulin in apple cider by UV radiation.

Science.gov (United States)

Dong, Qingfang; Manns, David C; Feng, Guoping; Yue, Tianli; Churey, John J; Worobo, Randy W

2010-01-01

The presence of the mycotoxin patulin in processed apple juice and cider presents a continual challenge to the food industry as both consumer health and product quality issues. Although several methods for control and/or elimination of patulin have been proposed, no unifying method has been commercially successful for reducing patulin burdens while maintaining product quality. In the present study, exposure to germicidal UV radiation was evaluated as a possible commercially viable alternative for the reduction and possible elimination of the patulin mycotoxin in fresh apple cider. UV exposure of 14.2 to 99.4 mJ/cm(2) resulted in a significant and nearly linear decrease in patulin levels while producing no quantifiable changes in the chemical composition (i.e., pH, Brix, and total acids) or organoleptic properties of the cider. For the range of UV doses tested, patulin levels decreased by 9.4 to 43.4%; the greatest reduction was achieved after less than 15 s of UV exposure. The method of UV radiation (the CiderSure 3500 system) is an easily implemented, high-throughput, and cost-effective method that offers simultaneous UV pasteurization of cider and juice products and reduction and/or elimination of patulin without unwanted alterations in the final product.

Objective evaluation by reflectance spectrophotometry can be of clinical value for the verification of blanching/non blanching erythema in the sacral area.

Science.gov (United States)

Sterner, Eila; Fossum, Bjöörn; Berg, Elisabeth; Lindholm, Christina; Stark, André

2014-08-01

Early detection of non blanching erythema (pressure ulcer category I) is necessary to prevent any further skin damage. An objective method to discriminate between blanching/non blanching erythema is presently not available. The purpose of this investigation was to explore if a non invasive objective method could differentiate between blanching/non blanching erythema in the sacral area of patients undergoing hip fracture surgery. Seventy-eight patients were included. The sacral area of all patients was assessed using (i) conventional finger-press test and (ii) digital reading of the erythema index assessed with reflectance spectrophotometry. The patients were examined at admission and during 5 days postsurgery. Reflectance spectrophotometry measurements proved able to discriminate between blanching/non blanching erythema. The reliability, quantified by the intra-class correlation coefficient, was excellent between repeated measurements over the measurement period, varying between 0·82 and 0·96, and a significant change was recorded in the areas from day 1 to day 5 (P < 0·0001). The value from the reference point did not show any significant changes over the same period (P = 0·32). An objective method proven to identify early pressure damage to tissue can be a valuable tool in clinical practice. © 2013 The Authors. International Wound Journal © 2013 Medicalhelplines.com Inc and John Wiley & Sons Ltd.

Determination of silver in soils, sediments, and rocks by organic-chelate extraction and atomic absorption spectrophotometry

Science.gov (United States)

Chao, T.T.; Ball, J.W.; Nakagawa, H.M.

1971-01-01

A useful method for the determination of silver in soil, sediment, and rock samples in geochemical exploration has been developed. The sample is digested with concentrated nitric acid, and the silver extracted with triisooctyl thiophosphate (TOTP) in methyl isobutyl ketone (MIBK) after dilution of the acid digest to approximately 6 M. The extraction of silver into the organic extractant is quantitative and not affected by the nitric acid concentration from 4 M to 8 M, or by different volumes of TOTP-MIBK. The extracted silver is stable and remains in the organic phase up to several days. The silver concentration is determined by atomic absorption spectrophotometry. ?? 1971.

Comparison of UV-Curing, Hotmelt, and Pressure Sensitive Adhesive as Roll-to-Roll Encapsulation Methods for Polymer Solar Cells

DEFF Research Database (Denmark)

Hösel, Markus; Søndergaard, Roar R.; Jørgensen, Mikkel

2013-01-01

The most distinct advantage of the polymer solar cell is the possibility for roll-to-roll (R2R) fabrication compatibility based on printing and coating processes. The R2R encapsulation is the last crucial process step in the manufacturing workflow and is evaluated in this study. Polymer solar cell...... modules are directly printed on barrier foil and encapsulated with the same barrier foil either on the backside or on both sides of the device. The three lamination methods comprise of UV-curable epoxy resin, hotmelt, and pressure sensitive adhesive (PSA). It is shown that a single sided encapsulation...... of the PSA method is the fastest method (in this study) it generates a considerable amount of waste (paper liner) and two lamination steps are required to achieve a sufficient lifetime. We conclude that UV-curing presents the largest advantages of all methods with a good upscaling potential and low embodied...

Comparative study of the UV spectra of various raw materials OF Urtica dioica L.

Directory of Open Access Journals (Sweden)

E. A. Balagozyan

2016-01-01

Full Text Available Stinging nettle (Urtica dioica L. is one of the famous and popular medicinal plants. In Russia the herbal materials are nettle’s leaves which have haemostatic effect. At the same time abroad the rhizomes and roots of nettle are the source of drugs with antitumor activity. The chemical composition of the rhizomes and roots of nettle is quite complicated and is represented by substances such as polysaccharides, lectins, sterols etc. The aim of the present study is the comparative phytochemical research of various parts of raw nettle by spectrophotometry. The study of extracts from various raw materials of nettle has shown, that the presence of flavonoids is peculiar for leaves, flowers and fruits. Sterols dominate in the rhizomes and roots of nettle. It was also noted that the UV-spectra of extracts of female inflorescences and fruits nettle have the same absorption maxima.

Antiproliferative effects of ZnO, ZnO-MTCP, and ZnO-CuMTCP nanoparticles with safe intensity UV and X-ray irradiation.

Science.gov (United States)

Sadjadpour, Susan; Safarian, Shahrokh; Zargar, Seyed Jalal; Sheibani, Nader

2016-01-01

In photodynamic therapy (PDT) of cancer both the light and the photosensitizing agent are normally harmless, but in combination they could result in selective tumor killing. Zinc oxide nanoparticles were synthesized and coated with the amino acid cysteine to provide an adequate arm for conjugation with porphyrin photosensitizers (meso-tetra (4-carboxyphenyl) porphyrin [MTCP] and CuMTCP). Porphyrin-conjugated nanoparticles were characterized by TEM, FTIR, and UV-vis, and fluorescence spectrophotometry. The 3-[4, 5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay was used to measure cell viability in the presence or absence of porphyrin conjugates following UV and X-ray irradiation. The uptake of the porphyrin-conjugated ZnO nanoparticles by cells was detected using fluorescence microscopy. Our results indicated that the survival of T-47D cells was significantly compromised in the presence of ZnO-MTCP-conjugated nanostructures with UV light exposure. Exhibition of cytotoxic activity of ZnO-MTCP for human prostate cancer (Du145) cells occurred at a higher concentration, indicating the more resistant nature of these tumor cells. ZnO-CuMTCP showed milder cytotoxic effects in human breast cancer (T-47D) and no cytotoxic effects in Du145 with UV light exposure, consistent with its lower cytotoxic potency as well as cellular uptake. Surprisingly, none of the ZnO-porphyrin conjugates exhibited cytotoxic effects with X-ray irradiation, whereas ZnO alone exerted cytotoxicity. Thus, ZnO and ZnO-porphyrin nanoparticles with UV or X-ray irradiation may provide a suitable treatment option for various cancers. © 2015 International Union of Biochemistry and Molecular Biology, Inc.

Ion-exclusion/cation-exchange chromatography with dual detection of the conductivity and spectrophotometry for the simultaneous determination of common inorganic anionic species and cations in river and wastewater.

Science.gov (United States)

Nakatani, Nobutake; Kozaki, Daisuke; Mori, Masanobu; Hasebe, Kiyoshi; Nakagoshi, Nobukazu; Tanaka, Kazuhiko

2011-01-01

Simultaneous determinations of common inorganic anionic species (SO(4)(2-), Cl(-), NO(3)(-), phosphate and silicate) and cations (Na(+), NH(4)(+), K(+), Mg(2+) and Ca(2+)) were conducted using an ion-chromatography system with dual detection of conductivity and spectrophotometry in tandem. The separation of ionic species on a weakly acidic cation-exchange resin was accomplished using a mixture of 100 mM ascorbic acid and 4 mM 18-crown-6 as an acidic eluent (pH 2.6), after which the ions were detected using a conductivity detector. Subsequently, phosphate and silicate were analyzed based on derivatization with molybdate and spectrophotometry at 700 nm. The detection limits at S/N = 3 ranged from 0.11 to 2.9 µM for analyte ionic species. This method was applied to practical river water and wastewater with acceptable criteria for the anion-cation balance and comparisons of the measured and calculated electrical conductivity, demonstrating the usefulness of the present method for water quality monitoring.

Simultaneous Determination of Cobalt (II and Nickel (II By First Order Derivative Spectrophotometry in Micellar Media

Directory of Open Access Journals (Sweden)

Rajni Rohilla

2012-01-01

Full Text Available A first-derivative spectrophotometry method for the simultaneous determination of Co (II and Ni (II with Alizarin Red S in presence of Triton X-100 is described. Measurements were made at the zero-crossing wavelengths at 549.0 nm for Co (II and 546.0 nm for Ni (II. The linearity is obtained in the range of 0.291- 4.676 μg/ml of Ni (II and 0.293- 4.124 μg/ml of Co (II in the presence of each other by using first derivative spectrophotometric method. The possible interfering effects of various ions were studied. The validity of the method was examined by using synthetic mixtures of Co (II and Ni (II. The developed derivative procedure, using the zero crossing technique, has been successfully applied for the simultaneous analysis of Co (II and Ni (II in spiked water samples.

Real-time UV imaging of nicotin release from transdermal patch

DEFF Research Database (Denmark)

Østergaard, Jesper; Meng-Lund, Emil; Larsen, Susan Weng

2010-01-01

PURPOSE: This study was conducted to characterize UV imaging as a platform for performing in vitro release studies using Nicorette® nicotine patches as a model drug delivery system. METHODS: The rate of nicotine release from 2 mm diameter patch samples (Nicorette®) into 0.067 M phosphate buffer, p......H 7.40, was studied by UV imaging (Actipix SDI300 dissolution imaging system) at 254 nm. The release rates were compared to those obtained using the paddle-over-disk method. RESULTS: Calibration curves were successfully established which allowed temporally and spatially resolved quantification...... of nicotine. Release profiles obtained from UV imaging were in qualitative agreement with results from the paddle-over-disk release method. CONCLUSION: Visualization as well as quantification of nicotine concentration gradients was achieved by UV imaging in real time. UV imaging has the potential to become...

UV patterned nanoporous solid-liquid core waveguides

DEFF Research Database (Denmark)

Gopalakrishnan, Nimi; Sagar, Kaushal Shashikant; Christiansen, Mads Brøkner

2010-01-01

Nanoporous Solid-Liquid core waveguides were prepared by UV induced surface modification of hydrophobic nanoporous polymers. With this method, the index contrast (delta n = 0.20) is a result of selective water infiltration. The waveguide core is defined by UV light, rendering the exposed part...

The nature of C-class asteroids from 3-micron spectrophotometry

Science.gov (United States)

Feierberg, M. A.; Lebofsky, L. A.; Tholen, D. J.

1985-01-01

Narrowband spectrophotometry between 2.3 and 3.5 micrometers is presented for 14 main-belt C asteroids greater than 100 km in diameter. Absorption features at 3 micrometers due to water of hydration are present in the spectra of nine of the asteroids, with intensities ranging from 6 to 23 percent. The other five asteroids have no such absorption greater than 2 percent in intensity. The present C-asteroid population may be fragments of larger parent bodies with anhydrous C3-like cores and hydrated C1I- or C2M-like mantles.

Comparative study between derivative spectrophotometry and multivariate calibration as analytical tools applied for the simultaneous quantitation of Amlodipine, Valsartan and Hydrochlorothiazide

Science.gov (United States)

Darwish, Hany W.; Hassan, Said A.; Salem, Maissa Y.; El-Zeany, Badr A.

2013-09-01

Four simple, accurate and specific methods were developed and validated for the simultaneous estimation of Amlodipine (AML), Valsartan (VAL) and Hydrochlorothiazide (HCT) in commercial tablets. The derivative spectrophotometric methods include Derivative Ratio Zero Crossing (DRZC) and Double Divisor Ratio Spectra-Derivative Spectrophotometry (DDRS-DS) methods, while the multivariate calibrations used are Principal Component Regression (PCR) and Partial Least Squares (PLSs). The proposed methods were applied successfully in the determination of the drugs in laboratory-prepared mixtures and in commercial pharmaceutical preparations. The validity of the proposed methods was assessed using the standard addition technique. The linearity of the proposed methods is investigated in the range of 2-32, 4-44 and 2-20 μg/mL for AML, VAL and HCT, respectively.

Intraoperative Vascular Neuromonitoring in Patients with Subarachnoid Hemorrhage: A Pilot Study Using Combined Laser-Doppler Spectrophotometry.

Science.gov (United States)

Schmitz, Emilija; Bischoff, Barbara; Wolf, Dennis; Schmitt, Hubert J; Eyupoglu, Ilker Y; Roessler, Karl; Buchfelder, Michael; Sommer, Björn

2017-11-01

Intraoperative monitoring of cerebral microcirculation in patients with subarachnoid hemorrhage (SAH) may predict the postoperative neurologic outcome. In this pilot study, we examined the value of a novel noninvasive real-time measurement technique for detecting changes in local microcirculation. We used the O2C (Oxygen to see) laser-Doppler spectrophotometry system in 14 patients with Hunt & Hess grade 2-5 SAH who underwent microsurgical cerebral aneurysm clipping. A subdural probe recorded capillary venous oxygenation (SO 2 ), relative hemoglobin concentration, blood cell velocity, and blood flow at a tissue depth of 7 mm. Data were recorded immediately before dural closure. We also recorded somatosensory evoked potentials (SEPs) with median and tibial nerve stimulation. Results were compared with neurologic performance, as measured on the modified Rankin Scale, at the day of discharge from the hospital and 12 months thereafter. Patient functional outcomes after discharge and 12 months were correlated with pathological decreased flow and increased SO 2 values. In 6 of 8 patients, microcirculatory monitoring parameters indicated ischemia during surgery, as shown by electrophysiological SEP changes and infarction detected on the postoperative computed tomography (CT) scan. Pathological SEP results correlated closely with infarct demarcation as seen on CT. Our results indicate the potential benefit of intraoperative combined laser-Doppler flowmetry and spectrophotometry for predicting postoperative clinical outcomes in this small patient sample. Larger-cohort testing is needed to verify our findings and show the possible merits of this novel method. Copyright © 2017 Elsevier Inc. All rights reserved.

UV spectroscopy applied to stratospheric chemistry, methods and results

Energy Technology Data Exchange (ETDEWEB)

Karlsen, K.

1996-03-01

The publication from the Norwegian Institute for Air Research (NILU) deals with an investigation done on stratospheric chemistry by UV spectroscopy. The scientific goals are briefly discussed, and it gives the results from the measuring and analysing techniques used in the investigation. 6 refs., 11 figs.

Chemical methods of rock analysis

National Research Council Canada - National Science Library

Jeffery, P. G; Hutchison, D

1981-01-01

.... Such methods include those based upon spectrophotometry, flame emission spectrometry and atomic absorption spectroscopy, as well as gravimetry, titrimetry and the use of ion-selective electrodes...

Extraction of phenolic compounds from extra virgin olive oil by a natural deep eutectic solvent: Data on UV absorption of the extracts.

Science.gov (United States)

Paradiso, Vito Michele; Clemente, Antonia; Summo, Carmine; Pasqualone, Antonella; Caponio, Francesco

2016-09-01

This data article refers to the paper "Towards green analysis of virgin olive oil phenolic compounds: extraction by a natural deep eutectic solvent and direct spectrophotometric detection" [1]. A deep eutectic solvent (DES) based on lactic acid and glucose was used as green solvent for phenolic compounds. Eight standard phenolic compounds were solubilized in the DES. Then, a set of extra virgin olive oil (EVOO) samples (n=65) were submitted to liquid-liquid extraction by the DES. The standard solutions and the extracts were analyzed by UV spectrophotometry. This article reports the spectral data of both the standard solutions and the 65 extracts, as well as the total phenolic content of the corresponding oils, assessed by the Folin-Ciocalteu assay.

Development and validation of a dissolution test for diltiazem hydrochloride in immediate release capsules

Directory of Open Access Journals (Sweden)

Taciane Ferreira Mendonça

2011-01-01

Full Text Available This work describes the development and validation of a dissolution test for 60 mg of diltiazem hydrochloride in immediate release capsules. The best dissolution in vitro profile was achieved using potassium phosphate buffer at pH 6.8 as the dissolution medium and paddle as the apparatus at 50 rpm. The drug concentrations in the dissolution media were determined by UV spectrophotometry and HPLC and a statistical analysis revealed that there were significant differences between HPLC and spectrophotometry. This study illustrates the importance of an official method for the dissolution test, since there is no official monograph for diltiazem hydrochloride in capsules.

Photochemical Synthesis of Complex Carbazoles: Evaluation of Electronic Effects in Both UV- and Visible-Light Methods in Continuous Flow.

Science.gov (United States)

Hernandez-Perez, Augusto C; Caron, Antoine; Collins, Shawn K

2015-11-09

An evaluation of both a visible-light- and UV-light-mediated synthesis of carbazoles from various triarylamines with differing electronic properties under continuous-flow conditions has been conducted. In general, triarylamines bearing electron-rich groups tend to produce higher yields than triarylamines possessing electron-withdrawing groups. The incorporation of nitrogen-based heterocycles, as well as halogen-containing arenes in carbazole skeletons, was well tolerated, and often synthetically useful complementarity was observed between the UV-light and visible-light (photoredox) methods. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Risks of increased UV-B radiation for humans

International Nuclear Information System (INIS)

Przybilla, B.; Eberlein-Koenig, B.; Bergner, T.

1994-01-01

If not compensated in any way, depletion of the stratospheric ozone layer leads to an increase of UV-B radiation at the earth's surface, especially towards the short-wave range, which is biologically the more active. The most concerning effect here is that of UV-B induced skin reactions, in particular malignant skintumors (malignant melanoma, spinocellular carcinoma, basalioma), whose incidence is expected to increase in future. As some photoreactions can be inhibited or enhanced also by radiation outside their action spectrum, it is possible for changes in solar spectral radiation flux density to influence photo-induced reactions that are driven at wavelengths outside the UV-B range. The authors have performed studies for developing methods of quantifying individual UV sensitivity. In vitro studies have shown that UV-A dependent photoreactions can be partly inhibited by UV-B. A number of drugs, as well as sulphites, which are used as preservatives amongst other things, have been shown to have phototoxic properties that may be relevant to photocarcinogenesis. Irradiation tests on cell cultures for different UV-B ranges have shown that irradiation at shorter wavelengths leads to a stronger release of proinflammatory cytokines that ar longer wavelengths with the same dose. Altogether it can be said that despite compelling theoretical evidence it is not easily possible to predict the actual consequences of an increase in particular of short-wave UV-B radiation at the earth's surface. The assumed effects must be examined individually by appropriate methods. (orig.) [de

Infrared spectrophotometry and radiative transfer in optically thick circumstellar dust envelopes

International Nuclear Information System (INIS)

Merrill, K.M.

1976-01-01

The Two-Micron Sky Survey of Neugebauer and Leighton and, more recently, the AFCRL Infrared Sky Survey of Walker and Price have detected numerous compact, isolated, bright infrared sources which are not identified with previously cataloged stars. Observations of many such objects suggest that extensive circumstellar dust envelopes modify the flux from a central source. The present investigations employ broad bandpass photometry at lambda lambda 1.65 μm to 12.5 μm and narrow bandpass spectrophotometry (Δ lambda/lambda approximately 0.015) at lambda lambda 2-4 μm and lambda lambda 8-13 μm to determine the properties of a large sample of such infrared sources. Infrared spectrophotometry can clearly differentiate between normal stars of spectral types M(''oxygen-rich'') and C (''carbon-rich'') on the basis of characteristic absorption bands arising in cool stellar atmospheres. Most of the 2 μ Sky Survey and many of the AFCRL Sky Survey sources appear to be stars of spectral types M and C which are differentiated from normal cool comparison stars only by the presence of extensive circumstellar dust envelopes. Due to the large optical depth of the envelopes, the flux from the star and from the dust cannot be simply separated. Hence solutions of radiative transfer through spherically symmetric envelopes of arbitrary optical depth were generated by a generalized computer code which employed opacities of real dust

The Adjoint Method for Gradient-based Dynamic Optimization of UV Flash Processes

DEFF Research Database (Denmark)

Ritschel, Tobias Kasper Skovborg; Capolei, Andrea; Jørgensen, John Bagterp

2017-01-01

This paper presents a novel single-shooting algorithm for gradient-based solution of optimal control problems with vapor-liquid equilibrium constraints. Dynamic optimization of UV flash processes is relevant in nonlinear model predictive control of distillation columns, certain two-phase flow pro......-component flash process which demonstrate the importance of the optimization solver, the compiler, and the linear algebra software for the efficiency of dynamic optimization of UV flash processes....

Quality assurance of the UV irradiances of the UV-B Monitoring and Research Program: the Mauna Loa test case

Science.gov (United States)

Zempila, Melina Maria; Davis, John; Janson, George; Olson, Becky; Chen, Maosi; Durham, Bill; Simpson, Scott; Straube, Jonathan; Sun, Zhibin; Gao, Wei

2017-09-01

The USDA UV-B Monitoring and Research Program (UVMRP) is an ongoing effort aiming to establish a valuable, longstanding database of ground-based ultraviolet (UV) solar radiation measurements over the US. Furthermore, the program aims to achieve a better understanding of UV variations through time, and develop a UV climatology for the Northern American section. By providing high quality radiometric measurements of UV solar radiation, UVMRP is also focusing on advancing science for agricultural, forest, and range systems in order to mitigate climate impacts. Within these foci, the goal of the present study is to investigate, analyze, and validate the accuracy of the measurements of the UV multi-filter rotating shadowband radiometer (UV-MFRSR) and Yankee (YES) UVB-1 sensor at the high altitude, pristine site at Mauna Loa, Hawaii. The response-weighted irradiances at 7 UV channels of the UV-MFRSR along with the erythemal dose rates from the UVB-1 radiometer are discussed, and evaluated for the period 2006-2015. Uncertainties during the calibration procedures are also analyzed, while collocated groundbased measurements from a Brewer spectrophotometer along with model simulations are used as a baseline for the validation of the data. Besides this quantitative research, the limitations and merits of the existing UVMRP methods are considered and further improvements are introduced.

UV scale calibration transfer from an improved pyroelectric detector standard to field UV-A meters and 365 nm excitation sources

Science.gov (United States)

Eppeldauer, G. P.; Podobedov, V. B.; Cooksey, C. C.

2017-05-01

Calibration of the emitted radiation from UV sources peaking at 365 nm, is necessary to perform the ASTM required 1 mW/cm2 minimum irradiance in certain military material (ships, airplanes etc) tests. These UV "black lights" are applied for crack-recognition using fluorescent liquid penetrant inspection. At present, these nondestructive tests are performed using Hg-lamps. Lack of a proper standard and the different spectral responsivities of the available UV meters cause significant measurement errors even if the same UV-365 source is measured. A pyroelectric radiometer standard with spectrally flat (constant) response in the UV-VIS range has been developed to solve the problem. The response curve of this standard determined from spectral reflectance measurement, is converted into spectral irradiance responsivity with UV sources (with different peaks and distributions) without using any source standard. Using this broadband calibration method, yearly spectral calibrations for the reference UV (LED) sources and irradiance meters is not needed. Field UV sources and meters can be calibrated against the pyroelectric radiometer standard for broadband (integrated) irradiance and integrated responsivity. Using the broadband measurement procedure, the UV measurements give uniform results with significantly decreased uncertainties.

Teaching Beer's Law and Absorption Spectrophotometry with a Smart Phone: A Substantially Simplified Protocol

Science.gov (United States)

Kuntzleman, Thomas S.; Jacobson, Erik C.

2016-01-01

A very simple protocol for teaching Beer's Law and absorption spectrophotometry using a smart phone is described. Materials commonly found in high school chemistry laboratories or even around the house may be used. Data collection and analysis is quick and easy. Despite the simple nature of the experiment, excellent results can be achieved.

Spatially Multiplexed Micro-Spectrophotometry in Bright Field Mode for Thin Film Characterization

Directory of Open Access Journals (Sweden)

Valerio Pini

2016-06-01

Full Text Available Thickness characterization of thin films is of primary importance in a variety of nanotechnology applications, either in the semiconductor industry, quality control in nanofabrication processes or engineering of nanoelectromechanical systems (NEMS because small thickness variability can strongly compromise the device performance. Here, we present an alternative optical method in bright field mode called Spatially Multiplexed Micro-Spectrophotometry that allows rapid and non-destructive characterization of thin films over areas of mm2 and with 1 μm of lateral resolution. We demonstrate an accuracy of 0.1% in the thickness characterization through measurements performed on four microcantilevers that expand an area of 1.8 mm2 in one minute of analysis time. The measured thickness variation in the range of few tens of nm translates into a mechanical variability that produces an error of up to 2% in the response of the studied devices when they are used to measure surface stress variations.

Determination of myoglobin based on its enzymatic activity by stopped-flow spectrophotometry

Science.gov (United States)

Zheng, Qi; Liu, Zhihong; Cai, Ruxiu

2005-04-01

A new method has been developed for the determination of myoglobin (Mb) based on its enzymatic activity for the oxidation of o-phenylenediamine (OPDA) with hydrogen peroxide. Stopped-flow spectrophotometry was used to study the kinetic behavior of the oxidation reaction. The catalytic activity of Mb was compared to other three kinds of catalyst. The time dependent absorbance of the reaction product, 2,3-diamimophenazine (DAPN), at a wavelength of 426 nm was recorded. The initial reaction rate obtained at 40 °C was found to be proportional to the concentration of Mb in the range of 1.0 × 10 -6 to 4.0 × 10 -9 mol L -1. The detection limit of Mb was found to be 9.93 × 10 -10 mol L -1. The relative standard deviations were within 5% for the determination of different concentrations of Mb. Excess of bovine serum albumin (BSA), Ca(II), Mg(II), Cu(II), glucose, caffeine, lactose and uric acid did not interfere.

Application of wavelet and Fuorier transforms as powerful alternatives for derivative spectrophotometry in analysis of binary mixtures: A comparative study

Science.gov (United States)

Hassan, Said A.; Abdel-Gawad, Sherif A.

2018-02-01

Two signal processing methods, namely, Continuous Wavelet Transform (CWT) and the second was Discrete Fourier Transform (DFT) were introduced as alternatives to the classical Derivative Spectrophotometry (DS) in analysis of binary mixtures. To show the advantages of these methods, a comparative study was performed on a binary mixture of Naltrexone (NTX) and Bupropion (BUP). The methods were compared by analyzing laboratory prepared mixtures of the two drugs. By comparing performance of the three methods, it was proved that CWT and DFT methods are more efficient and advantageous in analysis of mixtures with overlapped spectra than DS. The three signal processing methods were adopted for the quantification of NTX and BUP in pure and tablet forms. The adopted methods were validated according to the ICH guideline where accuracy, precision and specificity were found to be within appropriate limits.

Shortened screening method for phosphorus fractionation in sediments A complementary approach to the standards, measurements and testing harmonised protocol

International Nuclear Information System (INIS)

Pardo, Patricia; Rauret, Gemma; Lopez-Sanchez, Jose Fermin

2004-01-01

The SMT protocol, a sediment phosphorus fractionation method harmonised and validated in the frame of the standards, measurements and testing (SMT) programme (European Commission), establishes five fractions of phosphorus according to their extractability. The determination of phosphate extracted is carried out spectrophotometrically. This protocol has been applied to 11 sediments of different origin and characteristics and the phosphorus extracted in each fraction was determined not only by UV-Vis spectrophotometry, but also by inductively coupled plasma-atomic emission spectrometry. The use of these two determination techniques allowed the differentiation between phosphorus that was present in the extracts as soluble reactive phosphorus and as total phosphorus. From the comparison of data obtained with both determination techniques a shortened screening method, for a quick evaluation of the magnitude and importance of the fractions given by the SMT protocol, is proposed and validated using two certified reference materials

UV and humidity sensing properties of ZnO nanorods prepared by the arc discharge method

International Nuclear Information System (INIS)

Fang, F; Futter, J; Markwitz, A; Kennedy, J

2009-01-01

The UV and humidity sensing properties of ZnO nanorods prepared by arc discharge have been studied. Scanning electron microscopy and photoluminescence spectroscopy were carried out to analyze the morphology and optical properties of the as-synthesized ZnO nanorods. Proton induced x-ray emission was used to probe the impurities in the ZnO nanorods. A large quantity of high purity ZnO nanorod structures were obtained with lengths of 0.5-1 μm. The diameters of the as-synthesized ZnO nanorods were found to be between 40 and 400 nm. The nanorods interlace with each other, forming 3D networks which make them suitable for sensing application. The addition of a polymeric film-forming agent (BASF LUVISKOL VA 64) improved the conductivity, as it facilitates the construction of conducting networks. Ultrasonication helped to separate the ZnO nanorods and disperse them evenly through the polymeric agent. Improved photoconductivity was measured for a ZnO nanorod sensor annealed in air at 200 deg. C for 30 min. The ZnO nanorod sensors showed a UV-sensitive photoconduction, where the photocurrent increased by nearly four orders of magnitude from 2.7 x 10 -10 to 1.0 x 10 -6 A at 18 V under 340 nm UV illumination. High humidity sensitivity and good stability were also measured. The resistance of the ZnO nanorod sensor decreased almost linearly with increasing relative humidity (RH). The resistance of the ZnO nanorods changed by approximately five orders of magnitude from 4.35 x 10 11 Ω in dry air (7% RH) to about 4.95 x 10 6 Ω in 95% RH air. It is experimentally demonstrated that ZnO nanorods obtained by the arc discharge method show excellent performance and promise for applications in both UV and humidity sensors.

Simultaneous Determination of Amlodipine and Valsartan

OpenAIRE

Mohamed, Nashwah Gadallah

2011-01-01

A spectrophotometric method was developed for simultaneous determination of amlodipine (Aml) and valsartan (Val) without previous separation. In this method amlodipine in methanolic solution was determined using zero order UV spectrophotometry by measuring its absorbency at 360.5 nm without any interference from valsartan. Valsartan spectrum in zero order is totally overlapped with that of amlodipine. First, second and third derivative could not resolve the overlapped peaks. The first derivat...

Removal of phosphonates from industrial wastewater with UV/FeII, Fenton and UV/Fenton treatment.

Science.gov (United States)

Rott, Eduard; Minke, Ralf; Bali, Ulusoy; Steinmetz, Heidrun

2017-10-01

Phosphonates are an important group of phosphorus-containing compounds due to their increasing industrial use and possible eutrophication potential. This study involves investigations into the methods UV/Fe II , Fenton and UV/Fenton for their removal from a pure water matrix and industrial wastewaters. It could be shown that the degradability of phosphonates by UV/Fe II (6 kWh/m 3 ) in pure water crucially depended on the pH and was higher the less phosphonate groups a phosphonate contains. The UV/Fe II method is recommended in particular for the treatment of concentrates with nitrogen-free phosphonates, only little turbidity and a low content of organic compounds. Using Fenton reagent, the degradation of polyphosphonates was relatively weak in a pure water matrix (Fenton method (6 kWh/m 3 ), those phosphonates with the smallest numbers of phosphonate groups were easier degraded as well at pH 3.5 in a pure water matrix (o-PO 4 3- formation rates of up to 80%). Despite an incomplete transformation of organically bound phosphorus to o-PO 4 3- with Fenton reagent in an organically highly polluted wastewater (max. 15%), an almost total removal of the total P occurred. The most efficient total P elimination rates were achieved in accordance with the following Fenton implementation: reaction → sludge separation (acidic) → neutralization of the supernatant → sludge separation (neutral). Accordingly, a neutralization directly after the reaction phase led to a lower total P removal extent. Copyright © 2017 Elsevier Ltd. All rights reserved.

Photodegradation of sulfasalazine and its human metabolites in water by UV and UV/peroxydisulfate processes.

Science.gov (United States)

Ji, Yuefei; Yang, Yan; Zhou, Lei; Wang, Lu; Lu, Junhe; Ferronato, Corinne; Chovelon, Jean-Marc

2018-04-15

The widespread occurrence of pharmaceuticals and their metabolites in natural waters has raised great concerns about their potential risks on human health and ecological systems. This study systematically investigates the degradation of sulfasalazine (SSZ) and its two human metabolites, sulfapyridine (SPD) and 5-aminosalicylic acid (5-ASA), by UV and UV/peroxydisulfate (UV/PDS) processes. Experimental results show that SPD and 5-ASA were readily degraded upon UV 254 nm direct photolysis, with quantum yields measured to be (8.6 ± 0.8) × 10 -3 and (2.4 ± 0.1) × 10 -2  mol Einstein -1 , respectively. Although SSZ was resistant to direct UV photolysis, it could be effectively removed by both UV/H 2 O 2 and UV/PDS processes, with fluence-based pseudo-first-order rate constants determined to be 0.0030 and 0.0038 cm 2  mJ -1 , respectively. Second-order rate constant between SO 4 •- and SSZ was measured as (1.33 ± 0.01) × 10 9  M -1 s -1 by competition kinetic method. A kinetic model was established for predicting the degradation rate of SSZ in the UV/PDS process. Increasing the dosage of PDS significantly enhanced the degradation of SSZ in the UV/PDS process, which can be well predicted by the developed kinetic model. Natural water constituents, such as natural organic matter (NOM) and bicarbonate (HCO 3 - ), influenced the degradation of SSZ differently. The azo functional group of SSZ molecule was predicted as the reactive site susceptible to electrophilic attack by SO 4 •- by frontier electron densities (FEDs) calculations. Four intermediate products arising from azo bond cleavage and SO 2 extrusion were identified by solid phase extraction-liquid chromatography-triple quadrupole mass spectrometry (SPE-LC-MS/MS). Based on the products identified, detailed transformation pathways for SSZ degradation in the UV/PDS system were proposed. Results reveal that UV/PDS could be an efficient approach for remediation of water

[Wavelength Selection in Hemolytic Evaluation Systems with Spectrophotometry Detection].

Science.gov (United States)

Zhang, Hong; Su, Baochang; Ye, Xunda; Luo, Man

2016-04-01

Spectrophotometry is a simple hemolytic evaluation method commonly used in new drugs,biomedical materials and blood products.It is for the quantitative analysis of the characteristic absorption peaks of hemoglobin.Therefore,it is essential to select the correct detection wavelength when the evaluation system has influences on the conformation of hemoglobin.Based on the study of changes in the characteristic peaks over time of the hemolysis supernatant in four systems,namely,cell culture medium,phosphate buffered saline(PBS),physiological saline and banked blood preservation solution,using continuous wavelength scanning,the selections of detection wavelength were proposed as follows.In the cell culture medium system,the wavelength of 415 nm should be selected within 4h;,near 408 nm should be selected within 4~72h.In PBS system,within 4h,541 nm,577nm or 415 nm should be selected;4~72h,541 nm,577nm or near 406 nm should be selected.In physiological saline system,within 4h,414 nm should be selected;4~72h,near 405 nm should be selected;within 12 h,541nm or 577 nm could also be selected.In banked blood preservation solution system,within 72 h,415nm,540 nm or 576 nm should be selected.

Combination of solid phase extraction and dispersive liquid–liquid microextraction for separation/preconcentration of ultra trace amounts of uranium prior to its fiber optic-linear array spectrophotometry determination

International Nuclear Information System (INIS)

Dadfarnia, Shayessteh; Shabani, Ali Mohammad Haji; Shakerian, Farid; Shiralian Esfahani, Golnaz

2013-01-01

Graphical abstract: Pass the sample through the basic alumina column ⇒ elute retained uranium along with the cations ⇒ convert the uranium to its anionic benzoate complex ⇒ extract its ion pair with malachite green into small volume of chloroform by DLLME ⇒ measure its absorption at 621 nm using fiber optic-linear array detection spectrophotometry. -- Highlights: • By combination of SPE and DDLME a high preconcentration factor of 2500 was obtained. • Development of SPE-DDLME-Spectrophotometric method for det. of trace amounts of uranium. • Ultra trace amount of uranium in water samples was det. by the proposed method. • The detection limit of the proposed method is comparable to the most sensitive method. • The proposed method is a free interference spectrophotometric method for uranium det. -- Abstract: A simple and sensitive method for the separation and preconcentration of the ultra trace amounts of uranium and its determination by spectrophotometry was developed. The method is based on the combination of solid phase extraction and dispersive liquid–liquid microextraction. Thus, by passing the sample through the basic alumina column, the uranyl ion and some cations are separated from the sample matrix. The retained uranyl ion along with the cations are eluted with 5 mL of nitric acid (2 mol L −1 ) and after neutralization of the eluent, the extracted uranyl ion is converted to its anionic benzoate complex and is separated from other cations by extraction of its ion pair with malachite green into small volume of chloroform using dispersive liquid–liquid microextraction. The amount of uranium is then determined by the absorption measurement of the extracted ion pair at 621 nm using flow injection spectrophotometry. Under the optimum conditions, with 500 mL of the sample, a preconcentration factor of 1980, a detection limit of 40 ng L −1 , and a relative standard deviation of 4.1% (n = 6) at 400 ng L −1 were obtained. The method was

Analysis of trace metals in sodium by flameless atomic absorption spectrophotometry

International Nuclear Information System (INIS)

Mahalingam, T.R.; Geetha, R.; Thiruvengadasamy, A.; Mathews, C.K.

1981-01-01

The estimation of trace metallic impurities in sodium is normally carried out by distilling off the sodium in vacuuum and analysing the residue by atomic absorption spectrophotometry (AAS). This paper describes the direct determination of the following impurities (viz.) Fe, Co, Ni, Cr, Mn, Ca, and Cu in sodium without going through the distillation step. Here sodium is simply dissolved and the solution is subjected to analysis by AAS using flameless atomisation in a graphite furnace. The method of standard additions is employed. Preliminary experiments were carried out to study the matrix effect of sodium on the atomic absorption of cobalt. It has been found that if pyrolysis is done at 1250 0 C for 20 seconds prior to atomisation, the bulk of the sodium nitrate matrix could be successfully removed. The use of the optimum pyrolysis temperatures for the various elements listed above and the matrix interference on the absorbances of these analytes are discussed in this paper. The precision and accuracy of our analytical procedure is also presented. (orig.)

Protocol for Determining Ultraviolet Light Emitting Diode (UV-LED) Fluence for Microbial Inactivation Studies.

Science.gov (United States)

Kheyrandish, Ataollah; Mohseni, Madjid; Taghipour, Fariborz

2018-06-15

Determining fluence is essential to derive the inactivation kinetics of microorganisms and to design ultraviolet (UV) reactors for water disinfection. UV light emitting diodes (UV-LEDs) are emerging UV sources with various advantages compared to conventional UV lamps. Unlike conventional mercury lamps, no standard method is available to determine the average fluence of the UV-LEDs, and conventional methods used to determine the fluence for UV mercury lamps are not applicable to UV-LEDs due to the relatively low power output, polychromatic wavelength, and specific radiation profile of UV-LEDs. In this study, a method was developed to determine the average fluence inside a water suspension in a UV-LED experimental setup. In this method, the average fluence was estimated by measuring the irradiance at a few points for a collimated and uniform radiation on a Petri dish surface. New correction parameters were defined and proposed, and several of the existing parameters for determining the fluence of the UV mercury lamp apparatus were revised to measure and quantify the collimation and uniformity of the radiation. To study the effect of polychromatic output and radiation profile of the UV-LEDs, two UV-LEDs with peak wavelengths of 262 and 275 nm and different radiation profiles were selected as the representatives of typical UV-LEDs applied to microbial inactivation. The proper setup configuration for microorganism inactivation studies was also determined based on the defined correction factors.

UV Reconstruction Algorithm And Diurnal Cycle Variability

Science.gov (United States)

Curylo, Aleksander; Litynska, Zenobia; Krzyscin, Janusz; Bogdanska, Barbara

2009-03-01

UV reconstruction is a method of estimation of surface UV with the use of available actinometrical and aerological measurements. UV reconstruction is necessary for the study of long-term UV change. A typical series of UV measurements is not longer than 15 years, which is too short for trend estimation. The essential problem in the reconstruction algorithm is the good parameterization of clouds. In our previous algorithm we used an empirical relation between Cloud Modification Factor (CMF) in global radiation and CMF in UV. The CMF is defined as the ratio between measured and modelled irradiances. Clear sky irradiance was calculated with a solar radiative transfer model. In the proposed algorithm, the time variability of global radiation during the diurnal cycle is used as an additional source of information. For elaborating an improved reconstruction algorithm relevant data from Legionowo [52.4 N, 21.0 E, 96 m a.s.l], Poland were collected with the following instruments: NILU-UV multi channel radiometer, Kipp&Zonen pyranometer, radiosonde profiles of ozone, humidity and temperature. The proposed algorithm has been used for reconstruction of UV at four Polish sites: Mikolajki, Kolobrzeg, Warszawa-Bielany and Zakopane since the early 1960s. Krzyscin's reconstruction of total ozone has been used in the calculations.

USO DA ESPECTROFOTOMETRIA UV-VIS PARA DIFERENCIAR AS COLORAÇÕES DO BIODIESEL DE PALMA E DO CORANTE MARCADOR DE ÓLEO DIESEL

Directory of Open Access Journals (Sweden)

Maria S. M. Quintino

Full Text Available Currently, there are two mixtures of biodiesel/diesel fuel sold in Brazil: BX/S500 and BX /S10 (X = volume/volume biodiesel percentage; S500 and S10 = sulfur content in diesel fuels - 500 ppm and 10 ppm, respectively. In order to differentiate these mixtures, red dye is added to diesel oil as required by the National Agency for Petroleum, Natural Gas and Biofuels (ANP, regulatory agency in Brazil. Since the palm oil biodiesel has also a reddish color, mixing this product with diesel fuel leads to difficulty in visual differentiation of the mixtures BX/S500 and BX/S10. We propose the use of UV-Vis spectrophotometry, which is a low cost, simple and rapid technique. Spectra obtained for different mixtures show that qualitative distinction is possible. For quantification of red dye in the presence of palm oil biodiesel, the method is limited when dye is present in low concentrations (< 0.1 mg L-1 due to matrix effects. The method showed good repeatability of the absorbance responses, wide linear dynamic range (0.02 mg L-1 to 40.00 mg L-1 and low limits of detection and quantification (0.006 mg L-1 and 0.019 mg L-1, respectively.

Comparative study between derivative spectrophotometry and multivariate calibration as analytical tools applied for the simultaneous quantitation of Amlodipine, Valsartan and Hydrochlorothiazide.

Science.gov (United States)

Darwish, Hany W; Hassan, Said A; Salem, Maissa Y; El-Zeany, Badr A

2013-09-01

Four simple, accurate and specific methods were developed and validated for the simultaneous estimation of Amlodipine (AML), Valsartan (VAL) and Hydrochlorothiazide (HCT) in commercial tablets. The derivative spectrophotometric methods include Derivative Ratio Zero Crossing (DRZC) and Double Divisor Ratio Spectra-Derivative Spectrophotometry (DDRS-DS) methods, while the multivariate calibrations used are Principal Component Regression (PCR) and Partial Least Squares (PLSs). The proposed methods were applied successfully in the determination of the drugs in laboratory-prepared mixtures and in commercial pharmaceutical preparations. The validity of the proposed methods was assessed using the standard addition technique. The linearity of the proposed methods is investigated in the range of 2-32, 4-44 and 2-20 μg/mL for AML, VAL and HCT, respectively. Copyright © 2013 Elsevier B.V. All rights reserved.

A method for optimizing the cosine response of solar UV diffusers

Science.gov (United States)

Pulli, Tomi; Kärhä, Petri; Ikonen, Erkki

2013-07-01

Instruments measuring global solar ultraviolet (UV) irradiance at the surface of the Earth need to collect radiation from the entire hemisphere. Entrance optics with angular response as close as possible to the ideal cosine response are necessary to perform these measurements accurately. Typically, the cosine response is obtained using a transmitting diffuser. We have developed an efficient method based on a Monte Carlo algorithm to simulate radiation transport in the solar UV diffuser assembly. The algorithm takes into account propagation, absorption, and scattering of the radiation inside the diffuser material. The effects of the inner sidewalls of the diffuser housing, the shadow ring, and the protective weather dome are also accounted for. The software implementation of the algorithm is highly optimized: a simulation of 109 photons takes approximately 10 to 15 min to complete on a typical high-end PC. The results of the simulations agree well with the measured angular responses, indicating that the algorithm can be used to guide the diffuser design process. Cost savings can be obtained when simulations are carried out before diffuser fabrication as compared to a purely trial-and-error-based diffuser optimization. The algorithm was used to optimize two types of detectors, one with a planar diffuser and the other with a spherically shaped diffuser. The integrated cosine errors—which indicate the relative measurement error caused by the nonideal angular response under isotropic sky radiance—of these two detectors were calculated to be f2=1.4% and 0.66%, respectively.

Electrochemical methods as a tool for determining the antioxidant capacity of food and beverages: A review.

Science.gov (United States)

Hoyos-Arbeláez, Jorge; Vázquez, Mario; Contreras-Calderón, José

2017-04-15

The growing interest in functional foods had led to the use of analytical techniques to quantify some properties, among which is the antioxidant capacity (AC). In order to identify and quantify this capacity, some techniques are used, based on synthetic radicals capture; and they are monitored by UV-vis spectrophotometry. Electrochemical techniques are emerging as alternatives, given some of the disadvantages faced by spectrophotometric methods such as the use of expensive reagent not environmentally friendly, undefined reaction time, long sample pretreatment, and low precision and sensitivity. This review focuses on the four most commonly used electrochemical techniques (cyclic voltammetry, differential pulse voltammetry, square wave voltammetry and chronoamperometry). Some of the applications to determine AC in foods and beverages are presented, as well as the correlation between both spectrophotometric and electrochemical techniques that have been reported. Copyright © 2016 Elsevier Ltd. All rights reserved.

Thin film thickness measurement error reduction by wavelength selection in spectrophotometry

International Nuclear Information System (INIS)

Tsepulin, Vladimir G; Perchik, Alexey V; Tolstoguzov, Victor L; Karasik, Valeriy E

2015-01-01

Fast and accurate volumetric profilometry of thin film structures is an important problem in the electronic visual display industry. We propose to use spectrophotometry with a limited number of working wavelengths to achieve high-speed control and an approach to selecting the optimal working wavelengths to reduce the thickness measurement error. A simple expression for error estimation is presented and tested using a Monte Carlo simulation. The experimental setup is designed to confirm the stability of film thickness determination using a limited number of wavelengths

Analytical method for the determination of cyromazine and melamine residues in soil using LC-UV and GC-MSD.

Science.gov (United States)

Yokley, R A; Mayer, L C; Rezaaiyan, R; Manuli, M E; Cheung, M W

2000-08-01

A method is reported for the determination of cyromazine and melamine residues in soil. Soil samples are extracted twice via mechanical shaking, each time with 70% acetonitrile/30% 0.050 M ammomium carbonate for 30 min. An aliquot portion of the pooled extracts is subjected to strong cation exchange (SCX) purification on AG 50W-X4 resin. Final analysis is accomplished using liquid chromatography-ultraviolet (LC-UV) detection at a wavelength of 214 nm. Confirmatory analyses can be performed using gas chromatography-mass selective detection (GC-MSD) in the selected ion monitoring (SIM) mode. The limit of detection (LOD) is 2.5 ng injected and the limit of quantification (LOQ) is 10 ppb when using LC-UV for the analysis of N-cyclopropyl-1,3,5-triazine-2,4, 6-triamine (cyromazine) and 1,3,5-triazine-2,4,6-triamine (melamine). The LOD is 0.050 ng injected and the LOQ is 10 ppb when using GC-MSD for confirmatory analyses. The mean procedural recoveries were 97 and 95% and the standard deviations were 16 and 11% for cyromazine and melamine, respectively (n = 24), when using LC-UV. The mean procedural recoveries were 107 and 92% and the standard deviations were 9.9 and 16% for cyromazine and melamine, respectively (n = 29), when using GC-MSD. The method validation study was conducted under U.S. EPA FIFRA Good Laboratory Practice Guidelines 40 CFR 160. The method also passed an Independent Laboratory Validation (ILV) as per U.S. EPA FIFRA Subdivision N.

Derivative Quotient Spectrophotometry and an Eco-Friendly Micellar Chromatographic Approach with Time-Programmed UV-Detection for the Separation of Two Fluoroquinolones and Phenazopyridine

Science.gov (United States)

Tolba, Manar M.; Salim, Mohamed M.

2016-01-01

In this study, two analytical approaches were exploited for the resolution of binary mixtures of ciprofloxacin HCl (CIP) or norfloxacin (NOR) and phenazopyridine HCl (PHZ). In the first approach, the amplitudes of the first derivative of the ratio spectra were measured at 267 or 287 nm for CIP and at 268 or 291 nm for NOR. PHZ could be directly determined in the presence of CIP or NOR at 405 nm. The calibration graphs were rectilinear over the ranges of 1.0–16.0 µg/mL for CIP or NOR and 1.0–10.0 µg/mL for PHZ. In the second approach, an accurate, reliable and environmentally nontoxic micellar liquid chromatographic (MLC) method was developed. A good chromatographic separation was achieved using a 150 mm × 4.6 mm i.d., 5 µm particle size Spherisorb ODS-2 column. Eco-friendly mobile phase containing 0.12 M sodium dodecyl sulphate, 0.3% triethylamine and 6% n-butanol in 0.02 M orthophosphoric acid of pH 3.0 was pumped at a flow rate of 1 mL/min. Time programmed UV-detection was applied to allow sensitive determination of the studied drugs. The analytes were eluted without interferences in <10 min. Methocarbamol was used as an internal standard. The MLC method was found to be rectilinear over the concentration range of 0.5–20.0 μg/mL for CIP, NOR or PHZ. These optimized and validated methods were successfully applied for the simultaneous analysis of the studied drugs in their synthetic mixtures and co-formulated tablets. Moreover, the second method was further extended to the determination of these drugs in human urine with direct injection and without any pretreatment. PMID:26867555

An improved UHPLC-UV method for separation and quantification of carotenoids in vegetable crops.

Science.gov (United States)

Maurer, Megan M; Mein, Jonathan R; Chaudhuri, Swapan K; Constant, Howard L

2014-12-15

Carotenoid identification and quantitation is critical for the development of improved nutrition plant varieties. Industrial analysis of carotenoids is typically carried out on multiple crops with potentially thousands of samples per crop, placing critical needs on speed and broad utility of the analytical methods. Current chromatographic methods for carotenoid analysis have had limited industrial application due to their low throughput, requiring up to 60 min for complete separation of all compounds. We have developed an improved UHPLC-UV method that resolves all major carotenoids found in broccoli (Brassica oleracea L. var. italica), carrot (Daucus carota), corn (Zea mays), and tomato (Solanum lycopersicum). The chromatographic method is completed in 13.5 min allowing for the resolution of the 11 carotenoids of interest, including the structural isomers lutein/zeaxanthin and α-/β-carotene. Additional minor carotenoids have also been separated and identified with this method, demonstrating the utility of this method across major commercial food crops. Copyright © 2014 Elsevier Ltd. All rights reserved.

Direct imaging and spectrophotometry of Comet P/Tempel 2

International Nuclear Information System (INIS)

Boehnhardt, H.; Beisser, K.; Vanysek, V.; Mueller, B.E.A.; Weiss, M.

1990-01-01

Both direct imaging and spectrophotometry of Comet P/Tempel 2 during May-November 1988 have led to a nuclear diameter determination of the order of about 10 km. Sekanina's (1987) spin-vector model for this comet is judged capable of qualitatively accounting for both the visual light curve of the comet during this period, which exhibited a steep increase perihelion despite the normal, moderate-decrease perihelion, and an asymmetric extension of the fanlike coma in the solar direction. The late activity onset, the possible constant visual brightness immediately afterward, and the deviation of the fan axis orientation from the predicted value in May 1988, may all furnish additional constraints for P/Tempel 2 nucleus modeling. 24 refs

Diurnal changes in epidermal UV transmittance of plants in naturally high UV environments.

Science.gov (United States)

Barnes, Paul W; Flint, Stephan D; Slusser, James R; Gao, Wei; Ryel, Ronald J

2008-06-01

Studies were conducted on three herbaceous plant species growing in naturally high solar UV environments in the subalpine of Mauna Kea, Hawaii, USA, to determine if diurnal changes in epidermal UV transmittance (T(UV)) occur in these species, and to test whether manipulation of the solar radiation regime could alter these diurnal patterns. Additional field studies were conducted at Logan, Utah, USA, to determine if solar UV was causing diurnal T(UV) changes and to evaluate the relationship between diurnal changes in T(UV) and UV-absorbing pigments. Under clear skies, T(UV), as measured with a UV-A-pulse amplitude modulation fluorometer for leaves of Verbascum thapsus and Oenothera stricta growing in native soils and Vicia faba growing in pots, was highest at predawn and sunset and lowest at midday. These patterns in T(UV) closely tracked diurnal changes in solar radiation and were the result of correlated changes in fluorescence induced by UV-A and blue radiation but not photochemical efficiency (F(v)/F(m)) or initial fluorescence yield (F(o)). The magnitude of the midday reduction in T(UV) was greater for young leaves than for older leaves of Verbascum. Imposition of artificial shade eliminated the diurnal changes in T(UV) in Verbascum, but reduction in solar UV had no effect on diurnal T(UV) changes in Vicia. In Vicia, the diurnal changes in T(UV) occurred without detectable changes in the concentration of whole-leaf UV-absorbing compounds. Results suggest that plants actively control diurnal changes in UV shielding, and these changes occur in response to signals other than solar UV; however, the underlying mechanisms responsible for rapid changes in T(UV) remain unclear.

Standardisation Study of Kwatha Curnas

Directory of Open Access Journals (Sweden)

M. K. Santosh

2004-01-01

Full Text Available The present paper deals with the standardization of kwatha curnas such as dhanyapanchak kwatha curna, guduchyadigana kwatha curna and stanyajanankashaya curna. These are the important Ayurvedic formulations used for peri-natal care of mother and child health. Standardization of kwatha curnas were achieved by physico-chemical analysis, qualitative inorganic and organic analysis, thin layer chromatography (TLC, UV- visible spectrophotometry and high performance liquid chromatographic (HPLC fingerprint studies. TLC study of kwatha curnas was carried out in Ethyl acetate: Methanol: Water solvent system. Ethanol extracts of kwatha curnas were used for UV- visible spectrophotometry and qualitative HPLC fingerprint study.

H-point standard additions method for simultaneous determination of sulfamethoxazole and trimethoprim in pharmaceutical formulations and biological fluids with simultaneous addition of two analytes

Science.gov (United States)

Givianrad, M. H.; Saber-Tehrani, M.; Aberoomand-Azar, P.; Mohagheghian, M.

2011-03-01

The applicability of H-point standard additions method (HPSAM) to the resolving of overlapping spectra corresponding to the sulfamethoxazole and trimethoprim is verified by UV-vis spectrophotometry. The results show that the H-point standard additions method with simultaneous addition of both analytes is suitable for the simultaneous determination of sulfamethoxazole and trimethoprim in aqueous media. The results of applying the H-point standard additions method showed that the two drugs could be determined simultaneously with the concentration ratios of sulfamethoxazole to trimethoprim varying from 1:18 to 16:1 in the mixed samples. Also, the limits of detections were 0.58 and 0.37 μmol L -1 for sulfamethoxazole and trimethoprim, respectively. In addition the means of the calculated RSD (%) were 1.63 and 2.01 for SMX and TMP, respectively in synthetic mixtures. The proposed method has been successfully applied to the simultaneous determination of sulfamethoxazole and trimethoprim in some synthetic, pharmaceutical formulation and biological fluid samples.

Development, validation and comparison of two stability-indicating RP-LC methods using charged aerosol and UV detectors for analysis of lisdexamfetamine dimesylate in capsules

Directory of Open Access Journals (Sweden)

Graciela Carlos

2016-11-01

Full Text Available Two new stability-indicating liquid chromatographic methods using two detectors, an ultraviolet (UV and a charged aerosol detector (CAD simultaneously connected in series were validated for the assessment of lisdexamfetamine dimesylate (LDX in capsule. The method was optimized and the influence of individual parameters on UV and CAD response and sensitivity was studied. Chromatography was performed on a Zorbax CN column (250 mm × 4.6 mm, 5 μm in an isocratic elution mode, using acetonitrile and 20 mM ammonium formate at pH 4.0 (50:50, v/v as mobile phase and UV detection at 207 nm. The developed method was validated according to ICH guidelines and the parameters’ specificity, limit of detection, limit of quantitation, linearity, accuracy, precision and robustness were evaluated. CAD is designated to be a non-linear detector in a wide dynamic range, however, the method was linear over the concentration range of 70–130 μg mL−1 in both detectors. The method was precise and accurate. Robustness study was performed by a Plackett–Burman design, delivering results within the acceptable range. Neither the excipients nor the degradation products showed interference in the method after studies of specificity as well as under stress conditions. The results of the LC-UV and LC-CAD methods were statistically compared through ANOVA and showed no significant difference (p > 0.05. Both proposed methods could be considered interchangeable and stability-indicating, and can be applied as an appropriate quality control tool for routine analysis of LDX in capsule.

Co-ordinated ozone and UV project COZUV

International Nuclear Information System (INIS)

Braathen, Geir

1999-01-01

The project encompasses all the major Norwegian research groups in the field of stratospheric ozone and UV research. the duration is from the 1st January 1999 to the 31st December 2000. The tasks carried out will include investigations of the ozone layer over the North Polar and middle latitudes, 3-D chemical modelling, diagnosis of chemical ozone loss, investigations of transport mechanisms between the polar vortex and middle latitudes, study of the coupling between ozone change and climate change in the stratosphere and upper troposphere, scenario calculations in order to investigate the consequences of temperature change in the stratosphere, development of methods to measure global, direct and radiance distribution of UV, to improve UV dose calculations, investigate the influence of clouds on the surface UV radiation and to use existing surface UV radiation measurements together with existing radiation models to investigate the connection between UV radiation and ozone, clouds and surface albedo. The results will be published in various publications, progress reports, by participation in international conferences, through information to the environmental authorities and through information on the Internet

Film Formation of Ag Nanoparticles at the Organic-Aqueous Liquid Interface

Science.gov (United States)

Vigorita, John

2005-03-01

A wet-chemical method to make films by spontaneous assembly of passivated Ag nanoparticles at the organic-aqueous liquid interface is presented. The interfacial films exhibit a blue opalescence, or in other cases a silvery color, and are characterized with transmission electron microscopy and UV-visible spectrophotometry. Measurements indicate that nanoparticles in the interfacial film can form superlattices and in some cases nanostructures.

Inactivation efficiency of plasmid-encoded antibiotic resistance genes during water treatment with chlorine, UV, and UV/H2O2.

Science.gov (United States)

Yoon, Younggun; Chung, Hay Jung; Wen Di, Doris Yoong; Dodd, Michael C; Hur, Hor-Gil; Lee, Yunho

2017-10-15

This study assessed the inactivation efficiency of plasmid-encoded antibiotic resistance genes (ARGs) both in extracellular form (e-ARG) and present within Escherichia coli (intracellular form, i-ARG) during water treatment with chlorine, UV (254 nm), and UV/H 2 O 2 . A quantitative real-time PCR (qPCR) method was used to quantify the ARG damage to amp R (850 bp) and kan R (806 bp) amplicons, both of which are located in the pUC4K plasmid. The plate count and flow cytometry methods were also used to determine the bacterial inactivation parameters, such as culturability and membrane damage, respectively. In the first part of the study, the kinetics of E. coli inactivation and ARG damage were determined in phosphate buffered solutions. The ARG damage occurred much more slowly than E. coli inactivation in all cases. To achieve 4-log reduction of ARG concentration at pH 7, the required chlorine exposure and UV fluence were 33-72 (mg × min)/L for chlorine and 50-130 mJ/cm 2 for UV and UV/H 2 O 2 . After increasing pH from 7 to 8, the rates of ARG damage decreased for chlorine, while they did not vary for UV and UV/H 2 O 2 . The i-ARGs mostly showed lower rates of damage compared to the e-ARGs due to the protective roles of cellular components against oxidants and UV. The contribution of OH radicals to i-ARG damage was negligible in UV/H 2 O 2 due to significant OH radical scavenging by cellular components. In all cases, the ARG damage rates were similar for amp R versus kan R , except for the chlorination of e-ARGs, in which the damage to amp R occurred faster than that to kan R . Chlorine and UV dose-dependent ARG inactivation levels determined in a wastewater effluent matrix could be reasonably explained by the kinetic data obtained from the phosphate buffered solutions and the expected oxidant (chlorine and OH radicals) demands by water matrix components. These results can be useful in optimizing chlorine and UV-based disinfection systems to achieve ARG

A Facile, Nonreactive Hydrogen Peroxide (H2O2) Detection Method Enabled by Ion Chromatography with UV Detector.

Science.gov (United States)

Song, Mingrui; Wang, Junli; Chen, Baiyang; Wang, Lei

2017-11-07

Hydrogen peroxide (H 2 O 2 ) is ubiquitous in the natural environment, and it is now widely used for pollutant control in water and wastewater treatment processes. However, current analytical methods for H 2 O 2 inevitably require reactions between H 2 O 2 and other reactants to yield signals and are thus likely subjective to the interferences of coexisting colored, oxidative, and reductive compounds. In order to overcome these barriers, we herein for the first time propose to analyze H 2 O 2 by ion chromatography (IC) using an ultraviolet (UV) detector. The proposal is based on two principles: first, that H 2 O 2 can deprotonate to hydroperoxyl ion (HO 2 - ) when eluent pH is higher than the acid-dissociation coefficient of H 2 O 2 (pK a = 11.6); and second, that after separation from other compounds via IC column, H 2 O 2 can be quantified by a UV detector. Under favorable operating conditions, this method has successfully achieved acceptable recoveries (>91%) of H 2 O 2 dosed to ultrapure and natural waters, a calibration curve with R 2 > 0.99 for a wide range of H 2 O 2 concentrations from 0.1 to 50 mg/L and a method detection limit of 0.027 mg/L. In addition, this approach was shown to be capable of distinguishing H 2 O 2 from anions (e.g., fluoride and chloride) and organics (e.g., glycolate) and monochloramine, suggesting that it is insensitive to many neighboring compounds as long as they do not react quickly with H 2 O 2 . Hence, this study proves the combination of IC and UV detector a facile and reliable method for H 2 O 2 measurement.

Knowledge of outdoor workers on the effects of natural UV radiation and methods of protection against exposure.

Science.gov (United States)

Hault, K; Rönsch, H; Beissert, S; Knuschke, P; Bauer, A

2016-04-01

The most important but influenceable risk factor in the development of skin cancer is the unprotected exposure to solar ultraviolet (UV) radiation. In order to assure adequate and effective protection against UV exposure, a level of knowledge about solar radiation and its effects is required. The objective of this study was to assess the knowledge of workers in outdoor professions on the effects of natural UV radiation and methods of protection against exposure. Forty outdoor workers were given a standardized questionnaire designed to ascertain their level of knowledge. The majority of participants knew exposure to solar radiation can be detrimental depending on exposure time. Eighty-three percentage recognized that people working regularly in an outdoor environment may be at risk due to high exposure. Long-sleeved clothing plus headgear and sunscreen containing sun-protecting substances were deemed adequate methods of protection by 83% and 85% respectively. Seventy percentage of the outdoor workers were familiar with the definition of the sun protection factor (SPF), yet only 25% correctly identified the amount of sunscreen needed to achieve the SPF as indicated on the product. A mere 8% of participants knew that symptoms of a sunburn first became apparent 3 h after sun exposure and only 18% were able to accurately gauge the amount of time they could spend in the sun before developing one. Although 30% had heard of the ultraviolet index (UVI), only 13% understood that protecting your skin using additional measures is recommended as of UVI 3. Overall, 30% of the outdoor workers thought themselves sufficiently protected against the harmful effects of the sun. While the participants of this study had a basic fundamental understanding of the effects of solar radiation and methods of protection against exposure, there remains an urgent need for further clarification across all demographic groups. © 2016 European Academy of Dermatology and Venereology.

Water and Wastewater Disinfection with Peracetic Acid and UV Radiation and Using Advanced Oxidative Process PAA/UV

OpenAIRE

Beber de Souza, Jeanette; Queiroz Valdez, Fernanda; Jeranoski, Rhuan Felipe; Vidal, Carlos Magno de Sousa; Cavallini, Grasiele Soares

2015-01-01

The individual methods of disinfection peracetic acid (PAA) and UV radiation and combined process PAA/UV in water (synthetic) and sanitary wastewater were employed to verify the individual and combined action of these advanced oxidative processes on the effectiveness of inactivation of microorganisms indicators of fecal contamination E. coli, total coliforms (in the case of sanitary wastewater), and coliphages (such as virus indicators). Under the experimental conditions investigated, doses o...

Optical imagery and spectrophotometry of CTB 80

Science.gov (United States)

Hester, J. Jeff; Kulkarni, Shrinivas R.

1989-01-01

Narrow-band imagery and spectrophotometry of the central region of CTB 80 are presented. The images show weak forbidden O III and ubiquitous filamentary forbidden S II and H-alpha emission from the extended radio lobes in which the core is embedded. The data indicate that the extended component is shock heated. Balmer line-dominated emission is observed around the perimeter of the core. Assuming that the volume of the radio shell is similar to the volume of the thermal shell, it is found that a magnetic field of about 600 microG and a cosmic-ray proton-to-electron ratio of about 200 are required to explain the pressure and synchrotron volume emissivity in the radio shell. It is suggested that the optical emission form the core of CTB 80 arises behind shocks which are being driven into a magnetized thermal plasma by the confined relativistic wind from PSR 1951+32.

Determination of humic acid in alkali leaching solution of uranium by spectophotrometry-COD method

International Nuclear Information System (INIS)

Feng Yu; An Wei; Chen Shusen

2014-01-01

It is one of the main causes of extraction emulsification or resin toxicosis during alkali leaching process in uranium metallurgy which organic matters including humic acid exist in lixiviums. In order to study the effect of humic acid in uranium metallurgy, a method for determination of content of humic acid in aqueous solution need to be established. Spectrophotometry is a simple and convenient method in humic acid analysis. However, accuracy of spectrophotometry can be reduced greatly because of interference of uranium and other elements in the humic acid solutions. Although chemical oxygen demand (COD) method is a common analysis way of organic matters in aqueous solutions, the concentration of humic acid cannot be directly measured. In this paper, COD method is related with spectrophotometry to avoid the interference of uranium and ensure the accurate analysis of humic acid. The results showed that the detection limit of the method was 1.78 mg/L and the recovery rate was 101.2%. (authors)

Symbiotic stars: spectrophotometry at 3-4 and 8-13 μm

International Nuclear Information System (INIS)

Roche, P.F.; Aitken, D.K.

1983-01-01

Infrared spectrophotometry of 20 symbiotic stars, mostly of dust-rich variety, is presented. HDE 330036 is unique in showing an emission feature at 11.3 μm. The remainder combine a hot grey component and/or optically thin silicate emission. A model in which the grey component is due to optically thick silicate dust is not consistent with the spectra. It is proposed instead that iron-based grains, expected to form in the ejecta of cool stars, are heated by the ultraviolet radiation field of the hot companion. (author)

Spectral and spectral-frequency methods of investigating atmosphereless bodies of the Solar system

International Nuclear Information System (INIS)

Busarev, Vladimir V; Prokof'eva-Mikhailovskaya, Valentina V; Bochkov, Valerii V

2007-01-01

A method of reflectance spectrophotometry of atmosphereless bodies of the Solar system, its specificity, and the means of eliminating basic spectral noise are considered. As a development, joining the method of reflectance spectrophotometry with the frequency analysis of observational data series is proposed. The combined spectral-frequency method allows identification of formations with distinctive spectral features, and estimations of their sizes and distribution on the surface of atmospherelss celestial bodies. As applied to investigations of asteroids 21 Lutetia and 4 Vesta, the spectral frequency method has given us the possibility of obtaining fundamentally new information about minor planets. (instruments and methods of investigation)

In situ deposition of graphene nanosheets on wood surface by one-pot hydrothermal method for enhanced UV-resistant ability

International Nuclear Information System (INIS)

Wan, Caichao; Jiao, Yue; Li, Jian

2015-01-01

Graphical abstract: - Highlights: • The graphene/wood nanocomposites were fabricated via a mild fast one-pot hydrothermal method. • Graphene nanosheets were in situ deposited on the surface of the wood matrix. • The incorporation of graphene nanosheets results in the improvement in the thermal stability of the graphene/wood. • The graphene/wood exhibits superior UV resistance performance. - Abstract: Graphene nanosheets were successfully in situ deposited on the surface of the wood matrix via a mild fast one-pot hydrothermal method, and the resulting hybrid graphene/wood (GW) were characterized by scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Raman spectroscopy, and thermogravimetric analysis (TGA). According to the results, the wood matrix was evenly coated by dense uninterrupted multilayer graphene membrane structure, which was formed by layer-by-layer self-assembly of graphene nanosheets. Meanwhile, the graphene coating also induced significant improvement in the thermal stability of GW in comparison with that of the original wood (OW). Accelerated weathering tests were employed to measure and determine the UV-resistant ability of OW and GW. After about six hundred hours of experiments, the surface color change of GW was much less than that of OW; besides, the Fourier transform infrared spectroscopy (FTIR) analysis also proved the less significant changes in surface chemical compositions of GW. The results both indicated that the graphene coating effectively protected wood surface from UV damage. Therefore, this class of GW composite might be expected to be served as high-performance wooden building material for outdoor or some particular harsh environments like strong UV radiation regions use

Desenvolvimento e validação de método analítico para determinação do teor de sinvastatina em cápsulas magistrais

Directory of Open Access Journals (Sweden)

Hudson Caetano Polonini

2011-01-01

Full Text Available Simvastatin is an oral anti-hyperlipidemic that has been widely used to reduce the cardiovascular disease risk. There isn't any pharmacopoeic method to assay this drug in capsules. It was proposed and validated a method for determining the content of simvastatin in capsules by UV/visible spectrophotometry (l = 237 nm, a more affordable method for the compounding pharmacy. The method was validated for linearity, specificity, range, accuracy, precision, performance, robustness, and limits of detection and quantification.

Environmental samples analysis by Atomic Absorption Spectrophotometry and Inductively Coupled Plasma-Optical Emission Spectroscopy

International Nuclear Information System (INIS)

Popescu, I.V.; Iordan, M.; Stihi, C.; Bancuta, A.; Busuioc, G.; Dima, G.; Ciupina, V.; Belc, M.; Vlaicu, Gh.; Marian, R.

2002-01-01

Biological samples are interesting from many aspects of environmental monitoring. By analyzing tree leaves conclusions can be drown regarding the metal loading in the growth medium. So that, starting from assumption that the pollution factors from environmental medium can modify the normal concentration of elements, we decided to control the presence of toxic elements and the deviation from normal state of elements in leaves of different trees from areas situated at different distances of pollution source. The aim of this work is to determine the elemental composition of tree leaves using Atomic Absorption Spectrophotometry (AAS) method and Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES) method. Using AAS spectrophotometer SHIMADZU we identified and determined the concentration of: Cd, Co, Cu, Zn, Mn, Cr, Fe, Se, Pb with an instrumental error less than 1% for most of the elements analyzed. The same samples were analyzed by ICP-OES spectrometer, BAIRD ICP2070-Sequential Plasma spectrometer. We identified and determined in leaves of different trees the concentration of Mg, Ca, and Sr with a precision less than 6%. (authors)

Environmental occurrence and distribution of organic UV stabilizers and UV filters in the sediment of Chinese Bohai and Yellow Seas.

Science.gov (United States)

Apel, Christina; Tang, Jianhui; Ebinghaus, Ralf

2018-04-01

Organic UV stabilizers and UV filters are applied to industrial materials and cosmetics worldwide. In plastics they prevent photo-induced degradation, while in cosmetics they protect human skin against harmful effects of UV radiation. This study reports on the occurrence and distribution of organic UV stabilizers and UV filters in the surface sediment of the Chinese Bohai and Yellow Seas for the first time. In total, 16 out of 21 analyzed substances were positively detected. Concentrations ranged from sub-ng/g dw to low ng/g dw. The highest concentration of 25 ng/g dw was found for octocrylene (OC) in the Laizhou Bay. In the study area, characteristic composition profiles could be identified. In Korea Bay, the dominating substances were OC and ethylhexyl salicylate (EHS). All other analytes were below their method quantification limit (MQL). Around the Shandong Peninsula, highest concentrations of benzotriazole derivatives were observed in this study with octrizole (UV-329) as the predominant compound, reaching concentrations of 6.09 ng/g dw. The distribution pattern of UV-329 and bumetrizole (UV-326) were related (Pearson correlation coefficient r > 0.98, p « 0.01 around the Shandong Peninsula), indicating an identical input pathway and similar environmental behavior. Copyright © 2017 Elsevier Ltd. All rights reserved.

Optical fiber couplers for spectrophotometry. Perspectives for in-situ on-line and remote measurements

International Nuclear Information System (INIS)

Boisde, G.; Linger, C.; Chevalier, G.; Perez, J.J.

1983-01-01

Optical fiber couplers have been developed specially for nuclear chemical spectrophotometric applications. Coupling devices are described for TELEPHOT industrial photometers and some commercial spectrophotometer, together with the probes and measurement cells employed. The value of optical multiplexing is mentioned. Non nuclear applications in medical analysis are also mentioned, together with the possibilities offered by these devices for uses other than spectrophotometry [fr

Determination of Lead and Cadmium in environment materials from the planned area for a nuclear power plant by atomic absorption spectrophotometry method

International Nuclear Information System (INIS)

Supriyanto, C; Djokowidodo; Isyuniarto; Heri-Wahyudi; Ashar-Andrianto

1996-01-01

The determination of Pb and Cd in environment materials (water, cassava leaves and soil) have been done by atomic absorption spectrophotometry method, The determination of Pb and Cd was done with graphite tube atomizer (GTA) method at optimum condition : wavelength for Pb and Cd 217.0 nm and 228.8 nm; temperature/time ashing 550 o C/37 sec and 350 o C/52 sec; temperature/time atomizing 2000 o C/5.1 sec and 2000 o C/5.2 sec. Modifier for Pb was 3 μL of Mg 1000 μg/ml and Cd was 2 μL of Pd 2000 μg/ml. The content Pb in Spalun river, Hulu Putih river and sea water Lemah Abang was 0.94 ± 0.03; 0.91± 0.02; 4.71 ± 0.26 ng/ml respectively; the Cd content was 1.23 ± 0.11; 0.48 ± 0.01; 0.55 ± 0.01 ng/ml respectively. The Pb dan Cd content in cassava leaves was 163.24 ± 3.72 and 18.45 ± 1.46 ng/g respectively, while the Pb content in soil at the depth variation 0 - 5, 5 - 10, 10 - 20 and 20 - 30 Cm was 2.35 ± 0.15; 2.86 ± 0.16; 1.97 ± 0.11 and 2.19 ± 0.06 μg/g respectively and the Cd content was 43.67 ± 1.52; 37.01 ± 1.01; 31.68 ± 0.17 and 36.97 ± 1.63 ng/g respectively. SRM Citrous leaves from NSB and SRM Soil 7 from the IAEA local used to control the quality of the analyzed method. The Pb, Cd content in SRM was in accordance with the value in the certified legend

Determination of diethyl phthalate and polyhexamethylene guanidine in surrogate alcohol from Russia.

Science.gov (United States)

Monakhova, Yulia B; Kuballa, Thomas; Leitz, Jenny; Lachenmeier, Dirk W

2011-01-01

Analytical methods based on spectroscopic techniques were developed and validated for the determination of diethyl phthalate (DEP) and polyhexamethylene guanidine (PHMG), which may occur in unrecorded alcohol. Analysis for PHMG was based on UV-VIS spectrophotometry after derivatization with Eosin Y and (1)H NMR spectroscopy of the DMSO extract. Analysis of DEP was performed with direct UV-VIS and (1)H NMR methods. Multivariate curve resolution and spectra computation methods were used to confirm the presence of PHMG and DEP in the investigated beverages. Of 22 analysed alcohol samples, two contained DEP or PHMG. (1)H NMR analysis also revealed the presence of signals of hawthorn extract in three medicinal alcohols used as surrogate alcohol. The simple and cheap UV-VIS methods can be used for rapid screening of surrogate alcohol samples for impurities, while (1)H NMR is recommended for specific confirmatory analysis if required.

Determination of Diethyl Phthalate and Polyhexamethylene Guanidine in Surrogate Alcohol from Russia

Directory of Open Access Journals (Sweden)

Yulia B. Monakhova

2011-01-01

Full Text Available Analytical methods based on spectroscopic techniques were developed and validated for the determination of diethyl phthalate (DEP and polyhexamethylene guanidine (PHMG, which may occur in unrecorded alcohol. Analysis for PHMG was based on UV-VIS spectrophotometry after derivatization with Eosin Y and 1H NMR spectroscopy of the DMSO extract. Analysis of DEP was performed with direct UV-VIS and 1H NMR methods. Multivariate curve resolution and spectra computation methods were used to confirm the presence of PHMG and DEP in the investigated beverages. Of 22 analysed alcohol samples, two contained DEP or PHMG. 1H NMR analysis also revealed the presence of signals of hawthorn extract in three medicinal alcohols used as surrogate alcohol. The simple and cheap UV-VIS methods can be used for rapid screening of surrogate alcohol samples for impurities, while 1H NMR is recommended for specific confirmatory analysis if required.

The effect of fullerols under UV on cell

International Nuclear Information System (INIS)

Li Yuguo; Zhao Qunfen; Li Qingnuan; Xu Jingying; Li Wenxin; Ni Jin; Han Ling; Gao Fu

2004-01-01

The UV radioprotective effect of fullerols, which was compared with the effect of C 60 -PVP, was studied using cultured L02 cells. The cell survivals were determined by MTT method, SOD and MDA also were studied with chemistric colorimetry. The results showed that fullerols can effectively protect cells from damage induced by UV irradiation. The mechanism could be assosiated with the ability of fullerols to behave as an antioxidant compound, then fullerols protected cell membrane from damage by UV radiation. (authors)

Plant responses to UV-B irradiation are modified by UV-A irradiation

International Nuclear Information System (INIS)

Middleton, E.M.; Teramura, A.H.

1993-01-01

The increasing UV-B radiation (0.28-0.32 μm) reaching the earth's surface is an important concern. Plant response in artificial UV-B irradiation studies has been difficult to assess, especially regarding photosynthetic pigments, because the fluorescent lamps also produce UV-A (0.32-0.40μm) radiation which is involved with blue light in pigment synthesis. Both UV-A and UV-B irradiances were controlled in two glasshouse experiments conducted under relatively high PPFD (> 1300μmol m -2 s -1 ) at two biologically effective daily UV-B irradiances (10.7 and 14.1 kJ m -2 ); UV-A irradiances were matched in Controls (∼5, 9 kJ m -2 ). Normal, chlorophyll-deficient, and flavonoid-deficient isolines of soybean cultivar, Clark, were utilized. Many growth/ pigment variables exhibited a statistically significant interaction between light quality and quantity: in general, UV-A radiation moderated the damaging effects of UV-B radiation. Regression analyses demonstrated that a single negative function related photosynthetic efficiency to carotenoid Content (r 2 =0.73, P≤0.001), implying a open-quotes costclose quotes in maintaining carotenoids for photoprotection. A stomatal limitation to photosynthesis was verified and carotenoid content was correlated with UV-B absorbing compound levels, in UV-B irradiated plants

Qualitative and quantitative determination of yohimbine in authentic yohimbe bark and in commercial aphrodisiacs by HPLC-UV-API/ MS methods.

Science.gov (United States)

Zanolari, Boris; Ndjoko, Karine; Ioset, Jean-Robert; Marston, Andrew; Hostettmann, Kurt

2003-01-01

The development and validation of a rapid qualitative and quantitative method based on an HPLC-UV-MS technique with atmospheric pressure chemical ionisation and electrospray ionisation for the analysis of yohimbine in a number of commercial aphrodisiac products is reported. HPLC with multiple-stage mass spectrometry experiments allowed the identification of the target compound and increased the selectivity of complex analyses such as those involved with multi-botanical preparations. The precision and the robustness of the method were improved by the use of two internal standards: codeine for UV detection and deuterium-labelled yohimbine for MS detection. Twenty commercial aphrodisiac preparations were analysed and the amount of yohimbine measured and expressed as the maximal dose per day suggested on product labels ranged from 1.32 to 23.16 mg.

8- to 13-micron spectrophotometry of Comet IRAS-Araki-Alcock

Science.gov (United States)

Feierberg, M. A.; Witteborn, F. C.; Johnson, J. R.; Campins, H.

1984-01-01

Spectrophotometry between 8.0 and 13.0 microns at 2 percent spectral resolution is presented for areas in and near the nuclear condensation of Comet IRAS-Araki-Alcock (1983d) on May 11 and 12, 1983. All the spectra can be fit very well by blackbody curves, and no 10-micron silicate emissions are seen. The temperature structure of the coma suggests the presence of small (radii less than 5 microns) dust particles within 150 km of the nucleus and larger ones further out. The change in the spatial distribution of the infrared flux between the two nights suggests that an outburst may have occurred sometime on May 11.

Microbial UV fluence-response assessment using a novel UV-LED collimated beam system.

Science.gov (United States)

Bowker, Colleen; Sain, Amanda; Shatalov, Max; Ducoste, Joel

2011-02-01

A research study has been performed to determine the ultraviolet (UV) fluence-response of several target non-pathogenic microorganisms to UV light emitting diodes (UV-LEDs) by performing collimated beam tests. UV-LEDs do not contain toxic mercury, offer design flexibility due to their small size, and have a longer operational life than mercury lamps. Comsol Multiphysics was utilized to create an optimal UV-LED collimated beam design based on number and spacing of UV-LEDs and distance of the sample from the light source while minimizing the overall cost. The optimized UV-LED collimated beam apparatus and a low-pressure mercury lamp collimated beam apparatus were used to determine the UV fluence-response of three surrogate microorganisms (Escherichia coli, MS-2, T7) to 255 nm UV-LEDs, 275 nm UV-LEDs, and 254 nm low-pressure mercury lamps. Irradiation by low-pressure mercury lamps produced greater E. coli and MS-2 inactivation than 255 nm and 275 nm UV-LEDs and similar T7 inactivation to irradiation by 275 nm UV-LEDs. The 275 nm UV-LEDs produced more efficient T7 and E. coli inactivation than 255 nm UV-LEDs while both 255 nm and 275 nm UV-LEDs produced comparable microbial inactivation for MS-2. Differences may have been caused by a departure from the time-dose reciprocity law due to microbial repair mechanisms. Copyright © 2010 Elsevier Ltd. All rights reserved.

Biobased Nanoparticles for Broadband UV Protection with Photostabilized UV Filters

NARCIS (Netherlands)

Hayden, D.R.|info:eu-repo/dai/nl/412640694; Imhof, A.|info:eu-repo/dai/nl/145641600; Velikov, K. P.|info:eu-repo/dai/nl/239483472

2016-01-01

Sunscreens rely on multiple compounds to provide effective and safe protection against UV radiation. UV filters in sunscreens, in particular, provide broadband UV protection but are heavily linked to adverse health effects due to the generation of carcinogenic skin-damaging reactive oxygen species

Benchmark studies of UV-vis spectra simulation for cinnamates with UV filter profile.

Science.gov (United States)

Garcia, Ricardo D'A; Maltarollo, Vinícius G; Honório, Káthia M; Trossini, Gustavo H G

2015-06-01

Skin cancer is a serious public health problem worldwide, being incident over all five continents and affecting an increasing number of people. As sunscreens are considered an important preventive measure, studies to develop better and safer sunscreens are crucial. Cinnamates are UVB filters with good efficiency and cost-benefit, therefore, their study could lead to the development of new UV filters. A benchmark to define the most suitable density functional theory (DFT) functional to predict UV-vis spectra for ethylhexyl methoxycinnamate was performed. Time-dependent DFT (TD-DFT) calculations were then carried out [B3LYP/6-311 + G(d,p) and B3P86/6-311 + G(d,p) in methanol environment] for seven cinammete derivatives implemented in the Gaussian 03 package. All DFT/TD-DFT simulations were performed after a conformational search with the Monte-Carlo method and MMFF94 force field. B3LYP and B3P86 functionals were better at reproducing closely the experimental spectra of ethylhexyl methoxycinnamate. Calculations of seven cinnamates showed a λmax of around 310 nm, corroborating literature reports. It was observed that the energy for the main electronic transition was around 3.95 eV and could be explained by electron delocalization on the aromatic ring and ester group, which is important to UV absorption. The methodology employed proved to be suitable for determination of the UV spectra of cinnamates and could be used as a tool for the development of novel UV filters.

An HPLC-UV method for the measurement of permeability of marker drugs in the Caco-2 cell assay

Directory of Open Access Journals (Sweden)

J.M. Kratz

2011-06-01

Full Text Available The Caco-2 cell line has been used as a model to predict the in vitro permeability of the human intestinal barrier. The predictive potential of the assay relies on an appropriate in-house validation of the method. The objective of the present study was to develop a single HPLC-UV method for the identification and quantitation of marker drugs and to determine the suitability of the Caco-2 cell permeability assay. A simple chromatographic method was developed for the simultaneous determination of both passively (propranolol, carbamazepine, acyclovir, and hydrochlorothiazide and actively transported drugs (vinblastine and verapamil. Separation was achieved on a C18 column with step-gradient elution (acetonitrile and aqueous solution of ammonium acetate, pH 3.0 at a flow rate of 1.0 mL/min and UV detection at 275 nm during the total run time of 35 min. The method was validated and found to be specific, linear, precise, and accurate. This chromatographic system can be readily used on a routine basis and its utilization can be extended to other permeability models. The results obtained in the Caco-2 bi-directional transport experiments confirmed the validity of the assay, given that high and low permeability profiles were identified, and P-glycoprotein functionality was established.

UV-vis spectra as an alternative to the Lowry method for quantify hair damage induced by surfactants.

Science.gov (United States)

Pires-Oliveira, Rafael; Joekes, Inés

2014-11-01

It is well known that long term use of shampoo causes damage to human hair. Although the Lowry method has been widely used to quantify hair damage, it is unsuitable to determine this in the presence of some surfactants and there is no other method proposed in literature. In this work, a different method is used to investigate and compare the hair damage induced by four types of surfactants (including three commercial-grade surfactants) and water. Hair samples were immersed in aqueous solution of surfactants under conditions that resemble a shower (38 °C, constant shaking). These solutions become colored with time of contact with hair and its UV-vis spectra were recorded. For comparison, the amount of extracted proteins from hair by sodium dodecyl sulfate (SDS) and by water were estimated by the Lowry method. Additionally, non-pigmented vs. pigmented hair and also sepia melanin were used to understand the washing solution color and their spectra. The results presented herein show that hair degradation is mostly caused by the extraction of proteins, cuticle fragments and melanin granules from hair fiber. It was found that the intensity of solution color varies with the charge density of the surfactants. Furthermore, the intensity of solution color can be correlated to the amount of proteins quantified by the Lowry method as well as to the degree of hair damage. UV-vis spectrum of hair washing solutions is a simple and straightforward method to quantify and compare hair damages induced by different commercial surfactants. Copyright © 2014 Elsevier B.V. All rights reserved.

Optical properties of orthodontic aligners--spectrophotometry analysis of three types before and after aging.

Science.gov (United States)

Lombardo, Luca; Arreghini, Angela; Maccarrone, Roberta; Bianchi, Anna; Scalia, Santo; Siciliani, Giuseppe

2015-01-01

The aim was to assess and compare absorbance and transmittance values of three types of clear orthodontic aligners before and after two cycles of in vitro aging. Nine samples of orthodontic aligners from three different manufacturers (Invisalign, Align Technology, Santa Clara, CA, USA; All-In, Micerium, Avegno, GE, Italy; F22 Aligner, Sweden & Martina, Due Carrare, PD, Italy) were selected, and each sample was subjected to spectrophotometry analysis of both its transmittance and absorbance a total of 27 times. Samples were subsequently aged in vitro at a constant temperature in artificial saliva supplemented with food colouring for two cycles of 14 days each. The spectrophotometry protocol was then repeated, and the resulting data were analysed and compared by means of ANOVA (p < 0.05). All types of aligners tested yielded lower transmittance and higher absorbance values after aging, but the difference was not significant in any case. That being said, the F22 aligners were found to be most transparent, both before and after aging, followed by Invisalign and All-In, and these differences were statistically significant. Commercial aligners possess significantly different optical, and therefore aesthetic, properties, both as delivered and following aging.

The role of spectrophotometry in the diagnosis of melanoma

Science.gov (United States)

2010-01-01

Background Spectrophotometry (SPT) could represent a promising technique for the diagnosis of cutaneous melanoma (CM) at earlier stages of the disease. Starting from our experience, we further assessed the role of SPT in CM early detection. Methods During a health campaign for malignant melanoma at National Cancer Institute of Naples, we identified a subset of 54 lesions to be addressed to surgical excision and histological examination. Before surgery, all patients were investigated by clinical and epiluminescence microscopy (ELM) screenings; selected lesions underwent spectrophotometer analysis. For SPT, we used a video spectrophotometer imaging system (Spectroshade® MHT S.p.A., Verona, Italy). Results Among the 54 patients harbouring cutaneous pigmented lesions, we performed comparison between results from the SPT screening and the histological diagnoses as well as evaluation of both sensitivity and specificity in detecting CM using either SPT or conventional approaches. For all pigmented lesions, agreement between histology and SPT classification was 57.4%. The sensitivity and specificity of SPT in detecting melanoma were 66.6% and 76.2%, respectively. Conclusions Although SPT is still considered as a valuable diagnostic tool for CM, its low accuracy, sensitivity, and specificity represent the main hamper for the introduction of such a methodology in clinical practice. Dermoscopy remains the best diagnostic tool for the preoperative diagnosis of pigmented skin lesions. PMID:20707921

Optical bandgap of semiconductor nanostructures: Methods for experimental data analysis

Science.gov (United States)

Raciti, R.; Bahariqushchi, R.; Summonte, C.; Aydinli, A.; Terrasi, A.; Mirabella, S.

2017-06-01

Determination of the optical bandgap (Eg) in semiconductor nanostructures is a key issue in understanding the extent of quantum confinement effects (QCE) on electronic properties and it usually involves some analytical approximation in experimental data reduction and modeling of the light absorption processes. Here, we compare some of the analytical procedures frequently used to evaluate the optical bandgap from reflectance (R) and transmittance (T) spectra. Ge quantum wells and quantum dots embedded in SiO2 were produced by plasma enhanced chemical vapor deposition, and light absorption was characterized by UV-Vis/NIR spectrophotometry. R&T elaboration to extract the absorption spectra was conducted by two approximated methods (single or double pass approximation, single pass analysis, and double pass analysis, respectively) followed by Eg evaluation through linear fit of Tauc or Cody plots. Direct fitting of R&T spectra through a Tauc-Lorentz oscillator model is used as comparison. Methods and data are discussed also in terms of the light absorption process in the presence of QCE. The reported data show that, despite the approximation, the DPA approach joined with Tauc plot gives reliable results, with clear advantages in terms of computational efforts and understanding of QCE.

Synthesis of hybrid chitosan/calcium aluminosilicate using a sol-gel method for optical applications

Energy Technology Data Exchange (ETDEWEB)

Elnahrawy, Amany Mohamed [Department of Solid State, Physics Division, National Research Center (NRC), Giza 12622, Cairo (Egypt); Kim, Yong Soo, E-mail: yskim2@ulsan.ac.kr [Department of Physics and Energy Harvest-Storage Research Center (EHSRC), University of Ulsan, Ulsan 44610 (Korea, Republic of); Ali, Ahmed I., E-mail: Ahmed_ali_2010@helwan.edu.eg [Department of Physics and Energy Harvest-Storage Research Center (EHSRC), University of Ulsan, Ulsan 44610 (Korea, Republic of); Basic Science Department, Faculty of Industrial Education & Technology, Helwan University, Cairo 11281 (Egypt)

2016-08-15

Hybrid chitosan (CS)/calcium aluminosilicate nanocomposites thin films and membranes were prepared using a sol–gel method with three different concentrations of Al{sub 2}O{sub 3} (5, 7 and 10 mol. %). The prepared nanocomposites were characterized by transmission electron microscopy, X-ray diffraction and Fourier Transform Infrared spectroscopy. The optical properties of the prepared samples were analyzed by UV/Vis spectrophotometry and photoluminescence (PL) spectroscopy. The optical parameters revealed an increase in both the refractive index and band gap of the nanocomposites with increasing Al concentration. In addition, the PL spectra revealed a blue shift that was consistent with an increase in the optical band gap. These results suggest that CS/calcium aluminosilicate in two different forms can be a good candidate for optical sensors applications. - Highlights: • We show a large specific surface area of hybrid CS/calcium aluminosilicate thin films and membranes using sol-gel method. • Inorganic SiO{sub 2}-based phase are perfectly embedded onto chitosan matrix has a reliable stability. • CS/calcium aluminosilicate could be usable for optical sensors, planar waveguide, and bio-sensing.

Evaluation of the H-point standard additions method (HPSAM) and the generalized H-point standard additions method (GHPSAM) for the UV-analysis of two-component mixtures.

Science.gov (United States)

Hund, E; Massart, D L; Smeyers-Verbeke, J

1999-10-01

The H-point standard additions method (HPSAM) and two versions of the generalized H-point standard additions method (GHPSAM) are evaluated for the UV-analysis of two-component mixtures. Synthetic mixtures of anhydrous caffeine and phenazone as well as of atovaquone and proguanil hydrochloride were used. Furthermore, the method was applied to pharmaceutical formulations that contain these compounds as active drug substances. This paper shows both the difficulties that are related to the methods and the conditions by which acceptable results can be obtained.

Development and Validation of UV-Visible Spectrophotometric Methods for Simultaneous Estimation of Thiocolchicoside and Dexketoprofen in Bulk and Tablet Dosage Form

OpenAIRE

M. T. Harde; S. B. Jadhav; D. L. Dharam; P. D. Chaudhari

2012-01-01

Development and validation of two simple, accurate, precise and economical UV Spectrophotometric methods for simultaneous estimation of Thiocolchicoside and Dexketoprofen in bulk and in tablet dosage form. The methods employed were Method-1 Absorbance correction method and Method-2 First order derivative spectroscopic method. In method-1 Absorbance is measured at two wavelengths 370nm at which Dexketoprofen has no absorbance and 255nm at which both the drug have considerable absorbance. In me...

COMPARATIVE ANALYSIS OF UV-C AND UV-B RADIATION INFLUENCE ON PLANT OBJECTS

Directory of Open Access Journals (Sweden)

О. Міхєєв

2011-04-01

Full Text Available General aim of work – comparative research of temporal regularities of growth processes of pea,that was grown under normal conditions and with application of UV-C and UV-B irradiation ofstem part, and also detection of irradiation dose relations to parameter of root and stem part sproutsgrowth rate of Aronis pea. Research subject of UV-C and UV-B irradiation influence on dynamicsof plant growth parameters in each set of experiments was alteration of growth rate, pecularities ofgrowth dynamics in different conditions of experiment, detection of UV-C and UV-B irradiationdoses range, that stimulate or inhibit growth parameters of pea sprouts. The investigation resulted indetermination 1,3 times higher efficiency of UV-V irradiation comparing to UV-B irradiation.Reaction of root didn’t depend on the type of UV-radiation

DNA damage caused by UV- and near UV-irradiation

International Nuclear Information System (INIS)

Ohnishi, Takeo

1986-01-01

Much work with mutants deficient in DNA repair has been performed concerning UV-induced DNA damage under the condition where there is no artificial stimulation. In an attempt to infer the effects of solar wavelengths, the outcome of the work is discussed in terms of cellular radiation sensitivity, unscheduled DNA synthesis, and mutation induction, leading to the conclusion that some DNA damage occurs even by irradiation of the shorter wavelength light (270 - 315 nm) and is repaired by excision repair. It has been thought to date that pyrimidine dimer (PD) plays the most important role in UV-induced DNA damage, followed by (6 - 4) photoproducts. As for DNA damage induced by near UV irradiation, the yield of DNA single-strand breaks and of DNA-protein crosslinking, other than PD, is considered. The DNA-protein crosslinking has proved to be induced by irradiation at any wavelength of UV ranging from 260 to 425 nm. Near UV irradiation causes the inhibition of cell proliferation to take place. (Namekawa, K.)

A Facile Vortex-Assisted Dispersive Liquid-Liquid Microextraction Method for the Determination of Uranyl Ion at Low Levels by Spectrophotometry.