WorldWideScience
1

Spectrofluorimetric determination of glutathione in human plasma by solid-phase extraction using graphene as adsorbent  

Science.gov (United States)

An efficient solid phase extraction-spectrofluorimetric method using graphene as adsorbent was developed to sensitively determine glutathione (GSH) in biological samples. Fluorescent probe N-(4,4-difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-yl)methyl)iodoacetamide (BODIPY Fl-C 1-IA) was applied for the derivatization of GSH. The procedure was based on BODIPY Fl-C 1-IA selective reaction with GSH to form highly fluorescent product BODIPY Fl-C 1-IA-GSH, its extraction to the graphene-packed SPE cartridge and spectrofluorimetric determination. Some factors affecting the extraction efficiency, such as the type of the eluent and its volume, sample pH, extraction time, and sample volume were optimized. Comparative studies were also performed between graphene and other adsorbents including C 18 silica, graphitic carbon, and multi-walled carbon nanotubes for the extraction of analyte. The calibration graph using the pretreatment system for GSH was linear over the range of 0.5-200 nM. The limit of detection was 0.01 nM (signal-to-noise ratio = 3). Relative standard deviation for six replicate determinations of GSH at 80 nM concentration level was lower than 5.0%. The developed method was applied to the determination of GSH in human plasma with recoveries of 92-108%. This work revealed the great potentials of graphene as an excellent sorbent material in the analysis of biological samples.

Huang, Ke-Jing; Jing, Qiang-Shan; Wei, Cai-Yun; Wu, Ying-Ying

2011-09-01

2

Determination of polychlorinated biphenyls in transformer oil using various adsorbents for solid phase extraction.  

Science.gov (United States)

Various adsorbents for a solid phase extraction (SPE) method were used to study their ability to separate PCBs from transformer oil to rapidly determine their sub-ppm concentration in the transformer oil. Approximately 90% of the transformer oil could be removed from the PCBs by using a hydrophilic-lipophilic balanced copolymer (HLB) adsorbent, but the recovery of deca-chlorobiphenyl (deca-CB) used as a surrogate was only 24.5% due to lose during this cleanup process. The use of a silica adsorbent gave good results with 89.9% recovery of the deca-CB. The recovery of Aroclor 1242 and 1260 were 95.4 and 90.3% on silica, and 98.9 and 83.5% on HLB, respectively. Acid treatment was an essential step in removing the ambiguous interference peaks to help identify the PCBs. A decreased sensitivity of the electron capture detection (ECD) for PCBs was observed due to the presence of the remaining trace oil after the workup procedure. This loss in sensitivity was allowed for by using tetrachloroxylene as an internal standard, and this was found to be reliable for the criteria of quality control by employing an experiment in which LCS was spiked with 2mg/l of Aroclor 1260 and analyzed each day over a 25 day period. The MDL for the analytical method established in this study is 0.05 mg/l. PMID:18474390

Na, Yun-Cheol; Kim, Kang-Jin; Hong, Jongki; Seo, Jung-Ju

2008-08-01

3

Metal-organic framework derived magnetic nanoporous carbon: novel adsorbent for magnetic solid-phase extraction.  

Science.gov (United States)

The fabrication of a magnetic nanoporous carbon (MNPC) via one-step direct carbonization of Co-based metal-organic framework has been achieved without using any additional carbon precursors. The morphology, structure, and magnetic behavior of the as-prepared Co-MNPC were characterized by using the techniques of scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction, Raman spectroscopy, N2 adsorption, and vibrating sample magnetometer. The Co-MNPC has a high specific surface area, large pore volume, and super paramagnetism. Its performance was evaluated by the magnetic solid-phase extraction of some neonicotinoid insecticides from water and fatmelon samples followed by high-performance liquid chromatographic analysis. The effects of the main experimental parameters that could affect the extraction efficiencies were investigated. The results demonstrated that the Co-MNPC had an excellent adsorption capability for the compounds. PMID:25412429

Hao, Lin; Wang, Chun; Wu, Qiuhua; Li, Zhi; Zang, Xiaohuan; Wang, Zhi

2014-12-16

4

Solid phase extraction membrane  

Science.gov (United States)

A wet-laid, porous solid phase extraction sheet material that contains both active particles and binder and that possesses excellent wet strength is described. The binder is present in a relatively small amount while the particles are present in a relatively large amount. The sheet material is sufficiently strong and flexible so as to be pleatable so that, for example, it can be used in a cartridge device.

Carlson, Kurt C [Nashville, TN; Langer, Roger L [Hudson, WI

2002-11-05

5

Natural cotton fibers as adsorbent for solid-phase extraction of polycyclic aromatic hydrocarbons in water samples.  

Science.gov (United States)

A natural material, cotton fiber, has been applied as a solid-phase extraction (SPE) adsorbent for sample preparation for the analysis of polycyclic aromatic hydrocarbons (PAH) in water samples using high-performance liquid chromatography. The cotton fiber was used directly without any chemical modifications, which avoided a complex synthesis process and consumption of a large volume of organic solvent. The conditions affecting the extraction efficiency were optimized to achieve high detection sensitivity, and included elution solvent, ultrasonic elution time, extraction time, sample volume, salt concentration and organic modifier addition. Under the optimal conditions, the detection limits for seven PAH compounds could reach up to 0.1-2.0 ng L(-1). The method accuracy was evaluated using recovery measurements in standard spiked samples and good recoveries of 70.69-110.04% with relative standard deviations of less than 10% have been achieved. Consequently, the method developed was successfully applied for determining PAH in environmental samples: snow water, metal-fabrication factory wastewater and Xiangjiang River water, with PAH contents ranging from 13.2 to 83.1 ng L(-1). Therefore, using cotton fiber as a new SPE adsorbent, was easy to prepare, had a low cost and great reusability, and this implies it is a promising method for sample preparation. PMID:24872029

Wang, Jianping; Liu, Shengquan; Chen, Chunyan; Zou, Ying; Hu, Huiping; Cai, Qingyun; Yao, Shouzhuo

2014-07-21

6

Solid phase extraction of Zn as xylenol orange complex on naphthalene adsorbent and its determination by Flame Atomic Absorption Spectrometry  

International Nuclear Information System (INIS)

A solid-phase extraction method for determination of zinc by FAAS has been described. The proposed procedure was based on adsorption of zinc-xylenol orange complex on naphthalene methyltrioctyl ammonium chloride adsorbent on a column. The adsorbed metal complex was eluted from the column with nitric acid solution and determined by FAAS. Adsorption conditions including pH, reagent concentration, sample volume, flow rate, and concentration of interfering ions were investigated. Calibration plot was linear in 1?50 ng mL-1 concentration range of Zn in the initial solution, r = 0.9999. Limit of detection was calculated based on 3Sb criterion and equaled 0.60 ng mL-1 when 100 mL-in-volume samples were used, and 0.06 ng mL-1 in case of 1000 mL-in-volume samples. Relative standard deviation for ten replicate determinations of 5 and 20 ng mL-1 Zn was 3.8 and 1.1%, respectively. The proposed method was applied to determination of zinc in mineral and tap water samples, as well as in sodium sulfite salt from Merck. (authors)

7

N-methylimidazolium modified magnetic particles as adsorbents for solid phase extraction of genomic deoxyribonucleic acid from genetically modified soybeans.  

Science.gov (United States)

N-Methylimidazolium modified magnetic particles (MIm-MPs) were prepared and applied in the solid phase extraction of genomic deoxyribonucleic acid (DNA) from genetically modified soybeans. The adsorption of MIm-MPs for DNA mainly resulted from the strong electrostatic interaction between the positively charged MPs and the negatively charged DNA. The elution of DNA from MPs-DNA conjugates using phosphate buffer resulted from the stronger electrostatic interaction of phosphate ions with MPs than DNA. In the extraction procedure, no harmful reagents (e.g. phenol, chloroform and isopropanol, etc.) used, high yield (10.4 ?g DNA per 30 mg sample) and high quality (A260/A280=1.82) of DNA can be realized. The as-prepared DNA was used as template for duplex-polymerase chain reaction (PCR) and the PCR products were analyzed by a sieving capillary electrophoresis method. Quick and high quality extraction of DNA template, and fast and high resolution detection of duplex PCR products can be realized using the developed method. No toxic reagents are used throughout the method. PMID:23522109

Deng, Manchen; Jiang, Cheng; Jia, Li

2013-04-10

8

Solid Phase Micro Extraction (SPME)  

Science.gov (United States)

Internation Flavors and Fragrances Inc. proprietary research technology, Solid Phase Micro Extraction (SPME) utilizes a special fiber needle placed directly next to the bloom of the living flower to collect the fragrance molecules. SPME was used in the Space Flower experiment aboard STS-95 space shuttle mission, after which Dr. Braja Mookherjee (left) and Subha Patel of IFF will analyze the effects of gravity on the Overnight Scentsation rose plant.

1998-01-01

9

Synthesis, characterization, and application of polystyrene adsorbents containing tri-n-butylphosphate for solid-phase extraction of uranium (VI) from aqueous nitrate solutions  

International Nuclear Information System (INIS)

Polystyrene adsorbent for solid-phase extraction of U(VI) was developed through in situ copolymerization of styrene and divinylbenzene in the presence of tri-n-butylphosphate and its magnetic form was obtained by addition of fine particles of magnetite in an amount of 15 wt% of the total monomers used. The obtained adsorbents were characterized by means of scanning electron microscope, FTIR spectroscopy and X-ray powder diffraction. The adsorption behavior of U(VI) from aqueous nitrate solutions onto non-magnetic adsorbent RI (St-DVB-TBP) and its magnetic form RII (St-DVB-TBP-Fe3O4) at different experimental condition was studied using batch method. The adsorption results were found to fit Langmuir model. The magnetite-containing adsorbent showed higher uptake values relative to the corresponding magnetite-free one. The adsorption of U(VI) onto RI followed pseudo-first order kinetics whereas the adsorption onto RII followed pseudo-second order. Thermodynamic studies revealed that the adsorption process was a spontaneous exothermic reaction. Desorption of the loaded U(VI) was carried out using distilled water and found to be 97 and 93 % for RI and RII, respectively. (author)

10

A novel dispersive solid-phase extraction method using metal-organic framework MIL-101 as the adsorbent for the analysis of benzophenones in toner.  

Science.gov (United States)

Metal-organic frameworks (MOFs) have been paid widespread attention in the field of adsorption and separation materials due to its porosity, large specific surface area, unsaturated metal-ligand sites and structural diversity. In this study, the green powder MIL-101 was synthesized and used for the extraction of benzophenone, 2,4-dihydroxybenzophenone and 2-hydroxy-4-methoxy-benzophenone from toner samples for the first time. The synthesized MIL-101 was characterized by X-ray diffraction, scanning electron microscopy, thermogravimetry and nitrogen adsorption porosimetry. The MIL-101 was applied as the dispersive solid phase extraction (DSPE) adsorbent for the extraction and preconcentration of benzophenone, 2,4-dihydroxybenzophenone and 2-hydroxy-4-methoxy-benzophenone from toner samples. The extraction conditions were investigated. Under the optimized conditions, a DSPE-HPLC method for the determination of benzophenone, 2,4-dihydroxybenzophenone and 2-hydroxy-4-methoxy-benzophenone was developed. The method yielded a linear calibration curve in the concentration ranges from 4.0 to 3500?g L(-1) for the three analytes in toner samples with regression coefficients (r(2)) of 0.9992, 0.9999 and 0.9990, respectively. Limits of detection were 1.2, 1.2 and 0.9?g L(-1), respectively. Both the intra-day and inter-day precisions (RSDs) were <10%. PMID:25476369

Li, Ning; Zhu, Quanfei; Yang, Yang; Huang, Jianlin; Dang, Xueping; Chen, Huaixia

2015-01-15

11

Silica gel-polyethylene glycol as a new adsorbent for solid phase extraction of cobalt and nickel and determination by flame atomic absorption spectrometry.  

Science.gov (United States)

In this paper a novel solid phase extraction method to determine Co(II) and Ni(II) using silica gel-polyethylene glycol (Silica-PEG) as a new adsorbent is described. The method is based on the adsorption of cobalt and nickel ions in alkaline media on polyethylene glycol-silica gel in a mini-column, elution with nitric acid and determination by flame atomic absorption spectrometry. The adsorption conditions such as NaOH concentration, sample volume and amount of adsorbent were optimized in order to achieve highest sensitivity. The calibration graph was linear in the range of 0.5-200.0ngmL(-1) for Co(II) and 2.0-100.0ngmL(-1) for Ni(II) in the initial solution. The limit of detection based on 3S(b) was 0.37ngmL(-1) for Co(II) and 0.71ngmL(-1) for Ni(II). The relative standard deviations (R.S.D.) for ten replicate measurements of 40ngmL(-1) of Co(II), and Ni(II) were 3.24 and 3.13%, respectively. The method was applied to determine Co(II) and Ni(II) in black tea, rice flour, sesame seeds, tap water and river water samples. PMID:20298852

Pourreza, N; Zolgharnein, J; Kiasat, A R; Dastyar, T

2010-05-15

12

Solid phase extraction of chromium(VI) from aqueous solutions by adsorption of its diphenylcarbazide complex on a mixed bed adsorbent (acid activated montmorillonite-silica gel) column  

Science.gov (United States)

A novel approach has been developed for the solid phase extraction of chromium(VI) based on the adsorption of its diphenylcarbazide complex on a mixture of acid activated montmorillonite (AAM)-silica gel column. The effect of various parameters such as acidity, stability of the column, sample volume, interfering ions, etc., were studied in detail. The adsorbed complex could be easily eluted using polyethylene glycol-sulfuric acid mixture and the concentration of chromium has been determined using visible spectrophotometry. The calibration graph was linear in the range 0-1 ?g mL -1 chromium(VI) with a detection limit of 6 ?g L -1. A highest preconcentration factor of 25 could be obtained for 250 mL sample volume using glass wool as support for the mixed bed adsorbent. Chromium(VI) could be effectively separated from other ions such as nickel, copper, zinc, chloride, sulfate, nitrate, etc., and the method has been successfully applied to study the recovery of chromium in electroplating waste water and spiked water samples.

Rajesh, N.; Mishra, Braja Gopal; Pareek, Pawan Kumar

2008-02-01

13

Ionic liquid-modified magnetic polymeric microspheres as dispersive solid phase extraction adsorbent: a separation strategy applied to the screening of sulfamonomethoxine and sulfachloropyrazine from urine.  

Science.gov (United States)

Ionic liquid-modified magnetic polymeric microspheres (ILMPM) were prepared based on Fe3O4 magnetic nanoparticles (MNPs) and ionic liquids (ILs) incorporated into a polymer. The composites were characterized using scanning electron microscopy, Fourier transform infrared analysis, thermogravimetric analysis, X-ray diffraction, and vibrating magnetometer, which indicated that ILMPM had a regularly spherical shape and strong magnetic property. The obtained ILMPM were successfully applied as a special adsorbent of magnetic dispersive solid phase extraction (MDSPE) for the rapid extraction and isolation of sulfamonomethoxine sodium and sulfachloropyrazine sodium in urine. The factors that affected extraction efficiency, such as adsorption conditions, desorption conditions, washing and elution solvents, and pH of the sample solution, were optimized. Under the optimum condition, good linearity in the range of 0.005-2.0 ?g g(-1) (r???0.9996) was obtained for the two sulfonamides (SAs); the average recoveries at three spiked levels ranged from 86.9 to 102.1 %, with relative standard deviations of ?4.3 %. The presented ILMPM-MDSPE method combined the advantages of ILs, MNPs, and MDSPE and therefore could be potentially applied for rapid screening of SAs in urine. PMID:24573579

Yan, Hongyuan; Gao, Mengmeng; Yang, Chen; Qiu, Mande

2014-04-01

14

Allantoin as a solid phase adsorbent for removing endotoxins.  

Science.gov (United States)

In this study we present a simple and robust method for removing endotoxins from protein solutions by using crystals of the small-molecule compound 2,5-dioxo-4-imidazolidinyl urea (allantoin) as a solid phase adsorbent. Allantoin crystalline powder is added to a protein solution at supersaturated concentrations, endotoxins bind and undissolved allantoin crystals with bound endotoxins are removed by filtration or centrifugation. This method removes an average of 99.98% endotoxin for 20 test proteins. The average protein recovery is ?80%. Endotoxin binding is largely independent of pH, conductivity, reducing agent and various organic solvents. This is consistent with a hydrogen-bond based binding mechanism. Allantoin does not affect protein activity and stability, and the use of allantoin as a solid phase adsorbent provides better endotoxin removal than anion exchange, polymixin affinity and biological affinity methods for endotoxin clearance. PMID:24001944

Vagenende, Vincent; Ching, Tim-Jang; Chua, Rui-Jing; Gagnon, Pete

2013-10-01

15

Diaion HP-2MG modified with 2-(2,6-dichlorobenzylideneamino) benzenethiol as new adsorbent for solid phase extraction and flame atomic absorption spectrometric determination of metal ions.  

Science.gov (United States)

A solid phase extraction method for enrichment-separation and the determination of cobalt (Co(2+)), copper (Cu(2+)), nickel (Ni(2+)), zinc (Zn(2+)) and lead (Pb(2+)) ions in real samples has been proposed. The influences of some analytical parameters like pH, flow rate, eluent type and interference of matrix ions on recoveries of analytes were optimized. The limits of detection were found in the range of 1.6-3.9 µg L(-1), while preconcentration factor for all understudy metal ions were found to be 166 with loading half time (t 1/2) less than 10 min. The procedure was applied for the enrichment-separation of analyte ions in environmental samples with recoveries higher than 94.8% and relative SD <4.9% (N = 5). PMID:23613484

Ghaedi, M; Montazerozohori, M; Haghdoust, S; Zaare, F; Soylak, M

2013-04-01

16

Polypyrrole hollow fiber for solid phase extraction.  

Science.gov (United States)

We have developed a solid-phase extraction method based on conductive polypyrrole (PPy) hollow fibers which were fabricated by electrospinning and in situ polymerization. The electrospun poly (e-caprolactone) (PCL) fibers were employed as templates for the in situ surface polymerization of PPy under mechanical stirring or ultrasonication to obtain burr-shaped or smooth fiber shells, respectively. Hollow PPy fibers, achieved by removing the PCL templates, were the ideal sorbents for solid phase extraction of polar compounds due to their inherent multi-functionalities. By using the hollow PPy fibers, two important neuroendocrine markers of behavioural disorders, 5-hydroxyindole-3-acetic acid and homovanillic acid, were successfully extracted. Under the optimized conditions, the absolute recoveries of the above two neuroendocrine markers were 90.7% and 92.4%, respectively, in human plasma. Due to its simplicity, selectivity and sensitivity, the method may be applied to quantitatively analyse the concentrations of polar species in complex matrix samples. PMID:22398754

Tian, Tian; Deng, Jianjun; Xie, Zhuoying; Zhao, Yuanjin; Feng, Zhangqi; Kang, Xuejun; Gu, Zhongze

2012-04-21

17

Evaluation of multi-walled carbon nanotubes as solid-phase extraction adsorbents of pesticides from agricultural, ornamental and forestal soils.  

Science.gov (United States)

A new, simple and cost-effective method based on the use of multi-walled carbon nanotubes (MWCNTs) as solid-phase extraction stationary phases is proposed for the determination of a group of seven organophosphorus pesticides (i.e. ethoprophos, diazinon, chlorpyriphos-methyl, fenitrothion, malathion, chlorpyriphos and phosmet) and one thiadiazine (buprofezin) in different kinds of soil samples (forestal, ornamental and agricultural) using gas chromatography with nitrogen phosphorus detection. Soils were first ultrasound extracted with 10 mL 1:1 methanol/acetonitrile (v/v) and the evaporated extract redissolved in 20 mL water (pH 6.0) was passed through 100 mg of MWCNTs of 10-15 nm o.d., 2-6 nm i.d. and 0.1-10 microm length. Elution was carried out with 20 mL dichloromethane. The method was validated in terms of linearity, precision, recovery, accuracy and selectivity. Matrix-matched calibration was carried out for each type of soil since statistical differences between the calibration curves constructed in pure solvent and in the reconstituted soil extract were found for most of the pesticides under study. Recovery values of spiked samples ranged between 54 and 91% for the three types of soils (limits of detection (LODs) between 2.97 and 9.49 ngg(-1)), except for chlorpyrifos, chlorpyrifos-methyl and buprofezin which ranged between 12 and 54% (LODs between 3.14 and 72.4 ngg(-1)), which are the pesticides with the highest soil organic carbon sorption coefficient (K(OC)) values. Using a one-sample test (Student's t-test) with fortified samples at two concentration levels in each type of soil, no significant differences were observed between the real and the experimental values (accuracy percentages ranged between 87 and 117%). It is the first time that the adsorptive potential of MWCNTs for the extraction of organophosphorus pesticides from soils is investigated. PMID:19591701

Asensio-Ramos, M; Hernández-Borges, J; Borges-Miquel, T M; Rodríguez-Delgado, M A

2009-08-11

18

Determination of Pyrazole and Pyrrole Pesticides in Environmental Water Samples by Solid-Phase Extraction Using Multi-Walled Carbon Nanotubes as Adsorbent Coupled with High-Performance Liquid Chromatography.  

Science.gov (United States)

A solid-phase extraction (SPE) method using multi-walled carbon nanotubes as adsorbent coupled with high-performance liquid chromatography was developed for the determination of four pyrazole and pyrrole pesticides (fenpyroximate, chlorfenapyr, fipronil and flusilazole) in environmental water samples. Several parameters, such as extraction adsorbent, elution solvent and volume and sample loading flow rate were optimized to obtain high SPE recoveries and extraction efficiency. The calibration curves for the pesticides extracted were linear in the range of 0.05-10 ?g L(-1) for chlorfenapyr and fenpyroximate and 0.05-20 ?g L(-1) for fipronil and flusilazole, with the correlation coefficients (r(2)) between 0.9966 and 0.9990. The method gave good precisions (relative standard deviation %) from 2.9 to 10.1% for real spiked samples from reservoir water and seawater; method recoveries ranged 92.2-105.9 and 98.5-103.9% for real spiked samples from reservoir water and seawater, respectively. Limits of detection (S/N = 3) for the method were determined to be 8-19 ng L(-1). The optimized method was successfully applied to the determination of four pesticides of pyrazoles and pyrroles in real environmental water samples. PMID:24947489

Ma, Jiping; Lu, Xi; Xia, Yan; Yan, Fengli

2014-06-19

19

Facile preparation of surface-exchangeable core@shell iron oxide@gold nanoparticles for magnetic solid-phase extraction: Use of gold shell as the intermediate platform for versatile adsorbents with varying self-assembled monolayers  

International Nuclear Information System (INIS)

Graphical abstract: -- Highlights: •The core@shell Fe3O4@Au nanoparticles functionalized with SAMs were successfully constructed. •The SAMs could be transformed from one kind to another via thiol exchange process. •The developed nanomaterials could be applied in mode switching MSPE. -- Abstract: The core@shell Fe3O4@Au nanoparticles (NPs) functionalized with exchangeable self-assembled monolayers have been developed for mode switching magnetic solid-phase extraction (MSPE) using high performance liquid chromatography with ultraviolet detection. The adsorbents were synthesized by chemical coprecipitation to prepare magnetic cores followed by sonolysis to produce gold shells. Functionalization of Fe3O4@Au NPs surface was realized through self-assembly of commercially available low molecular weight thiol-containing ligands using gold shells as intermediate platform and the dynamic nature of Au–S chemistry allowed substituent of one thiol-containing ligand with another simply by thiol exchange process. The resultant adsorbents were characterized by transmission electronic microscopy, Fourier transform infrared spectroscopy, elemental analysis, contact angle measurement, and vibrating sample magnetometry. To evaluate the versatile performance of the developed MSPE adsorbents, they were applied for normal-phase SPE followed by reversed-phase SPE. A few kinds of diphenols and polycyclic aromatic hydrocarbons (PAHs) were employed as model analytes, respectively. The predominant parameters affecting extraction efficiency were investigated and optimized. Under the optimum experimental conditions, wide dynamic linear range (6.25–1600 ?g L?1 for diphenols and 1.56–100 ?g L?1 for PAHs) with good linearity (r2 ? 0.989) and low detection limits (0.34–16.67 ?g L?1 for diphenols and 0.26–0.52 ?g L?1 for PAHs) were achieved. The advantage of the developed method is that the Fe3O4@Au NPs could be reutilized for preconcentrating diverse target analytes in different SPE modes sequentially simply through treatment with desired thiol-containing ligands

20

Solid-phase extraction of carotenoids.  

Science.gov (United States)

In this work, solid-phase extraction (SPE) trapping performance of lutein and beta-carotene, which were used as the model molecules of carotenoids, was investigated. The absorption, elution, and enrichment of carotenoids on SPE cartridges with four different sorbents, i.e. C(30), C(18), diol, and silica, were compared respectively with the help of frontal analysis technique. The high retentions of both lutein and beta-carotene were achieved on the C(18) and C(30) cartridges. The diol and silica cartridges only had good retention for lutein. The optimized SPE method for sample pretreatment for the carotenoids analysis was obtained after the investigation of trapping performance. The method was applied successfully to the analysis of biological sample, i.e. serum and human breast milk. The recovery, accuracy, and precision of SPE method comparing with those of traditional liquid-liquid extraction (LLE) method for the sample pretreatment for the analysis of carotenoids owned a number of advantages such as rapid, no chloroform used, and accurate versus LLE. PMID:19539943

Shen, Yao; Hu, Yumin; Huang, Ke; Yin, Shi'an; Chen, Bo; Yao, Shouzhuo

2009-07-24

21

Facile preparation of surface-exchangeable core@shell iron oxide@gold nanoparticles for magnetic solid-phase extraction: Use of gold shell as the intermediate platform for versatile adsorbents with varying self-assembled monolayers  

Energy Technology Data Exchange (ETDEWEB)

Graphical abstract: -- Highlights: •The core@shell Fe{sub 3}O{sub 4}@Au nanoparticles functionalized with SAMs were successfully constructed. •The SAMs could be transformed from one kind to another via thiol exchange process. •The developed nanomaterials could be applied in mode switching MSPE. -- Abstract: The core@shell Fe{sub 3}O{sub 4}@Au nanoparticles (NPs) functionalized with exchangeable self-assembled monolayers have been developed for mode switching magnetic solid-phase extraction (MSPE) using high performance liquid chromatography with ultraviolet detection. The adsorbents were synthesized by chemical coprecipitation to prepare magnetic cores followed by sonolysis to produce gold shells. Functionalization of Fe{sub 3}O{sub 4}@Au NPs surface was realized through self-assembly of commercially available low molecular weight thiol-containing ligands using gold shells as intermediate platform and the dynamic nature of Au–S chemistry allowed substituent of one thiol-containing ligand with another simply by thiol exchange process. The resultant adsorbents were characterized by transmission electronic microscopy, Fourier transform infrared spectroscopy, elemental analysis, contact angle measurement, and vibrating sample magnetometry. To evaluate the versatile performance of the developed MSPE adsorbents, they were applied for normal-phase SPE followed by reversed-phase SPE. A few kinds of diphenols and polycyclic aromatic hydrocarbons (PAHs) were employed as model analytes, respectively. The predominant parameters affecting extraction efficiency were investigated and optimized. Under the optimum experimental conditions, wide dynamic linear range (6.25–1600 ?g L{sup ?1} for diphenols and 1.56–100 ?g L{sup ?1} for PAHs) with good linearity (r{sup 2} ? 0.989) and low detection limits (0.34–16.67 ?g L{sup ?1} for diphenols and 0.26–0.52 ?g L{sup ?1} for PAHs) were achieved. The advantage of the developed method is that the Fe{sub 3}O{sub 4}@Au NPs could be reutilized for preconcentrating diverse target analytes in different SPE modes sequentially simply through treatment with desired thiol-containing ligands.

Li, Yaping [Beijing National Laboratory of Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Graduate School, University of Chinese Academy of Sciences, Beijing 100049 (China); Qi, Li, E-mail: qili@iccas.ac.cn [Beijing National Laboratory of Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Shen, Ying [Beijing National Laboratory of Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Graduate School, University of Chinese Academy of Sciences, Beijing 100049 (China); Ma, Huimin [Beijing National Laboratory of Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China)

2014-02-06

22

Coordination polymer adsorbent for matrix solid-phase dispersion extraction of pesticides during analysis of dehydrated Hyptis pectinata medicinal plant by GC/MS.  

Science.gov (United States)

The coordination polymer [Zn(BDC)(H(2)O)(2)](n) was tested for extraction of pyrimethanil, ametryn, dichlofluanid, tetraconazole, flumetralin, kresoxim-methyl and tebuconazole from the medicinal plant Hyptis pectinata, with analysis using gas chromatography-mass spectrometry in selected ion monitoring mode (GC/MS, SIM). Experiments carried out at different fortification levels (0.1, 0.5 and 1.0 ?g g(-1)) resulted in recoveries in the range 73-97%, and RSD values were between 5 and 12% for the [Zn(BDC)(H(2)O)(2)](n) sorbent. Detection and quantification limits ranged from 0.02 to 0.07 ?g g(-1) and from 0.05 to 0.1 ?g g(-1), respectively, for the different pesticides studied. The method developed was linear over the range tested (0.04-14.0 ?g g(-1)), with correlation coefficients ranging from 0.9987 to 0.9998. Comparison between [Zn(BDC)(H(2)O)(2)](n) and the commercial phase C(18)-bonded silica showed good performance of the [Zn(BDC)(H(2)O)(2)](n) polymeric sorbent for the pesticides tested. PMID:21111184

Aquino, Adriano; Wanderley, Kaline A; Paiva-Santos, Carlos de Oliveira; de Sá, Gilberto F; Alexandre, Marcelo da R; Júnior, Severino A; Navickiene, Sandro

2010-12-15

23

Determination and speciation of trace and ultratrace selenium ions by energy-dispersive X-ray fluorescence spectrometry using graphene as solid adsorbent in dispersive micro-solid phase extraction.  

Science.gov (United States)

A dispersive micro-solid phase extraction (DMSPE) with graphene as a solid adsorbent and ammonium pyrrolidinedithiocarbamate (APDC) as a chelating agent was proposed for speciation and detemination of inorganic selenium by the energy-dispersive X-ray fluorescence spectrometry (EDXRF). In developed DMSPE, graphene particles are dispersed throughout the analyzed solution, therefore reaction between Se(IV)-APDC complexes and graphene nanoparticles occurs immediately. The concentration of Se(VI) is calculated as the difference between the concentration of selenite after and before prereduction of selenate. A central composite face-centered design with 3 center points was performed in order to optimize conditions and to study the effect of four variables (pH of the sample, concentration of APDC, concentration of Triton-X-100, and sample volume). The best results were obtained when suspension consisting of 200µg of graphene nanosheets, 1.2mg of APDC and 0.06mg of Triton-X-100 was rapidly injected to the 50mL of the analyzed solution. Under optimized conditions Se ions can be determined with a very good recovery (97.7±5.0% and 99.2±6.6% for Se(IV) and Se(VI), respectively) and precision (RSD=5.1-6.6%). Proposed DMSPE/EDXRF procedure allowed to obtain low detection limits (0.032ngmL(-1)) and high enrichment factor (1013±15). The proposed methodology was successfully applied for the determination of Se in mineral, tap, lake and sea water samples as well as in biological materials (Lobster Hepatopancreas and Pig Kidney). PMID:25618680

Kocot, Karina; Leardi, Riccardo; Walczak, Beata; Sitko, Rafal

2015-03-01

24

Solid-phase extraction in segmented flow.  

Science.gov (United States)

Two-phase flow systems are increasingly popular for miniaturized, high-throughput performance of analytical or chemical reactions. In this contribution, we extend a previously described method that allows to increase the range of applications of heterogeneous reactions in two-phase flow, i.e., reactions that rely on isolation and purification of the compound of interest for downstream analysis. Our concept is based on liquid plugs, which serve as miniaturized compartments for the analytical reactions. Purification of the target compound is achieved by extracting the analyte from the aqueous compartments using magnetic beads as solid carriers. In the present paper, we elucidate the influence of parameters such as the polarity of the liquid/liquid and solid/liquid interfaces, the magnetic forces and the fluidic conditions onto the extraction performance. The conditions for reliable extraction and purification of the target compounds are determined. Furthermore, we investigate how to facilitate breaking of the plugs through reduction of the surface tension of the solid/liquid interface. When a lower surface tension is employed, a smaller number of beads is required for the extraction process, which implies a higher sensitivity of the device. In addition, we generate channels with different surface chemistries, which are able to manipulate the flow of the two immiscible liquids. We describe a very simple way to generate such devices and show that we can achieve a transition from segmented flow of plugs to a side-by side flow of the two immiscible liquids, a key requirement for the purification of the compounds. PMID:25300748

Rendl, Martin; Brandstetter, Thomas; Rühe, Jürgen

2014-11-01

25

Solid phase micro-extraction in environmental atmosphere  

International Nuclear Information System (INIS)

Solid phase micro-extraction (SPME) is an advanced technique of sample pretreatment in environmental atmosphere analysis, i.e., a sampling method of extracting volatile organic compounds from environmental gas. According to the primary survey on the theory and application of SPME, a suitable extraction tip, i.e., a coated fused silica fiber, is selected to construct a SPME apparatus. This SPME apparatus is used to extract volatile organic compounds from environmental atmosphere and a qualitative detection is conducted in gas chromatography-mass spectrometer system. Good experimental results are obtained

26

Extraction of Pb2+ using Silica from Rice Husks Ash (RHA – Chitosan as Solid Phase  

Directory of Open Access Journals (Sweden)

Full Text Available The existence of lead (Pb compounds in waters can be caused of waste pollution from industrial activities such as dye and battery industries. Lead has toxic characteristic and is able to causing deseases. The levels of Cr(VI can be decreased by methods such as electroplating, oxidation, reduction, and membrane separation. But this methods require high cost and produce a lot of waste. Furthermore, those methods cannot determine the small concentration of Pb2+. Therefore, solid phase extraction is used because it’s a simple method and can be used to preconcentrate Pb2+ ion. The aim of this study is to create solid phase from nature material as an alternative method to determine Pb2+ in water samples. The solid phase is silica from rice husks ash (RHA that was modified using chitosan. To achieve that aim, the optimization of silica : chitosan composition was done. The influence of Pb2+ concentration and citric acid concentration was studied to obtain optimum recovery of Pb2+. Interaction between Pb2+ ion and solid phase silica – chitosan could be estimated based on the result. The result showed the optimum composition of silica : chitosan is 65% silica : 35% chitosan with Cation Exchange Capacity (CEC 0.00455 mek/g. Mass Adsorbed Pb2+for 1 g silica : chitosan 65% is 9.715 mg/g. Optimum recovery of Pb2+ on solid phase extraction is reached at concentration of Pb2+ 10 ppm and citric acid concentration 0.05 M (88.25 % and 81.18 %. This result showed that solid phase extraction using silica – chitosan can be used as an alternative method to determine Pb2+ in water.

Hanandayu Widwiastuti

2013-03-01

27

Liquid-solid extraction coupled with magnetic solid-phase extraction for determination of pyrethroid residues in vegetable samples by ultra fast liquid chromatography.  

Science.gov (United States)

In this study, liquid-solid extraction coupled with magnetic solid-phase extraction was successfully developed for the extraction of pyrethroid residues in vegetable samples. The analytes were determined by ultra fast liquid chromatography. The pyrethroids were extracted by liquid-solid extraction and then adsorbed onto magnetic adsorbent. Magnetic adsorbent, C18-functionalized ultrafine magnetic silica nanoparticles, was synthesized by chemical coprecipitation, silanization and alkylation. The analytes adsorbed onto the magnetic adsorbent can be simply and rapidly isolated from sample solution with a strong magnet on the bottom of the extraction vessel. The extraction parameters, such as liquid-solid extraction solvent, liquid-solid extraction time, the amount of magnetic adsorbent, magnetic solid-phase extraction time and magnetic solid-phase extraction desorption solvent, were optimized to improve the extraction efficiency. The analytical performances of this method, including linear range, detection limit, precision, and recovery were evaluated. The limits of detection for pyrethroid were between 0.63 and 1.2 ng g(-1). Recoveries obtained by analyzing the four spiked vegetable samples were between 76.0% and 99.5%. The results showed that the present method was a simple, accurate and high efficient approach for the determination of pyrethroids in the vegetable samples. PMID:23953457

Jiang, Chunzhu; Sun, Ying; Yu, Xi; Gao, Yan; Zhang, Lei; Wang, Yuanpeng; Zhang, Hanqi; Song, Daqian

2013-09-30

28

Simultaneous solid phase extraction of cobalt, strontium and cesium from liquid radioactive waste using microcrystalline naphthalene  

International Nuclear Information System (INIS)

Most of the procedures developed for the extraction of cobalt, strontium and cesium by solid phase extraction do not employ simultaneous extraction of them. In this study, rapid simultaneous removal of Co2+, Sr2+ and Cs+ on microcrystalline naphthalene as solid-phase extractant was investigated. These ions were allowed to form chelates with oxine and then adsorbed on freshly microcrystalline naphthalene from aqueous solutions. The solid phase extraction procedure (SPE) was optimized by using model solution containing Co2+, Sr2+ and Cs+ in batch system. The effects of different parameters such as variation in pH, reagent concentration, standing time, naphthalene solution concentration and contact time on the simultaneous removal of these ions was studied. The obtained results indicated that, sorption was found to be rapid, and the percentage removal of Co2+, Sr2+ and Cs+ was found to be 98, 79 and 68% within 10 min, respectively. The kinetics of the sorption process was investigated to understand the kinetic characteristics of sorption of metal chelates onto microcrystalline naphthalene. The developed procedure has been successfully applied to the removal and recovery of 60Co and 134Cs from liquid radioactive waste. The parameters can be used for designing a plant for treatment of wastewater economically.

29

Simultaneous solid phase extraction of cobalt, strontium and cesium from liquid radioactive waste using microcrystalline naphthalene  

Energy Technology Data Exchange (ETDEWEB)

Most of the procedures developed for the extraction of cobalt, strontium and cesium by solid phase extraction do not employ simultaneous extraction of them. In this study, rapid simultaneous removal of Co{sup 2+}, Sr{sup 2+} and Cs{sup +} on microcrystalline naphthalene as solid-phase extractant was investigated. These ions were allowed to form chelates with oxine and then adsorbed on freshly microcrystalline naphthalene from aqueous solutions. The solid phase extraction procedure (SPE) was optimized by using model solution containing Co{sup 2+}, Sr{sup 2+} and Cs{sup +} in batch system. The effects of different parameters such as variation in pH, reagent concentration, standing time, naphthalene solution concentration and contact time on the simultaneous removal of these ions was studied. The obtained results indicated that, sorption was found to be rapid, and the percentage removal of Co{sup 2+}, Sr{sup 2+} and Cs{sup +} was found to be 98, 79 and 68% within 10 min, respectively. The kinetics of the sorption process was investigated to understand the kinetic characteristics of sorption of metal chelates onto microcrystalline naphthalene. The developed procedure has been successfully applied to the removal and recovery of {sup 60}Co and {sup 134}Cs from liquid radioactive waste. The parameters can be used for designing a plant for treatment of wastewater economically.

Hamed, Mostafa Mohamed; Attallah, Mohamed Fathy; Metwally, Sayed Sayed [Atomic Energy Authority, Cairo (Egypt). Hot Labs. and Waste Management Center

2014-07-01

30

Preparation of bioconjugates by solid-phase conjugation to ion exchange matrix-adsorbed carrier proteins  

DEFF Research Database (Denmark)

A solid-phase conjugation method utilizing carrier protein bound to an ion exchange matrix was developed. Ovalbumin was adsorbed to an anion exchange matrix using a batch procedure, and the immobilized protein was then derivatized with iodoacetic acid N-hydroxysuccinimid ester. The activated protein was conjugated with glutathione, the conjugation ratio determined by acid hydrolysis, and amino acid analysis performed with quantification of carboxymethyl cysteine. Elution of conjugates from the resin by a salt gradient revealed considerable heterogeneity in the degree of derivatization, and immunization experiments with the eluted conjugates showed that the more substituted conjugates gave rise to the highest titers of glutathione antibodies. Direct immunization with the conjugates adsorbed to the ion exchange matrix was possible and gave rise to high titers of glutathione antibodies. Conjugates of ovalbumin and various peptides were prepared in a similar manner and used for production of peptide antisera by direct immunization with the conjugates bound to the ion exchanger. Advantages of the method are its solid-phase nature, allowing fast and efficient reactions and intermediate washings, and the ability to release conjugates from the solid phase under mild conditions.

Houen, G.; Olsen, D.T.

2003-01-01

31

Liquid-phase extraction coupled with metal-organic frameworks-based dispersive solid phase extraction of herbicides in peanuts.  

Science.gov (United States)

Liquid-phase extraction coupled with metal-organic frameworks-based dispersive solid phase extraction was developed and applied to the extraction of pesticides in high fatty matrices. The herbicides were ultrasonically extracted from peanut using ethyl acetate as extraction solvent. The separation of the analytes from a large amount of co-extractive fat was achieved by dispersive solid-phase extraction using MIL-101(Cr) as sorbent. In this step, the analytes were adsorbed on MIL-101(Cr) and the fat remained in bulk. The herbicides were separated and determined by high-performance liquid chromatography. The experimental parameters, including type and volume of extraction solvent, ultrasonication time, volume of hexane and eluting solvent, amount of MIL-101(Cr) and dispersive solid phase extraction time, were optimized. The limits of detection for herbicides range from 0.98 to 1.9 ?g/kg. The recoveries of the herbicides are in the range of 89.5-102.7% and relative standard deviations are equal or lower than 7.0%. The proposed method is simple, effective and suitable for treatment of the samples containing high content of fat. PMID:25059170

Li, Na; Wang, Zhibing; Zhang, Liyuan; Nian, Li; Lei, Lei; Yang, Xiao; Zhang, Hanqi; Yu, Aimin

2014-10-01

32

Advances in solid-phase extraction disks for environmental chemistry  

Science.gov (United States)

The development of solid-phase extraction (SPE) for environmental chemistry has progressed significantly over the last decade to include a number of new sorbents and new approaches to SPE. One SPE approach in particular, the SPE disk, has greatly reduced or eliminated the use of chlorinated solvents for the analysis of trace organic compounds. This article discusses the use and applicability of various SPE disks, including micro-sized disks, prior to gas chromatography-mass spectrometry for the analysis of trace organic compounds in water. Copyright (C) 2000 Elsevier Science B.V.

Thurman, E.M.; Snavely, K.

2000-01-01

33

A molecularly imprinted polymer for solid phase extraction of allantoin  

International Nuclear Information System (INIS)

We describe a molecularly imprinted polymer (MIP) for the solid-phase extraction of the skin protectant allantoin. The MIP was deposited on the surface of monodisperse silica microspheres possessing acroyl groups on the surface (MH-SiO2). The resulting MIP microspheres (MH-SiO2.MIP) showed a 3.4-fold higher adsorption capacity and a 1.9-fold better selectivity for allantoin than the respective non-imprinted polymer (MH-SiO2.NIP). The monolayer adsorption capacities of the MH-SiO2.MIP and the MH-SiO2.NIP were calculated with the help of the Langmuir model and found to be 6.8 and 1.9 mg•g?1, respectively. Adsorption kinetics fit a pseudo-second order rate mechanism, with an initial adsorption rate of 1.44 for the MH-SiO2.MIP, and of 0.07 mg•g?1•min?1 for the MH-SiO2.NIP. The material can be regenerated, and its adsorption capacity for allantoin remains stable for at least five regeneration cycles. It was successfully used as a sorbent for the selective solid-phase extraction of allantoin from Rhizoma dioscoreae. (author)

34

Determination of organophosphorus pesticides in peanut oil by dispersive solid phase extraction gas chromatography-mass spectrometry.  

Science.gov (United States)

The organophosphorus pesticides including phorate, diazinon, tolclofos-methyl, fenitrothin, malathion, fenthion, isocarbophos, quinalphos and phenamiphos, in peanut oils were determined by liquid-liquid extraction coupled with dispersive solid phase extraction and gas chromatography-mass spectrometry (GC-MS). The mixture of multi-walled carbon nanotubes and alumina was used as adsorbent in dispersive solid phase extraction. The effects of some experimental conditions, such as types of multi-walled carbon nanotubes, amount of adsorbents and extraction time were examined. The limits of detection for the analytes were between 0.7 and 1.6 ?g kg(-1). The obtained recoveries of the analytes in the samples were between 85.9 and 114.3% and relative standard deviations were lower than 8.48%. PMID:21963478

Su, Rui; Xu, Xu; Wang, Xinghua; Li, Dan; Li, Xueyuan; Zhang, Hanqi; Yu, Aimin

2011-11-15

35

Magnetic nanoparticle-based solid-phase extraction of vitamin B12 from pharmaceutical formulations.  

Science.gov (United States)

In the present study, a novel quantitative method, namely magnetic nanoparticle-based solid-phase extraction (MSPE), was applied to extract vitamin B(12) from pharmaceutical formulations. The technique involves the use of Fe(3)O(4) nanoparticles modified by sodium dodecyl sulfate (SDS) as an efficient adsorbent for solid-phase extraction of vitamin B(12). Collection of magnetic nanoparticles (MNPs) from aqueous solution was simply achieved by applying external magnetic field. The analyte was desorbed from MNPs using alkali 1-propanol. The extracted analyte was analyzed by using flow injection inductively coupled plasma-optical emission spectrometry. Factors affecting the extraction efficiency were investigated and optimized. Under the optimum conditions, enhancement factor of 184, linear dynamic range of 2.5-500 ?g L(-1) with correlation of determination (R(2) > 0.999), and limit of detection of 1.0 ?g L(-1) were obtained for vitamin B(12). The percent relative standard deviation based on five-replicate determination was less than 6.2%. The method was successfully applied for extraction and determination of vitamin B(12) in different types of pharmaceutical samples such as multivitamin tablet, effervescent tablet, and injection sample. The results showed that the proposed method based on SDS-Fe(3)O(4) MSPE was a simple, accurate, and highly efficient approach for analysis of vitamin B(12). PMID:22187326

Yamini, Yadollah; Tahmasebi, Elham; Ranjbar, Leila

2012-06-01

36

Highly selective solid-phase extraction of trace Pd(II) by murexide functionalized halloysite nanotubes  

International Nuclear Information System (INIS)

Graphical abstract: Murexide functionalized halloysite nanotubes have been developed to separate and concentrate trace Pd(II) from aqueous samples. Parameters that affected the sorption and elution efficiency were studied in column mode, and the new adsorbent presented high selectivity and adsorption capacity for the solid phase extraction of trace Pd(II). Highlights: ? Murexide modified halloysite nanotubes as adsorbent has been reported originally. ? This adsorbent has a unique selectivity for Pd(II) at pH 1.0. ? This adsorbent had high adsorption capacity for Pd(II). ? The precision and accuracy of the method are satisfactory. - Abstract: The originality on the high efficiency of murexide modified halloysite nanotubes as a new adsorbent of solid phase extraction has been reported to preconcentrate and separate Pd(II) in solution samples. The new adsorbent was confirmed by Fourier transformed infrared spectra, X-ray diffraction, scanning electron microscope, transmission electron microscope and N2 adsorption–desorption isotherms. Effective preconcentration conditions of analyte were examined using column procedures prior to detection by inductively coupled plasma-optical emission spectrometry (ICP-OES). The effects of pH, the amount of adsorbent, the sample flow rate and volume, the elution condition and the interfering ions were optimized in detail. Under the optimized conditions, Pd(II) could be retained on the column at pH 1.0 and quantitativcolumn at pH 1.0 and quantitatively eluted by 2.5 mL of 0.01 mol L?1 HCl–3% thiourea solution at a flow rate of 2.0 mL min?1. The analysis time was 5 min. An enrichment factor of 120 was accomplished. Common interfering ions did not interfere in both separation and determination. The maximum adsorption capacity of the adsorbent at optimum conditions was found to be 42.86 mg g?1 for Pd(II). The detection limit (3?) of the method was 0.29 ng mL?1, and the relative standard deviation (RSD) was 3.1% (n = 11). The method was validated using certified reference material, and has been applied for the determination of trace Pd(II) in actual samples with satisfactory results.

37

Highly selective solid-phase extraction of trace Pd(II) by murexide functionalized halloysite nanotubes  

Energy Technology Data Exchange (ETDEWEB)

Graphical abstract: Murexide functionalized halloysite nanotubes have been developed to separate and concentrate trace Pd(II) from aqueous samples. Parameters that affected the sorption and elution efficiency were studied in column mode, and the new adsorbent presented high selectivity and adsorption capacity for the solid phase extraction of trace Pd(II). Highlights: Black-Right-Pointing-Pointer Murexide modified halloysite nanotubes as adsorbent has been reported originally. Black-Right-Pointing-Pointer This adsorbent has a unique selectivity for Pd(II) at pH 1.0. Black-Right-Pointing-Pointer This adsorbent had high adsorption capacity for Pd(II). Black-Right-Pointing-Pointer The precision and accuracy of the method are satisfactory. - Abstract: The originality on the high efficiency of murexide modified halloysite nanotubes as a new adsorbent of solid phase extraction has been reported to preconcentrate and separate Pd(II) in solution samples. The new adsorbent was confirmed by Fourier transformed infrared spectra, X-ray diffraction, scanning electron microscope, transmission electron microscope and N{sub 2} adsorption-desorption isotherms. Effective preconcentration conditions of analyte were examined using column procedures prior to detection by inductively coupled plasma-optical emission spectrometry (ICP-OES). The effects of pH, the amount of adsorbent, the sample flow rate and volume, the elution condition and the interfering ions were optimized in detail. Under the optimized conditions, Pd(II) could be retained on the column at pH 1.0 and quantitatively eluted by 2.5 mL of 0.01 mol L{sup -1} HCl-3% thiourea solution at a flow rate of 2.0 mL min{sup -1}. The analysis time was 5 min. An enrichment factor of 120 was accomplished. Common interfering ions did not interfere in both separation and determination. The maximum adsorption capacity of the adsorbent at optimum conditions was found to be 42.86 mg g{sup -1} for Pd(II). The detection limit (3{sigma}) of the method was 0.29 ng mL{sup -1}, and the relative standard deviation (RSD) was 3.1% (n = 11). The method was validated using certified reference material, and has been applied for the determination of trace Pd(II) in actual samples with satisfactory results.

Li Ruijun; He Qun; Hu Zheng; Zhang Shengrui [Department of Chemistry, Lanzhou University, Lanzhou 730000 (China); Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, Lanzhou 730000 (China); Zhang Lijun [Faculty of Science and Engineer, Curtin University, Perth, WA 6845 (Australia); Chang Xijun, E-mail: lirj2010@lzu.edu.cn [Department of Chemistry, Lanzhou University, Lanzhou 730000 (China); Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, Lanzhou 730000 (China)

2012-02-03

38

Solid phase extraction-spectrophotometric determination of dissolved aluminum in soil extracts and ground waters.  

Science.gov (United States)

An on-line solid-phase extraction (SPE) technique, linked to spectrophotometry, has been developed to overcome the problem of high matrix concentration, which is thought to interfere with the determination of low levels of aluminum (Al) in environmental samples. Tiron modified resin was prepared and used as a SPE absorbent, which can quantitatively adsorb Al(III) at pH 4-6 with an adsorption capacity of 5.6 mg g(-1) resin. The main advantages of this novel method are: (1) a much higher sensitivity has been obtained by SPE technology; and (2) a large amount of Na(+), K(+), Ca(2+) and Mg(2+) can be removed and the interference of Fe(III), Mn(II) and F(-) can be efficiently eliminated by eluting with 0.25 mol l(-1) NaOH. It is a highly selective and sensitive method for simple and quick determination of dissolved Al in soil extracts and ground waters, particularly suitable for the analysis of complex environmental samples. PMID:14507474

Luo, Mingbiao; Bi, Shuping

2003-09-15

39

Spectrometric Determination of Rhodamine B in Chili Powder After Molecularly Imprinted Solid Phase Extraction  

Energy Technology Data Exchange (ETDEWEB)

This paper reports a method using molecularly imprinted polymers that are grafted onto the surface of carboxyl-modified multi-walled carbon nanotubes as the solid-phase extraction adsorbents to detect Rhodamine B in chili powder samples. The polymers were characterized by FTIR and TGA. Various parameters which probably influence efficiency of extraction were optimized. The analytical parameters such as precision, accuracy and linear working range were also determined in optimal experimental conditions. And the proposed method was applied to analysis of Rhodamine B in chili powder samples. The limits of detection and quantification were 2.57 and 8.56 ?g/g, respectively. The recoveries for analytes were higher than 95% and relative standard deviation values were found to be in the range of 0.83-4.15%. This method was successfully applied for the determination of Rhodamine B.

Liu, Xiuying; Zhang, Xuan; Zhou, Qian; Bai, Bing; Ji, Shujuan [Shenyang Agricultural Univ., Shenyang (China)

2013-11-15

40

Spectrometric Determination of Rhodamine B in Chili Powder After Molecularly Imprinted Solid Phase Extraction  

International Nuclear Information System (INIS)

This paper reports a method using molecularly imprinted polymers that are grafted onto the surface of carboxyl-modified multi-walled carbon nanotubes as the solid-phase extraction adsorbents to detect Rhodamine B in chili powder samples. The polymers were characterized by FTIR and TGA. Various parameters which probably influence efficiency of extraction were optimized. The analytical parameters such as precision, accuracy and linear working range were also determined in optimal experimental conditions. And the proposed method was applied to analysis of Rhodamine B in chili powder samples. The limits of detection and quantification were 2.57 and 8.56 ?g/g, respectively. The recoveries for analytes were higher than 95% and relative standard deviation values were found to be in the range of 0.83-4.15%. This method was successfully applied for the determination of Rhodamine B

41

[Corrected Title: Solid-Phase Extraction of Polar Compounds from Water] Automated Electrostatics Environmental Chamber  

Science.gov (United States)

A solid-phase extraction (SPE) process has been developed for removing alcohols, carboxylic acids, aldehydes, ketones, amines, and other polar organic compounds from water. This process can be either a subprocess of a water-reclamation process or a means of extracting organic compounds from water samples for gas-chromatographic analysis. This SPE process is an attractive alternative to an Environmental Protection Administration liquid-liquid extraction process that generates some pollution and does not work in a microgravitational environment. In this SPE process, one forces a water sample through a resin bed by use of positive pressure on the upstream side and/or suction on the downstream side, thereby causing organic compounds from the water to be adsorbed onto the resin. If gas-chromatographic analysis is to be done, the resin is dried by use of a suitable gas, then the adsorbed compounds are extracted from the resin by use of a solvent. Unlike the liquid-liquid process, the SPE process works in both microgravity and Earth gravity. In comparison with the liquid-liquid process, the SPE process is more efficient, extracts a wider range of organic compounds, generates less pollution, and costs less.

Sauer, Richard; Rutz, Jeffrey; Schultz, John

2005-01-01

42

New methods and materials for solid phase extraction and high performance liquid chromatography  

Energy Technology Data Exchange (ETDEWEB)

This paper describes methods for solid phase extraction and high performance liquid chromatography (HPLC). The following are described: Effects of Resin Sulfonation on the Retention of Polar Organic Compounds in Solid Phase Extraction; Ion-Chromatographic Separation of Alkali Metals In Non-Aqueous Solvents; Cation-Exchange Chromatography in Non-Aqueous Solvents; and Silicalite As a Stationary Phase For HPLC.

Dumont, P.J.

1996-04-23

43

MOLECULAR IMPRINTED SOLID PHASE EXTRACTION FOR DETERMINATION OF ATRAZINE IN ENVIRONMENTAL SAMPLES  

Directory of Open Access Journals (Sweden)

Full Text Available Solid phase extraction is one of the major applications of molecularly imprinted polymers fields for clean-up of environmental and biological samples namely molecularly imprinted solid-phase extraction. In this study, solid phase extraction using the imprinted polymer has been optimized with the experimental design approach for a triazine herbicide, named atrazine with regard to the critical factors which influence the molecular imprinted solid phase extraction efficiency such as sample pH, concentration, flow-rate, volume, elution solvent, washing solvent and sorbent mass. Optimization methods that involve changing one factor at a time can be laborious. A novel approach for the optimization of imprinted solid-phase extraction using chemometrics is described. The factors were evaluated statistically and also validated with spiked water samples and showed a good reproducibility over six consecutive days as well as six within-day experiments. Also, in order to the evaluate efficiency of the optimized molecularly imprinted solid-phase extraction protocols, enrichment capacity, reusability and cross-reactivity of cartridges have been also evaluated. Finally, selective molecularly imprinted solid-phase extraction of atrazine was successfully demonstrated with a recovery above 90% for spiked drinking water samples. It was concluded that the chemometrics is frequently employed for analytical method optimization and based on the obtained results, it is believed that the central composite design could prove beneficial for aiding the molecularly imprinted polymer and molecularly imprinted solid-phase extraction development.

A. R. Koohpaei ? S. J. Shahtaheri ? M. R. Ganjali ? A. Rahimi Forushani

2008-10-01

44

MOLECULARLY IMPRINTED SOLID PHASE EXTRACTION FOR TRACE ANALYSIS OF DIAZINON IN DRINKING WATER  

Directory of Open Access Journals (Sweden)

Full Text Available Amongst organophosphate pesticides, the one most widely used and common environmental contaminant is diazinon; thus methods for its trace analysis in environmental samples must be developed. Use of diazinon imprinted polymers such as sorbents in solid phase extraction, is a prominent and novel application area of molecular imprinted polymers. For diazinon extraction, high performance liquid chromatography analysis was demonstrated in this study. During optimization of the molecular imprinted solid phase extraction procedure for efficient solid phase extraction of diazinon, Plackett-Burman design was conducted. Eight experimental factors with critical influence on molecular imprinted solid phase extraction performance were selected, and 12 different experimental runs based on Plackett-Burman design were carried out. The applicability of diazinon imprinted polymers as the sorbent in solid phase extraction, presented obtained good recoveries of diazinon from LC-grade water. An increase in pH caused an increase in the recovery on molecular imprinted solid phase extraction. From these results, the optimal molecular imprinted solid phase extraction procedure was as follows: solid phase extraction packing with 100 mg diazinon imprinted polymers; conditioning with 5 mL of methanol and 6 mL of LC-grade water; sample loading containing diazinon (pH=10; washing with 1 mL of LC-grade water, 1 mL LC- grade water containing 30% acetonitrile and 0.5 mL of acetonitrile, respectively; eluting with 1 mL of methanol containing 2% acetic acid. The percentage recoveries obtained by the optimized molecular imprinted solid phase extraction were more than 90% with drinking water spiked at different trace levels of diazinon. Generally speaking, the molecular imprinted solid phase extraction procedure and subsequent high performance liquid chromatography analysis can be a relatively fast and proper approach for qualitative and quantitative analysis of diazinon in drinking water.

M. Rahiminejad ? S. J. Shahtaheri ? M. R. Ganjali ? A. Rahimi Forushani ? F. Golbabaei

2009-04-01

45

Novel materials and methods for solid-phase extraction and liquid chromatography  

Energy Technology Data Exchange (ETDEWEB)

This report contains a general introduction which discusses solid-phase extraction and solid-phase micro-extraction as sample preparation techniques for high-performance liquid chromatography, which is also evaluated in the study. This report also contains the Conclusions section. Four sections have been removed and processed separately: silicalite as a sorbent for solid-phase extraction; a new, high-capacity carboxylic acid functionalized resin for solid-phase extraction; semi-micro solid-phase extraction of organic compounds from aqueous and biological samples; and the high-performance liquid chromatographic determination of drugs and metabolites in human serum and urine using direct injection and a unique molecular sieve.

Ambrose, D.

1997-06-24

46

Improved resins and novel materials and methods for solid phase extraction and high performance liquid chromatography  

Energy Technology Data Exchange (ETDEWEB)

Solid-phase extraction (SPE) has grown to be one of the most widely used methods for isolation and preconcentration of a vast range of compounds from aqueous solutions. By modifying polymeric SPE resins with chelating functional groups, the selective uptake of metals was accomplished. The resin, along with adsorbed metals, was vaporized in the ICP and detection of the metals was then possible using either mass or emission spectroscopy. Drug analyses in biological fluids have received heightened attention as drug testing is on the increase both in sports and in the work environment. By using a direct-injection technique, biological fluids can be injected directly into the liquid chromatographic system with no pretreatment. A new surfactant, a sulfonated form of Brij-30 (Brij-S) is shown to prevent the uptake of serum proteins on commercial HPLC columns by forming a thin coating on the silica C18 surface. Excellent separations of eight or more drugs with a wide range of retention times were obtained. The separations had sharper peaks and lower retention times than similar separations performed with the surfactant sodium dodecylsulfate (SDS). Quantitative recovery of a number of drugs with limits of detection near 1 ppm with a 5 {micro}l injection volume were obtained. Finally, a method for solid-phase extraction in a syringe is introduced. The system greatly reduced the volume of solvent required to elute adsorbed analytes from the SPE bed while providing a semi-automated setup. SPE in a syringe consists of a very small bed of resin-loaded membrane packed into a GC or HPLC syringe. After extraction, elution was performed with just a few {micro}l of solvent. This small elution volume allowed injection of the eluent directly from the syringe into the chromatographic system, eliminating the handling problems associated with such small volumes.

Freeze, R.

1997-10-08

47

HPLC method for determination of verapamil in human plasma after solid-phase extraction.  

Science.gov (United States)

A simple, rapid and precise HPLC method has been developed for the assay of verapamil in human plasma. The clean up of the plasma samples was tested using several adsorbents for solid-phase extraction and best recovery was obtained using mixed-mode cartridges (HLB - hydrophilic-lipophilic balance) ranging between 94.70 and 103.71%. HPLC separation was performed with isocratic elution on Lichrospher 60 RP-select B column (250 mm x 4 mm I.D., 5 microm particle size). The mobile phase was 40% acetonitrile and 0.025 mol/L KH2PO4 with pH 2.5 at flow rate of 1 mL/min. Diltiazem was used as internal standard and the detection wavelength was 200 nm. The calibration curves were linear in the range of 10-500 ng/mL. The developed method is convenient for routine analysis of verapamil in human plasma. PMID:17977602

Ivanova, Violeta; Zendelovska, Dragica; Stefova, Marina; Stafilov, Trajce

2008-04-24

48

[A new solid-phase extraction method for human urinary 3-methoxy-4-hydroxyphenylethyleneglycol].  

Science.gov (United States)

A new solid-phase extraction procedure for urinary 3-methoxy-4-hydroxy-phenylethyleneglycol (MHPG) was established. Sep-Pak Diol cartridge was used, because MHPG is a neutral and alcoholic compound. Aqueous samples were adsorbed to the cartridge, then MHPG was eluted by the addition of ethyl acetate. After the eluate was evaporated, the residuum was dissolved with HPLC mobile phase and injected into HPLC. The extraction procedure was highly specific to MHPG, and none of other acidic catecholamine metabolites, such as vanillylmandelic acid (VMA), homovanillic acid (HVA) and 3,4-dihydroxyphenylacetic acid (DOPAC), was extracted. The recovery of MHPG using this method was over 90% and higher than those using previously described methods such as liquid-liquid extraction with ethyl acetate. Of the three vanillyl alcohol isomers, isovanillyl alcohol was the most suitable as an internal standard for the correction of column-to-column variation of the recovery. Human urinary unconjugated MHPG extracted by the new procedure could be measured by HPLC with a fluorescence detection. Further complicated derivatization and more sensitive detection systems, such as GC-MS and HPLC-electrochemical detector (ECD), were not needed due to high selectivity and high recovery of the extraction procedure. In addition, the urinary total (conjugated plus unconjugated) MHPG content could also be determined by the same procedure after an enzymatic hydrolysis of conjugated MHPG. The newly developed extraction procedure was simple, rapid and highly specific, and might be applicable to the analysis of MHPG in various body fluids. PMID:8950872

Hirata, K; Inagaki, H; Minami, M

1996-10-01

49

Determination of volatile organic compounds in river water by solid phase extraction and gas chromatography.  

Science.gov (United States)

A simple, rapid, and reproducible method is described employing solid-phase extraction (SPE) using dichloromethane followed by gas chromatography (GC) with flame ionization detection (FID) for determination of volatile organic compound (VOC) from the Buriganga River water of Bangladesh. The method was applied to detect the benzene, toluene, ethylbenzene, xylene and cumene (BTEXC) in the sample collected from the surface or 15 cm depth of water. Two-hundred ml of n-hexane-pretreated and filtered water samples were applied directly to a C18 SPE column. BTEXC were extracted with dichloromethane and average concentrations were obtained as 0.104 to 0.372 microg/ml. The highest concentration of benzene was found as 0.372 microg/ml with a relative standard deviation (RSD) of 6.2%, and cumene was not detected. Factors influencing SPE e.g., adsorbent types, sample load volume, eluting solvent, headspace and temperatures, were investigated. A cartridge containing a C18 adsorbent and using dichloromethane gave better performance for extraction of BTEXC from water. Average recoveries exceeding 90% could be achieved for cumene at 4 degrees C with a 2.7% RSD. PMID:15272731

Mottaleb, M A; Abedin, M Z; Islam, M S

2004-01-01

50

Poly-3,4-ethylenedioxythiophene nanoclusters for high effective solid phase extraction.  

Science.gov (United States)

Solid phase extraction (SPE) has emerged as the widely used technique for sample preparation in the analytical process. Recent research trends of SPE are toward developing novel adsorbents to enrich the analytes simply and effectively. In this study, we proposed the poly-3,4-ethylenedioxythiophene (PEDOT) nanoclusters as the SPE adsorbent. During the application, only a small amount of PEDOT nanoclusters was needed and placed in a pipet tip with glass wool on either side. Without complex preparation, the target analytes could be directly extracted from the sample onto the extraction material and eluted in this lab-in-a-pipet-tip system. The efficiency of this approach was demonstrated by detecting 20 kinds of sulfonamides (SAs) in honey with ultra-performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS). All the analytes were detected by multiple reaction monitoring (MRM) mode. The established method was extensively validated by determining the linearity (R(2)?0.991), average recovery (88.4-105.0%) and precision (relative standard deviation ?9.60%). Low detection limits (0.5-4 ?g kg(-1)), wide linearity (10-250 ?g kg(-1)) and short sample pretreatment time (20 min) were achieved under the optimized conditions. The absolute recoveries of the SAs at high level ranged from 71.1% to 91.4%. Due to its simplicity, selectivity and sensitivity, our new method has potential applications in quantitative analysis of the target compounds in complex samples. PMID:23305852

Tian, Tian; Zheng, Shenglan; Ye, Baofen; Qu, Bing; Zhao, Yuanjin; Kang, Xuejun; Gu, Zhongze

2013-02-01

51

Selective solid-phase extraction of uranium by salicylideneimine-functionalized hydrothermal carbon  

Energy Technology Data Exchange (ETDEWEB)

Highlights: Black-Right-Pointing-Pointer Hydrothermal carbon material as solid-phase extractant matrix. Black-Right-Pointing-Pointer An excellent hexavalent cation ligand, salicylideneimine, is grafted on the matrix. Black-Right-Pointing-Pointer Adsorbent shows high affinity and selectivity to U(VI) in simulated nuclear effluent. Black-Right-Pointing-Pointer Process is fast, endothermic, spontaneous, and pseudo-second-order chemisorption. - Abstract: A new salicylideneimine-functionalized hydrothermal-carbon-based solid-phase extractant was developed for the purpose of separating uranium selectively for sustainability of uranium resources. The resulting adsorption material was obtained via hydrothermal carbonization, calcination at mild temperature (573.15 K), amination, and grafting with salicylaldehyde in sequence. Both Fourier transform infrared spectra and elemental analysis proved the successful grafting of salicylideneimine onto hydrothermal carbon matrix. Adsorption behaviors of the extractant on uranium(VI) were investigated by varying pH values of solution, adsorbent amounts, contact times, initial metal concentrations, temperatures, and ionic strengths. An optimum adsorption capacity of 1.10 mmol g{sup -1} (261 mg g{sup -1}) for uranium(VI) was obtained at pH 4.3. The present adsorption process obeyed pseudo-second-order model and Langmuir isotherm. Thermodynamic parameters ({Delta}H = +8.81 kJ mol{sup -1}, {Delta}S = +110 J K{sup -1} mol{sup -1}, {Delta}G = -23.0 kJ mol{sup -1}) indicated the adsorption process was endothermic and spontaneous. Results from batch adsorption test in simulated nuclear industrial effluent, containing Cs{sup +}, Sr{sup 2+}, Ba{sup 2+}, Mn{sup 2+}, Co{sup 2+}, Ni{sup 2+}, Zn{sup 2+}, La{sup 3+}, Ce{sup 3+}, Nd{sup 3+}, Sm{sup 3+}, and Gd{sup 3+}, showed the adsorbent could separate uranium(VI) from those competitive ions with high selectivity. The adsorbent might be promising for use in certain key steps in any future sustainable nuclear fuel cycle.

Wang, Hang; Ma, Lijian; Cao, Kecheng; Geng, Junxia; Liu, Jun; Song, Qiang; Yang, Xiaodan [College of Chemistry, Sichuan University, Key Laboratory of Radiation Physics and Technology (Sichuan University), Ministry of Education, Chengdu 610064 (China); Li, Shoujian, E-mail: sjli000616@scu.edu.cn [College of Chemistry, Sichuan University, Key Laboratory of Radiation Physics and Technology (Sichuan University), Ministry of Education, Chengdu 610064 (China)

2012-08-30

52

Optimization of cloud point extraction and solid phase extraction methods for speciation of arsenic in natural water using multivariate technique  

International Nuclear Information System (INIS)

The simple and rapid pre-concentration techniques viz. cloud point extraction (CPE) and solid phase extraction (SPE) were applied for the determination of As3+ and total inorganic arsenic (iAs) in surface and ground water samples. The As3+ was formed complex with ammonium pyrrolidinedithiocarbamate (APDC) and extracted by surfactant-rich phases in the non-ionic surfactant Triton X-114, after centrifugation the surfactant-rich phase was diluted with 0.1 mol L-1 HNO3 in methanol. While total iAs in water samples was adsorbed on titanium dioxide (TiO2); after centrifugation, the solid phase was prepared to be slurry for determination. The extracted As species were determined by electrothermal atomic absorption spectrometry. The multivariate strategy was applied to estimate the optimum values of experimental factors for the recovery of As3+ and total iAs by CPE and SPE. The standard addition method was used to validate the optimized methods. The obtained result showed sufficient recoveries for As3+ and iAs (>98.0%). The concentration factor in both cases was found to be 40.

53

Enhanced spectrofluorimetric determination of aflatoxin M1 in liquid milk after magnetic solid phase extraction  

Science.gov (United States)

A simple and sensitive method using magnetic solid phase extraction (MSPE) followed by spectrofluorimetric detection has been developed for separation and determination of aflatoxin M1 (AFM1) in liquid milk. The method is based on the extraction of AFM1 on the modified magnetic nanoparticles (MMNPs) and subsequent derivatization of extracted AFM1 to AFM1 hemi-acetal derivative (AFM2a) by reaction with trifluoroacetic acid (TFA) for spectrofluorimetric detection. Magnetic nanoparticles (MNPs) coated by 3-(trimethoxysilyl)-1-propantiol (TMSPT) and modified with 2-amino-5-mercapto-1,3,4-thiadiazole (AMT) were used as adsorbent in MSPE procedure. Influential parameters affecting the extraction efficiency were investigated and optimized. Under the optimum conditions the calibration curve for AFM1 determination showed good linearity in the range 0.030-10.0 ?g L-1 (R2 = 0.9991). The repeatability and reproducibility (RSD%) for 0.050 ?g L-1 of AFM1 were 4.5% and 5.3%, respectively and limit of detection limit (S/N = 3) was estimated to be 0.010 ?g L-1. The developed method was successfully applied for extraction of AFM1 from spiked liquid milk and natural contaminated liquid milk. The good spiked recoveries ranging from 91.6% to 96.1% were obtained. The results demonstrated that the developed method is simple, inexpensive, accurate and remarkably free from interference effects.

Hashemi, Mahdi; Taherimaslak, Zohreh; Rashidi, Somayeh

2014-07-01

54

Mixed micelle cloud point-magnetic dispersive ?-solid phase extraction of doxazosin and alfuzosin.  

Science.gov (United States)

Mixed micelle cloud point extraction (MM-CPE) combined with magnetic dispersive ?-solid phase extraction (MD-?-SPE) has been developed as a new approach for the extraction of doxazosin (DOX) and alfuzosin (ALF) prior to fluorescence analysis. The mixed micelle anionic surfactant sodium dodecyl sulfate and non-ionic polyoxyethylene(7.5)nonylphenylether was used as the extraction solvent in MM-CPE, and diatomite bonding Fe?O? magnetic nanoparticles were used as the adsorbent in MD-?-SPE. The method was based on MM-CPE of DOX and ALF in the surfactant-rich phase. Magnetic materials were used to retrieve the surfactant-rich phase, which easily separated from the aqueous phase under magnetic field. At optimum conditions, a linear relationship between DOX and ALF was obtained in the range of 5-300 ng mL(-1), and the limits of detection were 0.21 and 0.16 ng mL(-1), respectively. The proposed method was successfully applied for the determination of the drugs in pharmaceutical preparations, urine samples, and plasma samples. PMID:24995413

Gao, Nannan; Wu, Hao; Chang, Yafen; Guo, Xiaozhen; Zhang, Lizhen; Du, Liming; Fu, Yunlong

2015-01-01

55

Mixed micelle cloud point-magnetic dispersive ?-solid phase extraction of doxazosin and alfuzosin  

Science.gov (United States)

Mixed micelle cloud point extraction (MM-CPE) combined with magnetic dispersive ?-solid phase extraction (MD-?-SPE) has been developed as a new approach for the extraction of doxazosin (DOX) and alfuzosin (ALF) prior to fluorescence analysis. The mixed micelle anionic surfactant sodium dodecyl sulfate and non-ionic polyoxyethylene(7.5)nonylphenylether was used as the extraction solvent in MM-CPE, and diatomite bonding Fe3O4 magnetic nanoparticles were used as the adsorbent in MD-?-SPE. The method was based on MM-CPE of DOX and ALF in the surfactant-rich phase. Magnetic materials were used to retrieve the surfactant-rich phase, which easily separated from the aqueous phase under magnetic field. At optimum conditions, a linear relationship between DOX and ALF was obtained in the range of 5-300 ng mL-1, and the limits of detection were 0.21 and 0.16 ng mL-1, respectively. The proposed method was successfully applied for the determination of the drugs in pharmaceutical preparations, urine samples, and plasma samples.

Gao, Nannan; Wu, Hao; Chang, Yafen; Guo, Xiaozhen; Zhang, Lizhen; Du, Liming; Fu, Yunlong

2015-01-01

56

Molecularly Imprinted Solid-Phase Extraction and Liquid Chromatography for Biological Samples  

OpenAIRE

This thesis focuses on the use of molecularly imprinted polymers as selective sorbents for solid-phase extraction (MISPE). The MISPE methods developed were mainly intended for use with biological samples, such as human urine and blood plasma. These body fluids are complex samples, which often need an effective clean-up step before analysis to reduce the levels of possible interfering substances from the matrix, especially if the analytes are present in trace amounts. Solid-phase extraction (S...

Mo?ller, Kristina

2006-01-01

57

Investigating the potential of metal-organic framework material as an adsorbent for matrix solid-phase dispersion extraction of pesticides during analysis of dehydrated Hyptis pectinata medicinal plant by GC/MS.  

Science.gov (United States)

Metal-organic frameworks aluminum terephthalate MIL-53 and Cu-benzene-1,3,5-tricarboxylate (BTC) were tested for extraction of pyrimethanil, ametryn, dichlofluanid, tetraconazole, flumetralin, kresoximmethyl, and tebuconazole from the medicinal plant Hyptis pectinata, with analysis using GC/MS in the selected ion monitoring mode. Experiments carried out at different fortification levels (0.1, 0.5, and 1.0 microg/g) resulted in recoveries in the range 61 to 107% with RSD values between 3 and 12% for the metal-organic framework materials. Detection and quantification limits ranged from 0.02 to 0.07 and 0.05 to 0.1 microg/g, respectively, for the different pesticides studied. The method developed was linear over the range tested (0.04-20.0 microg/g), with correlation coefficients ranging from 0.9987 to 0.9998. Comparison of MIL-53 and Cu-BTC with C18-bonded silica showed good performance of the MIL-53 metal-organic framework as a sorbent for the pesticides tested. PMID:23175963

Aquino, Adriano; Ferreira, Jordana Alves; Navickiene, Sandro; Wanderley, Kaline A; de Sá, Gilberto F; Júnior, Severino A

2012-01-01

58

Magnetic three-dimensional graphene solid-phase extraction of chlorophenols from honey samples.  

Science.gov (United States)

A novel magnetic three-dimensional graphene nano-composite (3D-G@Fe3O4) with a high surface area was synthesised by a vacuum freeze-dried method. Due to its high surface area, specific 3D nanoporous structure and excellent magnetic properties, it can be used as a magnetic solid-phase extraction adsorbent. Some chlorophenols in a honey samples were enriched by this nanocomposite prior to their determination by HPLC with ultraviolet detection. Factors that affect the extraction efficiency, such as the amount of 3D-G@Fe3O4, extraction time, sample pH, ionic strength and desorption conditions, were investigated and optimised. Under the optimum conditions, good linearity existed in the range of 10.0-1000.0 ng g(-1). The enrichment factors of the method for the analytes were in the range from 101 to 248. The limits of detection of the method (S/N = 3) were 1.0-1.5 ng g(-1). The recoveries of the method for the analytes at spiking levels of 100.0 and 400.0 ng g(-1) were in the range of 93.2-98.9%. The results showed that the proposed method is simple, reliable and sensitive. It will be a useful tool for the routine monitoring of chlorophenols in honey products. PMID:25397363

Liu, Xingli; Zhou, Xin; Wang, Chun; Wu, Qiuhua; Wang, Zhi

2015-01-01

59

Recovery evaluation of organophosphorus pesticides from bee pollen by matrix solid-phase dispersion extraction using sorbents based on silica and titania  

International Nuclear Information System (INIS)

This work focused on the evaluation of the recovery of organophosphorus pesticides from bee pollen after matrix solid phase-dispersion extraction (MSPD). Materials based on silica, titania and titania modified with polivylnylimidazole or polyestirene were used as adsorbents for the extraction of pesticides. Small amounts of fortified pollen (0.1 g, at 1 micro-g/g of pesticides), adsorbent (0.4 g) and solvent elution (1 mL de acetonitrile – ACN) were used in the extractions. For recovery evaluation, pollen extracts were analyzed by gas chromatography coupled with mass spectrometry.

60

Low level determination of pesticides in environmental water samples using solid-phase extraction and high performance liquid chromatography  

International Nuclear Information System (INIS)

A multi residue analytical method for pesticides in water that utilizes liquid sold extraction, commonly referred to as solid-phase extraction (SPE) with octadecyl bounded silica cartridges (C/sub 18/ BSc's) followed by reverse-phase high performance liquid chromatography (RP-HPLC) with UV-absorption detection was developed. Recoveries of most of pesticides were greater than 81% with C/sub 18/ cartridges from spiked water at 100 and 200 ppb levels. Low background in silica based adsorbent allows detection limits of 0.10-0.25 ppb levels. low background in silica based adsorbed allows detection limits of 0.10-0.25 ppb for the monitored pesticides. (author)

61

Evaluation of Superparamagnetic Silica Nanoparticles for Extraction of Triazines in Magnetic in-Tube Solid Phase Microextraction Coupled to Capillary Liquid Chromatography  

OpenAIRE

The use of magnetic nanomaterials for analytical applications has increased in the recent years. In particular, magnetic nanomaterials have shown great potential as adsorbent phase in several extraction procedures due to the significant advantages over the conventional methods. In the present work, the influence of magnetic forces over the extraction efficiency of triazines using superparamagnetic silica nanoparticles (NPs) in magnetic in tube solid phase microextraction (Magnetic-IT-SPME) co...

Gonza?lez-fuenzalida, R. A.; Moliner-marti?nez, Y.; Helena Prima-Garcia; Antonio Ribera; Campins-falco?, P.; Zaragoza?, Ramon J.

2014-01-01

62

Solid phase extraction of 22 drugs of interest in the forensic toxicology field  

OpenAIRE

Many solid phase extraction columns which are dedicated to the extraction of various drugs associated with their specific protocols are proposed to the analyst. We have optimised a one stage procedure for the extraction from whole blood of acidic, neutral and basic drugs. Each step of the protocol has been optimised so as to obtain the best extraction recovery. The analysis of the extracts (identification and quantification) has been realised with the help of High Performance Liquid Chromatog...

Mélinda Mancebo; Martine Perrin

2008-01-01

63

Adsorption and solid phase extraction of 8-hydroxyquinoline from aqueous solutions by using natural bentonite  

Energy Technology Data Exchange (ETDEWEB)

The nitrogen-heterocyclic compound 8-hydroxyquinoline (8HQ) is one of the components of coal tar and has a wide variety of uses in industry. Because of its toxicity for aquatic organisms and harmful effects for human health, the removal of 8HQ from aqueous solutions by adsorption onto natural bentonite was investigated in the present work. The experimental results show that the optimum pH value of 2.5 is favourable for the 8HQ adsorption. The experimental data were fitted well with the pseudo-second-order kinetic and Langmuir adsorption isotherm models at all studied temperatures. The maximum adsorption capacity obtained from the Langmuir isotherm model at 20 deg. C was 120.6 mg g{sup -1}. The calculated thermodynamic results such as {Delta}G{sup o} (-24.3 kJ mol{sup -1}) and {Delta}H{sup o} (-9.56 kJ mol{sup -1}) indicate that the adsorption process is spontaneous and exothermic in nature. Solid phase extraction of 8HQ was also performed. The X-ray diffractometry (XRD), Fourier Transform Infrared (FTIR) and thermogravimetric (TG) analyses were carried out in order to confirm the 8HQ adsorption onto bentonite. According to the obtained results, natural bentonite can be a reusable and effective adsorbent for the removal of 8HQ.

Erdem, Bilge; Ozcan, Adnan [Department of Chemistry, Faculty of Science, Anadolu University, Yunusemre Campus, 26470 Eskisehir (Turkey); Ozcan, A. Safa, E-mail: asozcan@anadolu.edu.tr [Department of Chemistry, Faculty of Science, Anadolu University, Yunusemre Campus, 26470 Eskisehir (Turkey)

2010-06-15

64

Adsorption and solid phase extraction of 8-hydroxyquinoline from aqueous solutions by using natural bentonite  

International Nuclear Information System (INIS)

The nitrogen-heterocyclic compound 8-hydroxyquinoline (8HQ) is one of the components of coal tar and has a wide variety of uses in industry. Because of its toxicity for aquatic organisms and harmful effects for human health, the removal of 8HQ from aqueous solutions by adsorption onto natural bentonite was investigated in the present work. The experimental results show that the optimum pH value of 2.5 is favourable for the 8HQ adsorption. The experimental data were fitted well with the pseudo-second-order kinetic and Langmuir adsorption isotherm models at all studied temperatures. The maximum adsorption capacity obtained from the Langmuir isotherm model at 20 deg. C was 120.6 mg g-1. The calculated thermodynamic results such as ?Go (-24.3 kJ mol-1) and ?Ho (-9.56 kJ mol-1) indicate that the adsorption process is spontaneous and exothermic in nature. Solid phase extraction of 8HQ was also performed. The X-ray diffractometry (XRD), Fourier Transform Infrared (FTIR) and thermogravimetric (TG) analyses were carried out in order to confirm the 8HQ adsorption onto bentonite. According to the obtained results, natural bentonite can be a reusable and effective adsorbent for the removal of 8HQ.

65

Solid-phase extraction of plant thionins employing aluminum silicate based extraction columns.  

Science.gov (United States)

Thionins belong to a family of cysteine-rich, low-molecular-weight (?5 KDa) biologically active proteins in the plant kingdom. They display a broad cellular toxicity against a wide range of organisms and eukaryotic cell lines. Thionins protect plants against different pathogens, including bacteria and fungi. A highly selective solid-phase extraction method for plant thionins is reported deploying aluminum silicate (3:2 mullite) powder as a sorbent in extraction columns. Mullite was shown to considerably improve selectivity compared to a previously described zirconium silicate embedded poly(styrene-co-divinylbenzene) monolithic polymer. Due to the presence of aluminum(III), mullite offers electrostatic interactions for the selective isolation of cysteine-rich proteins. In comparison to zirconium(IV) silicate, aluminum(III) silicate showed reduced interactions towards proteins which resulted into superior washings of unspecific compounds while still retaining cysteine-rich thionins. In the presented study, European mistletoe, wheat and barley samples were subjected to solid-phase extraction analysis for isolation of viscotoxins, purothionins and hordothionins, respectively. Matrix-assisted laser desorption/ionization time of flight mass spectroscopy was used for determining the selectivity of the sorbent toward thionins. The selectively retained thionins were quantified by colorimetric detection using the bicinchoninic acid assay. For peptide mass-fingerprint analysis tryptic digests of eluates were examined. PMID:24913248

Hussain, Shah; Güzel, Yüksel; Pezzei, Cornelia; Rainer, Matthias; Huck, Christian W; Bonn, Günther K

2014-08-01

66

Detection of ibuprofen and ciprofloxacin by solid-phase extraction and UV/Vis spectroscopy  

Science.gov (United States)

A simple and economic solid-phase extraction coupled with UV/Vis spectrophotometric method is described for the analysis of ibuprofen and ciprofloxacin. Following solid-phase extraction from model wastewater samples containing standard ibuprofen or ciprofloxacin, elutes were analyzed by a UV/Vis spectrophotometer at 225 nm for ibuprofen and 280 nm for ciprofloxacin. The assay was linear for both compounds with good coefficients of correlation. This method shows good recoveries for both compounds with 101.0 ± 9.8% for ibuprofen and 99.4 ± 11.8% ciprofloxacin.

Zhou, Zhengwei; Jiang, Jia Qian

2012-07-01

67

Temperature-swing solid-phase extraction of heavy metals on a poly(N-isopropylacrylamide) hydrogel.  

Science.gov (United States)

The feasibility of temperature-swing adsorption of heavy metals on a thermosensitive N-isopropylacrylamide (NIPA) hydrogel was examined. We have proposed a novel temperature-swing solid-phase extraction (TS-SPE) technique. First, a metal ion in an aqueous solution is complexed with an extractant. Subsequently, the metal-extractant complexes (or micelles) are adsorbed onto the NIPA hydrogel through a hydrophobic interaction above the lower critical solution temperature (LCST). Finally, the metal-extractant complexes are desorbed from the NIPA hydrogel after it is cooled below the LCST. In a model system consisting of Cu(II) ions, sodium n-dodecylbenzenesulfonate (SDBS), and NIPA hydrogel, the proposed TS-SPE technique has been successfully conducted. The following observations can be made: the amount of adsorbed Cu(II) ions increases with the increase in temperature, the maximum adsorption is attained at a temperature above the LCST, and the hydrogel adsorbs and desorbs Cu(II) ions reversibly due to the temperature-swing between 10 and 40 degrees C. The LCSTs of poly(NIPA) in aqueous SDBS solutions with/without CuCl2 and the surface tensions of their solutions suggest that the hydrophobicity of the complex Cu(DBS)2 is greater than the hydrophobicities of SDBS and DBS. In addition to the separation of heavy metals, TS-SPE is potentially applicable to cases such as the separation of biological molecules by means of metal-ion affinity. PMID:17999542

Tokuyama, Hideaki; Iwama, Takahiko

2007-12-18

68

Optimisation of the membrane-assisted passive sampler and its comparison with solid phase extraction technique  

Scientific Electronic Library Online (English)

Full Text Available SciELO South Africa | Language: English Abstract in english A novel membrane-assisted passive sampler was further optimised in the laboratory. It was then compared to the solid phase extraction technique in terms of the extraction efficiency, enrichment factor, detection limit and selectivity in wastewater. The passive sampler was exposed to 3 [...] /revistas/wsa/v36n4/a15exp01.gif"> wastewater samples under laboratory conditions for 3 days. Five hundred millilitres of wastewater was extracted with C18 cartridges. The extraction efficiency of the passive sampler ranged from 4 to 10% while in solid phase extraction it was 40 to 67% for the 3 chlorophenols. In both cases, extraction efficiency was highest for 2,4-dichlorophenol. The low extraction efficiency in the passive sampler supports the idea that it is not an exhaustive extraction technique and does not disturb the chemical equilibrium of the sample. It therefore measures the bioavailable fraction of the compound and can be used for equilibrium sampling and extraction. The obtained enrichment factors from the passive sampler were 89 and 295 for 2-chlorophenol and 2,4-dichlorophenol, respectively. From solid phase extraction, enrichment factors of 102, 113 and 167 were obtained for 2-chlorophenol, 4-chlorophenol and 2,4-dichlorophenol, respectively. The enrichment factor (~2.5) and sampling rates (~28 µ·h-1) were both low for 4-chlorophenol in wastewater from passive sampler extraction. The calculated sampling rates were found to be 2 604 µ·h-1 for 2-chlorophenol, 1 074 µ·h-1 for 4-chlorophenol and 5 089 µ·h-1 for 2,4-dichlorophenol in spiked deionised water. In wastewater, the sampling rates were found to be 1 544 µ·h-1 for 2-chlorophenol, 28 µ·h-1 for 4-chlorophenol and 5 106 µ·h-1 for 2,4-dichlorophenol. The passive sampler was found to be superior in its selectivity towards the target compounds compared to solid phase extraction technique with C18 sorbent. Chromatograms from solid phase extraction of wastewater contained high peaks of unidentified, potentially interfering compounds, especially in the early part of the chromatogram. In contrast, chromatograms from the passive sampler extraction were very clean. The detection limits of the passive sampler were comparable with that of solid phase extraction and were around 1.5 µg·-1 except for 4-chlorophenol that was high in wastewater (~100 µg·-1).

Hlengilizwe, Nyoni; Luke, Chimuka; Branislav, Vrana; Ewa, Cukrowska; Hlanganani, Tutu.

2010-07-01

69

Optimization of Solid Phase Micro-Extraction (SPME) for Monitoring Occupational Exposure to Ethyl Benzene  

OpenAIRE

Background and Objectives: Analytical methods for volatile organic compounds (VOCs) in different samples need extraction of compounds, by applying hazardous solvents. Solid phase micro-extraction (SPME) is a solvent-free equilibrium extraction method, in which proper calibration can allow quantitative determinations of VOCs at a very good sensitivity without the use of any organic solvent. VOCs are general...

Heidari, H.; Shahtaheri, S. J.; Alimohammadi, M.; Rahimi-froshani, A.; Golbabaei, F.

2012-01-01

70

Selective extraction of triazine herbicides based on a combination of membrane assisted solvent extraction and molecularly imprinted solid phase extraction.  

Science.gov (United States)

A selective extraction technique based on the combination of membrane assisted solvent extraction and molecularly imprinted solid phase extraction for triazine herbicides in food samples was developed. Simazine, atrazine, prometon, terbumeton, terbuthylazine and prometryn were extracted from aqueous food samples into a hydrophobic polypropylene membrane bag containing 1000?L of toluene as the acceptor phase along with 100mg of MIP particles. In the acceptor phase, the compounds were re-extracted onto MIP particles. The extraction technique was optimised for the type of organic acceptor solvent, amount of molecularly imprinted polymers particles in the organic acceptor phase, extraction time and addition of salt. Toluene as the acceptor phase was found to give higher triazine binding onto MIP particles compared to hexane and cyclohexane. Extraction time of 120min and 100mg of MIP were found to be optimum parameters. Addition of salt increased the extraction efficiency for more polar triazines. The selectivity of the technique was demonstrated by extracting spiked cow pea and corn extracts where clean chromatograms were obtained compared to only membrane assisted solvent extraction or only molecularly imprinted solid phase extraction. The study revealed that this combination may be a simple way of selectively extracting compounds in complex samples. PMID:21190688

Chimuka, Luke; van Pinxteren, Manuela; Billing, Johan; Yilmaz, Ecevit; Jönsson, Jan Åke

2011-02-01

71

Extraction of Genomic DNA Using Magnetic Nanoparticles (Fe3O4) as a Solid-Phase Support  

OpenAIRE

Magnetic separation technology, using magnetic particles, is quick and easy method for sensitive and reliable captures of specific proteins, genetic material and other biomolecules. The current paper describes a universal genomic DNA extraction method optimized in our laboratory using magnetic nanoparticles as a solid phase adsorbent. The yields of the isolated DNA with magnetic method were higher or equivalent to the conventional procedures in all the samples tested. Additionally, the magnet...

Saiyed, Z. M.; Ramchand, C. N.

2007-01-01

72

A simplified radiometabolite analysis procedure for PET radioligands using a solid phase extraction with micellar medium  

International Nuclear Information System (INIS)

A solid phase extraction method has been developed for simple and high-speed direct determination of PET radioligands in plasma. Methods: This methodology makes use of a micellar medium and a solid-phase extraction cartridge for displacement of plasma protein bound radioligand and separation of PET radioligands from their radiometabolites without significant preparation. The plasma samples taken from monkey or human during PET measurements were mixed with a micellar eluent containing an anionic surfactant sodium dodecyl sulphate and loaded onto SPE cartridges. The amount of radioactivity corresponding to parent radioligand (retained on the cartridge) and its radioactive metabolites (eluted with micellar eluent) was measured. Results: Under the optimized conditions, excellent separation of target PET radioligands from their radiometabolites was achieved with a single elution and short run-time of 1 min. This method was successfully applied to study the metabolism for 11C-labelled radioligands in human or monkey plasma. The amount of parent PET radioligands estimated by micellar solid phase extraction strongly corresponded with that determined by radio-LC. The improved throughput permitted the analysis of a large number of plasma samples (up to 13 samples per one PET study) for accurate estimation of metabolite-corrected input function during quantitative PET imaging studies. Conclusion: Solid phase extraction together with micellar medium is fast, sensitive and easy to use, and therefore it is an attractive alternative method to determine relative composition of PET radioligands in plasma

73

Use of Solid Phase Extraction in the Biochemistry Laboratory to Separate Different Lipids  

Science.gov (United States)

Solid-phase extraction (SPE) was used to demonstrate how various lipids and lipid classes could be separated in a biochemistry laboratory setting. Three different SPE methods were chosen on their ability to separate a lipid mixture, consisting of a combination of a either a fatty acid, a triacylglycerol, a mono- or diacylglycerol, phospholipid,…

Flurkey, William H.

2005-01-01

74

Extraction of Genomic DNA Using Magnetic Nanoparticles (Fe3O4 as a Solid-Phase Support  

Directory of Open Access Journals (Sweden)

Full Text Available Magnetic separation technology, using magnetic particles, is quick and easy method for sensitive and reliable captures of specific proteins, genetic material and other biomolecules. The current paper describes a universal genomic DNA extraction method optimized in our laboratory using magnetic nanoparticles as a solid phase adsorbent. The yields of the isolated DNA with magnetic method were higher or equivalent to the conventional procedures in all the samples tested. Additionally, the magnetic method takes less than 15 minutes to extract DNA as against several hours taken by conventional protocols. Furthermore, the isolated DNA was found to function satisfactorily in PCR amplification and restriction endonuclease digestion. The developed procedure is simple, quick, cheap, robust and does not require the use of organic solvents or sophisticated equipments; thereby making it more amenable to automation.

Z. M. Saiyed

2007-01-01

75

Using a new ligand for solid phase extraction of mercury  

International Nuclear Information System (INIS)

The octadecyl silica cartridge as a sorbent and 4-bpdb (1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene) as a ligand is a simple, rapid and reliable method for extracting and preconcentrating of Hg(II) in real samples prior to cold vapor atomic absorption spectrometry. Sample solutions were passed through a column at pH 4.5 then retained mercury ions on the column were eluted with minimal amount of 0.01 M nitric acid with 3 mL min-1 flow rate. The effect of pH, type of buffer, flow rate of sample and eluent, type and volume of the eluent were investigated and optimized. At optimum effective parameters, concentration factor and detection limit were achieved 128 and 1.87 ng L-1, respectively.

76

Using a new ligand for solid phase extraction of mercury  

Energy Technology Data Exchange (ETDEWEB)

The octadecyl silica cartridge as a sorbent and 4-bpdb (1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene) as a ligand is a simple, rapid and reliable method for extracting and preconcentrating of Hg(II) in real samples prior to cold vapor atomic absorption spectrometry. Sample solutions were passed through a column at pH 4.5 then retained mercury ions on the column were eluted with minimal amount of 0.01 M nitric acid with 3 mL min{sup -1} flow rate. The effect of pH, type of buffer, flow rate of sample and eluent, type and volume of the eluent were investigated and optimized. At optimum effective parameters, concentration factor and detection limit were achieved 128 and 1.87 ng L{sup -1}, respectively.

Soleimani, Majid, E-mail: m-soleimani@hotmail.com [Department of Chemistry, Faculty of Sciences, Imam Khomeini International University (IKIU), Qazvin (Iran, Islamic Republic of); Mahmodi, Mohamad Saleh [Department of Chemistry, Faculty of Sciences, Imam Khomeini International University (IKIU), Qazvin (Iran, Islamic Republic of); Morsali, Ali [Department of Chemistry, Faculty of Sciences, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Khani, Azam; Afshar, Majid Ghahraman [Department of Chemistry, Faculty of Sciences, Imam Khomeini International University (IKIU), Qazvin (Iran, Islamic Republic of)

2011-05-15

77

Solid-phase extraction of antioxidant compounds from commercial cranberry extract and its antiradical activity  

Directory of Open Access Journals (Sweden)

Full Text Available This study is concerned with the fractionation and determination of major antioxidant compounds (phenols, flavonoids, anthocyanins and vitamin C in commercial cranberry extract. The total content of phenolics, flavonoids and total and monomers of anthocyanins, determined spectrophotometrically, was 1.67 mg/g, 0.41 mg/g, 5.12 mg/g and 3.32 mg/g. The content of vitamin C, determined volumetrically, was 121.74 mg/g. Commercial cranberry extract was dissolved in 80 % acetone and the solution was fractionated using solid phase extraction (SPE in order to abstract vitamin C, neutral and acidic phenols. The free radical scavenging activity of the cranberry extract and its fractions was investigated on stable 2,2-diphenyl-1-picrylhydrazyl (DPPH and reactive hydroxyl radicals employing electron spin resonance (ESR spectroscopy. The most effective fractions were those containing vitamin C (AADPPH= AAOH=100%, neutral (AADPPH=89.50% and AAOH=43.11% and acidic (AADPPH=83.98% and AAOH=38.58% phenols. The presence of vitamin C, abstracted from cranberry extract, was determined by Fe(III-mediated ascorbate oxidation which yields characteristic ESR doublet spectrum of ascorbyl radical.

Tumbas Vesna T.

2007-01-01

78

Separation and Purification of Sulforaphane from Broccoli by Solid Phase Extraction  

OpenAIRE

A simple solid-phase extraction (SPE) method for the determination of sulforaphane in broccoli has been developed. The optimal conditions were found to be use of a silica SPE cartridge, and ethyl acetate and dichloromethane as washing and eluting solvents, respectively, which could eliminate interferences originating from the broccoli matrix. The extracts were sufficiently clean to be directly injected into high-performance liquid chromatography (HPLC) for further chromatographic analysis. Go...

Kyung Ho Row; Dandan Han

2011-01-01

79

Graphene oxide bound silica for solid-phase extraction of 14 polycyclic aromatic hydrocarbons in mainstream cigarette smoke.  

Science.gov (United States)

Polycyclic aromatic hydrocarbons (PAHs) were considered as a source of carcinogenicity in mainstream cigarette smoke (MSS). Accurate quantification of these components was necessary for assessing public health risk. In our study, a solid-phase extraction (SPE) method using graphene oxide (GO) bound silica as adsorbent for purification of 14 PAHs in MSS was developed. During SPE process, large matrices interferences of MSS were adsorbed on SPE column. The result of FTIR spectra demonstrated that these matrices interferences were adsorbed on GO mainly through OH and CO groups. The concentrations of PAHs in MSS extract were determined by gas chromatography-mass spectrometry (GC-MS). The limit of detection (LOD) and limit of quantification (LOQ) of the developed method for 14 PAHs ranged from 0.05 to 0.36ng/cig and 0.17 to 1.19ng/cig, respectively. The accuracy of the measurement of 14 PAHs was from 73 to 116%. The relative standard deviations of intra- and inter-day analysis were less than 7.8% and 13.9%, respectively. Moreover, the developed method was successfully applied for analysis of real cigarette containing 1R5F reference cigarette and 12 top-selling commercial cigarettes in China. PMID:25512123

Shi, Rui; Yan, Lihong; Xu, Tongguang; Liu, Dongye; Zhu, Yongfa; Zhou, Jun

2015-01-01

80

Molecularly imprinted polymer solid-phase extraction for detection of zearalenone in cereal sample extracts.  

Science.gov (United States)

The aim of this work was to develop a method for the clean-up and preconcentration of zearalenone from corn and wheat samples employing molecularly imprinted polymer (MIP) as selective sorbent for solid-phase extraction (SPE). Cereal samples were extracted with acetonitrile/water (75:25, v/v) and the extract was diluted with water and applied to an AFFINIMIP ZON MIP-SPE column. The column was then washed to eliminate the interferences and zearalenone was eluted with methanol and quantified using HPLC with fluorescence detection (lambda(exc)=275/lambda(em)=450 nm). The precision and accuracy of the method were satisfactory for both cereals at the different fortification levels tested and it gave recoveries between 82 and 87% (RSDr 2.5-6.2%, n=3) and 86 and 90% (RSDr 0.9-6.8%, n=3) for wheat and maize, respectively. MIP-SPE column capacity was determined to be not less than 6.6 microg of zearalenone and to be at least four times higher than that of immunoaffinity column (IAC). The application of AFFINIMIP ZON molecularly imprinted polymer as a selective sorbent material for detection of zearalenone fulfilled the method performance criteria required by the Commission Regulation (EC) No. 401/2006, demonstrating the suitability of the technique for the control of zearalenone in cereal samples. PMID:20579483

Lucci, Paolo; Derrien, Delphine; Alix, Florent; Pérollier, Céline; Bayoudh, Sami

2010-07-01

81

Determination of banned Sudan dyes in food samples by molecularly imprinted solid phase extraction - high performance liquid chromatography  

OpenAIRE

A method for molecularly imprinted solid-phase extraction of banned Sudan azo-dyes from food samples was investigated. The molecularly imprinted polymer was obtained by suspension polymerization using 1-(4-chlorophenyl)azonaphthalen-2-ol as the mimic template. The molecular recognition properties of imprinted beads were evaluated for use as a solid-phase extraction sorbent, in order to develop a selective extraction protocol for the Sudan class of dyes. The optimised extraction protocol re...

Giraudi, Gianfranco; Anfossi, Laura; Viscardi, Guido; Baggiani, Claudio; Baravalle, Patrizia Domenica; Giovannoli, Cristina; Barolo, Claudia

2009-01-01

82

Simultaneous in situ derivatization and ultrasound-assisted dispersive magnetic solid phase extraction for thiamine determination by spectrofluorimetry.  

Science.gov (United States)

A simple and rapid method for the simultaneous in situ derivatizaion, preconcentration and extraction of thiamine (vitamin B1) as a model analyte was developed by a novel quantitative method, namely ultrasound-assisted dispersive magnetic solid phase extraction spectrofluorimetry (USA-DMSPE-FL) from different real samples. This method consists of sample preparation, in situ derivatization, exhaustive extraction and clean up by a single process. High extraction efficiency and in situ derivatization in a short period of time is the main advantages of this procedure. For this purpose, the reusable magnetic multi-wall carbon nanotube (MMWCNT) nanocomposite was used as an adsorbent for preconcentration and determination of thiamine. Thiamine was, simultaneously, in situ derivatized as thiochrome by potassium hexacyanoferrate (III) and adsorbed on MMWCNT in an ultrasonic water bath. The MMWCNTs were then collected using an external magnetic field. Subsequently, the extracted thiochrome was washed from the surface of the adsorbent and determined by spectrofluorimetry. The developed method, which has been analytically characterized under its optimal operating conditions, allows the detection of the analyte in the samples with method detection limits of 0.37 µg L(-1). The repeatability of the method, expressed as the relative standard deviation (RSD, n=6), varies between 2.0% and 4.8% in different real samples, while the enhancement factor is 197. The proposed procedure has been applied for the determination of thiamine in biological (serum and urine), pharmaceutical (multivitamin tablet and B complex syrup) and foodstuff samples (cereal, wheat flour, banana and honey) with the good recoveries in the range from 90% to 105%. PMID:24725866

Tarigh, Ghazale Daneshvar; Shemirani, Farzaneh

2014-06-01

83

Micro-solid phase extraction of ochratoxin A, and its determination in urine using capillary electrophoresis  

International Nuclear Information System (INIS)

We describe a simple, environmentally friendly and selective technique for the determination of ochratoxin A (OTA) in urine. It involves (a) the use of a molecularly imprinted polymer as a sorbent in micro-solid-phase extraction in which the sorbent is contained in a propylene membrane envelope, and (b) separation and detection by capillary electrophoresis (CE). Under optimized conditions, response is linear in the range between 50 and 300 ng mL?1 (with a correlation coefficient of 0.9989), relative standard deviations range from 4 to 8 %, the detection limit for OTA in urine is 11.2 ng mL?1 (with a quantification limits of 32.5 ng mL?1) which is lower than those of previously reported methods for solid-phase extraction combined with CE. The recoveries of OTA from urine spiked at levels of 50, 150 and 300 ng mL?1 ranged from 93 to 97 %. (author)

84

Dispersive micro-solid phase extraction based on self-assembling, ionic liquid-coated magnetic particles for the determination of clofentezine and chlorfenapyr in environmental water samples.  

Science.gov (United States)

Two ionic liquid-coated-Fe3O4 magnetic particles (IL-Fe3O4 MPs) were developed for use in two types of dispersive micro-solid phase extraction (D-?-SPE) for the high-performance liquid chromatographic analysis of clofentezine and chlorfenapyr in environmental water samples. Self-assembling IL-Fe3O4 MPs were used in D-?-SPE as adsorbents. Two D-?-SPE extraction methods, namely, direct dispersive micro-solid phase extraction (d-D-?-SPE) and in situ solvent formation-based dispersive micro-solid phase extraction (ISF-D-?-SPE), were proposed, using [C8MIM][PF6] to extract analytes through two pathways. Lower IL doses were required in the extraction process compared with those in other IL-based methods. Fe3O4 MPs can also be recycled and reused after extraction and are thus environmentally friendly. These newly developed methods were demonstrated to be feasible for use in the quantitation of clofentezine and chlorfenapyr at trace levels, with lower limit of detection values ranging from 0.4 to 0.5 ng mL(-1) for d-D-?-SPE and 0.4 ng mL(-1) for ISF-D-?-SPE. Finally, relative standard deviations of less than 6.0% were obtained. PMID:24060962

Peng, Bing; Zhang, Jiaheng; Lu, Runhua; Zhang, Sanbing; Zhou, Wenfeng; Gao, Haixiang

2013-11-21

85

Selective extraction of organophosphorus nerve agent degradation products by molecularly imprinted solid-phase extraction.  

Science.gov (United States)

The analysis of alkyl alkylphosphonic acids, the degradation products of V and G nerve agents as VX, Sarin or Soman, is an important task for the verification of compliance to the Chemical Weapons Convention. The detection of these contaminants at low concentration levels is often difficult in complex matrices due to the amount of interfering substances. Molecularly imprinted solid-phase extraction technique should allow a selective extraction of these compounds from complex samples, and thus make their detection easier. Two molecularly imprinted polymers (MIPs) prepared with methacrylic acid (MAA) as monomer and pinacolyl methylphosphonic acid (PMPA) as template molecule were synthesised and tested. The first polymer, MIP A, was prepared with ethylene glycol dimethacrylate (EGDMA) in dichloromethane. The second polymer, MIP B, was synthesised using trimethylolpropane trimethacrylate (TRIM) in acetonitrile. To evaluate the selectivity provided by these MIPs, the retention of the ethyl methylphosphonic acid (EMPA) target molecule was studied in parallel on a non-imprinted polymer (NIP). While MIP A does not show any difference compared to NIP A, a good selectivity was obtained for MIP B. After the optimisation of the extraction process, 60% of EMPA can be removed from the NIP B without affecting the retention on the MIP B. A recovery of extraction of 93% was then obtained on the MIP B. Its capacity was then measured and corresponds to 97 microg of EMPA per gram of MIP. Finally, the selectivity of MIP B was clearly demonstrated by applying it to the clean-up of a soil extract spiked with EMPA. PMID:16451804

Le Moullec, Sophie; Bégos, Arlette; Pichon, Valérie; Bellier, Bruno

2006-03-01

86

Preconcentration and separation of nickel, copper and cobalt using solid phase extraction and their determination in some real samples.  

Science.gov (United States)

A solid phase extraction method has been developed to separate and concentrate trace amounts of nickel, cobalt and copper ions from aqueous samples for the measurement by flame atomic absorption spectrometry. By the passage of aqueous samples through activated carbon modified by dithioxamide (rubeanic acid) (DTO), Ni2+, Cu2+ and Co2+ ions adsorb quantitatively. The recoveries of analytes at pH 5.5 with 500 mg solid phase were greater than 95% without interference from alkaline, earth alkaline and some metal ions. The enrichment factor was 330. The detection limits by three sigma were 0.50 microg L(-1) for copper, 0.75 microg L(-1) for nickel and 0.80 microg L(-1) for cobalt. The loading capacity was 0.56 mg g(-1) for Ni2+, 0.50 mg g(-1) for Cu2+ and 0.47 mg g(-1) for Co2+. The presented procedure was applied to the determination of analytes in tap, river and sea waters, vegetable, soil and blood samples with successfully results (recoveries greater than 95%, R.S.D. lower than 2% for n=3). PMID:17303327

Ghaedi, M; Ahmadi, F; Soylak, M

2007-08-17

87

VOLATILE COMPOUNDS OF LITHRAEA CAUSTICA (LITRE) DETERMINATED BY SOLID PHASE MICRO-EXTRACTION (SPME)  

OpenAIRE

The head space of the aerial parts of Lithraea caustica was analyzed by Solid Phase Micro-Extraction (SPME) technique, obtaining as main volatile compounds the monoterpenes, myrcene, a -pinene, , p-cymene and limonene, as well as the sesquiterpene caryophylene.De las partes áereas de Lithraea caustica y usando la técnica de Micro-Extracción en Fase Sólida (MEFS), fueron identificados y cuantificados los principales compuestos volátiles: los monoterpenos, mirceno, a -pineno, p-cimeno ...

Garbarino, Juan A.; GIUSEPPE SALVATORE; MARISA PIVANOVO; MARÍA CRISTINA CHAMY; MARCELLO NICOLETTI; ALFREDO DE IOANNES

2002-01-01

88

Determination of fungicides in residual tanning floats using solid phase micro extraction  

OpenAIRE

Solid-phase microextraction (SPME) was optimized for extraction of the leather preservative agents 2-(thiocyanomethylthio)-benzothiazole (TCMTB), 4-chloro-3-methylphenol (PCMC), 2-phenylphenol (OPP), 2-Octyl-3(2H)-isothiazolone (OIT), 2-mercaptobenzothiazol (MBT) and 3-iodo-2-propynyl-butylcarbamate (IPBC) in spent tanning floats. Determination was carried out by high performance liquid chromatography (HPLC) with photo diode array detection (PDA). The following parameters were studied to ach...

Font Valle?s, Joaquim; Reyes Reyes, Maria; Cuadros, Sara; Bacardit Dalmases, Anna; Olle? Otero, Llui?s; Marsal Monge, Agusti?n

2013-01-01

89

Headspace Solid Phase Microextraction in Pesticide Residues Analysis:1. Optimisation of Extraction Conditions  

OpenAIRE

The method of headspace solid phase microextraction (HS/SPME) was successfully used in a simultaneous multicomponent analysis of hexachlorobenzene (HCB), tefluthrin, heptachlor, aldrin, chlorpyrifos, fenthion and bifenthrin in aqueous medium. Measurementswere performed using a nonpolar polydimethyl siloxane (PDMS) fiber. Detection and quantification were done by gas chromatography/mass spectrometry (GC/MS).Optimal conditions for HS/SPME were determined both by performing extraction at differe...

Rada ?urovi?; Jelena Milinovi?; Mirjana Markovi?; Dragan Markovi?

2007-01-01

90

Headspace Solid Phase Micro Extraction Gas Chromatographic Determination of Fenthion in Human Serum  

OpenAIRE

A simple and effective analytical procedure was developed for the determination of fenthion residues in human serum samples. The sample treatment was performed using the headspace solid-phase micro extraction with polyacrylate fiber, which has the advantage to require low amount of serum (1 mL) without tedious pre-treatment. The quantification of fenthion was carried out by gas chromatography-mass spectrometry and the recoveries ranged from 79 to 104% at two spiking levels for 6 replicates. D...

Kyriaki Machera; Haroutounian, Serkos A.; Theotokatos, Spiridon A.; Haris Carageorgiou; Tsakirakis, Angelos N.; Helen Souki; Kasiotis, Konstantinos M.

2008-01-01

91

Determination of phenols in landfill leachate-contaminated groundwaters by solid-phase extraction  

OpenAIRE

A solid-phase extraction method for phenols in landfill leachates was developed and optimized in order to solve the expected and observed problems associated with an anaerobic matrix containing high concentrations of salts and organic matter. Isolute ENV1 cartridges exhibited the best retention of phenols of the four sorbents examined, and was the only cartridge which a 1 L leachate sample could pass through. With the other cartridges, clogging made this impossible. The final meth...

Ask Reitzel, Lotte; Ledin, Anna

2006-01-01

92

Recent developments in automatic solid-phase extraction with renewable surfaces exploiting flow-based approaches  

OpenAIRE

Solid-phase extraction (SPE) is the most versatile sample-processing method for removal of interfering species and/or analyte enrichment. Although significant advances have been made over the past two decades in automating the entire analytical protocol involving SPE via flow-injection approaches,on-line SPE assays performed in permanent mode lack sufficient reliability as a consequence of progressively tighter packing of the bead reactor, contamination of the solid surfaces and potential ...

Miro?, Manuel; Hartwell, Supaporn Kradtap; Jakmunee, Jaroon; Grudpan, Kate; Hansen, Elo Harald

2008-01-01

93

PHARMACOKINETIC STUDY OF RISPERIDONE: APPLICATION OF A HPLC METHOD WITH SOLID PHASE EXTRACTION  

OpenAIRE

A new, simplified solid phase extraction procedure for the determination of risperidone and 9-hydroxyrisperidone in human plasma has been developed. This method involves the use of an optimized extraction protocol developed in Waters OASIS® HLB 30mg 1cc extraction columns using 1 mL of human serum. Separation was performed by HPLC using a Waters XTerra RP-18 (5 µm, 150x4,6 mm) column with a mobile phase consisting in acetonitrile - potassium dihydrogen phosphate 50 mM pH 3.4 (27/73). UV det...

Pablo Torres, V.; Jacqueline Sepu?lveda, M. C.; Carlos Von Plessing, R.

2011-01-01

94

Determination of organophosphorus pesticides using molecularly imprinted polymer solid phase extraction  

International Nuclear Information System (INIS)

Molecularly imprinted polymer solid phase extraction (MIP-SPE) method has been developed for the determination of organophosphorus pesticides (OPPs) in water samples. The MIP was prepared by thermo-polymerization method using methacrylic acid (MAA) as functional monomer, ethylene glycol dimethacrylate (EGDMA) as crosslinker, acetonitrile as porogenic solvent and quinalphos as the template molecule. The three OPPs (diazinon, quinalphos and chloropyrifos) were selected as target analytes as they are widely used in agriculture sector. Various parameters affecting the extraction efficiency of the imprinted polymers have been evaluated to optimize the selective preconcentration of OPPs from aqueous samples. The characteristics of the MIP-SPE method were validated by high performance liquid chromatography (HPLC). The accuracy and selectivity of the MIP-SPE process developed were verified using non-imprinted polymer solid phase extraction (NIP-SPE) and a commercial C18-SPE was used for comparison. The recoveries of the target analytes obtained using the MIPs as the solid phase sorbent ranged from 83% to 98% (RSDs 1.05 - 1.98 %; n=3) for water sample. The developed MIP-SPE method demonstrates that it could be applied for the determination of OPPs in water samples. (author)

95

Solid phase extraction of uranium (VI) using penicillium chrysogenum immobilized on silica gel  

International Nuclear Information System (INIS)

Uranium is a metal of strategic importance in the area of Nuclear Technology. It has due to its usage in power generation. Being a toxic element and due to environmental concerns its determination from water, soil and other samples has gained significance. The determination of traces of uranium in such samples requires a preconcentration step. Biosorption methods involving solid phase extraction utilizes various materials of biological origin, including bacteria, fungi, yeast, algae, etc. In the present work a solid phase extraction method for separation and enrichment of uranium (VI) was developed. A solid phase was prepared by immobilization 150 mg of Penicillium and 1.0 g silica. A 350 mg of Penicillium chrysogenum immobilized silica mixed with double distilled water packed in a glass column (150 mm length and 10 mm internal diameter) with wool as support and was systematically investigated to optimize the conditions for quantitative sorption and desorption of uranium (VI). It was determined spectrophotometrically using Arsenazo (III) at 650 nm

96

Solid phase extraction (SPE) and high performance liquid chromatography for fungicides  

International Nuclear Information System (INIS)

Three types of fungicides; oxycarboxin, thiuram disulfide and captafol were analyzed by reversed-phase high performance liquid chromatography (RP-HPLC). The analysis was carried out by using on ODS Hypersil column with acetonitrile-water (40:60) mixture. Solid phase extraction (SPE) was carried out by using a 1000 mg cartridge packed with C sub 18 to extract fungicides from spiked distilled water samples. The detection limits were between 0.5 to 20 ppm for the three fungicides. The percentage recoveries were between 87 to 98%

97

A solid phase radioimmunoassay for detection of antibodies to extractable nuclear antigens  

International Nuclear Information System (INIS)

A solid phase radioimmunoassay is described for the detection of autoantibodies to the saline-soluble extractable nuclear antigens, ribonucleoprotein (RNP) and SS-B (or La). This assay depends on enrichment of antigens from a crude, commercially available (Pel Freez, USA) extract of rabbit thymus by absorption to the F(ab)2 fraction of specific high titre antibody attached to a microtitre plate. Serum antibody reactive with this antigen is then detected by 125I-labelled Protein A. The assay is simple and is more sensitive than the gel diffusion assays in general use for detecting such antibodies. (Auth.)

98

Analysis of ecologically relevant pharmaceuticals in wastewater and surface water using selective solid phase extraction and UPLC/MS/MS  

Science.gov (United States)

A rapid and sensitive method has been developed for the analysis of 48 human prescription active pharmaceutical ingredients (APIs) and 6 metabolites of interest, utilizing selective solid-phase extraction (SPE) and ultra performance liquid chromatography in combination with tripl...

99

Determination of trace copper in food samples by flame atomic absorption spectrometry after solid phase extraction on modified soybean hull  

International Nuclear Information System (INIS)

Soybean hull was chemically modified with citric acid and used as a solid phase extraction adsorbent for the determination of trace amounts of Cu2+ in food samples by flame absorption spectrometry (FAAS). The effect of pH, sample flow rate and volume, elution flow rate and volume and co-existing ions on the recovery of the analyte were investigated. The results showed that Cu2+ could be adsorbed on the modified soybean hull at pH 8.0 and eluted by 2.0 mL of 1.0 mol L-1 HCl. Under the optimized conditions, the adsorption capacity of modified soybean hull was found to be 18.0 mg g-1 for Cu2+. The detection limit of the proposed method was 0.8 ng mL-1 for Cu2+ with an enrichment factor of 18. The analytical result for the certified reference tea sample (GBW07605) was in a good agreement with the certified value. The proposed method has also been successfully applied to the determination of trace Cu2+ in dried sweet potato, lake water and milk powder, the recovery of Cu2+ for spiked samples was between 91% and 109.6%.

100

Matrix solid-phase dispersion versus ultrasound assisted extraction with solid-phase extraction in the HPLC analysis of furanocoumarins from fruits of Archangelica officinalis Hoffm  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Neste estudo, um eficiente método, a dispersão da matriz em fase sólida (DMFS), foi usado para a determinação simultânea de furanocoumarinas de frutos de Archangelica officinalis Hoffm. Amostras da planta foram preparadas pelo procedimento MSPD otimizado, utilizando C18 como sorvente. A análise foi [...] realizada por cromatografia líquida de alta eficiência com detector de arranjo de diodos (HPLC-DAD). A eficiência do método DMFS também foi comparada com a extração assistida por ultra-som associada à extração em fase sólida (SPE com USAE). O MSPD extraiu furanocoumarins (isoimperatorin, imperatorin, bergapteno, isopimpinellin, xantotoxina, umbeliferona e xanthotoxol) de Archangelica officinalis com recuperações satisfatórias que variam de 91,43 a 96,07% e desvio padrão relativo menor do que 4,34% . O limite de detecção das várias furanocoumarinas, encontra-se na faixa de 0,37 mg mL-1 para a xanthotoxol e 10,82 mg mL-1 para imperatorin. Os resultados apresentados no manuscrito revelam que o método DMFS é eficiente, simples, rápido e de fácil execuçaõ, e é adequado para o isolamento de furanocoumarins a partir da plantas. Abstract in english In this study an efficient matrix solid-phase dispersion (MSPD) method for the simultaneous HPLC analysis of furanocoumarins from fruits of Archangelica officinalis Hoffm. was performed. Herbal samples were prepared by an optimized MSPD procedure using C18 as sorbent. The analysis was performed by h [...] igh performance liquid chromatography with diode array detector (HPLC-DAD). The efficiency of the MSPD method was also compared with ultrasound assisted extraction with solid-phase extraction (USAE with SPE). The MSPD extracted furanocoumarins (isoimperatorin, imperatorin, bergapten, isopimpinellin, xanthotoxin, umbelliferone and xanthotoxol) from Archangelica officinalis with satisfactory recoveries ranging from 91.43% to 96.07% and relative standard deviations lower than 4.34%. The detection limit of various furanocoumarins was found to be in the range of 0.37 mg mL-1 for xanthotoxol to 10.82 mg mL-1 for imperatorin. The results presented in the paper reveal that MSPD is efficient, fast, simple and easy to perform method suitable for the isolation of furanocoumarins from herbs.

Anna, Oniszczuk; Krystyna, Skalicka-Wo& #378; niak; Tomasz, Oniszczuk; Monika, Waksmundzka-Hajnos; Kaziemirz, G& #322; owniak.

1166-11-01

101

Halogen bonding: A new retention mechanism for the solid phase extraction of perfluorinated iodoalkanes  

Energy Technology Data Exchange (ETDEWEB)

Highlights: Black-Right-Pointing-Pointer Halogen bonding (XB) is firstly utilised in solid phase extraction. Black-Right-Pointing-Pointer The perfluorinated iodine alkanes can be extracted by C-I Midline-Horizontal-Ellipsis Cl{sup -} halogen bonding. Black-Right-Pointing-Pointer The C-I Midline-Horizontal-Ellipsis Cl{sup -} halogen bond is well characterised by spectroscopy methods. Black-Right-Pointing-Pointer The analytes with strong halogen-bonding abilities can be selectively extracted. - Abstract: For the first time, halogen-bonding interaction is utilised in the solid phase extraction of perfluorinated iodoalkane (PFI). Nine PFIs, as model analytes, were tested, and analyses by UV, {sup 19}F NMR and Raman spectroscopies demonstrate that the PFIs are extracted by a strong anion exchange (SAX) sorbent from n-hexane due to the C-I Midline-Horizontal-Ellipsis Cl{sup -} halogen-bonding interactions. The results also show that the adsorptivities of SAX for the diiodoperfluoro-alkanes (diiodo-PFIs) were much stronger than those for the perfluoroalkyl iodides (monoiodo-PFIs). Specifically, the recoveries for 1,6-diiodoperfluorohexane and 1,8-diiodoperfluorooctane were higher than 80% when 100 mL of sample spiked with a 5 ng mL{sup -1} analyte mixture was extracted. Interestingly, SAX had no adsorption for hexafluorobenzene at all, which is known to be unable to form a halogen bond with Cl{sup -}. The analytical performance of the halogen bond-based SPE-GC-MS method for the diiodo-PFIs was also examined in soil samples. The sorbent SAX enabled the selective extraction of four diiodo-PFIs successfully from soil samples. The recoveries of the diiodo-PFIs extracted from 5 g soil sample at the 100 ng g{sup -1} spike level were in the range of 73.2-93.8% except 26.8% for 1,2-diiodoperfluoroethane. The limit of detection varied from 0.02 to 0.04 ng g{sup -1} in soil samples. Overall, this work reveals the great application potential of halogen bonding in the field of solid phase extraction to selectively extract compounds with strong halogen-bonding abilities.

Yan Xiaoqing; Shen Qianjin; Zhao Xiaoran; Gao Haiyue; Pang Xue [College of Chemistry, Beijing Normal University, Beijing 100875 (China); Jin Weijun, E-mail: wjjin@bnu.edu.cn [College of Chemistry, Beijing Normal University, Beijing 100875 (China)

2012-11-13

102

Separation and Purification of Sulforaphane from Broccoli by Solid Phase Extraction  

Directory of Open Access Journals (Sweden)

Full Text Available A simple solid-phase extraction (SPE method for the determination of sulforaphane in broccoli has been developed. The optimal conditions were found to be use of a silica SPE cartridge, and ethyl acetate and dichloromethane as washing and eluting solvents, respectively, which could eliminate interferences originating from the broccoli matrix. The extracts were sufficiently clean to be directly injected into high-performance liquid chromatography (HPLC for further chromatographic analysis. Good linearity was obtained from 0.05 to 200 ?g/mL (r = 0.998 for sulforaphane with the relative standard deviations less than 3.6%. The mean recoveries of sulforaphane from broccoli were more than 90.8% and the detection limit (S/N = 3:1 was 0.02 ?g/mL. The SPE method provides a higher yield of sulforaphane from crude extracts compared to conventional liquid-liquid extraction.

Kyung Ho Row

2011-03-01

103

Preconcentration of trace uranium from seawater with solid phase extraction followed by differential pulse polarographic determination in chloroform eluate  

International Nuclear Information System (INIS)

In the present study, an effective method is presented for the separation and preconcentration of uranium (VI) by solid phase extraction (SPE). For this purpose, U(VI) oxinate is formed by the reaction of U(VI) with 8-hydroxyquinoline and adsorbed onto the octylsilane (C-8) SPE cartridge. The analyte is completely eluted with chloroform and determined by differential pulse polarography. The SPE conditions were optimized by evaluating the effective factors such as pH, oxine concentration, type and concentration of buffer and masking agent. By the proposed method a preconcentration factor of more than 100 was achieved. The average recovery of uranium (VI) oxinate (0.1 mg l-1) was 99.8%. The relative standard deviation was 1.6% for seven replicate determinations of uranyl ion in the solution with a concentration 20 ?g l-1. Some concomitant ions such as Ca+2, Mg+2 and Fe+3 which interfere in extraction or determination process of uranium were masked with EDTA in aqueous phase during the extraction process. The proposed method was successfully used for the determination of uranium in Caspian Sea and Persian Gulf water samples

104

A novel solid-phase extraction-spectrofluorimetric method for the direct determination of atenolol in human urine.  

Science.gov (United States)

A novel, simple, sensitive and selective solid-phase extraction (SPE)-spectrofluorimetric method has been developed for the determination of atenolol (ATE) in human urine. Because an extraction procedure is required to isolate ATE or eliminate the interfering molecules present in complex human urine for the direct spectrofluorimetric determination, a pH-sensitive poly(acrylic acid-ethylene glycol dimethacrylate) [poly(AA-EGDMA)] hydrogel was developed and used as a SPE adsorbent. Some factors affecting the ATE extraction efficiency, such as washing solvent type and volume, and the volume of elution solvent were optimized. Eluates from SPE cartridges were analyzed using a spectrofluorimeter (?(ex) ?=?277 nm and ?(em) ?=?300 nm). The calibration graph was linear over the concentration range 0.15-4.0 µg/mL. Limit of detection (LOD) and limit of quantification (LOQ) values were found to be 0.03 and 0.10 µg/mL, respectively. Relatively high intraday [2.06%, mean relative standard deviation (RSD)] and interday (2.6%, mean RSD) precisions were achieved. High mean recovery (95.4%) and low RSD values (3.8%) were obtained for spiked ATE in human urine. The spectrofluorimetric method presented here can be easily applied to assay trace amounts of ATE in pharmaceuticals and biological samples. PMID:23733327

Basan, Hasan; Yar?mkaya, Sezen

2014-05-01

105

Sampling volatile compounds from natural products with headspace/solid-phase micro-extraction.  

Science.gov (United States)

Recent advances in the development of analytical methods based on headspace/solid-phase micro-extraction (HS/SPME) of natural aroma compounds are reviewed, with special emphasis on increasing reproducibility. Representative examples of applications of HS/SPME to the determination of components at trace levels, strategies for fiber selection, and improvement of SPME sampling conditions are presented. Examples of applications to quality control and sample classification, based on aroma profiling were selected to highlight the use of multivariate statistical methods. PMID:17045655

Stashenko, Elena E; Martínez, Jairo R

2007-03-10

106

Solid-phase extraction and HPLC determination of levamisole hydrochloride in sheep plasma  

OpenAIRE

The anthelmintic, levamisole, was determined in sheep plasma by means of ion-pair solid-phase extraction (SPE) and reverse-phase liquid chromatography. The SPE columns were conditioned with 2 ml of methanol followed by 1 ml of octane sulphonic-acid buffer. After sample application, the columns were washed with 2 ml of the same buffer, followed by elution with 90/10 acetonitrile: buffer. A phenyl reversephase column (Spherisorb S5 Phenyl, 250 x 4,6 mm) was used with a mobile phase ...

Du Preez, J. L.; Lotter, A. P.

1996-01-01

107

Solid phase extraction and chromatographic determination of pesticide residues in water samples: DDT and its metabolites  

International Nuclear Information System (INIS)

Solid phase extraction cartridge embedded with octadecyl C/sub 18/ chain bounded to silica particles were used for the isolation and trace enrichment of pesticides from water samples collected from cotton, rice growing and municipal areas. The eluents were analyzed with HPLC using methanol (100%) as mobiles phase at different UV-Visible wavelengths. DDT and its metabolites were found in all areas but were not present in all samples. Concentration of pesticide residues varies from sample to sample and was in the range of 0.017 ng ml/sup -1/. Overall, recoveries ranged from 84%-91% for all target pesticides. (author)

108

Solid phase extraction of iron and lead in environmental matrices on amberlite xad-1180/pv  

OpenAIRE

A solid phase extraction procedure using Amberlite XAD-1180/Pyrocatechol violet (PV) chelating resin for the determination of iron and lead ions in various environmental samples was established. The procedure is based on the sorption of lead(II) and iron(III) ions onto the resin at pH 9, followed by elution with 1 mol/L HNO3 and determination by flame atomic absorption spectrometry. The influence of alkaline, earth alkaline and some transition metals, as interferents, are discussed. The recov...

Mustafa Soylak; Mustafa Tuzen; Ibrahim Narin

2006-01-01

109

VOLATILE COMPOUNDS OF LITHRAEA CAUSTICA (LITRE) DETERMINATED BY SOLID PHASE MICRO-EXTRACTION (SPME)  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in spanish De las partes áereas de Lithraea caustica y usando la técnica de Micro-Extracción en Fase Sólida (MEFS), fueron identificados y cuantificados los principales compuestos volátiles: los monoterpenos, mirceno, a -pineno, p-cimeno y limoneno, y el sesquiterpeno cariofileno. [...] Abstract in english The head space of the aerial parts of Lithraea caustica was analyzed by Solid Phase Micro-Extraction (SPME) technique, obtaining as main volatile compounds the monoterpenes, myrcene, a -pinene, , p-cymene and limonene, as well as the sesquiterpene caryophylene. [...

JUAN A, GARBARINO; GIUSEPPE, SALVATORE; MARISA, PIVANOVO; MARÍA CRISTINA, CHAMY; MARCELLO, NICOLETTI; ALFREDO, DE IOANNES.

2002-12-01

110

Solid phase extraction and spectrophotometric determination of palladium with 2-(2-quinolylazo)-5-diethylaminobenzoic acid  

OpenAIRE

Asensitive, selective and rapid method for the determination of palladium based on the rapid reaction of palladium(II) with 2-(2-quinolylazo)-5-diethylaminobenzoic acid (QADEAB) and the solid phase extraction of the Pd(II) –QADEAB chelate with a reversed phase polymer-based C18 cartridge was developed. In the presence of 0.05 – 0. 5 mol/L of hydrochloric acid solution and cetyl trimethylammonium bromide (CTAB) medium, QADEAB reacts with palladium(II) to form a violet complex with a mole r...

WEIZU YANG; QIUFEN HU; ZHANGJIE HUANG; JIAYUAN YIN; GANG XIE; JING CHEN

2006-01-01

111

Comparison of solvent extraction and solid-phase extraction for the determination of polychlorinated biphenyls in transformer oil.  

Science.gov (United States)

Solid-phase extraction (SPE) of nine polychlorinated biphenyls (PCBs) from transformer oil samples was evaluated using octadecyl (CI8)-bonded porous silica. The efficiency of SPE of these PCBs was compared with those obtained by solvent extraction with DMSO and hexane. Average recoveries exceeding 95% for these PCBs were obtained via the SPE method using small cartridges containing 100mg of 40 pm CI8-bonded porous silica. The average recovery by solvent extraction with DMSO and hexane exceeded 83%. It was concluded that the recoveries and precision for the solvent extraction of PCBs were poorer than those for the SPE. PMID:24083901

Mahindrakar, A N; Chandra, S; Shinde, L P

2014-01-01

112

Development of andrographolide molecularly imprinted polymer for solid-phase extraction  

Science.gov (United States)

A method employing molecularly imprinted polymer (MIP) as selective sorbent for solid-phase extraction (SPE) to pretreat samples was developed. The polymers were prepared by precipitation polymerization with andrographolide as template molecule. The structure of MIP was characterized and its static adsorption capacity was measured by the Scatchard equation. In comparison with C 18-SPE and non-imprinted polymer (NIP) SPE column, MIP-SPE column displays high selectivity and good affinity for andrographolide and dehydroandrographolide for extract of herb Andrographis paniculata ( Burm.f.) Nees (APN). MIP-SPE column capacity was 11.9 ± 0.6 ?mol/g and 12.1 ± 0.5 ?mol/g for andrographolide and dehydroandrographolide, respectively and was 2-3 times higher than that of other two columns. The precision and accuracy of the method developed were satisfactory with recoveries between 96.4% and 103.8% (RSD 3.1-4.3%, n = 5) and 96.0% and 104.2% (RSD 2.9-3.7%, n = 5) for andrographolide and dehydroandrographolide, respectively. Various real samples were employed to confirm the feasibility of method. This developed method demonstrates the potential of molecularly imprinted solid phase extraction for rapid, selective, and effective sample pretreatment.

Yin, Xiaoying; Liu, Qingshan; Jiang, Yifan; Luo, Yongming

2011-06-01

113

Spectrophotometric determination of iron in environmental and food samples using solid phase extraction.  

Science.gov (United States)

A simple, selective and highly sensitive extraction method has been developed for the determination of iron(II) spectrophotometrically after solid phase extraction. The absorbance is measured at ?max 644 nm. Beer's law was obeyed up to 450 ng mL(-1) of iron. The molar absorptivity, Sandell's sensitivity, detection and quantification limits were calculated and found to be 1.09×10(5) L mol(-1) cm(-1), 0.51 ng cm(-2), 1.98 and 6.0 ng mL(-1), respectively and compared with parameters obtained without using solid phase extraction method. After reduction of Fe(III) by addition of 2.0 mL of 10% hydroxylamine HCl, the system was applied to the total iron. The interference of various ions has been studied in detail and the statistical evaluation of the experimental results is reported. The proposed methods have been successfully applied for the determination of trace amount of iron in environment water, soil and botanical reference materials with recovery range (98.71-101.51%). PMID:23870913

Kassem, Mohammed A; Amin, Alaa S

2013-12-01

114

An interior needle electropolymerized pyrrole-based coating for headspace solid-phase dynamic extraction  

International Nuclear Information System (INIS)

A headspace solid-phase dynamic extraction (HS-SPDE) technique was developed by the use of polypyrrole (PPy) sorbent, electropolymerized inside the surface of a needle, as a possible alternative to solid-phase microextraction (SPME). Thermal desorption was subsequently, employed to transfer the extracted analytes into the injection port of a gas chromatography-mass spectrometry (GC-MS). The PPy sorbent including polypyrrole-dodecyl sulfate (PPy-DS) was deposited on the interior surface of a stainless steel needle from the corresponding aqueous electrolyte by applying a constant deposition potential. The homogeneity and the porous surface structure of the coating were examined using the scanning electron microscopy (SEM). The developed method was applied to the trace level extraction of some polycyclic aromatic hydrocarbons (PAHs) from aqueous sample. In order to enhance the extraction efficiency and increase the partition coefficient of analytes, the stainless steel needle was cooled at 5 deg. C, while the sample solution was kept at 80 deg. C. Optimization of influential experimental conditions including the voltage of power supply, the time of PPy electrodeposition, the extraction temperature, the ionic strength and the extraction time were also investigated. The detection limits of the method under optimized conditions were in the range of 0.002-0.01 ng mL-1. The relative standard deviations (R.S.D.) at a concentration level of 0.1 ng mL-1 werration level of 0.1 ng mL-1 were obtained between 7.54 and 11.4% (n = 6). The calibration curves of PAHs showed linearity in the range of 0.01-10 ng mL-1. The proposed method was successfully applied to the extraction of some selected PAHs from real-life water samples and the relative recoveries were higher than 90% for all the analytes

115

An interior needle electropolymerized pyrrole-based coating for headspace solid-phase dynamic extraction  

Energy Technology Data Exchange (ETDEWEB)

A headspace solid-phase dynamic extraction (HS-SPDE) technique was developed by the use of polypyrrole (PPy) sorbent, electropolymerized inside the surface of a needle, as a possible alternative to solid-phase microextraction (SPME). Thermal desorption was subsequently, employed to transfer the extracted analytes into the injection port of a gas chromatography-mass spectrometry (GC-MS). The PPy sorbent including polypyrrole-dodecyl sulfate (PPy-DS) was deposited on the interior surface of a stainless steel needle from the corresponding aqueous electrolyte by applying a constant deposition potential. The homogeneity and the porous surface structure of the coating were examined using the scanning electron microscopy (SEM). The developed method was applied to the trace level extraction of some polycyclic aromatic hydrocarbons (PAHs) from aqueous sample. In order to enhance the extraction efficiency and increase the partition coefficient of analytes, the stainless steel needle was cooled at 5 deg. C, while the sample solution was kept at 80 deg. C. Optimization of influential experimental conditions including the voltage of power supply, the time of PPy electrodeposition, the extraction temperature, the ionic strength and the extraction time were also investigated. The detection limits of the method under optimized conditions were in the range of 0.002-0.01 ng mL{sup -1}. The relative standard deviations (R.S.D.) at a concentration level of 0.1 ng mL{sup -1} were obtained between 7.54 and 11.4% (n = 6). The calibration curves of PAHs showed linearity in the range of 0.01-10 ng mL{sup -1}. The proposed method was successfully applied to the extraction of some selected PAHs from real-life water samples and the relative recoveries were higher than 90% for all the analytes.

Bagheri, Habib [Department of Chemistry, Sharif University of Technology, Azadi Av., P.O. Box 11365-9516, Tehran (Iran, Islamic Republic of)], E-mail: bagheri@sharif.edu; Babanezhad, Esmaeil; Khalilian, Faezeh [Department of Chemistry, Sharif University of Technology, Azadi Av., P.O. Box 11365-9516, Tehran (Iran, Islamic Republic of)

2009-02-23

116

An interior needle electropolymerized pyrrole-based coating for headspace solid-phase dynamic extraction.  

Science.gov (United States)

A headspace solid-phase dynamic extraction (HS-SPDE) technique was developed by the use of polypyrrole (PPy) sorbent, electropolymerized inside the surface of a needle, as a possible alternative to solid-phase microextraction (SPME). Thermal desorption was subsequently, employed to transfer the extracted analytes into the injection port of a gas chromatography-mass spectrometry (GC-MS). The PPy sorbent including polypyrrole-dodecyl sulfate (PPy-DS) was deposited on the interior surface of a stainless steel needle from the corresponding aqueous electrolyte by applying a constant deposition potential. The homogeneity and the porous surface structure of the coating were examined using the scanning electron microscopy (SEM). The developed method was applied to the trace level extraction of some polycyclic aromatic hydrocarbons (PAHs) from aqueous sample. In order to enhance the extraction efficiency and increase the partition coefficient of analytes, the stainless steel needle was cooled at 5 degrees C, while the sample solution was kept at 80 degrees C. Optimization of influential experimental conditions including the voltage of power supply, the time of PPy electrodeposition, the extraction temperature, the ionic strength and the extraction time were also investigated. The detection limits of the method under optimized conditions were in the range of 0.002-0.01 ng mL(-1). The relative standard deviations (R.S.D.) at a concentration level of 0.1 ng mL(-1) were obtained between 7.54 and 11.4% (n=6). The calibration curves of PAHs showed linearity in the range of 0.01-10 ng mL(-1). The proposed method was successfully applied to the extraction of some selected PAHs from real-life water samples and the relative recoveries were higher than 90% for all the analytes. PMID:19185122

Bagheri, Habib; Babanezhad, Esmaeil; Khalilian, Faezeh

2009-02-23

117

Hydrophilic solid-phase extraction of melamine with ampholine-modified hybrid organic-inorganic silica material.  

Science.gov (United States)

In this work, an ampholine-functionalized hybrid organic-inorganic silica sorbent was successfully used to extract melamine from a milk formula sample by a hydrophilic interaction solid-phase extraction protocol. Primary factors affecting the extraction efficiency of the material such as extraction solvent, elution solvent, sample loading volume, and elution volume have been thoroughly optimized. Under the optimized hydrophilic solid-phase extraction conditions, the recoveries of melamine spiked in milk formula samples ranged from 86.2 to 101.8% with relative standard deviations of 4.1-9.4% (n = 3). The limit of detection (S/N = 3) was 0.32 ?g/g. The adsorption capacity toward melamine was 30 ?g of melamine per grams of sorbent. Due to its simplicity, rapidity and cost effectiveness, the newly developed hydrophilic solid-phase extraction method should provide a promising tool for daily monitoring of doped melamine in milk formula. PMID:25330461

Wang, Tingting; Zhu, Yiming; Ma, Junfeng; Xuan, Rongrong; Gao, Haoqi; Liang, Zhen; Zhang, Lihua; Zhang, Yukui

2015-01-01

118

Colorimetric detection of uranium(VI) on building surfaces after enrichment by solid phase extraction.  

Science.gov (United States)

A method for detecting and quantifying uranium(VI) levels on building materials that include concrete, Plexiglas, glass and steel surfaces is presented. Uranium(VI) was extracted from building material surfaces using a pH 2.2 buffer rinse and, subsequently complexed by an organic chelating agent, arsenazo III. The application of a uranium-chelating molecule, arsenazo III, allows for concentration enhancement using C(18) solid phase extraction and colorimetric detection of the uranium complex using ultraviolet-visible spectroscopy at 654nm. The method has a detection limit (based on 3sigma) of 40ng/L (5ng/cm(2)) and an overall extraction efficiency greater than 80% for each surface type (concrete, Plexiglas, glass, steel). Methods to prevent interference by metal ions commonly found on building materials are discussed. PMID:18970078

Greene, Philip A; Copper, Christine L; Berv, David E; Ramsey, Jeremy D; Collins, Greg E

2005-05-15

119

Hemimicelle capped functionalized carbon nanotubes-based nanosized solid-phase extraction of arsenic from environmental water samples  

International Nuclear Information System (INIS)

The end functionalization of CNTs can introduce oxygen-containing negatively functional groups such as -COOH, -OH, or -C=O on their surface site. If cationic surfactant such as cetyltrimethylammonium chloride (CTAC) was added to the functionalized CNTs, then interactions such as hydrophobic and ionic may lead to formation of hemimicelle/admicelle aggregates on the CNTs, a new kind of adsorbents, namely, the hemimicelle capped CMMWCNTs, is obtained. The application of the hemimicelle capped carbon nanotubes-based nanosized solid-phase extraction (SPE) adsorbents in environmental analysis is reported for the first time using arsenic as model target. The effect of adsorption and desorption conditions for arsenic including the amount of surfactant, initial pH of sample solution, the ultrasonic time of sample solution, the amount of electrolyte, flow rate, eluent and its amount were investigated and optimized prior to its determination by atomic fluorescence spectrophotometry (AFS). Arsenic can be quantitatively retained on the hemimicelle capped CMMWCNTs at pH 5-6 from sample volume up to 500 mL and then eluted completely with 2 mol L-1 HNO3 in the presence of 10 mg L-1 CTAC. The method detection limit for arsenic determination with AFS detection was 2 ng L-1, and the relative standard deviation (RSD, n = 11) was 5.3% at the 0.5 ?g L-1 level. The recoveries of arsenic in the spiked environmental water samples ranged piked environmental water samples ranged from 94% to 104.29% with 500 mL of water sample. The proposed method has been applied successfully to the analysis of arsenic in aqueous environmental samples, which demonstrates the hemimicelle capped CMMWCNTs can be an excellent SPE adsorbents for arsenic pretreatment and enrichment from real water samples

120

Hemimicelle capped functionalized carbon nanotubes-based nanosized solid-phase extraction of arsenic from environmental water samples  

Energy Technology Data Exchange (ETDEWEB)

The end functionalization of CNTs can introduce oxygen-containing negatively functional groups such as -COOH, -OH, or -C=O on their surface site. If cationic surfactant such as cetyltrimethylammonium chloride (CTAC) was added to the functionalized CNTs, then interactions such as hydrophobic and ionic may lead to formation of hemimicelle/admicelle aggregates on the CNTs, a new kind of adsorbents, namely, the hemimicelle capped CMMWCNTs, is obtained. The application of the hemimicelle capped carbon nanotubes-based nanosized solid-phase extraction (SPE) adsorbents in environmental analysis is reported for the first time using arsenic as model target. The effect of adsorption and desorption conditions for arsenic including the amount of surfactant, initial pH of sample solution, the ultrasonic time of sample solution, the amount of electrolyte, flow rate, eluent and its amount were investigated and optimized prior to its determination by atomic fluorescence spectrophotometry (AFS). Arsenic can be quantitatively retained on the hemimicelle capped CMMWCNTs at pH 5-6 from sample volume up to 500 mL and then eluted completely with 2 mol L{sup -1} HNO{sub 3} in the presence of 10 mg L{sup -1} CTAC. The method detection limit for arsenic determination with AFS detection was 2 ng L{sup -1}, and the relative standard deviation (RSD, n = 11) was 5.3% at the 0.5 {mu}g L{sup -1} level. The recoveries of arsenic in the spiked environmental water samples ranged from 94% to 104.29% with 500 mL of water sample. The proposed method has been applied successfully to the analysis of arsenic in aqueous environmental samples, which demonstrates the hemimicelle capped CMMWCNTs can be an excellent SPE adsorbents for arsenic pretreatment and enrichment from real water samples.

Li Lu [College of Chemistry and Chemical Engineering, Southwest University, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Key Laboratory of Luminescence and Realtime Analysis, Ministry of Education, Beibei, Chongqing 400715 (China); Huang Yuming [College of Chemistry and Chemical Engineering, Southwest University, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Key Laboratory of Luminescence and Realtime Analysis, Ministry of Education, Beibei, Chongqing 400715 (China)], E-mail: yuminghuang2000@yahoo.com; Wang Yan; Wang Weidong [College of Chemistry and Chemical Engineering, Southwest University, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Key Laboratory of Luminescence and Realtime Analysis, Ministry of Education, Beibei, Chongqing 400715 (China)

2009-01-12

121

Determination of triazine herbicides in seaweeds: development of a sample preparation method based on Matrix Solid Phase Dispersion and Solid Phase Extraction Clean-up.  

Science.gov (United States)

A method using dual process columns of Matrix Solid Phase Dispersion (MSPD) and Solid Phase Extraction (SPE) has been developed for extracting and cleaning-up of nine triazine herbicides (ametryn, atrazine, cyanazine, prometryn, propazine, simazine, simetryn, terbuthylazine and terbutryn) in seaweed samples. Under optimized conditions, samples were blended with 2g of octasilyl-derivatized silica (C8) and transferred into an SPE cartridge containing ENVI-Carb II/PSA (0.5/0.5 g) as a clean up co-sorbent. Then the dispersed sample was washed with 10 mL of n-hexane and triazines were eluted with 20 mL ethyl acetate and 5 mL acetonitrile. Finally the extract was concentrated to dryness, re-constituted with 1 mL methanol:water (1:1) and injected into the HPLC-DAD system. The linearity of the calibration curves was excellent in matrix matched standards, and yielded the coefficients of determination>0.995 for all the target analytes. The recoveries ranged from 75% to 100% with relative standard deviations lower than 7%. The achieved LOQs (<10 µg kg(-1)) for all triazines under study permits to ensure proper determination at the maximum allowed residue levels set in the European Union Legislation. Samples of three seaweeds were subjected to the procedure proving the suitability of MSPD method for the analysis of triazines in different seaweeds samples. PMID:24607126

Rodríguez-González, N; González-Castro, M J; Beceiro-González, E; Muniategui-Lorenzo, S; Prada-Rodríguez, D

2014-04-01

122

Novel polymeric resin for solid phase extraction and determination of lead in waters  

Energy Technology Data Exchange (ETDEWEB)

Interest in preconcentration techniques for the determination of metals at ultratrace levels still continues increasingly because of some disadvantages of flameless atomic absorption spectrometry and the high costs of other sensitive methods in compared to flame atomic absorption spectrometry (FAAS). Among preconcentration techniques, solid-phase extraction is the most popular because of a number of advantages. In this work, thiol-containing sulfonamide resin was synthesized, characterized, and applied as a new sorption material for solid phase extraction and determination of lead in natural water samples. The optimization of experimental conditions was performed using the parameters including pH, contact time, and volumes of initial and elution solutions. After preconcentration procedure, FAAS was used for determinations. The synthesized resin exhibits the superiority in compared to the other adsorption reagents because of the fact that there is no necessity of any complexing reagent as well as high sorption capacity. Consequently, 280-fold improvement in the sensitivity of analytical scheme was achieved by combining the slotted tube atom trap-atomic absorption spectrometry (STAT-FAAS) and the developed preconcentration method. The limit of detection was found to be 0.15 ng mL{sup -1}. The Pb{sup 2+} concentrations in the studied water samples were found to be in the range of 0.9-6.7 ng mL{sup -1}. (Copyright copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Karaaslan, Nagihan M.; Cengiz, Emine; Yaman, Mehmet [Science Faculty, Department of Chemistry, Firat University, Elazig (Turkey); Senkal, B. Filiz [Science and Arts Faculty, Department of Chemistry, Istanbul Technical University, Istanbul (Turkey)

2010-11-15

123

Monitoring of chloropesticide methoxychlor preconcentration from waste water using hplc - solid phase extraction (abstract)  

International Nuclear Information System (INIS)

The method involves preconcentration of methoxychlor by solid phase extraction (SPE) with 1 mL silica based C-18 and 3 mL polymer based C-18 cartridge and then quantification by high performance liquid chromatography with UV detector (HPLC-UV). Optimization of HPLC parameters was done by determining max of methoxychlor on a double beam UV/Visible spectrophotometer, flow rate of mobile phase on reversed phase columns. Lowest detection limit for methoxychlor dissolved in water and methanol was 0.2ppm and 0.1ppm respectively. For solid phase extraction recovery studies and effect of different parameters such as initial concentration of analyte 0.01 to 0.05 ppm, loading rate 1 and 2mL/min, nature of desorbing solvent (methanol, ethyl acetate and acetonitrile) were investigated. Periodic self degradation of methoxychlor, and reusing potential of both SPE materials was also explored. Lower initial concentrations and slower loading rate of methoxychlor solutions gave improved recoveries. Recoveries were in the range of 80 to 90% for new SPE cartridge and reduced to 35 to 57% for once used silica based C-18 tubes. It was around 73 % for HLB C18 on their second use, and decreased on their repeated reuse. Lastly recoveries for stimulant and real waste water samples were determined to be 77 and 60% respectively. (author)

124

Solid phase extraction and spectrophotometric determination of palladium with 2-(2-quinolylazo-5-diethylaminobenzoic acid  

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Full Text Available Asensitive, selective and rapid method for the determination of palladium based on the rapid reaction of palladium(II with 2-(2-quinolylazo-5-diethylaminobenzoic acid (QADEAB and the solid phase extraction of the Pd(II –QADEAB chelate with a reversed phase polymer-based C18 cartridge was developed. In the presence of 0.05 – 0. 5 mol/L of hydrochloric acid solution and cetyl trimethylammonium bromide (CTAB medium, QADEAB reacts with palladium(II to form a violet complex with a mole ratio 1:2 (palladium to QADEAB. The chelate was enriched by solid phase extraction with a reversed phase polymer-based C18 cartridge. An enrichment factor of 200 was obtained by elution of the chelate form the cartridge with the minimal amount of isopentyl alcohol. The molar absorptivity of the chelate in the isopentyl alcohol medium was 1.43 × 105 L mol-1 cm-1 at 628 nm. Beer’s law was obeyed in the range of 0.01 – 1.2 mg/mL. The relative standard deviation for eleven replicate samples at the 0.2 mg/L level was 2.18 %. The attained detection limit amounted to 0.02 mg/L in the original samples. This method was applied to the determination of palladium in environmental samples with good results.

WEIZU YANG

2006-07-01

125

An Economical Online Solid-Phase Extraction LC-MS/MS Method for Quantifying Methylprednisolone.  

Science.gov (United States)

An economical, reproducible and automated online solid-phase extraction coupled with liquid chromatography-tandem mass spectrometry method was developed to quantify methylprednisolone in human plasma. The method was validated in terms of selectivity, precision/accuracy, process efficiency, stability, cartridge reproducibility and carryover studies. Sample pretreatment was performed by protein precipitation and elimination using methanol followed by water dilution. Then, the mixture was passed onto the HySphere C8 EC-SE online solid-phase extraction cartridge followed by the separation of the analytes on an Agilent Eclipse XDB column. Electrospray ionization in positive ion mode and multiple reaction monitoring were used to monitor the ion transitions at m/z 375.4/160.8 for methylprednisolone, and m/z 361.2/147.0 for prednisolone. The calibration curve ranged from 5.25 to 525 ng/mL. Meanwhile both the intra-day and inter-day precision values (relative standard deviation) were within 4.45%. The method which turns out to be less laborious, faster and lower consumable cost per sample has already been successfully applied to a pharmacokinetic study in which the oral administration of 16 mg methylprednisolone was conducted in Chinese volunteers. PMID:25404561

Hu, Xingjiang; Zheng, Yunliang; Wu, Guolan; Liu, Jian; Chen, Junchun; Huang, Mingzhu; Zhou, Huili; Wu, Lihua; Shen-Tu, Jianzhong

2014-11-16

126

[Study on solid phase extraction spectrophotometric determination of zinc with 2-(2-quinolylazo)-5-dimthylaminophenol].  

Science.gov (United States)

A highly sensitive, selective and rapid method for the determination of zinc based on the rapid reaction of zinc(II) with 2-(2-quinolylazo)-5-dimthylaminophenol (QADMAP) and the solid phase extraction of zinc ion with anion exchange resin cartridge was developed. In the presence of pH 8.5 buffer solution and Triton X-100 medium, QADMAP can react with zinc(II) to form a stable 2 :1 complex (QADMAP:Zn(II)). The molar absorptivity is 1.22 x 10(5)L x moL(-1) x cm(-1) at 590 nm. Beer's law is obeyed in the range of 0-1.0 microg x mL(-1). The zinc ions in the samples can be enriched and separated by solid phase extraction with anion exchange resincartridge. Testing results show that recovery for zinc(II) was from 95% to 104%, and RSD was below 3%. This method was applied to the determination of zinc in water and food with good results. PMID:16395909

Zhou, Shi-ping; Duan, Chang-qun; Liu, Hong-cheng; Hu, Qiu-fen

2005-10-01

127

Utility of solid phase extraction for spectrophotometric determination of gold in water, jewel and ore samples  

Science.gov (United States)

A highly sensitive, selective and rapid method for the determination ?g L -1 level of Au(III) based on the rapid reaction of Au(III) with 2,3-dichloro-6-(3-carboxy-2-hydroxy-1-naphthylazo)quinoxaline (DCHNAQ) and the solid phase extraction of the colored complex with a reversed phase polymer-based C18 cartridge have been developed. The DCHNAQ reacted with Au(III) to form a violet complex of a molar ratio 3:1 [DCHNAQ to Au(III)] in the presence of 5.0 M of phosphoric acid solution and Triton X-100 medium. This complex was enriched by the solid phase extraction with a polymer-based C18 cartridge. The enrichment factor of 100 was achieved. The molar absorptivity of the complex is 2.73 × 10 5 l mol -1 cm -1 at 633 nm in the measured solution. The system obeys Beer's law in the range of 0.02-1.30 ?g ml -1, whereas the optimum concentration ranges obtained from Ringbom plot was 0.08-1.24 ?g ml -1. The relative standard deviation for ten replicates sample of 0.6 ?g ml -1 level is 1.28%. The detection and quantification limits, are 6.1 and 19.5 ng ml -1 in the original sample. This method was applied to the determination of gold in water, jewel and ore samples with good results comparing to the GFAAS method.

Amin, Alaa S.

2010-12-01

128

Determination of quinolones in milk samples using a combination of magnetic solid-phase extraction and capillary electrophoresis.  

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A magnetic solid-phase extraction (MSPE) method combined with capillary electrophoresis for the simultaneous determination of seven quinolones (QNs) (danofloxacin, ciprofloxacin, marbofloxacin, enrofloxacin, difloxacin, oxolinic acid, and flumequine), using (S)-(+)-6-methoxy-?-methyl-2-naphthaleneacetic acid as internal standard, in milk samples was developed. The variables involved in the preconcentration magnetic procedure were: the composition of the magnetic support composition, the sample pH, and the weight of magnetic adsorbent used. The variables were optimized using a simplex-lattice design. Different magnetite covered with octyl-phenyl silica adsorbents were synthesized by varying the molar ratio of phenyltrimethylsilane and octyltrimethoxysilane; the solids were evaluated for QN preconcentration. Under optimal conditions, a linear range was obtained from 27 to 1000 ?g L(-1) with limits of detection ranging from 9 to 12 ?g L(-1) for the seven QNs. The absolute recoveries of the seven QNs at three different spiked levels (40, 150, and 400 ?g L(-1) ) ranged from 74% to 98% with a relative standard deviation less than 10% in all cases. The proposed method was applied to analyze 20 whole milk samples of different brands. All samples were positive for the presence of QN residues; in some cases, extract dilution was required. The concentrations found are in the range from 31.1 to 5047.3 ?g L(-1) . Marbofloxacin was the most frequently found. The method proposed offers advantages in terms of simplicity, sensitivity, efficiency, cost, and analysis time making it an alternative for the analysis of QNs in whole milk samples. PMID:22806471

Ibarra, Israel S; Rodriguez, Jose A; Páez-Hernández, Ma Elena; Santos, Eva M; Miranda, Jose M

2012-07-01

129

Determination of chloroacetic acids in drinking water using suppressed ion chromatography with solid-phase extraction.  

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Suppressed ion chromatography with a conductivity detector was developed for the determination of trace amounts of underivatized chloroacetic acids (CAAs). When sodium carbonate and methanol were used as a mobile phase, the simultaneous determination of each CAA took approximately 25 min. The linearity, reproducibility and detection limits were determined for the proposed method. For the solid-phase extraction step, the effects of the pH of the sample solution, sample volume and the eluting agent were tested. Under the optimized extracting conditions, the average recoveries for CAAs spiked in tap water were 83-107%, with an optimal preconcentration factor of 20. The reproducibility of recovery rate for CAAs was 1.2-3.8%, based upon 6 repetitions of the recovery experiments. PMID:20009341

Yoshikawa, Kenji; Soda, Yuko; Sakuragawa, Akio

2009-12-01

130

Solid phase extraction of 22 drugs of interest in the forensic toxicology field  

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Full Text Available Many solid phase extraction columns which are dedicated to the extraction of various drugs associated with their specific protocols are proposed to the analyst. We have optimised a one stage procedure for the extraction from whole blood of acidic, neutral and basic drugs. Each step of the protocol has been optimised so as to obtain the best extraction recovery. The analysis of the extracts (identification and quantification has been realised with the help of High Performance Liquid Chromatography system coupled with a Diode Array Detector (HPLC-DAD. The SPE Evolute ABN column (Acid Base Neutral by Argonaut is the column which does extract the more and the best the different analysed components among all the columns which have been tested. Oasis HLB column (Hydrophilic Lipophilic Balance by Waters also allows the extraction of the whole list of active principles studied but with lower recoveries. The other columns studied (sold by Varian and Phenomenex presented insufficient results for this project. In the last step of the work we checked if the results did fit to the forensic toxicology purpose; detection and quantification limits have been compared to therapeutic and toxic concentrations usually found in forensic toxicology. Implementing this new procedure allowed us to create a method of comprehensive screening of drugs frequently implicated in forensic toxicology.

Mélinda Mancebo

2008-01-01

131

Single-walled carbon nanotubes as an effective adsorbent in solid-phase microextraction of low level methyl tert-butyl ether, ethyl tert-butyl ether and methyl tert-amyl ether from human urine.  

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Carbon nanotubes (CNTs) are a kind of new carbon-based nano-materials which have drawn great attention in many application fields. The potential single-walled carbon nanotubes (SWCNTs) as solid-phase microextraction (SPME) adsorbents for the preconcentration of environmental pollutants have been investigated in recent years. The goal of this work was to investigate the feasibility of SWCNTs used as adsorbents for solid-phase microextraction of methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE) and tert-amyl methyl ether (TAME) in human urine. SWCNTs were attached onto a stainless steel wire through organic binder. Potential factors affecting the extraction efficiency were optimized, including extraction time, extraction temperature, desorption time, desorption temperature, and salinity. The developed method showed good performance according to the ICH performance criteria for bioanalytical methods. The calibration curves of the ethers were linear (r(2)>or=0.992) in the range from 10 to 5000 ng L(-1). The limits of detection at a signal-to-noise (S/N) ratio of 3 were 10 ng L(-1) for all the analytes. In addition, compared with the commercial carboxen/polydimethylsiloxane (CAR/PDMS) fiber, the SWCNT fiber showed better thermal stability (over 350 degrees C) and longer life span (over 150 times). The developed method was applied successfully to determine trace level of the ethers in urine of 10 healthy male volunteers. PMID:19395320

Rastkari, Noushin; Ahmadkhaniha, Reza; Yunesian, Masud

2009-05-15

132

Principles and applications of colorimetric solid-phase extraction with negligible depletion  

International Nuclear Information System (INIS)

Colorimetric solid-phase extraction (C-SPE) is an integrated technique in which an analyte is selectively concentrated onto a disk and then quantitated by diffuse reflectance spectroscopy. This paper describes the results of an investigation that applies the concept of negligible depletion (ND) to C-SPE, representing the first application of ND concepts to solid-phase extractions. The approach relies on passing the minimal volume of sample through the disk required to reach an equilibrium in which the concentration of analyte in the sample entering and exiting the disk are equal. At this point, the amount of analyte extracted by the disk is proportional to the sample concentration but is independent of the sample volume passed through the disk. With this new method, called C-SPE/ND, the precise measurement of sample volume is no longer necessary. The work herein details the general principles of this new methodology, and validates its basic tenets in an investigation of the extraction of the organic dye methyl violet. The analytical capabilities of C-SPE/ND are then demonstrated by its application to measurements of iodine. Iodine is a biocide increasingly used as a simple and effective disinfectant for water in locations where municipal water treatment systems are potentially compromised. Thus, the ability to operate C-SPE in an ND mode notably enhances the broad-based utility of this methodology as a reliable and an easy-to-use analysis tool for water quality assessuse analysis tool for water quality assessments. Since iodine is also the biocide used on NASAs Space Shuttle, C-SPE/ND has the potential to overcome problems associated with the removal of air bubbles entrapped in a water sample in the microgravity environment encountered in space exploration. Extensions of C-SPE/ND to facile determinations of other water quality parameters with respect to both earth- and space-based needs are briefly discussed

133

Extraction of pesticides from plants using solid phase microextraction and QuEChERS  

Scientific Electronic Library Online (English)

Full Text Available SciELO South Africa | Language: English Abstract in english A study employing dispersive solid phase extraction in the form of the quick, easy, cheap, effective, rugged and safe (QuEChERS) method and solid phase microextraction (SPME) for the cleanup of pesticides in plant samples from the Okavango Delta (Botswana) is presented. Concentration levels of aldri [...] n, 1,1-dichloro-2,4-bis[chlorophenyl]ethane (DDD), 1,1-dichloro-2,2-bis[p-chlorophenyl]ethylene(DDE), 1,1,1-trichloro-2,2-bis[p-chlorophenyl]ethane (DDT), dieldrin, endosulfan and endrin were investigated using gas chromatography with electron capture detection (GC-ECD) and confirmed with gas chromatography with high resolution time of flight mass spectrometry (GC-TOFMS). Parameters affecting the extraction efficiencies of both techniques were optimized. In the absence of CRMs for the plants under investigation, method validation and evaluation of the extraction efficiencies were achieved through spiking of Nymphaea nouchali (Tswii) leaves at two concentration levels with trichlorobenzene as an internal standard. Recoveries for both SPME and QuEChERS were in the range 61-95 %. The calibration plots were reproducible and linear (R² > 0.995) with limits of detection ranging from 0.102 to 1.693 µg L-1 for all the pesticides. The optimal conditions for QuEChERS and SPME were applied to the extraction of pesticides residues from the edible parts (leaves, roots and/ or stems) of Asparagus africanus, Cleome hirta and Nymphaea nouchali plants. No pesticides were detected in the leaves and stems of all the plants studied. Aldrin and endosulfan were detected in the Nymphaea nouchali roots at concentrations of 3-21 µg kg-1 and 5-3 µg kg-1, respectively. Pentachlorobenzene (PCB) and hexachlorobenzene (HCB) were also detected but were not quantified.

Veronica C., Obuseng; Beauty M., Mookantsa; Harriet, Okatch; Ketlhatlogile, Mosepele; Nelson, Torto.

2013-08-01

134

Combined liquid and solid-phase extraction improves quantification of brain estrogen content  

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Full Text Available Accuracy in quantifying brain-derived steroid hormones (‘neurosteroids’ has become increasingly important for understanding the modulation of neuronal activity, development, and physiology. Relative to other neuroactive compounds and classical neurotransmitters, steroids pose particular challenges with regard to isolation and analysis, owing to their lipid solubility. Consequently, anatomical studies of the distribution of neurosteroids have relied primarily on the expression of neurosteroid synthesis enzymes. To evaluate the distribution of synthesis enzymes vis-à-vis the actual steroids themselves, traditional steroid quantification assays, including radioimmunoassays (RIA, have successfully employed liquid extraction methods (e.g., ether, dichloromethane or methanol to isolate steroids from microdissected brain tissue. Due to their sensitivity, safety and reliability, the use of commercial enzyme immunoassays (EIA for laboratory quantification of steroids in plasma and brain has become increasingly widespread. However, EIAs rely on enzymatic reactions in vitro, making them sensitive to interfering substances in brain tissue and thus producing unreliable results. Here, we evaluate the effectiveness of a protocol for combined, two-stage liquid/solid phase extraction as compared to conventional liquid extraction alone for the isolation of estradiol (E2 from brain tissue. We employ the songbird model system, in which brain steroid production is pronounced and linked to neural mechanisms of learning and plasticity. This study outlines a combined liquid-solid phase extraction protocol that improves the performance of a commercial EIA for the quantification of brain E2 content. We demonstrate the effectiveness of our optimized method for evaluating the region specificity of brain E2 content, compare these results to established anatomy of the estrogen synthesis enzyme and estrogen receptor, and discuss the nature of potential EIA interfering substances.

LukeRemage-Healey

2011-09-01

135

Suitability of microwave-assisted extraction coupled with solid-phase extraction for organophosphorus pesticide determination in olive oil.  

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A systematic study of the microwave-assisted extraction coupled to solid-phase extraction of nine organophosphorus pesticides (dimethoate, diazinon, pirimiphos methyl, parathion methyl, malathion, fenthion, chlorpyriphos, methidathion and azinphos methyl) from olive oil is described. The method is based on microwave-assisted liquid-liquid extraction with partition of organophosphorus pesticides between an acetonitrile-dichloromethane mixture and oil. Cleanup of extracts was performed with ENVI-Carb solid-phase extraction cartridge using dichloromethane as the elution solvent. The determination of pesticides in the final extracts was carried out by gas chromatography-flame photometric detection and gas chromatography-tandem mass spectrometry, using a triple quadrupole mass analyzer, for confirmative purposes. The study and optimization of the method was achieved through experimental design where recovery of compounds using acetonitrile for partition ranged from 62 to 99%. By adding dichloromethane to the extracting solution, the recoveries of more hydrophobic compounds were significantly increased. Under optimized conditions recoveries of pesticides from oil were equal to or higher than 73%, except for fenthion and chlorpyriphos at concentrations higher than 0.06microgg(-1) and diazinon at 0.03microgg(-1), with RSDs equal to or lower than 11% and quantification limits ranging from 0.007 to 0.020microgg(-1). The proposed method was applied to residue determination of the selected pesticides in commercial olive and avocado oil produced in Chile. PMID:18774576

Fuentes, Edwar; Báez, María E; Quiñones, Adalí

2008-10-17

136

Headspace Solid Phase Microextraction in Pesticide Residues Analysis:1. Optimisation of Extraction Conditions  

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Full Text Available The method of headspace solid phase microextraction (HS/SPME was successfully used in a simultaneous multicomponent analysis of hexachlorobenzene (HCB, tefluthrin, heptachlor, aldrin, chlorpyrifos, fenthion and bifenthrin in aqueous medium. Measurementswere performed using a nonpolar polydimethyl siloxane (PDMS fiber. Detection and quantification were done by gas chromatography/mass spectrometry (GC/MS.Optimal conditions for HS/SPME were determined both by performing extraction at different temperatures and examining extraction time profiles at constant temperature. Optimal extraction temperature for each pesticide studied was determined as follows: 60°C for HCB and for heptachlor, 80°C for aldrin and for chlorpyrifos, fenthion and tefluthrin, and temperature exceeding 80°C for bifenthrin. For the pesticide mixture studied, 60°C was identified as the optimum extraction temperature.Based on the time profiles obtained, it was confirmed that satisfactory extraction sensitivity can be obtained even for extraction times shorter than the time required to reach a sorption equilibrium. This conclusion was confirmed by linear concentration profiles obtained for the following ranges: 0.05-10 ng/ml (HCB, 0.05-25 ng/ml (tefluthrin, 0.05-40 ng/ml (heptachlor, 0.05-40 ng/ml (aldrin, 0.05-25 ng/ml (chlorpyrifos, 0.05-25 ng/ml (fenthionand 0.05-25 ng/ml (bifenthrin.Relative standard deviation (RSD values for triplicate measurements did not exceed 15%.

Rada ?urovi?

2007-01-01

137

Development of solid-phase extraction and solid-phase microextraction methods for the determination of chlorophenols in cork macerate and wine samples.  

Science.gov (United States)

Tri-, tetra- and pentachlorophenol (TCP, TeCP and PCP) can be considered the precursors in the formation of corresponding chloroanisoles, known to be powerful odorants in corks and wine. Determining the presence of these chlorophenolic compounds in cork soaking solutions (ethanol/water mixtures, 12% (v/v) ethanol used for cork quality control testing), or in wine can be achieved by acetylation/gas chromatography electron-capture detection. In order to reach the required sensitivity, a previous preconcentration step is necessary. Solid-phase extraction (SPE) and headspace solid-phase microextraction (HS-SPME) have given good results for the preconcentration of TCP, TeCP and PCP in such matrices. The use of Oasis HLB cartridges gives acceptable recoveries for the three compounds when different volumes (50-250 mL) of cork macerate with concentrations ranging from 20 to 150 ng/L are processed. Preconcentration based on HS-SPME has also been optimised with a 100 microm polydimethylsiloxane fibre and in situ derivatization. The HS-SPME method allows chlorophenols in a cork soaking solution and in wine to be determined with a limit of detection of 1 ng/L for each compound (in cork macerate) and a repeatability of around 0.5%-5% (n=8) for a concentration level of 30 ng/L. PMID:15481456

Insa, S; Salvadó, V; Anticó, E

2004-08-20

138

Ultrasonic assisted extraction combined with titanium-plate based solid phase extraction for the analysis of PAHs in soil samples by HPLC-FLD.  

Science.gov (United States)

In this work, ultrasonic assisted extraction combined with solid phase extraction (SPE) was applied in the analysis of polycyclic aromatic hydrocarbons (PAHs) in environment samples. A titania nanotubes/titanium plate was modified with n-octadecanethiol monolayer-protected Ag nanoparticles, and developed as the adsorbent in SPE of PAHs. Six different PAHs in soil samples were analyzed with high performance liquid chromatography-fluorescence detection. The experiment conditions including the deposition time of Ag nanoparticles, extraction solvent properties, the amount of extraction solvent, the amount of organic modifier, extraction time, and desorption solvent properties were optimized. Under the optimized conditions, good linearity and low limits of detection of 0.0015-0.4 ng g(-1) were obtained. The analysis of PAHs in real soil samples gave satisfactory recoveries ranging from 70.32% to 115.51% with 3.14%-13.56% intra-day relative standard deviations (RSD) and 4.92%-14.87% inter-day RSD. PMID:23601878

Pan, Di; Wang, Jianping; Chen, Chunyan; Huang, Chen'an; Cai, Qingyun; Yao, Shouzhuo

2013-04-15

139

Quantitative separation of zinc traces from cadmium matrices by solid-phase extraction with polyurethane foam.  

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A system for separation of zinc traces from large amounts of cadmium is proposed in this paper. It is based on the solid-phase extraction of the zinc in the form of thiocyanate complexes by the polyurethane foam. The following parameters were studied: effect of pH and of the thiocyanate concentration on the zinc extraction, shaking time required for quantitative extraction, amount of PU foam necessary for complete extraction, conditions for the separation of zinc from cadmium, influence of other cations and anions on the zinc sorption by PU foam, and required conditions for back extraction of zinc from the PU foam. The results show that zinc traces can be separated from large amounts of cadmium at pH 3.0+/-0.50, with the range of thiocyanate concentration from 0.15 to 0.20 mol l(-1), and the shaking time of 5 min. The back extraction of zinc can be done by shaking it with water for 10 min. Calcium, barium, strontium, magnesium, aluminum, nickel and iron(II) are efficiently separated. Iron(III), copper(II) and cobalt(II) are extracted simultaneously with zinc, but the iron reduction with ascorbic acid and the use of citrate to mask copper(II) and cobalt(II) increase the selectivity of the zinc extraction. The anions nitrate, chloride, sulfate, acetate, thiosulphate, tartarate, oxalate, fluoride, citrate, and carbonate do not affect the zinc extraction. Phosphate and EDTA must be absent. The method proposed was applied to determine zinc in cadmium salts using 4-(2-pyridylazo)-resorcinol (PAR) as a spectrophotometric reagent. The result achieved did not show significant difference in the accuracy and precision (95% confidence level) with those obtained by ICP-AES analysis. PMID:18967283

Santiago de Jesus, D; Souza de Carvalho, M; Spínola Costa, A C; Costa Ferreira, S L

1998-08-01

140

Headspace Solid Phase Micro Extraction Gas Chromatographic Determination of Fenthion in Human Serum  

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Full Text Available A simple and effective analytical procedure was developed for the determination of fenthion residues in human serum samples. The sample treatment was performed using the headspace solid-phase micro extraction with polyacrylate fiber, which has the advantage to require low amount of serum (1 mL without tedious pre-treatment. The quantification of fenthion was carried out by gas chromatography-mass spectrometry and the recoveries ranged from 79 to 104% at two spiking levels for 6 replicates. Detection and quantification limits were calculated as 1.51 and 4.54 ng/mL of serum respectively. Two fenthion metabolites − fenoxon and fenthion–sulfoxide − were also identified.

Kyriaki Machera

2008-05-01

141

Development of magnetic micro-solid phase extraction for analysis of phthalate esters in packaged food.  

Science.gov (United States)

A novel, simple and low cost magnetic multi-walled carbon nanotubes-poly (vinyl alcohol) cryogel-micro-solid phase extraction (magnetic-MWCNTs-PVA cryogel-?-SPE) sorbent was synthesized by incorporating magnetic particles and MWCNTs into a PVA cryogel. The magnetic-MWCNTs-PVA cryogel-?-SPE sorbent developed, with a large surface area and macro-porous structure, provided good sorbent-to-sorbent reproducibility (%RSDplastic bags were found in the range 0.04-0.15 ?g mL(-1) and 0.03-0.20 ?g mL(-1), respectively, but only DEHP was found in clear chicken soup samples in the range 0.02-0.07 ?g mL(-1). PMID:25053056

Makkliang, Fonthip; Kanatharana, Proespichaya; Thavarungkul, Panote; Thammakhet, Chongdee

2015-01-01

142

Ionic liquid-modified materials for solid-phase extraction and separation: a review.  

Science.gov (United States)

In recent years, materials science has propelled to the research forefront. Ionic liquids with unique and fascinating properties have also left their footprints to the developments of materials science during the last years. In this review we highlight some of their recent advances and provide an overview at the current status of ionic liquid-modified materials applied in solid-phase extraction, liquid and gas chromatography and capillary electrochromatography with reference to recent applications. In addition, the potential of ionic liquids in the modification of capillary inner wall in capillary electrophoresis is demonstrated. The main target material modified with ionic liquids is silica, but polymers and monoliths have recently joined the studies. Although imidazolium is still clearly the most commonly used ionic liquid for the covalently modification of materials, the exploitation of pyridinium and phosphonium will most probably increase in the future. PMID:22244164

Vidal, Lorena; Riekkola, Marja-Liisa; Canals, Antonio

2012-02-17

143

Solid Phase Extraction (SPE) of REE's and uranium using sequestered resin  

International Nuclear Information System (INIS)

A novel resin has been designed and developed for the pre-concentration and separation of trace amounts of rare earth elements (REE's) from uranium containing aqueous effluent by solid phase extraction technique. Determinations of Gadolinium (Gd) and Uranium (U) have been carried out by ICP-AES. Experiments were carried out using both batch and column techniques. Parameters such as equilibration rate, effect of concentration on sorption and desorption of metal ions have been studied. The maximum separation factor capacities for Gd and U were found to be 0.98 at pH 1.5 for Gd and same for U at pH 1.00 respectively when contacted originally 20 ppm Gadolinium and 10 ppm Uranium containing simulated solution. The designed sequestered resin was reusable even after 10 cycles

144

Headspace solid phase micro extraction gas chromatographic determination of fenthion in human serum.  

Science.gov (United States)

A simple and effective analytical procedure was developed for the determination of fenthion residues in human serum samples. The sample treatment was performed using the headspace solid-phase micro extraction with polyacrylate fiber, which has the advantage to require low amount of serum (1 mL) without tedious pre-treatment. The quantification of fenthion was carried out by gas chromatography-mass spectrometry and the recoveries ranged from 79 to 104% at two spiking levels for 6 replicates. Detection and quantification limits were calculated as 1.51 and 4.54 ng/mL of serum respectively. Two fenthion metabolites fenoxon and fenthion-sulfoxide were also identified. PMID:19325792

Kasiotis, Konstantinos M; Souki, Helen; Tsakirakis, Angelos N; Carageorgiou, Haris; Theotokatos, Spiridon A; Haroutounian, Serkos A; Machera, Kyriaki

2008-05-01

145

Solid phase extraction of iron and lead in environmental matrices on amberlite xad-1180/pv  

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Full Text Available A solid phase extraction procedure using Amberlite XAD-1180/Pyrocatechol violet (PV chelating resin for the determination of iron and lead ions in various environmental samples was established. The procedure is based on the sorption of lead(II and iron(III ions onto the resin at pH 9, followed by elution with 1 mol/L HNO3 and determination by flame atomic absorption spectrometry. The influence of alkaline, earth alkaline and some transition metals, as interferents, are discussed. The recoveries for the spiked analytes were greater than 95%. The detection limits for lead and iron by FAAS were 0.37 µg/L and 0.20 µg/L, respectively. Validation of the method described here was performed by using three certified reference materials (SRM 1515 Apple Leaves, SRM 2711 Montana Soil and NRCC-SLRS-4 Riverine Water. The procedure was successfully applied to natural waters and human hair.

Mustafa Soylak

2006-04-01

146

Determination of degradation products of doxercalciferol by solid-phase extraction and reversed-phase HPLC.  

Science.gov (United States)

In the current study, injectable formulations containing Doxercalciferol as the active pharmaceutical ingredient are analyzed by using gradient-elution high-performance liquid chromatography with ultraviolet detection. Various related impurities and degradants are quantified by using solid-phase extraction (SPE) for enhanced sensitivity. The assay of possible related impurities and Doxercalciferol analogues present at trace quantities is performed by using Trans-1-?-hydroxy vitamin D2 (Doxercalciferol related degradation product/Impurity B) as standard and 1-?-hydroxy vitamin D2 (Doxercalciferol related degradation product/Impurity C) as internal standards for the SPE study. The current method is shown to be stability-indicating and free from interferences from any of the formulation excipients and potential degradation products and impurities. The validated method is shown to be reproducible, accurate, sensitive and selective. PMID:23780943

Simonzadeh, Ninus; Ronsen, Bruce; Upadhyaya, Subhash; Wilkinson, Erik; Kanesvaran, Kiran; Patel, Vijay; Bendale, Pravin

2014-07-01

147

[Study on solid phase extraction and spectrophotometric determination of palladium with MCI-GEL resin].  

Science.gov (United States)

Based on the color reaction of 2-(2-quinolinylazo)-5-diethylaminoaniline (QADEAA) with palladium(II) and the solid phase extraction of its colored complex with MCI-GEL reversed phase cartridge, a new method for the determination of trace palladium was established. In the presence of 0.2-2.0 mol x L(-1) of hydrochloric acid solution and CTMAB medium, QADEAA reacts with palladium(II) to form a stable 2:1 complex. The colored complex can be enriched by MCI-GEL reversed phase cartridge, and the retained chelates was then eluted by acetone. The eluant was determined by spectrophotometry at 615 nm. Beer's law is obeyed in the range of 0.01-1.5 mg x L(-1). This method was applied to the determination of palladium with good results. PMID:17514976

Zhong, Yi-hui; Huang, Qi-lin; Zhang, Xin; Huang, Zhang-jie; Hu, Qiu-feng; Yang, Guang-yu

2007-02-01

148

Solid-Phase Extraction and Spectrophotometric Determination of Mercury with 6-Mercaptopurine in Environmental Samples  

International Nuclear Information System (INIS)

A highly selective, sensitive and rapid method for the determination of trace amounts of inorganic mercury based on the reaction of Hg (2) with 6-mercaptopurine and the solid phase extraction of the complex on C18 membrane disks was developed. The 6-mercaptopurine selectively reacts with Hg (2) to form a complex in the pH range of 5-8. This complex was preconcentrated by solid phase extraction with C18 disks. An enrichment factor of 100 was achieved. The molar absorptivity of the complex is 0.26 x10-6 L. mol-1. cm-1 measured at 315 nm. The Beer's law is obeyed in the concentration range of 0.002 - 0.048 ?g mL-1. The relative standard deviation for eleven-replicated measurement of 0.04 ?g mL-1 is 1.5 %. The detection limit is 0.001 ?g mL-1 in the water samples. The advantage of the method is that the determination of Hg (2) is free from interference of almost all the cations and anions found in environment and wastewater samples. The determination of Hg (2) in water samples of different origins and marine sediment were carried out by the present method and cold vapor atomic absorption spectrometry (CVAAS). Also the method's accuracy was investigated by using SRM 2709. The obtained results by the present procedure were in good agreement with those of the CVAAS and certified value, so that the applicability of the proposed method was confirmed for the real samples for the real samples

149

Solid-phase extraction and spectrophotometric determination of mercury with 6-mercaptopurine in environmental samples.  

Science.gov (United States)

A highly selective, sensitive and rapid method for the determination of trace amounts of inorganic mercury based on the reaction of Hg (II) with 6-mercaptopurine and the solid phase extraction of the complex on C18 membrane disks was developed. The 6-mercaptopurine selectively reacts with Hg (II) to form a complex in the pH range of 5-8. This complex was preconcentrated by solid phase extraction with C18 disks. An enrichment factor of 100 was achieved. The molar absorptivity of the complex is 0.26 x 10(-6) L. mol(-1) cm(-1) measured at 315 nm. The Beer's law is obeyed in the concentration range of 0.002-0.048 microg mL(-1). The relative standard deviation for eleven-replicated measurement of 0.04 microg mL(-1) is 1.5 %. The detection limit is 0.001 microg mL(-1) in the water samples. The advantage of the method is that the determination of Hg (II) is free from interference of almost all the cations and anions found in environment and wastewater samples. The determination of Hg (II) in water samples of different origins and marine sediment were carried out by the present method and cold vapor atomic absorption spectrometry (CVAAS). Also the method's accuracy was investigated by using SRM 2709. The obtained results by the present procedure were in good agreement with those of the CVAAS and certified value, so that the applicability of the proposed method was confirmed for the real samples. PMID:17899881

Saber-Tehrani, Mohammad; Hashemi-Moghaddam, Hamid; Husain, S Waqif; Zare, Karim

2007-08-01

150

Carbon nanotubes as solid-phase extraction sorbents prior to atomic spectrometric determination of metal species: A review  

Energy Technology Data Exchange (ETDEWEB)

Highlights: Black-Right-Pointing-Pointer The use of CNTs as sorbent for metal species in solid phase extraction has been described. Black-Right-Pointing-Pointer Physical and chemical strategies for functionalization of carbon nanotubes have been discussed. Black-Right-Pointing-Pointer Published analytical methods concerning solid phase extraction and atomic spectrometric determination have been reviewed. - Abstract: New materials have significant impact on the development of new methods and instrumentation for chemical analysis. From the discovery of carbon nanotubes in 1991, single and multi-walled carbon nanotubes - due to their high adsorption and desorption capacities - have been employed as sorption substrates in solid-phase extraction for the preconcentration of metal species from diverse matrices. Looking for successive improvements in sensitivity and selectivity, in the past few years, carbon nanotubes have been utilized as sorbents for solid phase extraction in three different ways: like as-grown, oxidized and functionalized nanotubes. In the present paper, an overview of the recent trends in the use of carbon nanotubes for solid phase extraction of metal species in environmental, biological and food samples is presented. The determination procedures involved the adsorption of metals on the nanotube surface, their quantitative desorption and subsequent measurement by means of atomic spectrometric techniques such as flame atomic absorption spectrometry, electrothermal atomic absorption spectrometry or inductively coupled plasma atomic emission spectrometry/mass spectrometry, among others. Synthesis, purification and types of carbon nanotubes, as well as the diverse chemical and physical strategies for their functionalization are described. Based on 140 references, the performance and general properties of the applications of solid phase extraction based on carbon nanotubes for metal species atomic spectrometric determination are discussed.

Herrero Latorre, C., E-mail: carlos.herrero@usc.es [Universidad de Santiago de Compostela, Dpto. Quimica Analitica, Nutricion y Bromatologia, Facultad de Ciencias, Alfonso X el Sabio s/n, 27002 Lugo (Spain); Alvarez Mendez, J.; Barciela Garcia, J.; Garcia Martin, S.; Pena Crecente, R.M. [Universidad de Santiago de Compostela, Dpto. Quimica Analitica, Nutricion y Bromatologia, Facultad de Ciencias, Alfonso X el Sabio s/n, 27002 Lugo (Spain)

2012-10-24

151

Carbon nanotubes as solid-phase extraction sorbents prior to atomic spectrometric determination of metal species: A review  

International Nuclear Information System (INIS)

Highlights: ? The use of CNTs as sorbent for metal species in solid phase extraction has been described. ? Physical and chemical strategies for functionalization of carbon nanotubes have been discussed. ? Published analytical methods concerning solid phase extraction and atomic spectrometric determination have been reviewed. - Abstract: New materials have significant impact on the development of new methods and instrumentation for chemical analysis. From the discovery of carbon nanotubes in 1991, single and multi-walled carbon nanotubes – due to their high adsorption and desorption capacities – have been employed as sorption substrates in solid-phase extraction for the preconcentration of metal species from diverse matrices. Looking for successive improvements in sensitivity and selectivity, in the past few years, carbon nanotubes have been utilized as sorbents for solid phase extraction in three different ways: like as-grown, oxidized and functionalized nanotubes. In the present paper, an overview of the recent trends in the use of carbon nanotubes for solid phase extraction of metal species in environmental, biological and food samples is presented. The determination procedures involved the adsorption of metals on the nanotube surface, their quantitative desorption and subsequent measurement by means of atomic spectrometric techniques such as flame atomic absorption spectrometry, electrothermal atomic absorption spectrometry or inductively coupled plasma a or inductively coupled plasma atomic emission spectrometry/mass spectrometry, among others. Synthesis, purification and types of carbon nanotubes, as well as the diverse chemical and physical strategies for their functionalization are described. Based on 140 references, the performance and general properties of the applications of solid phase extraction based on carbon nanotubes for metal species atomic spectrometric determination are discussed.

152

Optimization of Solid Phase Micro-Extraction (SPME for Monitoring Occupational Exposure to Ethyl Benzene  

Directory of Open Access Journals (Sweden)

Full Text Available

Background and Objectives: Analytical methods for volatile organic compounds (VOCs in different samples need extraction of compounds, by applying hazardous solvents. Solid phase micro-extraction (SPME is a solvent-free equilibrium extraction method, in which proper calibration can allow quantitative determinations of VOCs at a very good sensitivity without the use of any organic solvent. VOCs are generally present in urine only at trace levels, therefore, a sensitive procedure is needed for their trace determinations. Throughout this study, headspace solid phase micro-extraction (HS-SPME was followed by GC-FID for ethyl benzene in spiked urine was optimized.

Methods: In this study, the parameters influencing SPME and gas chromatography of ethyl benzene, including extraction time, temperature, desorption temperature, desorption time, salt addition, sample pH, sample volume and sample agitation were investigated.

Results: Extraction procedure was performed at 30°C for 6 min, using 0.2 gml-1 of NaCl in the sample solution. The sample volume and sample pH were optimized at 5 ml and 7 (neutral pH, respectively. Desorption of the ethyl benzene was carried out for 60 sec. at 250°C. The method was also validated with three different spiked urine samples and illustrated an appropriate reproducibility over six consecutive days as well as six within-day experiments. During this investigation, parameters of accuracy, linearity, and detection limits of the procedure were also evaluated.

Conclusion: The developed method of HS- SPME-GC-FID proved to be a simple, convenient, and practical procedure, and was successfully used for measuring of ethyl benzene in spiked urine.

H Heidari

2012-05-01

153

Sodium dodecyl sulfate coated ?-alumina support modified by a new Schiff base for solid phase extraction and flame-AAS determination of lead and copper ions  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english A simple and fast approach for solid phase extraction is herein described, and used to determine trace amounts of Pb2+ and Cu2+ metal ions. The solid phase support is sodium dodecyl sulfate (SDS)-coated ?-alumina modified with bis(2-hydroxy acetophenone)-1,6-hexanediimine (BHAH) ligand. The adsorbed [...] ions were stripped from the solid phase by 6 mL of 4 M nitric acid as eluent. The eluting solution was analyzed by flame atomic absorption spectrometry (FAAS). The sorption recovery of metal ions was investigated with regard to the effects of pH, amount of ligand, ?-alumina and surfactant and the amount and type of eluent. Complexation of BHAH with Pb2+ or Cu2+ ions was examined via spectrophotometry using the HypSpec program. The detection limit for Cu2+ was 7.9 µg L-1 with a relative standard deviation of 1.67%, while that for Pb2+ was 6.4 µg L-1 with a relative standard deviation of 1.64%. A preconcentration factor of 100 was achieved for these ions. The method was successfully applied to determine analyte concentrations in samples of liver, parsley, cabbage, and water.

Ardeshir, Shokrollahi; Morteza, Montazerozohori; Tahere, Mehrpour; Hossein, Tavallali; Batool Zare, Khafri; Zohreh, Montaseri.

1354-13-01

154

Determination of volatile organic hydrocarbons in water samples by solid-phase dynamic extraction  

Energy Technology Data Exchange (ETDEWEB)

In the present study a headspace solid-phase dynamic extraction method coupled to gas chromatography-mass spectrometry (HS-SPDE-GC/MS) for the trace determination of volatile halogenated hydrocarbons and benzene from groundwater samples was developed and evaluated. As target compounds, benzene as well as 11 chlorinated and brominated hydrocarbons (vinyl chloride, dichloromethane, cis-1,2-dichloroethylene, trans-1,2-dichloroethylene, carbon tetrachloride, chloroform, trichloroethylene, tetrachloroethylene, bromoform) of environmental and toxicological concern were included in this study. The analytes were extracted using a SPDE needle device, coated with a poly(dimethylsiloxane) with 10% embedded activated carbon phase (50-{mu}m film thickness and 56-mm film length) and were analyzed by GC/MS in full-scan mode. Parameters that affect the extraction yield such as extraction and desorption temperature, salting-out, extraction and desorption flow rate, extraction volume and desorption volume, the number of extraction cycles, and the pre-desorption time have been evaluated and optimized. The linearity of the HS-SPDE-GC/MS method was established over several orders of magnitude. Method detection limits (MDLs) for the compounds investigated ranged between 12 ng/L for cis-dichloroethylene and trans-dichloroethylene and 870 ng/L for vinyl chloride. The method was thoroughly validated, and the precision at two concentration levels (0.1 mg/L and a concentration 5 times above the MDL) was between 3.1 and 16% for the analytes investigated. SPDE provides high sensitivity, short sample preparation and extraction times and a high sample throughput because of full automation. Finally, the applicability to real environmental samples is shown exemplarily for various groundwater samples from a former waste-oil recycling facility. Groundwater from the site showed a complex contamination with chlorinated volatile organic compounds and aromatic hydrocarbons. (orig.)

Jochmann, Maik A.; Schmidt, Torsten C. [Eberhard-Karls-Universitaet Tuebingen, Center for Applied Geoscience (ZAG), Tuebingen (Germany); Chair of Instrumental Analysis, University Duisburg-Essen, Duisburg (Germany); Yuan, Xue [Eberhard-Karls-Universitaet Tuebingen, Center for Applied Geoscience (ZAG), Tuebingen (Germany)

2007-03-15

155

Determination of volatile organic hydrocarbons in water samples by solid-phase dynamic extraction.  

Science.gov (United States)

In the present study a headspace solid-phase dynamic extraction method coupled to gas chromatography-mass spectrometry (HS-SPDE-GC/MS) for the trace determination of volatile halogenated hydrocarbons and benzene from groundwater samples was developed and evaluated. As target compounds, benzene as well as 11 chlorinated and brominated hydrocarbons (vinyl chloride, dichloromethane, cis-1,2-dichloroethylene, trans-1,2-dichloroethylene, carbon tetrachloride, chloroform, trichloroethylene, tetrachloroethylene, bromoform) of environmental and toxicological concern were included in this study. The analytes were extracted using a SPDE needle device, coated with a poly(dimethylsiloxane) with 10% embedded activated carbon phase (50-microm film thickness and 56-mm film length) and were analyzed by GC/MS in full-scan mode. Parameters that affect the extraction yield such as extraction and desorption temperature, salting-out, extraction and desorption flow rate, extraction volume and desorption volume, the number of extraction cycles, and the pre-desorption time have been evaluated and optimized. The linearity of the HS-SPDE-GC/MS method was established over several orders of magnitude. Method detection limits (MDLs) for the compounds investigated ranged between 12 ng/L for cis-dichloroethylene and trans-dichloroethylene and 870 ng/L for vinyl chloride. The method was thoroughly validated, and the precision at two concentration levels (0.1 mg/L and a concentration 5 times above the MDL) was between 3.1 and 16% for the analytes investigated. SPDE provides high sensitivity, short sample preparation and extraction times and a high sample throughput because of full automation. Finally, the applicability to real environmental samples is shown exemplarily for various groundwater samples from a former waste-oil recycling facility. Groundwater from the site showed a complex contamination with chlorinated volatile organic compounds and aromatic hydrocarbons. PMID:17242891

Jochmann, Maik A; Yuan, Xue; Schmidt, Torsten C

2007-03-01

156

Bioactive phenols in algae: the application of pressurized-liquid and solid-phase extraction techniques.  

Science.gov (United States)

A new extraction technique based on the off-line combination of pressurized-liquid with solid-phase extraction (PLE-SPE) is described. The method was used for the extraction of bioactive phenolic acids (protocatechuic, p-hydroxybenzoic, 2,3-dihydroxybenzoic, chlorogenic, vanillic, caffeic, p-coumaric, salicylic acid), cinnamic acid and hydroxybenzaldehydes (p-hydroxybenzaldehyde, 3,4-dihydroxybenzaldehyde, vanillin) from in vitro culture of two freshwater algae (Anabaena doliolum and Spongiochloris spongiosa) and from food products of marine macroalgae Porphyra tenera (nori) and Undaria pinnatifida (wakame). For the identification and quantification of the compounds the molecular ions [M-H](-) and specific fragments were analyzed by quadrupole mass spectrometry analyzer connected on-line with a reversed-phase HPLC system. Our analysis showed that the freshwater algae and marine algal products contained submicrogram or microgram level of above-mentioned phenols per gram of lyophilized sample. In addition, the total phenol content (Folin-Ciocalteu assay) and antioxidant activity (TEAC assay, Trolox equivalent antioxidant capacity assay) of the PLE-SPE extracts were determined and discussed. PMID:19410410

Onofrejová, L; Vasícková, J; Klejdus, B; Stratil, P; Misurcová, L; Krácmar, S; Kopecký, J; Vacek, J

2010-01-20

157

Solid-phase extraction for the enrichment of actinides from radioactive waste  

Energy Technology Data Exchange (ETDEWEB)

For the destructive characterisation of radioactive waste, the actinides to be analysed must be separated from matrix components, if possible, in an element-specific manner. Microwave pressure digestion is a time-saving digestion method for radioactive waste samples. The partitioning of the actinides from the liquid samples are carried out with the aid of solid-phase extraction. For the experiments, on the one hand, commercially available extraction resins such as actinide, TRU, UTEVA and TEVA Resin{sup TM} from Eichrom were used. On the other hand, an extraction resin with Cyanex 301 produced in-house was employed specifically for actinide-lanthanide partitioning. It was possible to separate 99.4% of the lanthanides by a two-stage partitioning process. It is particularly meaningful to perform a prior matrix partitioning with Actinide Resin{sup TM}. The extractant, which was eluted from the column together with the actinides, was destroyed oxidatively by means of a newly developed technique using microwave pressure digestion. (orig.)

Maischak, S.; Fachinger, J.; Modolo, G. [Inst. of Safety Research and Reactor Technology, Forschungszentrum Juelich, Juelich (Germany)

2003-07-01

158

Solid phase microextraction and stir bar sorptive extraction for organotin compounds - a comparison (P9)  

International Nuclear Information System (INIS)

Full text: Organotin compounds have been largely used in agricultural and industrial applications. Hyphenated techniques were developed for the sensitive and selective determination of such species. For this task GC has been coupled with atomic emission detection. Derivatization to transform the Sn-compounds into sufficiently volatile compounds was necessary and carried out using sodium tetrapropylborate. For sample preparation the application of solid phase microextraction (SPME) give recent advances in comparison to classical liquid-liquid extraction (LEE). A problem in the usage of SPME exists however in the small volume of the PDMS coating for enrichment the analytes. For improvement of both sample enrichment and extraction of the organotin compounds stir bar sorptive extraction (SBSE) was applied. It base on the application of stir bars coated with PDMS. Here the extraction yield is substantially higher. Aim of this study was to compare the capabilities of GC-AED in combination with SPME and SBSE. After optimization of the experimental parameters it was possible to reach detection limits in the pg / 1 - level. A comparison of both methods shows the expected results. By application of SBSE it was possible to increase the detection limits one order of magnitude. With SPME the reproducibility of the analytical results (in the 1 ng / 1 concentration range) was found to be between 10 and 15 %, it could be enhanced to 5-8 % by application of SBSE. These low limits of detection and the good reproducibility allowed the determination of organotin compounds according required regulations. Ref. 1 (author)

159

Application of solid-phase extraction to agar-supported fermentation.  

Science.gov (United States)

Agar-supported fermentation (Ag-SF), a variant of solid-state fermentation, has recently been improved by the development of a dedicated 2 m(2) scale pilot facility, Platotex. We investigated the application of solid-phase extraction (SPE) to Ag-SF in order to increase yields and minimize the contamination of the extracts with agar constituents. The selection of the appropriate resin was conducted on liquid-state fermentation and Diaion HP-20 exhibited the highest recovery yield and selectivity for the metabolites of the model fungal strains Phomopsis sp. and Fusarium sp. SPE applied to Ag-SF resulted in a particular compartmentalization of the culture. The mycelium that requires oxygen to grow migrates to the top layer and formed a thick biofilm. The resin beads intercalate between the agar surface and the mycelium layer, and trap directly the compounds secreted by the mycelium through a "solid-solid extraction" (SSE) process. The resin/mycelium layer is easily recovered by scraping the surface and the target metabolites extracted by methanol. Ag-SF associated to SSE represents an ideal compromise for the production of bioactive secondary metabolites with limited economic and environmental impact. PMID:23263569

Le Goff, Géraldine; Adelin, Emilie; Cortial, Sylvie; Servy, Claudine; Ouazzani, Jamal

2013-09-01

160

PHARMACOKINETIC STUDY OF RISPERIDONE: APPLICATION OF A HPLC METHOD WITH SOLID PHASE EXTRACTION  

Directory of Open Access Journals (Sweden)

Full Text Available A new, simplified solid phase extraction procedure for the determination of risperidone and 9-hydroxyrisperidone in human plasma has been developed. This method involves the use of an optimized extraction protocol developed in Waters OASIS® HLB 30mg 1cc extraction columns using 1 mL of human serum. Separation was performed by HPLC using a Waters XTerra RP-18 (5 µm, 150x4,6 mm column with a mobile phase consisting in acetonitrile - potassium dihydrogen phosphate 50 mM pH 3.4 (27/73. UV detection at 278 nm was used to quantify analytes, encountering good linearity (r² > 0.999 in the 2-100 ng/mL concentration range. The mean recovery was 92.4 % and 92.8 % for risperidone and 9-hydroxyrisperidone respectively, with an intraday - interday precision below 7%, and accuracy below 115 %. The method has been successfully applied in pharmacokinetic studies that require a large sample number.

PABLO TORRES V

2011-01-01

161

PHARMACOKINETIC STUDY OF RISPERIDONE: APPLICATION OF A HPLC METHOD WITH SOLID PHASE EXTRACTION  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in english A new, simplified solid phase extraction procedure for the determination of risperidone and 9-hydroxyrisperidone in human plasma has been developed. This method involves the use of an optimized extraction protocol developed in Waters OASIS® HLB 30mg 1cc extraction columns using 1 mL of human serum. [...] Separation was performed by HPLC using a Waters XTerra RP-18 (5 µm, 150x4,6 mm) column with a mobile phase consisting in acetonitrile - potassium dihydrogen phosphate 50 mM pH 3.4 (27/73). UV detection at 278 nm was used to quantify analytes, encountering good linearity (r² > 0.999) in the 2-100 ng/mL concentration range. The mean recovery was 92.4 % and 92.8 % for risperidone and 9-hydroxyrisperidone respectively, with an intraday - interday precision below 7%, and accuracy below 115 %. The method has been successfully applied in pharmacokinetic studies that require a large sample number.

PABLO, TORRES V; M. JACQUELINE, SEPÚLVEDA C; CARLOS, VON PLESSING R.

162

[Optimization of solid-phase extraction for enrichment of toxic organic compounds in water samples].  

Science.gov (United States)

A concentration method for enrichment of toxic organic compounds in water samples has been developed based on combined solid-phase extraction (SPE) to reduce impurities and improve recoveries of target compounds. This SPE method was evaluated in every stage to identify the source of impurities. Based on the analysis of Waters Oasis HLB without water samples, the eluent of SPE sorbent after dichloromethane and acetone contributed 85% of impurities during SPE process. In order to reduce the impurities from SPE sorbent, soxhlet extraction of dichloromethane followed by acetone and lastly methanol was applied to the sorbents for 24 hours and the results had proven that impurities were reduced significantly. In addition to soxhlet extraction, six types of prevalent SPE sorbents were used to absorb 40 target compounds, the lgK(ow) values of which were within the range of 1.46 and 8.1, and recovery rates were compared. It was noticed and confirmed that Waters Oasis HLB had shown the best recovery results for most of the common testing samples among all three styrenedivinylbenzene (SDB) polymer sorbents, which were 77% on average. Furthermore, Waters SepPak AC-2 provided good recovery results for pesticides among three types of activated carbon sorbents and the average recovery rates reached 74%. Therefore, Waters Oasis HLB and Waters SepPak AC-2 were combined to obtain a better recovery and the average recovery rate for the tested 40 compounds of this new SPE method was 87%. PMID:23914538

Zhang, Ming-quan; Li, Feng-min; Wu, Qian-yuan; Hu, Hong-ying

2013-05-01

163

Application of solid phase micro extraction (SPME) in profiling hydrocarbons in oil spill cases  

International Nuclear Information System (INIS)

In environmental forensic, it is extremely important to have a fast and reliable method in identifying sources of spilled oil and petroleum products. In this study, solid phase micro extraction (SPME) method coupled to gas chromatography-mass spectrometry was developed for the analysis of hydrocarbons in diesel and petroleum contaminated soil samples. Optimization of SPME parameters such as extraction time, extraction temperature and desorption time, was performed using 100-?m poly dimethylsiloxane (PDMS) fiber. These parameters were studied at three levels by means of a central composite experimental design and the optimum experimental conditions were determined using response surface method. The developed SPME method was applied to determine the profiles of hydrocarbons in several oil contaminated soil sample. The SPME method was also used to study the effects of weathering on the profiles of hydrocarbons in unleaded gasoline, diesel and kerosene contaminated soil samples. After several days, significant losses of the lighter hydrocarbons were observed compared to the heavier ones. From these data, SPME method can be used to differentiate possible candidate sources in oil spill cases. (author)

164

Molecularly imprinted polymers based on SBA-15 for selective solid-phase extraction of baicalein from plasma samples.  

Science.gov (United States)

Highly selective molecularly imprinted mesoporous silica polymer (SBA-15@MIP) for baicalein (BAI) extraction was synthesized using a surface molecular imprinting technique on the SBA-15 supporter. Computational simulation was used to predict the optimal functional monomer for the rational design of SBA-15@MIP. Meanwhile, high adsorption capacity was obtained when a suitable yield of molecularly imprinted polymers (MIPs) layer was grafted onto the surface of SBA-15. Characterization and performance tests of the obtained polymer revealed that SBA-15@MIP possessed a highly ordered mesoporous structure, reached saturated adsorption within 60 min, and exhibited higher sorption capacity to the target molecule BAI compared with non-imprinted mesoporous silica polymer (SBA-15@NIP) and SBA-15. Finally, SBA-15@MIP was successfully applied to solid-phase extraction (SPE) coupled with high-performance liquid chromatography and ultraviolet detection (HPLC-UV) for the determination of trace BAI in plasma samples. Mean recoveries of BAI through the molecularly imprinted solid-phase extraction (MISPE) sorbent, non-imprinted solid-phase extraction (NISPE) sorbent, and SBA-15 solid-phase extraction (SBA-15-SPE) sorbent were 94.4, 22.7, and 10.7 %, respectively, and the relative standard deviations were 2.9, 2.6, and 3.6 %, respectively. These results reveal that SBA-15@MIP as a SPE sorbent has good applicability to selectively separate and enrich trace BAI from complex samples. PMID:25395202

He, Hongliang; Gu, Xiaoli; Shi, Liying; Hong, Junli; Zhang, Hongjuan; Gao, Yankun; Du, Shuhu; Chen, Lina

2015-01-01

165

Design of a new cartridge for selective solid phase extraction using molecularly imprinted polymers: selective extraction of theophylline from human serum samples.  

Science.gov (United States)

This paper describes design of a new cartridge for selective solid phase extraction (SPE) using molecularly imprinted polymers (MIPs). The apparatus which is termed solvent extraction-MISPE (SE-MISPE) cartridge, consisted of a modified conventional micro test tube and has been developed to perform simultaneous forward-extraction of analyte from aqueous sample solution to an organic phase and back-extraction to MIP solid phase. In order to evaluate the performance of the proposed method, extraction of theophylline (THP) from human serum sample was investigated. An appropriate amount of THP-imprinted polymer was placed in the bottom of the micro tube and an organic solvent pipetted onto it and left to swell the polymer completely. A polyethylene frit to secure MIP particles was positioned by two Teflon rings such that it was fixed below the level of the organic layer. Then, aqueous sample solution containing THP was layered over the organic phase and the lid was closed. After completion of extraction, the organic and aqueous phases were removed and the adsorbed analyte was desorbed using a polar organic solvent. In order to reach the highest recovery, the experimental parameters such as the type of organic solvent, pH and ionic strength of aqueous phase, organic to aqueous volume ratio, time of extraction, type and amount of desorbent solvent were optimized. Under the experimental conditions, a plot of HPLC peak areas vs. initial concentrations of THP in the concentration interval of 0.5-30 microg ml(-1) showed a good linearity (r=0.9974). The limit of detection (LOD) and limit of quantification (LOQ) based on three and ten times of the noise of HPLC profile were 0.09 and 0.3 microg ml(-1), respectively. The relative standard deviation (RSD) of the proposed method for the extraction and determination of 5 microg THP from 200 microl standard sample solution for 3 replicate measurements was 3.5%. The results showed that by means of the proposed cartridge, THP could significantly separate from the other structurally related compounds such as theobromine (THB) and caffeine (CAF). The added THP could be quantitatively recovered (79-83%) from the serum samples by the proposed procedure, being thus a guarantee of the accuracy of the SE-MISPE procedure. In addition, the loss of capability of the SE-MISPE cartridge was not considerably observed after 10 times loading and elution cycles. PMID:19157845

Khorrami, Afshin Rajabi; Rashidpur, Amene

2009-11-15

166

Dispersive micro-solid phase extraction combined with gas chromatography-chemical ionization mass spectrometry for the determination of N-nitrosamines in swimming pool water samples.  

Science.gov (United States)

A simple sample pretreatment technique, dispersive micro-solid phase extraction, was applied for the extraction of N-nitrosodimethylamine (NDMA) and other four N-nitrosamines (NAs) from samples of swimming pool water. The parameters affecting the extraction efficiency were systematically investigated. The best extraction conditions involved immersing 75 mg of carbon molecular sieve, Carboxen™ 1003 (as an adsorbent), in a 50-mL water sample (pH 7.0) containing 5% sodium chloride in a sample tube. After 20 min of extraction by vigorous shaking, the adsorbent was collected on a filter and the NAs desorbed by treatment with 150 ?L of dichloromethane. A 10-?L aliquot was then directly determined by large-volume injection gas chromatography with chemical ionization mass spectrometry using the selected ion storage mode. The limits of quantitation were <0.9 ng/L. The precision for these analytes, as indicated by relative standard deviations, were <8% for both intra- and inter-day analyses. Accuracy, expressed as the mean extraction recovery, was between 62% and 109%. A preliminary analysis of swimming pool water samples revealed that NDMA was present in the highest concentration, in the range from n.d. to 100 ng/L. PMID:22222914

Fu, Ssu-Chieh; Tzing, Shin-Hwa; Chen, Hsin-Chang; Wang, Yu-Chen; Ding, Wang-Hsien

2012-02-01

167

Determination of Scopolamine in Human Saliva Using Solid Phase Extraction and LC/MS/MS  

Science.gov (United States)

Purpose: Scopolamine is the preferred treatment for motion sickness during space flight because of its quick onset of action, short half-life and favorable side-effect profile. The dose administered depends on the mode of administration and usually ranges between 0.1 and 0.8 mg. Such small doses make it difficult to detect concentrations of scopolamine in biological fluids by using conventional HPLC methods. To measure scopolamine in saliva and thereby to evaluate the pharmacokinetics of scopolamine, we developed an LC/MS/MS method using off-line solid phase extraction. Method: Samples (0.5mL) were loaded onto Waters Oasis HLB co-polymer cartridges (10 mg, 1 mL) and eluted with 0.5 mL methanol without evaporation and reconstitution. HPLC separation of the eluted sample was performed using an Agilent Zorbax SB-CN column (50 x 2.1 mm) at a flow rate of 0.2 mL/min for 4 minutes. The mobile phase for separation was 90:10 (v/v) methanol: ammonium acetate (2 mM) in water, pH 5.0 +/- 0.1. Concentrations of scopolamine were determined using a Micromass Quattro Micro(TM) mass spectrometer with electrospray ionization (ESI). ESI mass spectra were acquired in positive ion mode with multiple reaction monitoring for the determination of scopolamine m/z = 304.2 yields 138.1 and internal standard (IS) hyoscyamine m/z = 290.2 yields 124.1. Results: The method is rapid, reproducible, specific and has the following parameters: scopolamine and the IS are eluted at 1.7 and 3.2 min respectively. The linear range is 50-5000 pg/mL for scopolamine in saliva with correlation coefficients > 0.99 with a CV scopolamine in human saliva. Conclusion: Solid phase extraction allows more rapid sample preparation and greater precision than liquid extraction. Furthermore, we increased the sensitivity and specificity by adjusting the LC mobile phase and using an MS/MS detector.

Wang, Zuwei; Vaksman, Zalman; Boyd, Jason; Putcha, Lakshmi

2007-01-01

168

Determination of Scopolamine in Human Saliva Using Solid Phase Extraction and LC/MS/MS  

Science.gov (United States)

Purpose: Scopolamine is the preferred treatment for motion sickness during space flight because of its quick onset of action, short half-life and favorable side-effect profile. The dose administered depends on the mode of administration and usually ranges between 0.1 and 0.8 mg. Such small doses make it difficult to detect concentrations of scopolamine in biological fluids by using conventional HPLC methods. To measure scopolamine in saliva and thereby to evaluate the pharmacokinetics of scopolamine, we developed an LC/MS/MS method using off-line solid phase extraction. Method: Samples (0.5mL) were loaded onto Waters Oasis HLB co-polymer cartridges (10 mg, 1 mL) and eluted with 0.5 mL methanol without evaporation and reconstitution. HPLC separation of the eluted sample was performed using an Agilent Zorbax SB-CN column (50 x 2.1 mm) at a flow rate of 0.2 mL/min for 4 minutes. The mobile phase for separation was 90:10 (v/v) methanol: ammonium acetate (2 mM) in water, pH 5.0 +/- 0.1. Concentrations of scopolamine were determined using a Micromass Quattro Micro(TM) mass spectrometer with electrospray ionization (ESI). ESI mass spectra were acquired in positive ion mode with multiple reaction monitoring for the determination of scopolamine m/z = 304.2 yields 138.1 and internal standard (IS) hyoscyamine m/z = 290.2 yields 124.1. Results: The method is rapid, reproducible, specific and has the following parameters: scopolamine and the IS are eluted at 1.7 and 3.2 min respectively. The linear range is 50-5000 pg/mL for scopolamine in saliva with correlation coefficients > 0.99 with a CV saliva. Conclusion: Solid phase extraction allows more rapid sample preparation and greater precision than liquid extraction. Furthermore, we increased the sensitivity and specificity by adjusting the LC mobile phase and using an MS/MS detector.

Wang, Zuwei; Vaksman, Zalman; Boyd, Jason; Putcha, Lakshmi

2007-01-01

169

Combination of solid phase extraction and in vial solid phase derivatization using a strong anion exchange disk for the determination of nerve agent markers.  

Science.gov (United States)

Alkylphosphonic acids (APAs) are degradation products and chemical markers of organophosphorous (OP) nerve agents (chemical warfare agents). Anion exchange disk-based solid phase extraction (SPE) has been combined with in vial solid phase derivatization (SPD) and GC-MS analysis for the determination of APAs in aqueous samples. The optimization of critical method parameters, such as the SPD reaction, was achieved using statistical experimental design and multivariate data analysis. The optimized method achieved quantitative recoveries in the range from 83% to 101% (n=13, RSD from 4% to 10%). The method was sensitive, with LODs in SIM mode of 0.14 ppb, and demonstrated excellent linearity with an average R(2)>or=0.99 over the concentration range of 0.07-1.4 ppm in full scan mode and from 0.14 ppb to 14 ppb in SIM mode. For forensic applications, aqueous samples containing APAs at concentrations exceeding 14 ppb were concentrated and target analytes were successfully identified by spectral library and retention index matching. Method robustness was evaluated using aqueous samples from the official OPCW Proficiency Test (round 19) and all APAs present in the sample were conclusively identified. The SPE disk retained the underivatized APAs in a stable condition for extended periods of time. No significant losses of APAs from the disk were observed over a 36-day period. Overall, the method is well suited to the qualitative and quantitative analysis of degradation markers of OP nerve agents in aqueous matrices with simplicity, a low risk of cross-contamination and trace level sensitivity. PMID:19854444

Subramaniam, Raja; Astot, Crister; Nilsson, Calle; Ostin, Anders

2009-11-27

170

Sample digestion and solid-phase extraction for the enrichment of actinides from radioactive waste  

International Nuclear Information System (INIS)

For the destructive characterization of radioactive waste, the actinides to be analysed must be separated from matrix components, if possible, in an element-specific manner. Microwave pressure digestion is a time-saving digestion method for radioactive waste samples. This method serves to digest solid samples in teflon pressure autoclaves with the addition of various acids. Different microwave programs have been developed for all common radioactive waste matrices such as cement, ion exchange resins, filter dusts, sludges and mineral blasting sands permitting digestion times of approx. 1.5 hours including time for cooling. The partitioning of the actinides from the liquid samples was carried out with the aid of solid-phase extraction. For the experiments, on the one hand, commercially available extraction resins such as Actinide, TRU, UTEVA and TEVA resinTM from Eichrom were used. On the other hand, an extraction resin with Cyanex 301 produced in-house was employed specifically for actinide-lanthanide partitioning. It was possible to separate 99.4% of the lanthanides by a two-stage partitioning process. A partitioning run using the Eichrom resins was successfully adapted to the waste matrices and automated with the aid of a laboratory robot. It is particularly meaningful to perform a prior matrix partitioning with Actinide resinTM. A rough qualification of the sample is possible by the ?-analysis of the actinide fraction. The extractant, which watinide fraction. The extractant, which was eluted from the column together with the actinides, was destroyed oxidatively by means of a newly developed technique using microwave pressure digestion. The final determination of the actinides was performed with the aid of ?-spectrometry. Electrodeposition proved to be a suitable method for the preparation of samples with minimum possible layer thickness. This preparation technique was optimized so as to provide samples with half-widths of 18 keV in the ?-spectrometer. (orig.)

171

Cyclodextrin polymer/Fe3O4 nanocomposites as solid phase extraction material coupled with UV-vis spectrometry for the analysis of rutin  

Science.gov (United States)

In this paper, carboxymethyl-hydroxypropyl-?-cyclodextrin polymer modified magnetic particles Fe3O4 (CM-HP-?-CDCP-MNPs) were prepared and applied to magnetic solid phase extraction of rutin combined with UV-visible spectrometry detection. The synthesized magnetic particles were characterized by element analysis, Fourier transform infrared spectra, thermal gravimetric analysis, and transmission electron microscopy. Several variables affecting the extraction and desorption of rutin such as pH, the amount of adsorbent, the type and volume of eluent, extraction and desorption time, and temperature were investigated. The maximum adsorption capacity was 67.0 mg g-1 for rutin with the equilibrium time of 30 min at room temperature, and the adsorbent could be reused for 10 times. A calibration curve was linear in the range of 0.05-8.00 ?g mL-1 with a relative standard deviation of 2.9% (n = 5, c = 4.0 ?g mL-1). The limit of detection was 7.0 ng mL-1. The interaction mechanism between the adsorbent and rutin was also studied. Feasibility of this method was validated by the analysis of rutin tablets and lotus plumule.

Gong, Aiqin; Ping, Wenhui; Wang, Jue; Zhu, Xiashi

2014-03-01

172

Studies on the separation of rare earth elements and yttrium using a new solid phase adsorbent xylenol orange immobilized on silica: application to geological samples  

International Nuclear Information System (INIS)

This paper presents the investigation carried out on a new solid phase adsorbent developed in our laboratory, xylenol orange immobilized on silica (XO-Si) by a single step process. Preparation of silica from sodium meta-silicate solution and immobilization of xylenol orange on it takes place simultaneously in presence of cationic surfactant cetyl-tri-methyl ammonium bromide (CTAB). It was observed that in the absence of surfactant, xylenol orange was completely removed from the silica surface during washing. The surfactant CTAB acts as a bridge between silica and xylenol orange molecule

173

The use of solid phase extraction method for analysis of residues of pesticides used in banana production in Costa Rica  

International Nuclear Information System (INIS)

Different solid phase extraction devices were tested for the analysis of residues of eleven pesticides used in banana production in Costa Rica. The analysis was performed by using gas chromatograph equipped with NPD and ECD detectors. In general low recoveries and high variation coefficients were found for chlorothalonil, imazalil, terbufos and thiabendazole. For the other pesticides recoveries ranged between 60 and over 100%. (author)

174

Solid Phase Extraction for Monitoring of Occupational Exposure to Cr (III  

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Full Text Available Chromium is an important constituent widely used in different industrial processes for production of various synthetic materials. For evaluation of workers’ exposure to trace toxic metal of Cr (III, environmental and biological monitoring are essential processes, in which, preparation of samples is one of the most time-consuming and error-prone aspects prior to analysis. The use of solid-phase extraction (SPE has grown and is a fertile technique of sample preparation as it provides better results than those produced by liquid-liquid extraction (LLE. SPE using mini columns filled with XAD-4 resin was optimized regarding to sample pH, ligand concentration, loading flow rate, elution solvent, sample volume, elution volume, amount of resins, and sample matrix interferences. Chromium was retained on solid sorbent and was eluted with 2 M HNO3 followed by simple determination of analytes by using flame atomic absorption spectrometery. Obtained recoveries of metal ion were more than 92%. The optimized procedure was also validated with three different pools of spiked urine samples and showed a good reproducibility over six consecutive days as well as six within-day experiments. Through this study, suitable results were obtained for relative standard deviation, therefore, it is concluded that, this optimized method can be considered to be successful in simplifying sample preparation for trace residue analysis of Cr in different matrices for evaluation of occupational and environmental exposures. To evaluate occupational exposure to chromium, 16 urine samples were taken, prepared, and analyzed based on optimized procedure.

S.J. Shahtaheri

2007-01-01

175

Ferrofluid based dispersive-solid phase extraction for spectrophotometric determination of dyes.  

Science.gov (United States)

For the first time, ferrofluid based dispersive-solid phase extraction (D-SPE) has been applied for determination of trace levels of dyes in aqueous and fish samples. The contaminant used as a model compound was crystal violet (CV), a cationic dye, and was preconcentrated without any derivatization or ion-pair formation. The method is based on rapid injection of ferrofluid into the aqueous sample by a syringe. The sample preparation time is decreased by the fact that the sorbent dispersed in the bulk solution and extraction can be achieved very fast. In this way, the separation of sorbent from the aqueous bulk was achieved by a magnet, and no centrifugation is required. These significant features which obtained with this method are of key interest for routine trace laboratory analysis. The influence of different variables on D-SPE was investigated. Under optimum conditions, the calibration graph was linear over the range of 3.3-90 ?g L(-1), and the enrichment factor (EF) 267 was obtained. Detection limit was 1.51 ?g L(-1) (n=7), and the relative standard deviation of 5.6% at 50 ng mL(-1) was obtained (n=7). The proposed method was successfully applied for the determination of crystal violet in various samples. PMID:23849184

Davudabadi Farahani, Malihe; Shemirani, Farzaneh

2013-10-01

176

Preconcentration of trace uranium from natural water with solid-phase extraction  

International Nuclear Information System (INIS)

In the present study, an effective method was used for the preconcentration and determination of uranium(VI) by solid-phase extraction (SPE). For this purpose, a microcolumn of alumina modified with sodium dodecyl sulfate (SDS) and 1-(2-pyridylazo)-2-naphthol (PAN) was prepared for the preconcentration of trace uranyl(VI) from water samples. The uranium(VI) was completely eluted with 6.0 mol dm-3 HCl and determined by a spectrophotometric method with Arsenazo III. The SPE conditions were optimized by evaluating the effective factors such as pH, flow rate and masking agent. By the proposed method a preconcentration factor more than 150 was achieved. The average recovery of uranium(VI) was 99.8%. The relative standard deviation was 2.6% for ten replicate determinations of uranyl(VI) ion in a solution with a concentration of 50 ng cm-3. Some concomitant ions such as Cd2+, Ni2+, MoO42-, Cu2+, Th4+ and Ce3+, which interfere in the determination process of uranium(VI), were masked with EDTA in the aqueous phase during the extraction process. The proposed method was successfully used for the determination of uranium in natural water. (author)

177

Preconcentration of trace uranium from natural water with solid-phase extraction  

Energy Technology Data Exchange (ETDEWEB)

In the present study, an effective method was used for the preconcentration and determination of uranium(VI) by solid-phase extraction (SPE). For this purpose, a microcolumn of alumina modified with sodium dodecyl sulfate (SDS) and 1-(2-pyridylazo)-2-naphthol (PAN) was prepared for the preconcentration of trace uranyl(VI) from water samples. The uranium(VI) was completely eluted with 6.0 mol dm{sup -3} HCl and determined by a spectrophotometric method with Arsenazo III. The SPE conditions were optimized by evaluating the effective factors such as pH, flow rate and masking agent. By the proposed method a preconcentration factor more than 150 was achieved. The average recovery of uranium(VI) was 99.8%. The relative standard deviation was 2.6% for ten replicate determinations of uranyl(VI) ion in a solution with a concentration of 50 ng cm{sup -3}. Some concomitant ions such as Cd{sup 2+}, Ni{sup 2+}, MoO{sub 4}{sup 2-}, Cu{sup 2+}, Th{sup 4+} and Ce{sup 3+}, which interfere in the determination process of uranium(VI), were masked with EDTA in the aqueous phase during the extraction process. The proposed method was successfully used for the determination of uranium in natural water. (author)

Farzaneh Shemirani; Shiva Dehghan Abkenar; Mohammad Reza Jamali [University of Tehran, Faculty of Science, Tehran (Iran)

2003-03-01

178

On-line solid-phase extraction for liquid chromatography-mass spectrometry analysis of pesticides.  

Science.gov (United States)

Public concern about pesticides in food and water has increased dramatically in the last two decades. In order to guarantee consumers' health and safety, analytical methods that could provide fast and reliable answers without compromising accuracy and precision are required. Sample treatment is probably the most tedious and time-consuming step in many analytical procedures and, despite the significant advances in chromatographic separations and mass spectrometry techniques, sample treatment is still one of the most important parts of the analytical process for achieving good analytical results. Therefore, over the last years, considerable efforts have been made to simplify the stage and to develop fast, accurate, and robust methods that allow the determination of a wide range of pesticides without compromising the integrity of the extraction process. This review article intends to give a short overview of recently developed on-line solid-phase extraction, preconcentration, and clean-up procedures for the determination of pesticides in complex matrices by liquid chromatography-mass spectrometry techniques. PMID:25103367

Lucci, Paolo; Núñez, Oscar

2014-10-01

179

Solid-phase extraction of 1,4-benzodiazepines from biological fluids.  

Science.gov (United States)

The solid-phase extraction (SPE) of seven 1,4-benzodiazepines (oxazepam, diazepam, temazepam, nordazepam, brotizolam, adinazolam and midazolam) using prazepam as internal standard was investigated. The 1,4-benzodiazepines were recovered from an aqueous buffer of suitable pH, using C18 Sep-Pak cartridges and mixtures of methanol-water as elution solvent. The recovery of oxazepam using different sorbent materials (C2, C8, C18, cyanopropyl, phenyl and cyclohexyl Bond-Elut) was also examined as a function of pH and the composition of the elution solvent. The SPE of oxazepam was investigated using spiked urine samples and the C2 cartridge gave rise to the cleanest urine extracts. The recoveries of the other 1,4-benzodiazepines from spiked urine and plasma samples using the C2 cartridge was then found to be higher than 90%, without any interference from endogenous compounds of the samples. Finally, the influence of other factors such as drug concentration, sample volume and the number of times the SPE cartridge had been used was also examined. PMID:8357864

Casas, M; Berrueta, L A; Gallo, B; Vicente, F

1993-01-01

180

Determination of nanomolar chromate in drinking water with solid phase extraction and a portable spectrophotometer.  

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Determination of chromate at low concentration levels in drinking water is an important analytical objective for both human health and environmental science. Here we report the use of solid phase extraction (SPE) in combination with a custom-made portable light-emitting diode (LED) spectrophotometer to achieve detection of chromate in the field at nanomolar levels. The measurement chemistry is based on a highly selective reaction between 1,5-diphenylcarbazide (DPC) and chromate under acidic conditions. The Cr-DPC complex formed in the reaction can be extracted on a commercial C18 SPE cartridge. Concentrated Cr-DPC is subsequently eluted with methanol and detected by spectrophotometry. Optimization of analytical conditions involved investigation of reagent compositions and concentrations, eluent type, flow rate (sample loading), sample volume, and stability of the SPE cartridge. Under optimized conditions, detection limits are on the order of 3 nM. Only 50 mL of sample is required for an analysis, and total analysis time is around 10 min. The targeted analytical range of 0-500 nM can be easily extended by changing the sample volume. Compared to previous SPE-based spectrophotometric methods, this analytical procedure offers the benefits of improved sensitivity, reduced sample consumption, shorter analysis time, greater operational convenience, and lower cost. PMID:22525482

Ma, Jian; Yang, Bo; Byrne, Robert H

2012-06-15

181

Hemimicelles/admicelles supported on magnetic graphene sheets for enhanced magnetic solid-phase extraction.  

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In this work, superparamagnetic nanoparticle-decorated graphene (MG) sheets were synthesized and used as support for hemimicelles/admicelles for solid-phase extraction (SPE) of different compounds from environmental water samples for the first time. The MG sheets were facilely synthesized by a one-step, one-pot redox reaction between graphene oxide and Fe(II). Due to the large surface area and unique nanosheet morphology, MG served as an excellent nano-scaled support material for hemimicelles and admicelles, exhibiting higher loading capacity than conventional materials and pure Fe?O? nanoparticles. The MG sheets could be negatively or positively charged depending on solution pH, allowing the extraction to be conducted in different modes. In cationic mode, cetyltrimethylammonium bromide (CTAB) was used as micelle-forming reagent, and perfluoroalkyl and polyfluoroalkyl substances (PFASs) and alkylphenols were used as model analytes. In anionic mode, sodium dodecyl sulfate (SDS) was used as micelle-forming reagent and alkyltrimethylammonium salts were selected as analytes. In both modes, the formation processes of hemimicelles/admicelles on MG sheets were studied and the extraction conditions were optimized. For PFASs, the analytical sensitivity was enhanced by 50-113-fold by the extraction, and the method detection limits (MDLs) ranged from 0.15 to 0.50 ng/L. For alkyltrimethylammonium salts, the MDLs were in the range of 1.4-8.0 ng/L. In both modes, good recoveries (56.3-93.9%) and reproducibility (run-to-run RSDsgraphene in analytical sample preparation. PMID:22921358

Liu, Qian; Shi, Jianbo; Wang, Thanh; Guo, Feng; Liu, Lihong; Jiang, Guibin

2012-09-28

182

Magnetically assisted solid phase extraction using Fe3O4 nanoparticles combined with enhanced spectrofluorimetric detection for aflatoxin M1 determination in milk samples.  

Science.gov (United States)

A novel, facile and inexpensive solid phase extraction (SPE) method using ethylene glycol bis-mercaptoacetate modified 3-(trimethoxysilyl)-1-propanethiol grafted Fe(3)O(4) nanoparticles coupled with spectrofluorimetric detection was proposed for determination of aflatoxin M1 (AFM1) in liquid milk samples. The method uses the advantage fluorescence enhancement by ?-cyclodexterin complexation of AFM1 in 12% (v/v) acetonitrile-water and the remarkable properties of Fe(3)O(4) nanoparticles namely high surface area and strong magnetization were utilized to achieve high enrichment factor (57) and satisfactory extraction recoveries (91-102%) using only 100 mg of magnetic adsorbent. Furthermore, fast separation time of about 15 min avoids many time-consuming column-passing procedures of conventional SPE. The main factors affecting extraction efficiency including pH value, desorption conditions, extraction/desorption time, sample volume, and adsorbent amount were evaluated and optimized. Under the optimal conditions, a wide linear range of 0.04-8 ng mL(-1) with a low detection limit of 0.015 ng mL(-1) was obtained. The developed method was applied for extraction and preconcentration of AFM1 in three commercially available milk samples and the results were compared with the official AOAC method. PMID:25127653

Taherimaslak, Zohreh; Amoli-Diva, Mitra; Allahyary, Mehdi; Pourghazi, Kamyar

2014-09-01

183

Magnetic single-walled carbon nanotubes-dispersive solid-phase extraction method combined with liquid chromatography-tandem mass spectrometry for the determination of paraquat in urine.  

Science.gov (United States)

In this study, magnetic single-walled carbon nanotubes (MSWCNTs) were prepared by impregnating magnetic Fe3O4 nanoparticles onto the surfaces of carboxylic single-walled carbon nanotubes based on electrostatic interactions. The prepared MSWCNTs were used as the adsorbent for the dispersive solid-phase extraction (DSPE) of paraquat from human urine. After adsorption, the paraquat was quantitatively desorbed with 5%TFA in acetonitrile and determined by HPLC-MS. Extraction parameters such as the type of CNT adsorbent, extraction time, sample volume, wash solvent, and the type and volume of desorption solvent were optimized to obtain high DSPE recoveries and extraction efficiencies. Under the optimized conditions, the calibration curve was linear in the range 3.75-375.0 ?g/L with a correlation coefficient of 0.999 45. The LOD (S/N=3) and LOQ (S/N=10) were 0.94 and 2.82 ?g/L, respectively. The recoveries ranged from 92.89 to 108.9% for spiked real urine samples with RSDs below 3.21%. Finally, the new method was successfully used to determine paraquat in urine samples of suspected paraquat poisoning patients. The MSWCNTs exhibited suitable properties and a high adsorption capacity for the extraction of paraquat. PMID:24999616

Ruan, Xiao-Lin; Qiu, Jing-Jing; Wu, Chuan; Huang, Tao; Meng, Rui-Bo; Lai, Yong-Qiang

2014-08-15

184

Extraction and on-fiber derivatization of chlorophenols in leather by internally cooled solid phase microextraction  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Neste estudo é proposto um novo procedimento analítico para a determinação de fenóis em amostras de couro utilizando a técnica de microextração em fase sólida refrigerada internamente (CF-SPME) com derivatização direta na fibra e cromatografia gasosa acoplada a espectrometria de massas com monitoram [...] ento de íons selecionados (GC-SIM-MS). As condições experimentais para a extração e derivatização foram otimizadas utilizando procedimentos quimiométricos, sendo tempo de extração e temperatura da amostra de 5 min e 170 ºC, temperatura do recobrimento da fibra de 20 ºC, e exposição da fibra ao headspace de 70 µL do agente derivatizante bis(trimetilsilil)trifluor-acetamida por 23 min. Limites de detecção variaram entre 1,03 e 2,68 µg g-1 e o desvio padrão relativo (RSD) foi menor que 15% (n = 5). Estudos de recuperações em três níveis de concentração variaram entre 64,5 e 92,3%. Abstract in english This study proposes a new analytical procedure based on an internally cooled solid phase microextraction technique (CF-SPME) combined with on-fiber derivatization and gas chromatography-selected ion monitoring-mass spectrometry (GC-SIM-MS) for the determination of phenols extracted directly from lea [...] ther samples. The extraction and derivatization conditions were optimized using experimental designs, such as: extraction time and sample temperature of 5 min and 170 ºC, fiber recoat temperature of 20 ºC, and exposing the fiber to the headspace of 70 µL of bis(trimethylsylyl)trifluoro-acetamide derivatizing agent for 23 min. Detection limits ranging from 1.03 to 2.68 µg g-1 and relative standard deviation (RSD) lower than 15% (n = 5) were obtained. The recovery was studied at three concentration levels and excellent recoveries ranging from 64.5 to 92.3% were obtained.

Cristine D. de Souza, Silveira; Josias, Merib; Edmar, Martendal; Eduardo, Carasek.

2232-22-01

185

Core-Shell Diamond as a Support for Solid-Phase Extraction and High-Performance Liquid Chromatography  

International Nuclear Information System (INIS)

We report the formation of core-shell diamond particles for solid phase extraction (SPE) and high performance liquid chromatography (HPLC) made by layer-by-layer (LbL) deposition. Their synthesis begins with the amine functionalization of microdiamond by its immersion in an aqueous solution of a primary amine-containing polymer (polyallylamine (PAAm)). The amine-terminated microdiamond is then immersed in an aqueous suspension of nanodiamond, which leads to adsorption of the nanodiamond. Alternating (self-limiting) immersions in the solutions of the amine-containing polymer and the suspension of nanodiamond are continued until the desired number of nanodiamond layers is formed around the microdiamond. Finally, the core-shell particles are cross-linked with 1,2,5,6-diepoxycyclooctane or reacted with 1,2-epoxyoctadecane. Layer-by-layer deposition of PAAm and nanodiamond is also studied on planar Si/SiO2 surfaces, which were characterized by SEM, Rutherford backscattering spectrometry (RBS) and nuclear reaction analysis (NRA). Core-shell particles are characterized by diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), environmental scanning electron microscopy (ESEM), and Brunauer Emmett Teller (BET) surface area and pore size measurements. Larger (ca. 50 ?m) core-shell diamond particles have much higher surface areas, and analyte loading capacities in SPE than nonporous solid diamond particles. Smaller (ca. 3 ?m), normal and reversed phase, core-shell m), normal and reversed phase, core-shell diamond particles have been used for HPLC, with 36,300 plates per meter for mesitylene in a separation of benzene and alkyl benzenes on a C18 adsorbent, and 54,800 plates per meter for diazinon in a similar separation of two pesticides.

186

Core-Shell Diamond as a Support for Solid-Phase Extraction and High-Performance Liquid Chromatography  

Energy Technology Data Exchange (ETDEWEB)

We report the formation of core-shell diamond particles for solid phase extraction (SPE) and high performance liquid chromatography (HPLC) made by layer-by-layer (LbL) deposition. Their synthesis begins with the amine functionalization of microdiamond by its immersion in an aqueous solution of a primary amine-containing polymer (polyallylamine (PAAm)). The amine-terminated microdiamond is then immersed in an aqueous suspension of nanodiamond, which leads to adsorption of the nanodiamond. Alternating (self-limiting) immersions in the solutions of the amine-containing polymer and the suspension of nanodiamond are continued until the desired number of nanodiamond layers is formed around the microdiamond. Finally, the core-shell particles are cross-linked with 1,2,5,6-diepoxycyclooctane or reacted with 1,2-epoxyoctadecane. Layer-by-layer deposition of PAAm and nanodiamond is also studied on planar Si/SiO2 surfaces, which were characterized by SEM, Rutherford backscattering spectrometry (RBS) and nuclear reaction analysis (NRA). Core-shell particles are characterized by diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), environmental scanning electron microscopy (ESEM), and Brunauer Emmett Teller (BET) surface area and pore size measurements. Larger (ca. 50 ?m) core-shell diamond particles have much higher surface areas, and analyte loading capacities in SPE than nonporous solid diamond particles. Smaller (ca. 3 ?m), normal and reversed phase, core-shell diamond particles have been used for HPLC, with 36,300 plates per meter for mesitylene in a separation of benzene and alkyl benzenes on a C18 adsorbent, and 54,800 plates per meter for diazinon in a similar separation of two pesticides.

Saini, Gaurav; Jensen, David S.; Wiest, Landon A.; Vail, Michael A.; Dadson, Andrew; Lee, Milton L.; Shutthanandan, V.; Linford, Matthew R.

2010-06-01

187

Determination of rhodamine B in soft drink, waste water and lipstick samples after solid phase extraction.  

Science.gov (United States)

A new solid phase extraction method is described for sensitive and selective determination of trace levels of rhodamine B in soft drink, food and industrial waste water samples. The method is based on the adsorption of rhodamine B on the Sepabeads SP 70 resin and its elution with 5 mL of acetonitrile in a mini chromatographic column. Rhodamine B was determined by using UV visible spectrophotometry at 556 nm. The effects of different parameters such as pH, amount of rhodamine B, flow rates of sample and eluent solutions, resin amount, and sample volume were investigated. The influences of some alkali, alkali earth and transition metals on the recoveries of rhodamine B were investigated. The preconcentration factor was found 40. The detection limit based on three times the standard deviation of the reagent blank for rhodamine B was 3.14 ?g L?¹. The relative standard deviations of the procedure were found as 5% in 1×10?? mol L?¹ rhodamine B. The presented procedure was successfully applied to real samples including soft drink, food and industrial waste water and lipstick samples. PMID:21570440

Soylak, Mustafa; Unsal, Yunus Emre; Yilmaz, Erkan; Tuzen, Mustafa

2011-08-01

188

Determination of Phthalate Esters in Drinking Water using Solid-phase Extraction and Gas Chromatography  

Directory of Open Access Journals (Sweden)

Full Text Available Phthalate esters are widely used as plasticizer. They can migrate from plastic materials to the environment. Some of these compounds may have risk to get cancer. Phthalate esters; dimethyl phthalate (DMP, diethyl phthalate (DEP, dibutyl phthalate (DBP and bis(2-ethylhexyl phthalate (DEHP were extracted simultaneously using solid-phase and analyzed by gas chromatograph. The percentage recoveries were carried out on LC-18 and Florisil cartridge using various eluting solvent. The 6 mL Florisil (1 g with 5 mL of ethyl acetate as eluting solvent showed good recoveries in the range of 98.2-110.0% and the limit of determination in the range of 0.025-00.05 mg L-1. This proposed method was successfully applied to analysis of phthalates in drinking water. The contamination of DMP, DEP and DBP in drinking water samples were in the safe levels, except DEHP concentration in three samples were found out of regulated maximum admissible concentration.

W. Kanchanamayoon

2010-01-01

189

Tandem Solid Phase Extraction for the Determination of Pharmaceuticals in Wastewater  

International Nuclear Information System (INIS)

In this study, a simple and rapid tandem solid phase extraction (SPE) was developed for the analysis of seven pharmaceuticals (acetaminophen, caffeine, carbamazepine, diclofenac, naproxen, ibuprofen and metaprolol) in wastewater sample. The novel aspect of coupling SPE cartridge in tandem is the ability to simplify the SPE procedure (sample introduction step) as no single sorbent was able to retain and concentrate all selected compounds since these compounds are of different physicochemical properties. A tandem SPE cartridges using Oasis HLB and octadecyl bonded silica (C18) was found to be efficient with the advantages of minimizing sample volume and reducing analysis time. Using this approach, carbamazepine, diclofenac, naproxen and metaprolol were trapped in the Oasis HLB while acetaminophen, caffeine and ibuprofen were trapped in the second cartridge (C18). The instrumental limits of detection (LOD) ranged from 0.01 to 0.04 ?g/ L and satisfactory recoveries were obtained between 76 % to 104 %. The calibration curves were linear from 0.1 to 5.0 ?g/ mL, with correlation coefficients (R2) in the range of 0.995 to 0.999. The developed method was applied to the analysis of pharmaceuticals in wastewater samples. The amount of pharmaceuticals detected in wastewater samples varied from 0.4 to 24.5 mg/ L. (author)

190

Solid-phase dispersive extraction method for analysis of benzodiazepine drugs in serum and urine samples.  

Science.gov (United States)

A simple yet highly efficient pretreatment method called solid-phase dispersive extraction (SPDE) was developed and used in combination with liquid chromatography/time-of-flight mass spectrometry (LC/TOF-MS) for the analysis of benzodiazepines (BZPs) in serum and urine samples. By using a custom-made centrifugal filter, SPDE could be performed in a closed system, thereby minimizing exposure to infectious microbes or hazardous chemicals. The limit of detection and the limit of quantification of nine BZPs were 1-10 and 5-50ng/mL, respectively. The average recoveries of BZPs from pooled serum samples spiked at 50 and 500ng/mL were 89.6-105.0% (RSD: 2.1-6.8%) and 93.6-110.4% (RSD: 2.1-4.2%), respectively, and those from urine samples were 88.7-105.5% (RSD: 2.9-6.4%) and 91.5-101.1% (RSD: 3.6-5.5%), respectively. SPDE-LC/TOF-MS has potential application in forensic science and emergency medicine. PMID:25126966

Saito, Koichi; Kikuchi, Yuu; Saito, Rieko

2014-11-01

191

Identification and fingerprinting of biodiesel blends by solid phase extraction and gas chromatography-mass spectrometry  

International Nuclear Information System (INIS)

Interest in biodiesel as a replacement for petroleum diesel fuel is growing. In North America, biodiesels are produced by the methyl esterification of plant and animal triglycerides, resulting in complex mixtures composed of fatty acid methyl esters (FAMEs). It is important for both environmental forensic and remediation purposes to determine diesel and biodiesel origins, and the biodiesel content when it is blended with conventional petroleum diesel. This paper reported on a study that combined 2 methods to determine biodiesel levels in blended fuels. Micro-column fractionation of FAMEs involving solid phase extraction (SPE) was combined with gas chromatography-mass spectrometry (GC/MS) to achieve detailed chemical fingerprinting of blends, including the identification and quantification of individual aliphatic hydrocarbons, aromatic hydrocarbons, fatty acid alkyl esters, and free sterols. Fractionation of the fuel samples was optimized for separation of fatty acid esters, free sterols from petroleum hydrocarbons into 4 fractions, notably aliphatic, aromatic, fatty-acid ester and polar components. A sum of the FAME components was used to determine an unknown blend level in freshly-prepared samples. This study showed that this method has great potential for identifying biodiesel in diesel fuel blends and could form the basis of a method for biodiesel-contaminated environmental samples. 28 refs., 5 tabs., 4 figs.

192

A rapid ceramide synthase activity using NBD-sphinganine and solid phase extraction.  

Science.gov (United States)

Ceramides are synthesized by six mammalian ceramide synthases (CerSs), each of which uses fatty acyl-CoAs of different chain lengths for N-acylation of the sphingoid long-chain base. We now describe a rapid and reliable CerS assay that uses a fluorescent N-[6-[(7-nitrobenzo-2-oxa-1,3-diazol-4-yl) (NBD) sphinganine substrate followed by separation of the NBD-lipid substrate and products using solid phase extraction (SPE) C18 chromatography. SPE chromatography is a quick and reliable alternative to TLC, and moreover, there is no degradation of either NBD-sphinganine or NBD-ceramide. We have optimized the assay for use with minimal amounts of protein in a minimal volume. This assay will prove useful for the analysis of CerS activity, which is of particular importance in light of the growing involvement of CerS in cell regulation and in the pathology of human diseases. PMID:25368106

Tidhar, Rotem; Sims, Kacee; Rosenfeld-Gur, Eden; Shaw, Walter; Futerman, Anthony H

2015-01-01

193

Solid-phase extraction of antipyrine dye for spectrophotometric determination of phenolic compounds in water.  

Science.gov (United States)

In order to determine phenolic compounds in water, we propose a method based on the reaction of phenolic compounds with 4-aminoantipyrine in the presence of peroxodisulfate at pH 10 to form antipyrine dye and the solid-phase extraction of dye with a Varian Bond Elut Plexa cartridge. Dye collected on the cartridge is eluted with acetonitrile and the absorbance is measured at 475 nm. In our experiments, recovery ratios of >90% were obtained for phenol, o-aminophenol, m-aminophenol, o-methoxyphenol, m-methoxyphenol, p-methoxyphenol, o-cresol, m-cresol, o-chlorophenol, m-chlorophenol, p-chlorophenol, 2,5-dimethylphenol, and 2,4-dichlorophenol. The calibration curve obeyed Beer's law in the range 0 - 0.30 µg ml(-1) phenol. The precision of repeated tests (n = 4) was 1.7% of the phenol solution (0.10 µg ml(-1)); the detection limit was 0.0011 µg ml(-1). Recovery tests using river water, waste water, and sewage influent gave highly satisfactory results. PMID:21558654

Morita, Emi; Nakamura, Eiko

2011-01-01

194

Solid phase extraction of iron and lead in environmental matrices on amberlite xad-1180/pv  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english A solid phase extraction procedure using Amberlite XAD-1180/Pyrocatechol violet (PV) chelating resin for the determination of iron and lead ions in various environmental samples was established. The procedure is based on the sorption of lead(II) and iron(III) ions onto the resin at pH 9, followed by [...] elution with 1 mol/L HNO3 and determination by flame atomic absorption spectrometry. The influence of alkaline, earth alkaline and some transition metals, as interferents, are discussed. The recoveries for the spiked analytes were greater than 95%. The detection limits for lead and iron by FAAS were 0.37 µg/L and 0.20 µg/L, respectively. Validation of the method described here was performed by using three certified reference materials (SRM 1515 Apple Leaves, SRM 2711 Montana Soil and NRCC-SLRS-4 Riverine Water). The procedure was successfully applied to natural waters and human hair.

Mustafa, Soylak; Mustafa, Tuzen; Ibrahim, Narin.

2006-04-01

195

Chromium speciation by surfactant assisted solid-phase extraction and flame atomic absorption spectrometric detection.  

Science.gov (United States)

A new procedure has been developed for chromium speciation in aqueous solution by the use of micellar, ion-association, solid-phase extraction techniques (SPE) followed by flame atomic absorption spectrometry. The method was based on the use of C-18 bonded phase silica SPE disks for retention of ion-associated Cr(VI) with cetyl trimethyl ammonium bromide (CTAB), elution of the retained species and subsequent detection by flame atomic absorption spectrometry (FAAS). Cr(III) was oxidized by potassium persulfate to Cr(VI), then the total chromium was retained on the disk and determined by FAAS. The amount of Cr(III) was calculated by the difference between the total and Cr(VI) values. The calculated limit of detections (LOD) (based on 3sigma) are 15 microg L(-1) and 20 microg L(-1) for Cr(VI) and Cr(III) respectively. No considerable interferences have been observed from other investigated anions and cations and the method has been successfully applied to water samples taken from the Karoon River in Khuzestan province. PMID:15279102

Saber Tehrani, Mohammad; Afshar Ebrahimi, Arash; Rastegar, Faramarz

2004-01-01

196

Highly sensitive phosphoproteomics by tailoring solid-phase extraction to electrostatic repulsion-hydrophilic interaction chromatography.  

Science.gov (United States)

In the past decade, several strategies for comprehensive phosphoproteome analysis have been introduced. Most of them combine different phosphopeptide enrichment techniques and require starting material in the milligram range, as a consequence of their insufficient sensitivity. This limitation impairs the applicability of phosphoproteomics to a wide variety of clinical research, where sample material is highly limited. Here we introduce a highly sensitive and easy-to-establish 2D bottom-up strategy for µg-scale phosphoproteomics, based on electrostatic repulsion-hydrophilic interaction chromatography (ERLIC), a simple solid phase-extraction step by strong cation exchange (SCX) or reversed phase (RP) and LC-MS analysis. With only 100 µg of tryptic digested, non-stimulated HeLa protein and 45 h of LC-MS analysis time, we identified ? 7500 non-redundant and highly confident phosphorylation sites (per replicate). We assigned all phosphorylation sites to 3,013 phosphoproteins, covering the entire dynamic range from 107 down to a few copies per cell. Compared to affinity-based-enrichment methods using Ti4+, our ERLIC-based strategy enriched considerably longer and more acidic phosphopeptides and consequently, we identified 327 phosphorylated C-terminal peptides. The simplicity and high sensitivity of ERLIC-SCX/RP-LC-MS render its future promising for µg-scale-phosphoproteomics in biological, biomedical and clinical research. PMID:25405705

Loroch, Stefan; Zahedi, René Peiman; Sickmann, Albert

2014-11-18

197

Determination of phenols in landfill leachate-contaminated groundwaters by solid-phase extraction  

DEFF Research Database (Denmark)

A solid-phase extraction method for phenols in landfill leachates was developed and optimized in order to solve the expected and observed problems associated with an anaerobic matrix containing high concentrations of salts and organic matter. Isolute ENV1 cartridges exhibited the best retention of phenols of the four sorbents examined, and was the only cartridge which a 1 L leachate sample could pass through. With the other cartridges, clogging made this impossible. The final method, which included 27 different phenols, gave detection limits of ,0.1 mg/L (drinking water concentration limit for pesticides) for most phenols (25), and for 12 phenols ,0.01 mg/ L. Recovery rates (determined for four concentrations in the range 1–25 mg/ L, two replicates of each) were in the range 79–104% (SD 1–12%), except for phenol (2661.3%) and 2-methoxyphenol (6264.2%). Up to 12 different phenols could be identified in leachates from three Danish landfills, ranging in concentration from 0.01 to 29 mg/ L, which is at the lower end of the concentration range usually found for phenols in landfill leachates (sub-mg/L to mg/L). ? 2002 Elsevier Science B.V. All rights reserved.

Ask Reitzel, Lotte; Ledin, Anna

2002-01-01

198

Automated and portable solid phase extraction platform for immuno-detection of 17?-estradiol in water.  

Science.gov (United States)

A fully automated and portable system for solid phase extraction (SPE) has been developed for the analysis of the natural hormone 17?-estradiol (E2) in environmental water by enzyme linked immuno-sorbent assay (ELISA). The system has been validated with de-ionized and artificial sea water as model samples and allowed for pre-concentration of E2 at levels of 1, 10 and 100ng/L with only 100ml of sample. Recoveries ranged from 24±3% to 107±6% depending on the concentration and sample matrix. The method successfully allowed us to determine the concentration of two seawater samples. A concentration of 15.1±0.3ng/L of E2 was measured in a sample obtained from a food production process, and 8.8±0.7ng/L in a sample from the Adriatic Sea. The system would be suitable for continuous monitoring of water quality as it is user friendly, and as the method is reproducible and totally compatible with the analysis of water sample by simple immunoassays and other detection methods such as biosensors. PMID:25604269

Heub, Sarah; Tscharner, Noe; Monnier, Véronique; Kehl, Florian; Dittrich, Petra S; Follonier, Stéphane; Barbe, Laurent

2015-02-13

199

Recent developments in automatic solid-phase extraction with renewable surfaces exploiting flow-based approaches  

DEFF Research Database (Denmark)

Solid-phase extraction (SPE) is the most versatile sample-processing method for removal of interfering species and/or analyte enrichment. Although significant advances have been made over the past two decades in automating the entire analytical protocol involving SPE via flow-injection approaches,on-line SPE assays performed in permanent mode lack sufficient reliability as a consequence of progressively tighter packing of the bead reactor, contamination of the solid surfaces and potential leakage of functional moieties. This article overviews the current state-of-the-art of an appealing tool for overcoming the above shortcomings, so-called bead-injection (BI) analysis, based on automated renewal of the sorbent material per assay exploiting the various generations of flow-injection analysis. It addresses novel instrumental developments for implementing BI and a number of alternatives for online chemical-derivatization reactions, and it pinpoints the most common instrumental detection techniques utilized. We present and discuss in detail relevant environmental and bioanalytical applications reported in the past few years.

Miró, Manuel; Hartwell, Supaporn Kradtap

2008-01-01

200

Determination of cotinine by LC-MS-MS with automated solid-phase extraction.  

Science.gov (United States)

Cotinine is the primary metabolite of nicotine and the preferred biomarker for assessing cigarette smoke exposure. Several liquid chromatography-tandem mass spectrometry (LC-MS-MS) methods have been described for measuring cotinine in biological fluids. Sample preparation typically involves manual solvent evaporation and reconstitution steps. This study describes a novel LC-MS-MS method for the quantification of cotinine by using electrospray ionization with multiple reaction monitoring and cotinine-d3 as internal standard, coupled with an automated solid-phase extraction (SPE) procedure. The assay was linear over the analytical range of 0.5-1,000 ng/mL. The limits of detection and quantification were 0.13 and 0.20 ng/mL, respectively. Intra-assay and inter-assay imprecision of cotinine in all samples was 95-100%. Matrix effects in serum and plasma were protocol. The application of this method to an epidemiological study has demonstrated its utility for batch analyses of a large sample set (>500 samples). PMID:23625914

Dunlop, Allan J; Clunie, Iain; Stephen, Duncan W S; Allison, James J

2014-04-01

201

Bio-inspired solid phase extraction sorbent material for cocaine: a cross reactivity study.  

Science.gov (United States)

The binding specificity of a bio-inspired hexapeptide (QHWWDW) versus cocaine and four other drugs such as 3,4-methylenedioxy-N-methylamphetamine (MDMA), 3,4-methylenedioxy-N-ethylamphetamine (MDEA), phencyclidine and morphine was computationally studied and then experimentally confirmed in solid phase extraction (SPE) followed by liquid chromatography-mass spectrometry (LC/MS) detection. In simulation, the hexapeptide-drug complexes were docked with different scoring functions and considering pH chemical environment. In experimental, the cross reactivity of the selected hexapeptide was tested as SPE sorbent versus cocaine and other four drugs using buffer solutions at pH 4 and 7. Significant differences in specific retention were found between cocaine (97% of recovery) and both morphine (45% of recovery) and phencyclidine (60% of recovery), but less for ecstasies (average recovery 69%). In agreement with docking simulation, the hexapeptide showed the highest recovery with best specificity versus cocaine at pH 7 with an experimentally binding constant of 2.9 × 10(6)M(-1). The bio-inspired sorbent material analytical performances were compared with a commercial reversed phase cartridge confirming the hexapeptide specificity to cocaine and validating simulated data. PMID:25159425

Montesano, Camilla; Sergi, Manuel; Perez, German; Curini, Roberta; Compagnone, Dario; Mascini, Marcello

2014-12-01

202

Solid Phase Extraction and spectrophotometric determination of palladium using hexyl benzimidazolyl sulfide as a chromogenic agent  

International Nuclear Information System (INIS)

Synthesis and application of hexyl benzimidazolyl sulfide (HBMS) as a new chromogenic reagent for determination of palladium has been described. Highly sensitive, selective, and fast method for determination of palladium based on its rapid reaction with HBMS and solid phase extraction of the colored complex on the CLEAN-UP C8 cartridge has been developed. In the presence of 0.01-0.1 mol L-1 HCl solution and polyoxyethylene-nonylphenol ether (emulsifier-OP) medium, HBMS reacted with palladium to form colored complex of palladium-to-HBMS molar ratio of 1:2. The crystal structure of the Pd(II)-HBMS complex has been determined using single-crystal X-ray diffraction. The complex was eluted from the cartridge with N,N-dimethylformamide (DMF) and enrichment factor of 50 was achieved. In DMF medium, molar absorptivity of the complex was 2.08 x 105 L mol-1 cm-1 at 452 nm. Beer's law was obeyed in the concentration range 0.01-0.6 ?g mL-1 Pd(II)-HBMS. Relative standard deviation for eleven replicate determinations of 0.001 ?g mL-1 Pd(II)-HBMS was 2.8%. In the original sample detection limit was 0.1 ?g L-1. The proposed method was applied to the determination of trace palladium in automobile exhaust gas converter catalysts with good result. (authors)

203

Molecularly imprinted polymers-curcuminoids and its application for solid phase extraction  

Science.gov (United States)

Molecularly Imprinted Polymers (MIPs) for the selective recognition properties of curcumin (CUR), a cancer chemopreventive agent were obtained by a non-covalent imprinting approach with bisdemetoxycurcumin (BDMC) as the template molecule. The double bond of BDMC has been reduced in order not to be involved in polymerization and make the template molecules easy to be eluted. Several functional monomers have been evaluated to maximize the interactions with the template molecule during polymerization. MIPs prepared by bulk of N-(2-aminoethyl) metacrylamid hydrochlorideas functional monomer, ethylene glycol dimethacrylate as crosslinker, 2,2'-azobis (2'4-dimethyl valeronitril) as initiator and acetonitrile as porogen. Non-imprinted polymer (NIP) have been also synthesized for reference purposes. UV-vis spectroscopy has been used to predict the template to functional monomer ratio which indicates the formation of 2:1 complexes between monomer and curcumin and the association constants (K11 = 2529 ?M and K12 = 1960.75 ?M in acetonitrile). The capacity and imprinting factor have been evaluated as stationary phases in high-pressure liquid chromatography to CUR and BDMC. The binding properties and the homogeneity of the binding sites of the different polymers have been studied by Freundlich isotherm modeling and weight average affinity and number of binding sites. One of the foremost applications of molecular imprinting has been in molecularly imprinted solid phase extraction and it has the ability to separate and preconcentrate between closely related compounds in curcuminoids.

Wulandari, Meyliana; Amran, M. B.; Lopez, A. B. Descalzo; Urraca, J. L.; Moreno-Bondi, M. C.

2014-03-01

204

Molecularly imprinted solid-phase extraction of glutathione from urine samples.  

Science.gov (United States)

Molecularly imprinted polymer (MIP) particles for glutathione were synthesized through iniferter-controlled living radical precipitation polymerization (IRPP) under ultraviolet radiation at ambient temperature. Static adsorption, solid-phase extraction, and high-performance liquid chromatography were carried out to evaluate the adsorption properties and selective recognition characteristics of the polymers for glutathione and its structural analogs. The obtained IRPP-MIP particles exhibited a regularly spherical shape, rapid binding kinetics, high imprinting factor, and high selectivity compared with the MIP particles prepared using traditional free-radical precipitation polymerization. The selective separation and enrichment of glutathione from the mixture of glycyl-glycine and glutathione disulfide could be achieved on the IRPP-MIP cartridge. The recoveries of glutathione, glycyl-glycine, and glutathione disulfide were 95.6% ± 3.65%, 29.5% ± 1.26%, and 49.9% ± 1.71%, respectively. The detection limit (S/N=3) of glutathione was 0.5 mg·L(-1). The relative standard deviations (RSDs) for 10 replicate detections of 50 mg·L(-1) of glutathione were 5.76%, and the linear range of the calibration curve was 0.5 mg·L(-1) to 200 mg·L(-1) under optimized conditions. The proposed approach was successfully applied to determine glutathione in spiked human urine samples with recoveries of 90.24% to 96.20% and RSDs of 0.48% to 5.67%. PMID:25280681

Song, Renyuan; Hu, Xiaoling; Guan, Ping; Li, Ji; Zhao, Na; Wang, Qiaoli

2014-11-01

205

Magnetic solid phase extraction of gemfibrozil from human serum and pharmaceutical wastewater samples utilizing a ?-cyclodextrin grafted graphene oxide-magnetite nano-hybrid.  

Science.gov (United States)

A magnetic solid phase extraction method based on ?-cyclodextrin (?-CD) grafted graphene oxide (GO)/magnetite (Fe3O4) nano-hybrid as an innovative adsorbent was developed for the separation and pre-concentration of gemfibrozil prior to its determination by spectrofluorometry. The as-prepared ?-CD/GO/Fe3O4 nano-hybrid possesses the magnetism property of Fe3O4 nano-particles that makes it easily manipulated by an external magnetic field. On the other hand, the surface modification of GO by ?-CD leads to selective separation of the target analyte from sample matrices. The structure and morphology of the synthesized adsorbent were characterized using powder X-ray diffraction, Fourier transform infrared spectroscopy, and field emission scanning electron microscopy. The experimental factors affecting the extraction/pre-concentration and determination of the analyte were investigated and optimized. Under the optimized experimental conditions, the calibration graph was linear in the range between 10 and 5000pgmL(-1) with a correlation coefficient of 0.9989. The limit of detection and enrichment factor for gemfibrozil were 3pgmL(-1) and 100, respectively. The maximum sorption capacity of the adsorbent for gemfibrozil was 49.8mgg(-1). The method was successfully applied to monitoring gemfibrozil in human serum and pharmaceutical wastewaters samples with recoveries in the range of 96.0-104.0% for the spiked samples. PMID:25618684

Abdolmohammad-Zadeh, Hossein; Talleb, Zeynab

2015-03-01

206

A combination of ultracentrifugation and solid-phase extraction with subsequent chromatographic analysis of ?-tocopherol in erythrocyte membranes.  

Science.gov (United States)

A novel and rapid sample pre-treatment technique based on a combination of ultracentrifugation and solid-phase extraction for the determination of ?-tocopherol in human erythrocyte membranes by high-performance liquid chromatography with ultraviolet detection is presented in this work. Red blood cell samples were ultracentrifuged (288 000×g, 3 minutes, 4°C) in the presence of d-mannitol, 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid and calcium chloride. The ?-tocopherol was then extracted from the erythrocyte membranes by solid-phase extraction with n-hexane in the presence of ascorbic acid. Tocopherol acetate was used as the internal standard. The extract was dissolved in methanol and separated on the monolithic column Chromolith Performance RP-18e (100 × 4.6 mm) using 100% methanol as the mobile phase. The absorbance of ?-tocopherol was measured at a wavelength of 295 nm. The method was validated and showed sufficient accuracy and precision, ranging from 96.4 to 100.8% and from 4.5 to 6.3%, respectively. Moreover, the developed method was applied to the determination of erythrocyte ?-tocopherol in real samples from patients. The combined ultracentrifugation and solid-phase extraction technique substantially decreased the time for the sample pre-treatment step compared to liquid-liquid extraction and could be applicable for quantitation of other analytes in erythrocyte membranes. This article is protected by copyright. All rights reserved. PMID:25476725

Plíšek, Ji?í; Pospíchalová, Na?a; Khalikova, Maria; Aufartová, Jana; Solichová, Dagmar; Kr?mová, Lenka Kujovská; Solich, Petr

2014-12-01

207

Comparison of various sorbent of solid phase extraction for analysis of polychlorinated biphenyls in transformer oil  

Energy Technology Data Exchange (ETDEWEB)

Methods of analyzing polychlorinated biphenyls (PCBs) in transformer oils typically use diluted oil solutions to remove unwanted substances through a combination of acid cleanup and adsorption chromatography. However, the hydrocarbon transformer oils used in the process have similar physical and chemical properties as PCBs. In this study, solid phase extraction (SPE) was used to improve silica and florisil column cleanup for the monitoring of PCBs in transformer oil. The behavior of PCBs on various sorbent types were studied to separate transformer oil effectively. Cartridges containing pesticide residue consisting of N-vinylpyrrolidone and divinylbenzene, Aroclors, deca-chlorobiphenyl (deca-B), and tetrachloro-m-xylene were used with an HP-5MS column. The elution patterns collected from the solvent samples were measured by a gas chromatography electron capture detector (GC-ECD) for the Aroclors and deca-B, as well as by gas chromatography mass spectroscopy (GC-MS) for the transformer oil. In order to validate the method, 100 mg of transformer oil was spiked with 2 00 ng of Aroclors and 20 ng of deca-CB with n-hexane and a treatment of c-H{sub 2}SO{sub 4} until no change in the colour of the aqueous layer was observed. The portion of the extract containing the PCBs was then collected. The recovery measured by GC-ECD was then calculated. Results showed that the oil was captured for a longer time on the C8 sorbents. A reversed elution pattern of silica was observed. The HLB sorbent separated the PCBs and the transformer oil more efficiently than other sorbents. It was concluded that although the HLB sorbent was effective, a cleanup procedure was needed to secure the accurate quantification of PCBs. 7 refs., 1 tab., 1 fig.

Na, Y.; Seo, J.J. [Korea Basic Science Inst., Seoul (Korea, Republic of). Hazardous Substance Research Team; Kim, K.J. [Korea University, Seoul (Korea, Republic of). Dept. of Chemistry; Hong, J. [Kyung Hee Univ., Seoul (Korea, Republic of). College of Pharmacy

2005-07-01

208

Solid-phase extraction in the determination of gold, palladium, and platinum.  

Science.gov (United States)

A simple classification of various sorbents and solid-phase extraction procedures used for preconcentration of trace levels of Au, Pd, and Pt from different sample types is proposed in this review article. The large variety of available sorbents/procedures has been organized according to expected mechanisms of sorption process (complex formation; ion exchange; adsorption; ion-imprinted or molecularly imprinted polymers); according to the kind of monomeric units of the polymer matrix as well as on the basis of the kind of functional group responsible for main performance characteristics (selectivity, capacity) of the sorbent. Advantages of chemically modified sorbents, sulfur-containing sorbent extractants, and ion-imprinted polymers, together with rational pretreatment by means of microwave treatments, scaling down of enrichment, and quantification by means of flow and flow injection approaches are given. Preferred instrumental techniques for quantification of ppb levels of Au, Pd, and Pt in prepared concentrates/column eluates are multielement instrumental techniques: inductively coupled plasma optical emission spectrometry (ICP-OES), and inductively coupled plasma mass spectrometry (ICPMS). Excellent limits of detection at picogram levels of these analytes are provided by electrothermal atomic absorption spectrometry (ETAAS), generally in single-element mode and the neutron activation analysis (NAA), while X-ray fluorescence spectrometry and flame AAS are rarely applied because of lack of sensitivity at sub-ppm levels of Au, Pd, and Pt. Some problems of atomic spectrometric quantification techniques and their representative limits of detection are given. Recent applications to geological, industrial, pharmaceutical, biological, and other materials are tabulated. References have been selected mostly from the period 1995 to 2010. PMID:22733506

Mladenova, Elisaveta; Karadjova, Irina; Tsalev, Dimiter L

2012-06-01

209

[Application of molecularly imprinted solid phase extraction in the separation and determination of active constituents from natural compounds].  

Science.gov (United States)

The active constituents of natural medicine resources are complicated and in low content, which are difficult to be extracted and separated by general methods. Molecularly imprinted polymers are functional porous materials with molecular-specific recognition sites to a particular target molecule. The molecularly imprinted solid phase extraction has been used as a sample preparation technique for the separation of active constituents from natural medicine resources. The target molecules in a mixture of chemical species can be recognized selectively. In this review, the applications of the molecularly imprinted solid phase extraction for the determination and separation of active constituents (e. g. flavonoids, polyphenols, alkaloids, organic acids, phenylpropanoids, terpenoids, etc. ) from natural compounds in recent years are summarized. PMID:24164030

Chen, Fangfang; Shi, Yanping

2013-07-01

210

Methods of Imazethapyr Extraction from Soil and Cleaning up by Solid Phase Extraction  

OpenAIRE

The aim of this work was to optimize the determination methods of imazethapyr residues in soil using HPLC with DAD and C 18 (Hypersil ODS, 5 ?m, 2.0 x 250 mm) columns and to find the most appropiate solvent for imazethapyr extraction as well as the most suitable SPE cartridges for extract purification. For soil extract purification we decided to use SPE Amino/Carbon, C 18 and SDB-1 cartridges. On the basis of the perfomed chromatography method for optimising imazethapyrdetermination in soil ...

Sanja Lazi?; Vojislava Bursi?; Slavica Vukovi?

2007-01-01

211

Novel sol-gel hybrid methyltrimethoxysilane-tetraethoxysilane as solid phase extraction sorbent for organophosphorus pesticides.  

Science.gov (United States)

A novel sol-gel hybrid methyltrimethoxysilane-tetraethoxysilane (MTMOS-TEOS) was produced and applied as sorbent for solid phase extraction (SPE). Five selected organophosphorus pesticides (OPPs) were employed as model compounds to evaluate the extraction performance of the synthesized sol-gel organic-inorganic hybrid MTMOS-TEOS. Analysis was performed using gas chromatography-mass spectrometry. Several important SPE parameters were optimized. Under the optimum extraction conditions, the method using the sol-gel organic-inorganic hybrid MTMOS-TEOS as SPE sorbent showed good linearity in the range of 0.001-1 ?g L(-1), good repeatability (RSD 2.1-3.1%, n=5), low limits of detection at S/N=3 (0.5-0.9 pg mL(-1)) and limit of quantification (1-3 pg mL(-1), S/N=10). The performance of the MTMOS-TEOS SPE was compared to commercial C18 Supelclean SPE since C18 SPE is widely used for OPPs. The MTMOS-TEOS SPE method LOD was 500-600 × lower than the LOD of commercial C18 SPE. The LOD achieved with the sol-gel organic-inorganic hybrid MTMOS-TEOS SPE sorbent allowed the detection of these OPPs in drinking water well below the level set by European Union (EU) at 0.1 ?g L(-1) of each pesticides. The developed MTMOS-TEOS SPE method was successfully applied to real sample analysis of the selected OPPs from several water samples and its application extended to the analysis of several fruits samples. Excellent recoveries and RSDs of the OPPs were obtained from the various water samples (recoveries: 97-111%, RSDs 0.4-2.8%, n=3) and fruit samples (recoveries: 96-111%), RSDs 1-4%, n=5) using the sol-gel organic-inorganic hybrid MTMOS-TEOS SPE sorbent. Recoveries and RSDs of OPPs from river water samples and fruit samples using C18 Supelclean SPE sorbent were 91-97%, RSD 0.9-2.6, n=3 and 86-96%, RSD 3-8%, n=5, respectively). The novel sol-gel hybrid MTMOS-TEOS SPE sorbent demonstrate the potential as an alternative inexpensive extraction sorbent for OPPs with higher sensitivity for the OPPs. PMID:22326188

Wan Ibrahim, Wan Aini; Veloo, Krishna Veni; Sanagi, Mohd Marsin

2012-03-16

212

Simultaneous spectrophotometric determination of trace amount of polycyclic aromatic hydrocarbons in water samples after magnetic solid-phase extraction by using projection pursuit regression.  

Science.gov (United States)

Magnetic solid-phase extraction based on coated nano-magnets Fe(3)O(4) was applied for the preconcentration of four polycyclic aromatic hydrocarbons (PAHs; anthracene, phenanthrene, fluorine, and pyrene) in environmental water samples prior to simultaneous spectrophotometric determination using multivariate calibration method. Magnetic nanoparticles, carrying target metals, were easily separated from the aqueous solution by applying an external magnetic field so, no filtration or centrifugation was necessary. After elution of the adsorbed PAHs, the concentration of PAHs was determined spectrophotometrically with the aid of a new and efficient multivariate spectral analysis base on principal component analysis-projection pursuit regression, without separation of analytes. The obtained results revealed that using projection pursuit regression as a flexible modeling approach improves the predictive quality of the developed models compared with partial least squares and least squares support vector machine methods. The method was used to determine four PAHs in environmental water samples. PMID:22684809

Ghasemi, Jahan B; Zolfonoun, E

2013-03-01

213

State-of-the-art in solid-phase extraction of biofluids (M10)  

International Nuclear Information System (INIS)

Full text: A major drawback of many SPE protocols in bioanalytical LC is a rather unselective and/or time consuming clean-up procedure. In order to optimize SPE based sample processing with regard to selectivity and speed we investigated tailor-made SPE adorbents, distinct SPE column hardware as well as a novel software (ChromSword ADS, Merck KGaA) for LC(MS)-integrated SPE using column-switching. Restricted Access Materials (RAM) are one family of such special SPE column packing. RAMs are characterized in that they have a defined size-selective exclusion barrier and a non-adsorptive outer particle surface towards macromolecular matrix components (e.g. proteins, nucleic acids, polysaccharides). Low-molecular compounds (e.g. drugs) have free access to the binding centers and thus can be extracted and enriched prior to their analytical separation and MS detection. A RAM-SPE column (e.g. LiChrospher ADS, Merck KGaA, Germany) allows the direct, multiple injection and fractionation of crude, complex samples such as hemolyzed blood, plasma, serum, milk, saliva, urine, fermentation broth and cell-culture or tissue homogenate supernatant. In order to improve the selectivity, we extended this on-line sample clean-up protocol by coupling a reversed-phase modified RAM-SPE column with a second short column packed with a Molecularly Imprinted Polymeric (MIP) adsorbent. MIP-SPE adsorbents can be compared with immunoaffinity adsorbents. Besides selective/specific molecular recognition properties, these artificial antibodies exhibit a high stability with respect to pressure, pH, temperature as well as organic solvents. These innovative adsorbents are also attractive because of the ease, low-cost and high reproducibility of preparation. Using MIPS in combination with RAMs we developed a generic SPE platform and protocol, respectively, for highly selective clean-up of complex (bio)fluids. Finally, we succeeded in speeding up the RAM fractionation step (e.g. extraction of 50 pl of human plasma in less than 60 seconds) by applying an optimized column size and flow-rate, respectively. In conclusion, tailor-made SPE-column packing and hardware allow a robust and rugged operation of on-line (high speed) SPE-(LC)-MS(MS). Refs. 6 (author)

214

Elemental analysis of iron and steel by solid-phase extraction/ICP-MS using a cation exchange extraction disk  

International Nuclear Information System (INIS)

A simple pretreating method which consists of solid phase extraction using cation exchange extraction disk was tried for the determination of trace elements in iron and steel samples by means of inductively coupled plasma mass spectrometry (ICP-MS). The sample of 0.100 g was dissolved by nitric acid, subsequently adding 8 cm3 of 10 w/v% ethylenediaminetetraacetic acid disodium salt (EDTA) solution as masking agent for the iron matrix. The sample solution was adjusted by the dilution with water to pH 1.8 or more and poured into the extraction disk. The target elements retained in the extraction disk were then eluted using 10 cm3 of 3 kmol/m3 nitric acid. Quantities of the obtained target elements were determined using ICP-MS. Highly sensitive quantification was established for 6 trace elements in iron and steel, and for Ca, Mn, Mg, Ba, Tl and Sr with the following detection limits [3?; ng/g (ppb)]: Ca: 4.75, Mn: 0.26, Mg: 0.40, Ba: 0.014, Tl: 0.033 and Sr: 0.11. This method is extremely easy, is rapid, the amount of the reagent used is a little, and a free skill and the zero emission are achieved. (author)

215

Determination of Sr-90 in environmental samples using solid phase extraction disk  

International Nuclear Information System (INIS)

A method is described for determination of Sr-90 in environmental samples using solid phase extraction disk (Empore TM Strontium Rad Disk) and GM counter. To determine the optimum condition for capacity of Empore TM Strontium Rad Disk, its characterization studies such as the effects Sr content, acidity (molarity) of acids, presence of Ca2+ and other major ions (Na+, Mg2+ etc), influence of interference (Pb and Bi) and others were carried out. An optimized the using of Empore TM Strontium Rad Disk for determination of Sr-90 was validated by application to environmental samples. Quantitative recoveries above 95%for Sr (stable) were recorded in 6M HCl condition. Typical environmental samples may contain an assortment of anionic and cationic species, but in general, Empore TM Strontium Rad Disk has enough capacity to effectively separate Sr for wide variety of aqueous solutions. Sr recovery in a matrix-free or the content of matrix less than 300 mg/sample is typically greater than 99% is reported in this research work. In particular, sample, which may contain interference such as Pb and Bi would require an addition separation step before processing to ensure an accurate measurement of Sr. In this research work, radiotracer 85Sr was used to monitor the behavior of Sr and calculation its recovery. For analytical methods that can count Y-90, the Sr-90 activity/concentration in environmenSr-90 activity/concentration in environmental sample was calculated. The concentration of Sr-90 in ash sample (Quality Controled Sample) of 276 ± 18 Bq/kg ash was determined from Y-90 activity. The relative percent difference of 1.1% was achievable for Empore TM Sr-Rad Disk methods when compared to the conventional method (fumed-HNO3 method) - 279 ± 11 Bq/kg ash. (Author)

216

Chromatographic determination of drugs of abuse in vitreous humor using solid-phase extraction.  

Science.gov (United States)

A simple method is presented for the simultaneous determination of morphine, 6-acetylmorphine, codeine, cocaine, benzoylecgonine, cocaethylene, methadone and 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) in vitreous humor by high-performance liquid chromatography with photodiode array detector after solid-phase extraction with Oasis® HLB cartridges and dichloromethane as eluent. The chromatographic process was carried out using an XTerra® RP8 column (250?×?4.6?mm i.d., 5?µm particle size) and a mobile phase composed of acetonitrile and pH 6.5 phosphate buffer in gradient mode. A linear response from the detector was obtained within the concentration range of 0.1-4?µg ml(-1) , with correlation coefficients higher than 0.99. The limits of detection were lower than 30?ng ml(-1) for all the drugs studied, the coefficients of variation fluctuated between 0.1 and 12.4%, and the average recoveries were higher than 78% for all the drugs except for EDDP, with a value of 66.4%. Finally, the proposed method was applied to 15 vitreous humor samples coming from individuals who had died from opiate and/or cocaine overdose, showing consumption of cocaine in 14 cases, methadone in five cases and heroin in three cases. Average concentrations of 0.30?µg ml(-1) for morphine, 0.24?µg ml(-1) for 6-acetylmorphine, 0.10?µg ml(-1) for codeine, 0.81?µg ml(-1) for cocaine, 1.26?µg ml(-1) for benzoylecgonine, 0.15?µg ml(-1) for cocaethylene, 0.11?µg ml(-1) for methadone and 0.68?µg ml(-1) for EDDP were obtained. PMID:22337121

Fernández, Purificación; Seoane, Santiago; Vázquez, Cristina; Tabernero, María Jesús; Carro, Antonia M; Lorenzo, Rosa A

2013-08-01

217

Utilizing ion-pairing hydrophilic interaction chromatography solid phase extraction for efficient glycopeptide enrichment in glycoproteomics  

DEFF Research Database (Denmark)

Glycopeptide enrichment is a prerequisite to enable structural characterization of protein glycosylation in glycoproteomics. Here we present an improved method for glycopeptide enrichment based on zwitter-ionic hydrophilic interaction chromatography solid phase extraction (ZIC-HILIC SPE) in a microcolumn format. The method involves TFA ion pairing (IP) to increase the hydrophilicity difference between glycopeptides and nonglycosylated peptides. Three mobile phases were investigated, i.e., 2% formic acid (defined as IP(2% FA) ZIC-HILIC SPE), 0.1% TFA and 1% TFA (defined as IP(0.1% TFA) and IP(1% TFA) ZIC-HILIC SPE) all containing 80% acetonitrile. Samples of increasing complexities, i.e., digests of single glycoproteins, a five-glycoprotein mixture, and depleted plasma, were used in the study. The presence of TFA in the mobile phase significantly improved the glycopeptide enrichment for all complexities, as evaluated by enhanced glycopeptide detection using MALDI-TOF MS and RP-LC-ESI-MS/MS, e.g., the glycopeptide ion signals were increased by up to 3.7-fold compared to IP(2% FA) conditions. The enhanced glycopeptide detection was promoted by a substantial depletion of nonglycosylated peptides, offering an almost complete isolation of IgG glycopeptides using a single SPE enrichment step and a reduction from 711 nonglycosylated peptides observed in the IP(2% FA) ZIC-HILIC SPE retained plasma fraction, to only 157 and 97 when 0.1% and 1% TFA was used in the mobile phase. In conclusion, this systematic study has shown that TFA-containing mobile phases increase glycopeptide enrichment efficiency considerably for a broad range of sample complexities when using ZIC-HILIC SPE.

Mysling, Simon; Palmisano, Giuseppe

2010-01-01

218

Matrix supported tailored polymer for solid phase extraction of fluoride from variety of aqueous streams  

International Nuclear Information System (INIS)

Highlights: ? Th complexed with poly (bis[2-(methacryloyloxy)-ethyl]phosphate) as tailored polymer membranes. ? Membranes offered high capacity and selectivity for fluoride in aqueous media. ? Quantitative uptake (80 ± 5%) of fluoride. ? Fast sorption kinetics. ? Reusability of polymer membranes. - Abstract: Fluoride related health hazards (fluorosis) are a major environmental problem in many regions of the world. It affects teeth; skeleton and its accumulation over a long period can lead to changes in the DNA structure. It is thus absolutely essential to bring down the fluoride levels to acceptable limits. Here, we present a new inorganic–organic hybrid polymer sorbent having tailored fixed-sites for fluoride sorption. The matrix supported poly (bis[2-(methacryloyloxy)-ethyl]phosphate) was prepared by photo-initiator induced graft-polymerization in fibrous and microporous (sheet) host poly(propylene) substrates. These substrates were conditioned for selective fluoride sorption by forming thorium complex with phosphate groups on bis[2-methacryloyloxy)-ethyl] phosphate (MEP). These tailored sorbents were studied for their selectivity towards fluoride in aqueous media having different chemical conditions. The fibrous sorbent was found to take up fluoride with a faster rate (15 min for ?76% sorption) than the sheet sorbent. But, the fluoride loading capacity of sheet sorbent (4320 mg kg?1), was higher than fibrous and any other sorbent reporteany other sorbent reported in the literature so far. The sorbent developed in the present work was found to be reusable after desorption of fluoride using NaOH solution. It was tested for solid phase extraction of fluoride from natural water samples.

219

Flame atomic absorption spectrometric determination of trace amounts of heavy metal ions after solid phase extraction using modified sodium dodecyl sulfate coated on alumina  

Energy Technology Data Exchange (ETDEWEB)

A sensitive and selective solid phase extraction procedure for the determination of traces of Cu(II), Zn(II), Pb(II) and Fe(III) has been developed. An alumina-sodium dodecyl sulfate (SDS) coated on with meso-phenyl bis(indolyl) methane (MPBIM) was used for preconcentration and determination of Cu(II), Zn(II), Pb(II) and Fe(III) ions by flame atomic absorption spectrometry. The analyte ions were adsorbed quantitatively on adsorbent due to their complexation with MPBIM. Adsorbed metals were quantitatively eluted using 6 mL of 4 mol L{sup -1} nitric acid. The effects of parameters such as pH, amount of alumina, amount of MBITP, flow rate, type and concentration of eluting agent were examined. The effects of interfering ions on the separation-preconcentration of analytes were also investigated. The relative standard deviation of the method was found to be less than 3.0%. The presented procedure was successfully applied for determination of analytes in real samples.

Ghaedi, Mehrorang [Chemistry Department, Yasouj University, Yasouj 75914-353 (Iran, Islamic Republic of)], E-mail: m_ghaedi@mail.yu.ac.ir; Niknam, Khodabakhsh [Chemistry Department, Persian Gulf University, Bushehr (Iran, Islamic Republic of); Shokrollahi, Ardeshir; Niknam, Ebrahim; Rajabi, Hamid Reza [Chemistry Department, Yasouj University, Yasouj 75914-353 (Iran, Islamic Republic of); Soylak, Mustafa [Chemistry Department, University of Erciyes, 38039 Kayseri (Turkey)

2008-06-30

220

Chromium speciation by solid phase extraction on Dowex M 4195 chelating resin and determination by atomic absorption spectrometry  

International Nuclear Information System (INIS)

A solid phase extraction procedure has been established for chromium speciation in natural water samples prior to determination by atomic absorption spectrometry. The procedure is based on the solid phase extraction of the Cr(VI)- Dowex M 4195 chelating resin. After oxidation of Cr(III) to Cr(VI) by using H2O2, the presented method was applied to the determination of the total chromium. The level of Cr(III) is calculated by difference of total chromium and Cr(VI) levels. The procedure was optimized for some analytical parameters including pH, eluent type, flow rates of sample and eluent, matrix effects, etc. The presented method was applied for the speciation of chromium in natural water samples with satisfactory results (recoveries >95%, RSDs <10%). In the determinations of chromium species, flame atomic absorption spectrometer was used. The results were checked by using NIST SRM 2711 Montana soil and GBW 07603 Bush branched and leaves

221

Speciation of copper and manganese in milk by solid-phase extraction inductively coupled plasma-atomic emission spectrometry  

OpenAIRE

A speciation method was developed to study distribution of copper and manganese species in cow milk. The method is based upon solid-phase extraction of selective fractions of the analytes, followed by elution and determination by inductively coupled plasma-atomic emission spectrometry (ICP-AES), using it as a flow-injection detector. Fractions detected were cationic, anionic, neutral and casein-bound. A different behaviour is observed for the two metals.

Mentasti, Edoardo; Bruzzoniti, Maria Concetta; Aceto, Maurizio; Abollino, Ornella; Sarzanini, Corrado

1998-01-01

222

Solid-Phase Microextraction in Polymer Analysis - Extraction of Volatiles from Virgin and Recycled Polyamide 6.6  

OpenAIRE

The extraction and quantitative analysis of low molar mass compounds in polymers is an analytical challenge. It is also important from a practical point of view because the low molar mass compounds in time will migrate from the polymers into the surrounding environment. It is especially important to gain knowledge about the migrating compounds in applications such as medical implants, packaging materials and car interiors. The main aim of this thesis was to develop headspace solid phase micro...

Gro?ning, Mikael

2004-01-01

223

Polymer Microchips Integrating Solid Phase Extraction and High Performance Liquid Chromatography Using Reversed-Phase Polymethacrylate Monoliths  

OpenAIRE

Polymer microfluidic chips employing in situ photopolymerized polymethacrylate monoliths for high performance liquid chromatography separations of peptides is described. The integrated chip design employs a 15 cm long separation column containing a reversed-phase polymethacrylate monolith as a stationary phase, with its front end seamlessly coupled to a 5 mm long methacrylate monolith which functions as a solid phase extraction (SPE) element for sample cleanup and enrichment, serving to incre...

Liu, Jikun; Chen, C. F.; Tsao, C. W.; Chang, C. C.; Chu, C. C.; Devoe, D. L.

2009-01-01

224

Serum protein profiling by miniaturized solid-phase extraction and matrix-assisted laser desorption/ionization mass spectrometry.  

OpenAIRE

Serum profiling by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) holds promise as a clinical tool for early diagnosis of cancer and other human diseases. Sample preparation is key to achieving reproducible and well-resolved signals in MALDI-MS; a prerequisite for translation of MALDI-MS based diagnostic methods to clinical applications. We have investigated a number of MALDI matrices and several miniaturized solid-phase extraction (SPE) methods for serum protein con...

Callesen, Ak; Mohammed, S.; Bunkenborg, J.; Kruse, Ta; Cold, S.; Mogensen, O.; Christensen, R.; Vach, W.; Jørgensen, Pe; Jensen, On

2005-01-01

225

A novel dispersive micro solid phase extraction using zein nanoparticles as the sorbent combined with headspace solid phase micro-extraction to determine chlorophenols in water and honey samples by GC-ECD.  

Science.gov (United States)

This study presents a new technique, dispersive micro solid phase extraction (DMSPE) combined with headspace solid phase micro-extraction (HS-SPME) for extraction and determination of chlorophenols (CPs) in water and honey samples using a Gas Chromatography-Electron Capture Detector (GC-ECD). Zein nanoparticles were made by liquid-liquid dispersion and applied for the first time as the sorbent phase in DMSPE. In the proposed DMSPE-HS-SPME method, 1% w/v of ethanolic zein solution was added to an aqueous sample and then a dose of the in-situ generated zein nanoparticles was applied to a pre-concentration of target analytes. Thermal desorption of analytes was performed after the isolating sorbent phase, and then HS-SPME was applied for enrichment prior to introducing to gas chromatography. All the important parameters influencing efficiency of the extraction process such effects of salt, pH, sorbent concentration, temperature, sorbent solution volume in DMSPE procedure, extraction temperature, extraction time, desorption temperature and time in the HS-SPME procedure were investigated and optimized. Results showed that under optimum extraction conditions, detection limits (signal to noise ratio=3) were in the range of 0.08-0.6 ng mL(-1) and evaluations for relative standard deviations (RSDs %) were between 6.62% and 8.36%. PMID:25059191

Farhadi, Khalil; Matin, Amir Abbas; Amanzadeh, Hatam; Biparva, Pourya; Tajik, Hossein; Farshid, Amir Abbas; Pirkharrati, Hossein

2014-10-01

226

Extraction chromatography of thorium ion by solid phase impregnated resins containing bi-functional organic extractants  

International Nuclear Information System (INIS)

Macroporous methyl methacrylate polymeric resin (XAD-7) was investigated incorporating both acidic organophosphorous extractant (cyanex-301) and one neutral extractant from the followings: dibenzo 18 crown 6 (DB18C6), 18 crown 6 (18C6) and 15 crown 5 (15C5). The sorption behavior of the solvent impregnated resin (SIR) towards thorium ion, including batch equilibrium, and kinetic operation are described. Different factors affecting the uptake of metal ions and hence, the separation efficiency of the impregnated resins were investigated. The maximum uptakes of Th4+ were found to be 62.9, 66.7 and 92.6% for DB18C6, 18C6 and 15C5, respectively. Synergistic extraction of various CE towards thorium ion was tested with cyanex-301 to enhance the sorption capacity as well as the selective separation efficiency. A relatively high capacity of the chelating resin towards tetravalent thorium was found. The capacities of the co-impregnated resins were found to be 2.11, 2.42 and 3.85 mmol/g for DB18C6, 18C6 and 15C5, respectively. The impregnated resin containing cyanex-301 and 15C5 can be utilized for selective separation and pre-concentration of thorium ion from nitrate medium in the presence of several interfering metal ions. (author)

227

A Nanoparticle-based Solid Phase Extraction Method for Liquid Chromatography-Electrospray Ionization-Tandem Mass Spectrometric Analysis  

OpenAIRE

A solid-phase extraction (SPE) procedure with the use of superparamagnetic Fe3O4 nanoparticles as extracting agent was developed for HPLC-ESI-MS/MS analysis. Four most heavily used triazine pesticides (herbicides) were taken as the test compounds. The NPs showed an excellent capability to retain the compounds tested, and a quantitative extraction was achieved within 10 min under the testing conditions, i.e. 100 ?L NP solution was added to 400 mL sample in a beaker with stirring. After extrac...

Song, Yaru; Zhao, Shulin; Tchounwou, Paul; Liu, Yi-ming

2007-01-01

228

Automated solid-phase extraction method for the determination of atovaquone in capillary blood applied onto sampling paper by rapid high-performance liquid chromatography.  

OpenAIRE

A bioanalytical method for the determination of atovaquone in 100 microl blood-spots by solid-phase extraction and high-performance liquid chromatography has been developed and validated. Atovaquone was extracted from the sampling paper in 0.2 M phosphoric acid and a structurally similar internal standard was added with acetonitrile before being loaded onto a C8 end-capped solid-phase extraction column. Atovaquone and internal standard were analysed by high-performance liquid chromatography o...

Lindega?rth, N.; Funding, L.; Bergqvist, Y.

2001-01-01

229

Multi-residue determination of pesticides in water using multi-walled carbon nanotubes solid-phase extraction and gas chromatography-mass spectrometry.  

Science.gov (United States)

A reliable multi-residue method which was based on solid-phase extraction (SPE) with multi-walled carbon nanotubes (MWCNTs) as adsorbent was developed for determination and quantitation of 12 pesticides (carbofuran, iprobenfos, parathion-methyl, prometryn, fenitrothion, parathion-ethyl, isocarbofos, phenthoate, methidathion, endrin, ethion, methoxychlor) in surface water by gas chromatography-mass spectrometry (GC-MS). Parameters that might influence the extraction efficiency such as the eluent volume, the sample flow rate and the sample loading volume were optimized. The experimental results showed the excellent linearity of 12 pesticides (R(2)>0.99) over the range of 0.04-4 microg L(-1), and the precisions (RSD) were 3.1-15.1% under the optimal conditions. The detection limits of proposed method could reach 0.01-0.03 microg L(-1) based on the ratio of chromatographic signal to base line noise (S/N=3). Good recoveries achieved with spiked water samples were in the range of 82.0-103.7%. The results indicated that MWCNTs have good adsorbability to the 12 pesticides tested in this study. With less cost, less analytical time and less solvent-consuming, the developed multi-residue method could be used to determine multi-class pesticides in water simultaneously. PMID:17697685

Wang, Shuo; Zhao, Peng; Min, Guang; Fang, Guozhen

2007-09-21

230

Investigating the Retention Mechanisms of Liquid Chromatography Using Solid-Phase Extraction Cartridges  

Science.gov (United States)

Liquid chromatography (LC) experiments for the undergraduate analytical laboratory course often illustrate the application of reversed-phase LC to solve a separation problem, but rarely compare LC retention mechanisms. In addition, a high-performance liquid chromatography instrument may be beyond what some small colleges can purchase. Solid-phase

O'Donnell, Mary E.; Musial, Beata A.; Bretz, Stacey Lowery; Danielson, Neil D.; Ca, Diep

2009-01-01

231

Rapid magnetic solid phase extraction with in situ derivatization of methylmercury in seawater by Fe3O4/polyaniline nanoparticle.  

Science.gov (United States)

A new Fe(3)O(4)/polyaniline nanoparticle (PANI) material has been successfully developed as magnetic solid-phase extraction sorbent in dispersion mode for the determination of methylmercury (MeHg) in aqueous samples, via quantification by gas chromatography/mass spectrometry (GC-MS). The resultant core-shell magnetic solid-phase extraction nanoparticle (MSPE-NP) sorbent was characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS) and Fourier transform-infrared (FTIR) spectroscopy. Fe(3)O(4)/PANI composites showed fibrous structure with diameters between 50 and 100 nm for fibers. The MSPE-NP process involved the dispersion of the Fe(3)O(4)/PANI nanoparticles in water samples with sonication, followed by magnetic aided retrieval of the sorbent and then, solvent (hexane) desorption of extracted MeHg for GC-MS analysis. The extraction, derivatization and adsorption conditions were optimized by selecting the appropriate extraction parameters including the amount of sorbent, extraction time, derivatizing reagent volume and extraction solvent. The calibration graph was linear in the concentration range of 0.5-300 ng mL(-1) (R(2)>0.993) with detection limit of 0.1 ng mL(-1) (n=3), while the repeatability was 4.1% (n=5). Enrichment factor was obtained as 91. Seawater sample was analyzed as real sample and good recoveries (>98%) were obtained at different spiked values. PMID:21621779

Mehdinia, Ali; Roohi, Fateme; Jabbari, Ali

2011-07-15

232

Determination of trace labile copper in environmental waters by magnetic nanoparticle solid phase extraction and high-performance chelation ion chromatography.  

Science.gov (United States)

Cobalt magnetic nanoparticles surface functionalised with iminodiacetic acid were evaluated as a nano-particulate solid phase extraction absorbent for copper ions (Cu(2+)) from environmental water samples. Using an external magnetic field, the collector nanoparticles could be separated from the aqueous phase, and adsorbed ions simply decomplexed using dilute HNO3. Effects of pH, buffer concentration, sample and sorbent volume, extraction equilibrium time, and interfering ion concentration on extraction efficiency were investigated. Optimal conditions were then applied to the extraction of Cu(2+) ions from natural water samples, prior to their quantitation using high-performance chelation ion chromatography. The limits of detection (LOD) of the combined extraction and chromatographic method were ~0.1ngml(-1), based upon a 100-fold preconcentration factor (chromatographic performance; LOD=9.2ngml(-1) Cu(2+)), analytical linear range from 20 to 5000ngmL(-1), and relative standard deviations=4.9% (c=1000ngml(-1), n=7). Accuracy and precision of the combined approach was verified using a certified reference standard estuarine water sample (SLEW-2) and comparison of sample determinations with sector field inductively coupled plasma mass spectrometry. Recoveries from the addition of Cu(2+) to impacted estuarine and rain water samples were 103.5% and 108.5%, respectively. Coastal seawater samples, both with and without prior UV irradiation and dissolved organic matter removal were also investigated using the new methodology. The effect of DOM concentration on copper availability was demonstrated. PMID:25640140

Wei, Z; Sandron, S; Townsend, A T; Nesterenko, P N; Paull, B

2015-04-01

233

Evaluation of Superparamagnetic Silica Nanoparticles for Extraction of Triazines in Magnetic in-Tube Solid Phase Microextraction Coupled to Capillary Liquid Chromatography  

Directory of Open Access Journals (Sweden)

Full Text Available The use of magnetic nanomaterials for analytical applications has increased in the recent years. In particular, magnetic nanomaterials have shown great potential as adsorbent phase in several extraction procedures due to the significant advantages over the conventional methods. In the present work, the influence of magnetic forces over the extraction efficiency of triazines using superparamagnetic silica nanoparticles (NPs in magnetic in tube solid phase microextraction (Magnetic-IT-SPME coupled to CapLC has been evaluated. Atrazine, terbutylazine and simazine has been selected as target analytes. The superparamagnetic silica nanomaterial (SiO2-Fe3O4 deposited onto the surface of a capillary column gave rise to a magnetic extraction phase for IT-SPME that provided a enhancemment of the extraction efficiency for triazines. This improvement is based on two phenomena, the superparamegnetic behavior of Fe3O4 NPs and the diamagnetic repulsions that take place in a microfluidic device such a capillary column. A systematic study of analytes adsorption and desorption was conducted as function of the magnetic field and the relationship with triazines magnetic susceptibility. The positive influence of magnetism on the extraction procedure was demonstrated. The analytical characteristics of the optimized procedure were established and the method was applied to the determination of the target analytes in water samples with satisfactory results. When coupling Magnetic-IT-SPME with CapLC, improved adsorption efficiencies (60%–63% were achieved compared with conventional adsorption materials (0.8%–3%.

R. A. González-Fuenzalida

2014-04-01

234

Molecularly imprinted solid-phase extraction for selective extraction of bisphenol analogues in beverages and canned food.  

Science.gov (United States)

This study aimed to develop a selective analytical method for the simultaneous determination of seven bisphenol analogues in beverage and canned food samples by using a new molecularly imprinted polymer (MIP) as a sorbent for solid-phase extraction (SPE). Liquid chromatography coupled to triple-quadruple tandem mass spectrometry (LC-MS/MS) was used to identify and quantify the target analytes. The MIP-SPE method exhibited a higher level of selectivity and purification than the traditional SPE method. The developed procedures were further validated in terms of accuracy, precision, and sensitivity. The obtained recoveries varied from 50% to 103% at three fortification levels and yielded a relative standard deviation (RSD, %) of less than 15% for all of the analytes. The limits of quantification (LOQ) for the seven analytes varied from 0.002 to 0.15 ng/mL for beverage samples and from 0.03 to 1.5 ng/g for canned food samples. This method was used to analyze real samples that were collected from a supermarket in Beijing. Overall, the results revealed that bisphenol A and bisphenol F were the most frequently detected bisphenols in the beverage and canned food samples and that their concentrations were closely associated with the type of packaging material. This study provides an alternative method of traditional SPE extraction for screening bisphenol analogues in food matrices. PMID:25350221

Yang, Yunjia; Yu, Jianlong; Yin, Jie; Shao, Bing; Zhang, Jing

2014-11-19

235

Magnetic solid phase extraction based on magnetite/reduced graphene oxide nanoparticles for determination of trace isocarbophos residues in different matrices.  

Science.gov (United States)

A simple one-step solvothermal method was applied for the preparation of magnetite/reduced graphene oxide (MRGO), and the synthetic nanocomposites with a magnetic particle size of ?8nm were used as an adsorbent for magnetic solid phase extraction of isocarbophos (ICP) in different sample matrices prior to gas chromatography (GC) detection. The identity of the nanomaterial was confirmed using Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy and transmission electron microscopy. It was shown that Fe3O4 nanoparticles with a uniform size were homogeneously anchored on RGO nanosheets. Increased oxidation degrees of graphite oxide, big particle sizes and large loading amounts of Fe3O4 on the surface of RGO led to a decrease of adsorption capacity of MRGO to ICP. The adsorption behavior of this adsorbent was better fitted by the pseudo-second-order kinetic model. Several parameters affecting the extraction efficiency were investigated and optimized, including adsorbent dosage, extraction time, ionic strength and desorption conditions. And then, a rapid and effective method based on MRGO combined with GC was developed for the determination of ICP in aqueous samples. A linear range from 0.05 to 50ngmL(-1) was obtained with a high correlation coefficient (R(2)) of 0.9995, and the limit of detection was found to be 0.0044ngmL(-1). This method was successfully applied to the analysis of ICP in five kinds of samples, including apple, rice, lake water, cowpea and cabbage. The recoveries in different sample matrices were in the range from 81.00% to 108.51% with relative standard deviations less than 9.72%. It can be concluded that the proposed analytical method is highly-efficient, sensitive, precise, accurate and practicable. PMID:24800969

Yan, Shan; Qi, Ting-Ting; Chen, De-Wen; Li, Zhao; Li, Xiu-Juan; Pan, Si-Yi

2014-06-20

236

[Simultaneous determination of saccharin sodium and synthetic colours in flavourings by solid phase extraction and high performance liquid chromatography].  

Science.gov (United States)

A method for the simultaneous determination of saccharin sodium and synthetic colours in flavourings by solid phase extraction (SPE) and high performance liquid chromatography with variable wavelengths was established. After degreased with petroleum ether, extracted, purified with SPE, and concentrated, the sample was separated on a C18 column with a gradient elution of 0.02 mol/L ammonium acetate and methanol, and detected at 230, 510, 484 and 510 nm, separately. The saccharin sodium and synthetic colours were separated with this method. The recoveries were 88.6% - 97.1% with the RSD flavourings. PMID:24010353

Zhao, Fei; Gao, Guanghui; Na, Haiqiu; Ma, Dianjun; Wang, Xiaoli

2013-05-01

237

Monitoring of N-methyl carbamate pesticide residues in water using hollow fibre supported liquid membrane and solid phase extraction  

Science.gov (United States)

The aim of this work was to develop a method for the determination of N-methyl carbamates in water involving hollow fibre supported liquid membrane (HFSLM) and solid phase extraction (SPE) as sample preparation methods. Four N-methyl carbamate pesticides, aldicarb, carbaryl, carbofuran and methiocarb sulfoxide, were simultaneously extracted and analysed by a liquid chromatograph with a diode array detector (LC-UV/DAD) and a liquid chromatograph coupled to a ion trap quadrupole mass spectrometer (LC-ESI-MS). The high performance liquid chromatography (HPLC) separation of carabamate extracts was performed on a C18 column with water-acetonitrile as the mobile phase. The mass spectrometry analyses were carried out in the positive mode, operating under both the selected ion monitoring (SIM) and full scan modes. The solid phase recoveries of the extracts ranged between 8% and 98%, with aldicarb having the highest recoveries, followed by carbaryl, carbofuran and methiocarb had the lowest recovery. The HFSLM recovery ranged between 8% and 58% and the order of recovery was similar to the SPE trend. Factors controlling the efficiency of the HFSLM extraction such as sample pH, stripping phase pH, enrichment time, stirring speed as well as organic solvent used for entrapment of analytes, were optimised to achieve the highest enrichment factors.

Msagati, Titus A. M.; Mamba, Bhekie B.

238

Investigation of improving innovative dioxins analyis method using Solid phase MicroExtraction (SPME)-HRGC-HRMS  

Energy Technology Data Exchange (ETDEWEB)

A new rapid, simple, inexpensive and accurate dioxin extraction and analysis procedure has been developed using Solid Phase Micro Extraction (SPME) coupled with HRGC-HRMS. This innovative, rapid dioxin analysis method uses carbon coated SPME fibers without the complicated sample cleanup steps that are currently being used for conventional dioxin analytical methods. During the development of the new SPME method, we noticed a few problems that needed to be addressed. One is the carryover of isomers after analyzing a sample containing a high concentration of dioxin isomers. The second concern are extracts that can not be concentrated to small volumes, for example, 50-100uL due to precipitation because the extract contains a large amount of interfering sample matrices. This paper describes the research focused on reducing the carryover and the precipitation problems with concentrated samples along with evaluating a new extraction method.

Maeoka, M. [Japan Quality Assurance Organization Kansai Environment Testing Lab., Osaka (Japan); Robillard, M.; Shirey, R. [Supelco, Bellfonte, PA (United States); Kaneko, T. [Sigma-Aldrich Japan, Tokyo (Japan)

2004-09-15

239

Extração em fase sólida (SPE) e micro extração em fase sólida (SPME) de piretróides em água / Solid-phase extraction (SPE) and solid-phase microextraction of pyrethroids in water  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese [...] Abstract in english The pyrethroids bifenthrin, permethrin, cypermethrin and deltamethrin were extracted by solid phase extraction (SPE) and solid phase microextraction (SPME). The analysis were performed on a gas chromatograph with electron capture detection (GC-ECD). Octadecil Silano-C18, Florisil and Silica stationa [...] ry phases were studied for SPE. Better results were obtained for Florisil which gave recoveries from 80% to 108%. Pyrethroids extraction by SPME showed a linear response and a detection limit of 10 pg ml-1. Although the data showed that the two extraction methods were able to isolate the pesticide residues from water samples, the best results were obtained by using SPME which is more sensitive, faster, cheeper, being a more useful technique for the analysis of pyrethroids in drinking water.

Wilma Regina, Barrionuevo; Fernando Mauro, Lanças.

2001-04-01

240

Extração em fase sólida (SPE e micro extração em fase sólida (SPME de piretróides em água Solid-phase extraction (SPE and solid-phase microextraction of pyrethroids in water  

Directory of Open Access Journals (Sweden)

Full Text Available The pyrethroids bifenthrin, permethrin, cypermethrin and deltamethrin were extracted by solid phase extraction (SPE and solid phase microextraction (SPME. The analysis were performed on a gas chromatograph with electron capture detection (GC-ECD. Octadecil Silano-C18, Florisil and Silica stationary phases were studied for SPE. Better results were obtained for Florisil which gave recoveries from 80% to 108%. Pyrethroids extraction by SPME showed a linear response and a detection limit of 10 pg ml-1. Although the data showed that the two extraction methods were able to isolate the pesticide residues from water samples, the best results were obtained by using SPME which is more sensitive, faster, cheeper, being a more useful technique for the analysis of pyrethroids in drinking water.

Wilma Regina Barrionuevo

2001-04-01

241

Comparison of liquid-liquid extraction and solid phase extraction for manganese in water analyzed by neutron activation analysis  

International Nuclear Information System (INIS)

Full text: The concentrations of total manganese in most natural water systems are in the range of 0.001 to 1.0 mgl-1. The maximum contaminant level (MCL) of manganese in drinking water as recommended by US Environmental Protection Agency (EPA) is 0.05 mg/l. Analytical methods capable of measuring the low level of manganese are necessary for evaluating the quality of natural water. Neutron activation analysis (NAA) is one of the most sensitive techniques for the determination of trace elements. However, direct application of neutron activation for analysis of trace elements in a complex system such as natural waters is generally difficult because of matrix interference. Preconcentration and/or matrix separation procedures are often required before irradiation to eliminate such interferences. In this study two methods based on solid phase extraction (SPE) and liquid-liquid extraction (LLE) has been developed for the extraction of manganese in water prior to irradiation. Experimental parameters such as effect of pH, type and volume of the chelating agent and flow rate were studied and optimized. Analytical parameters such as linearity, precision, accuracy, detection and quantitation limits, and matrix effects for SPE and LLE methods were evaluated for comparison purposes with the aim of selecting the most appropriate depending on the high recoveries and lower detection capabilities required. Both methods can be applied to real samples and give the same resultd to real samples and give the same results, but SPE allows the high recovery of 99.8% of manganese with lower detection limit of 0.001 ?gl-1 as compared to LLE (90.5% of manganese recovery with lower detection limit of 0.73 ?gl-1). Furthermore, the SPE is easily used compared with LLE and not time consuming which allows analysis of a large number of samples. (author)

242

Automated solid-phase extraction method for the determination of piperaquine in capillary blood applied onto sampling paper by liquid chromatography.  

OpenAIRE

A bioanalytical method for the determination of piperaquine in 100 microL blood applied onto sampling paper, by solid-phase extraction and liquid chromatography, has been developed and validated. Blood spots were cut into small pieces prior to addition of 0.3M perchloric acid, acetonitrile and phosphate buffer containing an internal standard. The liquid phase was loaded onto a mixed phase cation-exchange (MPC) solid-phase extraction column. Piperaquine and the internal standard were analysed ...

Malm, M.; Lindega?rdh, N.; Bergqvist, Y.

2004-01-01

243

Multiplexed colorimetric solid-phase extraction: determination of silver(I), nickel(II), and sample Ph.  

Science.gov (United States)

This paper reports the design and ground-based testing of a multiplexed colorimetric solid-phase extraction (MC-SPE) platform for the rapid determination of multiple water quality parameters in a simple set of operational steps. Colorimetric solid-phase extraction (C-SPE) is an analytical platform that combines impregnated colorimetric reagents on a solid-phase extraction membrane and diffuse reflectance spectroscopy to quantify trace analytes in water. In extending C-SPE to MC-SPE, a filter holder that incorporates discrete analysis channels and a jig that facilitates the concurrent operation of multiple syringes have been designed, enabling the simultaneous determination of three different measures of water quality. Separate, single-parameter membranes, placed in a readout cartridge create unique, parameter-specific addresses at the exit of each channel. Following sample exposure, the diffuse reflectance spectrum of each address is collected serially and the Kubelka-Munk function is used to quantify each water quality parameter via calibration curves. Performance evaluations of the MC-SPE platform were conducted using sample pH, silver(I), and nickel(II). Determinations of silver(I) (0.05-0.5 ppm) and nickel(II) (1.8-5.0 ppm) follow established C-SPE methods on reversed-phase extraction membranes using 5-(p-dimethylaminobenzylidene)rhodanine and dimethylglyoxime, respectively, as colorimetric reagents. Sample pH (2.5-5.0) is measured using an anion-exchange membrane impregnated with fluorescein. These determinations require approximately 120 s to complete using a total sample volume of 3.0 mL. The extension of MC-SPE to the determination of a greater number of analytes and its potential application to space and earth-bound monitoring needs are briefly discussed. PMID:15307801

Gazda, Daniel B; Fritz, James S; Porter, Marc D

2004-08-15

244

Spectrophotometric Determination of Aluminium in Iron Ores Using Solid-Phase Extraction  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese No presente trabalho, um procedimento para separação e determinação de alumínio em matrizes de ferro é proposto. Este é baseado na extração em fase sólida do ferro sob a forma de tiocianatos complexos, pela espuma de poliuretano. Os seguintes parâmetros foram estudados: efeito de pH e da concentraçã [...] o de tiocianato sob a extração do ferro, tempo de agitação necessário para extração quantitativa, quantidade de espuma requerida, separação de alumínio de ferro e de outros elementos, influência de ânions sob a sorção de ferro pela espuma e características analíticas do procedimento para determinação de alumínio usando o azul de metiltimol (MTB) como reagente cromogênico. Os resultados demonstraram que na faixa de pH de 1,5 a 4,7, com tiocianato na concentração de 0.80 mol L-1, tempo de agitação de 1 min e usando 1 g de espuma de poliuretano para extração, é possível separar alumínio(40 mig) de: grandes quantidades de ferro (10 mg), 800 mig de cobre(II), cobalto(II), zinco(II), mercúrio(II), manganês(II), estanho(IV) e tungstênio(V); 100 mig de chumbo(II) e titânio(IV) e 50 mig de vanádio(V). Cálcio(II), bário(II), estrôncio(II) e magnésio(II) não são separados por este processo; entretanto, não reagem com o MTB nas condições estabelecidas para determinação de alumínio. Os ânions nitrato, cloreto, sulfato e acetato não afetam a extração do ferro. Fosfato e EDTA devem estar ausentes. O azul de metiltimol possibilita a determinação espectrofotométrica de alumínio, com absortividade molar de 1,32 x 10(4) L mol-1 cm-1(em 528 nm), sensibilidade de calibração de 0,491 mL mig-1, limite de detecção de 5 ng mL-1, intervalo dinâmico de aplicação de 15 ng mL-1 a 1,00 mig mL-1 e coeficiente de variação de 0,73%. O procedimento proposto foi aplicado para determinação de alumínio em padrões de minérios de ferro e ligas metálicas. Os resultados encontrados não exibiram diferenças significativas em relação aos valores certificados. Abstract in english In the present paper, a procedure for separation and determination of aluminium in iron matrices is proposed. It is based on the solid-phase extraction of the iron, in the form of thiocyanate complexes, by a polyurethane(PU) foam. The followings parameters were studied: effect of pH and of the thioc [...] yanate concentration on the iron extraction, shaking time required for quantitative extraction, amount of PU foam necessary for complete extraction of iron, aluminium separation from other cations, influence of anions on the iron sorption by PU foam and analytical characteristics of the procedure for aluminium determination using methylthymol blue as chromogenic reagent. The results show that, in the pH range from 1.5 to 4.7, with a thiocyanate concentration of 0.80 mol L-1, by extraction using 1 g of polyurethane foam and a shaking time of 1 min, aluminium (40 mug) can be separated from large amounts of iron (10 mg), 800 mug of copper(II), cobalt(II), zinc(II), mercury(II), tin(IV), manganese(II) and tungsten(V); 100 mug of titanium(IV) and lead(II); and 50 mug of vanadium(V). Calcium(II), barium(II), strontium(II) and magnesium(II) can not be separated by this process, but do not react with MTB under the conditions used for aluminium determination. The anions nitrate, chloride, sulfate and acetate do not affect the iron extraction. Phosphate and EDTA must be absent. The methylthymol blue allowed the spectrophotometric determination of aluminium with molar absorptivity of 1.32 x 10(4) L mol-1 cm-1 (528 nm), calibration sensitivity of 0.491 mL g-1, detection limit of 5 ng mL-1 and dynamic interval of application of 15 ng mL-1 to 1.00 mg mL-1 and variation coefficient of 0.73%. The proposed procedure was applied for aluminium determination in iron ores and metal-base alloy standards. The obtained results did not show significant difference from the certified values.

Sérgio Luis Costa, Ferreira; Valfredo Azevedo, Lemos; Antônio Celso Spinola, Costa; Djane Santiago de, Jesus; Marcelo Souza de, Carvalho.

1998-04-01

245

Novel phenyl-iminodiacetic acid grafted multiwalled carbon nanotubes for solid phase extraction of iron, copper and lead ions from aqueous medium  

International Nuclear Information System (INIS)

We have covalently grafted phenyl-iminodiacetic acid groups onto multi-walled carbon nanotubes via a diazotization reaction. The resulting material was characterized by FT-IR and UV-vis spectroscopy, by TGA, XPS and SEM. It is shown to be a valuable solid-phase extraction adsorbent for the preconcentration of trace quantities of Fe(III), Cu(II) and Pb(II) ion from aqueous solution prior to their determination by ICP-OES. Various factors affecting the separation and preconcentration were investigated. The enrichment factor typically is 100. Under optimized experimental conditions, the maximum adsorption capacities for Fe(III), Cu(II) and Pb (II) are 64.5, 30.5 and 17.0 mg g-1, respectively, the detection limits are 0.26, 0.15 and 0.18 ng mL-1, and the relative standard deviations are <2.5% (n = 6). The new adsorbent shows superior reusability and stability. The procedure was successfully applied to the determination of trace quantities of Fe(III), Cu(II) and Pb (II) in water samples. (author)

246

One-step synthesis of magnetic graphene oxide nanocomposite and its application in magnetic solid phase extraction of heavy metal ions from biological samples.  

Science.gov (United States)

A novel magnetic graphene oxide nanocomposite was synthesized by one-step coprecipitation method and characterized by transmission electron microscopy, X-ray photoelectron spectroscopy and vibrating sample magnetometer. The nanocomposite beard many intriguing properties, including chemical stability, high adsorption capacity, and superparamagnetic. These properties evoked great interest and desire of its exploration in magnetic solid-phase extraction of heavy metal ions from complex samples. Several parameters effecting the analytical performance, such as the sample pH, amounts of adsorbent, sample volumes, elution volumes, and coexisting ions, had been investigated in detail. The adsorbed metal ions were easy eluted by controlling the pH condition and the materials could be reused more than 20 times. Under the optimized conditions, the limits of detection were 0.016, 0.046, 0.395, 0.038, 0.157?gL(-1) for Co(2+), Ni(2+), Cu(2+), Cd(2+), and Pb(2+), respectively. The intra-day relative standard deviations (n=5) were in the range of 1.8-5.5% at 10?gL(-1). The proposed method was successfully applied to biological sample analysis and got excellent recoveries in the range of 81-113% even the matrix was complex. PMID:25476344

Sun, Jieping; Liang, Qionglin; Han, Qiang; Zhang, Xiaoqiong; Ding, Mingyu

2015-01-15

247

POLYELECTROLYTE MODIFIED SILICA GEL MICRO-COLUMN SOLID PHASE EXTRACTION FOR THE DETERMINATION OF SILVER IN ENVIRONMENTAL WATER SAMPLES BY FLAME ATOMIC ABSORPTION SPECTROMETRY  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in english Silica gel was chemically modified with polyelectrolyte and used as a solid phase extraction adsorbent for the determination of trace silver in environmental water samples by flame absorption spectrometry (FAAS). The effects of pH, sample flow rate and volume, elution conditions and co-existing ions [...] on the recovery of the analyte were investigated. The results showed that silver could be adsorbed at pH 5.0 and eluted by 5.0 mL 2% thiourea in HNO3 (0.1 mol L-1). Under the optimized conditions, the adsorption capacity of modified silica gel was found to be 8.6 mg g-1 for silver. The detection limit of the proposed method was 1.0 ng mL-1 for silver with an enrichment factor of 18.7. The analytical result for the certified reference water sample (GBW08610) was in a good agreement with the certified value. The proposed method has also been successfully applied to the determination of trace silver in drinking water, well water, snow water and waste water with the recoveries for spiked samples between 94% and 105%.

GUOQIANG, XIANG; LULU, LI; XIUMING, JIANG; LIJUN, HE; LU, FAN.

2182-21-01

248

Automated solid-phase extraction hyphenated to voltammetry for the determination of quercetin using magnetic nanoparticles and sequential injection lab-on-valve approach.  

Science.gov (United States)

In this study, an automated sequential injection lab-on-valve (SI-LOV) system was designed for the on-line matrix removal and preconcentration of quercetin. Octadecyl functionalized magnetic silica nanoparticles were prepared and packed into the microcolumn of the LOV as adsorbents. After being adsorbed through hydrophobic interaction, the analyte was eluted and subsequently introduced into the electrochemical flow cell by voltammetric quantification. The main parameters affecting the performance of solid-phase extraction, such as sample pH and flow rate, eluent solution and volume, accumulation potential and accumulation time were investigated in detail. Under the optimum experimental conditions, a linear calibration curve was obtained in the range of 1.0 × 10(-8) to 1 × 10(-5) mol L(-1) with R(2) = 0.9979. The limit of detection (LOD) and limit of quantitation (LOQ) were 1.3 × 10(-9) and 4.3 × 10(-9) mol L(-1), respectively. The relative standard deviation (RSD) for the determination of 1.0 × 10(-6) mol L(-1) quercetin was found to be 2.9% (n = 11) along with a sampling frequency of 40 h(-1). The applicability and reliability of the automated method described here had been applied to the determination of quercetin in human urine and red wine samples through recovery experiments, and the obtained results were in good agreement with those obtained by the HPLC method. PMID:22489286

Wang, Yang; Wang, Lu; Tian, Tian; Hu, Xiaoya; Yang, Chun; Xu, Qin

2012-05-21

249

Dispersive solid-phase microextraction and capillary electrophoresis separation of food colorants in beverages using diamino moiety functionalized silica nanoparticles as both extractant and pseudostationary phase.  

Science.gov (United States)

In this work, a new method for the determination of food colorants in beverage samples is developed, using diamino moiety functionalized silica nanoparticles (dASNPs) as both adsorbents in dispersive solid-phase microextraction (dSPME) and pseudostationary phases (PSPs) in capillary electrophoresis (CE) separation. dASNPs were firstly used as adsorbents for the preconcentration of four colorants by the dSPME process. After that, colorants were efficiently separated by CE using 30mM phosphate buffer (pH 6.0) containing 2mM ?-CD and 0.9mg/mL dASNPs as additives. All factors influencing dSPME and CE separations were optimized in detail. The investigated analytes showed good linearities with correlation coefficients (R(2)) higher than 0.9932. The limits of detection for the four food colorants were between 0.030 and 0.36mg/L, which are lower than those reported previously. The established method was also used to analyze four colorants in beverage samples with recoveries ranging from 82.7% to 114.6%. To the best of our knowledge, this is the first time to use NPs both as extractants in dSPME and pseudostationary phases in CE for the analytical purpose. PMID:25476319

Liu, Feng-Jie; Liu, Chuan-Ting; Li, Wei; Tang, An-Na

2015-01-15

250

[Rapid determination of six preservative residues in fruits and vegetables by high performance liquid chromatography using dispersive solid phase extraction].  

Science.gov (United States)

A dispersive solid phase extraction-high performance liquid chromatographic (HPLC) method was established for the simultaneous determination of 2,4-D, thiabendazole, 2-naphthol, o-phenyl phenol, diphenyl ether and biphenyl in the fruits and vegetables. The samples were vortexed for extraction with acetonitrile containing sodium chloride and anhydrous magnesium sulfate. The acetonitrile extraction was purified by acidic alumina dispersed solid phase extraction. The analysis was performed on an Agilent TC C18 column (250 mm x 4.6 mm, 5 microm) and an ultraviolet detector at 235 nm with a mobile phase of methanol-0.02 mol/L (pH 6) potassium dihydrogen phosphate solution, at a flow rate of 1.0 mL/min with gradient elution. Good linearities were observed in the range of 0.5-20 mg/L with correlation coefficients greater than 0.99. The average recoveries of the six preservatives in fruits and vegetables were in the range of 84.2% -99. 1% at three spiked levels of 1, 2 and 10 mg/kg (n = 6) and the relative standard deviations (RSDs) were in the range of 1.67%-10.3%. The limits of quantification were 1 mg/kg. This method is simple, accurate and suitable for the determination of the six preservatives in fruits and vegetables. PMID:23697184

Lin, Haidan; Zou, Zhifei; Qin, Yan; Xie, Shouxin; Chen, Yufang; Xu, Juan; Wang, Lan; Chen, Chuying

2013-02-01

251

Speciation analysis of thallium using solid phase extraction and electrothermal atomic absorption spectrometry  

International Nuclear Information System (INIS)

Complete text of publication follows. Thallium is a heavy, very toxic metallic element, which occurs in earth's crust in an estimated abundance from 0.1 to 0.8 mg.kg-1. In the environment, it is mainly combined with other elements (primarily oxygen, sulfur, halogens, potassium and rubidium) in inorganic compounds. During the weathering processes it can be mobilized by aqueous media and accumulated in sediments and soils. The main sources of pollution nowadays come from anthropogenic emissions from refineries, coal-fired power stations, mining activities, metal smelters and the cement industry. Thallium exists in natural waters as either Tl(I) (thallous) or Tl(III) (thallic) species. The oxidation state of Tl affects its complexation and subsequent bioavailability and toxicity in the environment. Thallium content in surface waters is within the range 1-82 ng l-1. Due to this low contents of Tl in water samples, it is necessary to combine the laboratory separation, preconcentration and determination techniques for the purpose of Tl speciation analysis. The scope of the presented work was to use an solid phase extraction (SPE) for the separation and preconcentration of Tl species in water samples followed by the determination using electrothermal atomic absorption spectrometry (ET AAS). In this method, Tl(III) was stabilized by formation of a Tl(III)-DTPA complex. Tl(I) species remained in its original form. These two species were then separated by These two species were then separated by using a cation exchange resin Amberlite IR120 and nitric acid as the eluent in a batch SPE protocol. The potential interferences of Fe (III), Al, Ca, Mg and other metals were investigated. The optimized experimental conditions for separation/preconcentration step (pH 2-3, time 15 min, temperature 60 deg C) and Zeeman ET AAS determination (chemical modifier Pd + ascorbic acid, atomization temperature 2100 deg C) were used for the speciation analysis of thallium in filtered acid water samples from open quartzite mine in the Banska Stiavnica - Sobov region (Slovakia) where an acid mine drainage is present mainly as a product of pyrite oxidation. For both Tl species the preconcentration factor about 40 was achieved, LOD and LOQ were 25 and 90 ng l-1, the calibration curve was linear from 75 ng l-1 to 25 ?g l-1, the precision expressed by a RSD ranged from 3 to 19%. The accuracy of analytical results was checked by the analyte addition technique and by analysis of water CRM samples. The work was supported by Slovak Research and Development Agency under the contracts No. LPP-0038-06, LPP-0188-06, SK-CZ-0044-07 and LPP-0146-09, by Scientific Grant Agency of Ministry of Education of Slovak Republic and the Slovak Academy of Sciences under the contracts No. VEGA 1/4463/07, VEGA 1/4464/07 and VEGA 1/0272/08 and by Ministry of Education, Youth and Sports of Czech Republic under the contract No. MEB 080813.

252

Novel dispersive micro-solid-phase extraction combined with ultrahigh-performance liquid chromatography-high-resolution mass spectrometry to determine morpholine residues in citrus and apples.  

Science.gov (United States)

This paper presents a new analytical method for the determination of morpholine residues in citrus and apples using a novel dispersive micro-solid-phase extraction (DMSPE), followed by ultrahigh-performance liquid chromatography-high-resolution mass spectrometry (UHPLC-HRMS). Samples were extracted with 1% formic acid in acetonitrile/water (1:1, v/v) and then cleaned up using the DMSPE procedure. Morpholine from the extract was adsorbed to a polymer cation exchange sorbent and eluted with ammonium hydroxide/acetonitrile (3:97, v/v) through a 1 mL syringe with a 0.22 ?m nylon syringe filter. All of the samples were analyzed by UHPLC-HRMS/MS on a Waters Acquity BEH hydrophilic interaction chromatography column using 0.1% formic acid and 4 mM ammonium formate in water/acetonitrile as the mobile phase with gradient elution. The method showed good linearity (R(2) > 0.999) in the range of 1-100 ?g/L for the analyte. The limit of detection and limit of quantitation values of morpholine were 2 and 5 ?g/kg, respectively. The average recoveries of morpholine from the citrus and apple samples spiked at three different concentrations (5, 20, and 100 ?g/kg) were in a range from 78.4 to 102.7%. PMID:25539135

Chen, Dawei; Miao, Hong; Zou, Jianhong; Cao, Pei; Ma, Ning; Zhao, Yunfeng; Wu, Yongning

2015-01-21

253

Determination of fipronil in bovine plasma by solid-phase extraction and liquid chromatography with ultraviolet detection  

OpenAIRE

A fast and efficient method has been developed and validated for the determination of fipronil in bovine plasma. Samples were subjected to solid-phase extraction (SPE) followed by reversed phase liquid chromatography (LC) separation, using acetonitrile/water (60:40 v/v) as the mobile phase with a flow rate of 1.0 mL/min and ultraviolet (UV) detection at 210 nm. Ethiprole was used as the internal standard (IS). The method was found to be linear over the range 5-500 ng/mL (r = 0.999). The limit...

Cid, Yara P.; Ferreira, Thais P.; Medeiros, Deborah M. V. C.; Oliveira, Rodrigo M.; Silva, Natha?lia C. C.; Magalha?es, Viviane S.; Scott, Fa?bio B.

2012-01-01

254

Solid phase extraction and a spectrophotometric method for the determination of trace amounts of gold with 4-rhodanineazo benzoic acid  

OpenAIRE

The synthesis and application of 4-rhodanineazo benzoic acid (4-BARA) as a new chromogenic reagent for the determination of gold is des¬cribed. A highly sensitive, selective, and fast method for the determination of gold based on its rapid reaction with 4-rhodanineazo benzoic acid and the solid phase extraction of the colored complex on a reversed phase Clean-up® C5 cartridge was developed. In the presence of 0.02–0.2 mol/L phosphoric acid solution and a polyoxyethylene nonylphenol ether ...

ZHANG JIE HUANG; XIAO GUO WANG; JUN ZHANG

2009-01-01

255

Quantification of endogenous brassinosteroids in sub-gram plant tissues by in-line matrix solid-phase dispersion-tandem solid phase extraction coupled with high performance liquid chromatography-tandem mass spectrometry.  

Science.gov (United States)

A matrix solid-phase dispersion (MSPD)-tandem mixed mode anion exchange (MAX)-mixed mode cation exchange (MCX) solid phase extraction-high performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) method was developed for quantification of six endogenous brassinosteroids (BRs) (24-epibrassinolide, 24-epicastasterone, 6-deoxo-24-epicastasterone, dolichosterone, teasterone and typhasterol) in rice plant tissues. Non-polar interferences were removed effectively by C8 dispersant used in MSPD, while the following tandem MAX-MCX process facilitated the elimination of polar and ionizable compounds. The weak reversed-phase retention feature of MAX-MCX leaded to good compatibility of the elution solvents in the in-line coupled MSPD-MAX-MCX system. This system was optimized for extraction and purification of BRs in plant samples. The effects of the type of solid phase, the elution solvent, the extraction temperature and the clean-up material were studied. Before HPLC separation, BRs purified were derivatized by m-aminophenylboronic acid to enhance the sensitivity of MS/MS to BRs. Compared with traditional liquid-liquid extraction and solid phase extraction (LLE-SPE), the proposed MSPD-MAX-MCX method showed higher extraction efficiency, lower matrix effect, and advantages of easy manipulation and time-saving. The in-line MSPD-MAX-MCX coupled with HPLC-MS/MS method provided a linear response over two orders of magnitude of BRs concentration with correlation coefficients above 0.9982, limits of detection between 0.008 and 0.04ngmL(-1), relative standard deviations (RSDs) below 29.4%, and recoveries above 77.8%. The proposed method has been successfully applied to analysis of endogenous BRs in rice plant at booting stage and maturity stage. PMID:25092597

Wang, Lu; Duan, Chunfeng; Wu, Dapeng; Guan, Yafeng

2014-09-12

256

Dynamic microwave-assisted extraction coupled on-line with solid-phase extraction: determination of polycyclic aromatic hydrocarbons in sediment and soil.  

Science.gov (United States)

This paper describes a new extraction tool for the determination of polycyclic aromatic hydrocarbons (PAHs) in soil and sediment samples, using dynamic microwave-assisted extraction combined with solid-phase extraction (DMAE-SPE). The critical variables for DMAE-SPE are investigated and optimized in an experimental design. The technique proved to be fast, accurate and able to yield quantitative extraction of PAHs from naturally contaminated sediment and soil samples. The set-up is fully automated and features monitored extraction, which facilitates rapid optimization of the method. In addition, only small quantities of solvent and sample are required. PMID:12198838

Ericsson, Magnus; Colmsjö, Anders

2002-07-26

257

Supported liquid membrane-protected molecularly imprinted beads for micro-solid phase extraction of sulfonamides in environmental waters.  

Science.gov (United States)

In this work, molecularly imprinted polymer (MIP) beads have been prepared and evaluated for the development of a supported liquid membrane-protected micro-solid phase extraction method for the analysis of sulfonamides (SAs) in aqueous samples. The performance of MIP beads was firstly evaluated in cartridges by conventional solid-phase extraction for the simultaneous analysis of SAs. Afterward, beads were packed into a polypropylene hollow fiber protected by an organic solvent immobilized in the pores of the capillary wall. During the process, the analytes were extracted from the aqueous sample to the immobilized organic solvent and then selectively retained by the MIP beads located inside the capillary. The effect of various experimental parameters as sample pH, time and stirring-rate among others, were studied for the establishment of optimum rebinding conditions. Relative recoveries for all sulfonamides tested in river and reservoir water samples by the proposed method using 100mL water sample spiked with 50?g L-1 of each sulfonamide were within 70-120%, with a relative standard deviation (RSD) <10% (n=3). The detection limits (LODs) were within 0.2-3?gL(-1), depending upon the sulfonamide and the type of water used. PMID:24780262

Díaz-Álvarez, M; Barahona, F; Turiel, E; Martín-Esteban, A

2014-08-29

258

Analysis of acidic endogenous phytohormones in grapes by using online solid-phase extraction coupled with LC-MS/MS.  

Science.gov (United States)

Phytohormones play important roles in regulating numerous plant physiological and developmental processes, even during the postharvest storage period. In order to determine the functions and changes of gibberellins acid (GA3), indoleacetic acid (IAA), abscisic acid (ABA), indolebutyric acid (IBA) and jasmonic acid (JA) in grape berries during storage, an ultrasensitive method based on direct injection online solid-phase extraction coupled with high-performance liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed. Grape berries were extracted with cold methanol. After centrifugation, the supernatants were concentrated with a vacuum centrifugal concentrator and injected into an online solid-phase extraction column. After the cleanup procedure, the analytes were determined by LC-MS/MS. The results showed that the linearity of the proposed method was 10-210 µg kg(-1) for ABA, 20-200 µg kg(-1) for IBA, 15-320 µg kg(-1) for IAA, 20-320 µg kg(-1) for GA3 and 3.0-90.0 µg kg(-1) for JA. The limits of detection of the method were 0.71, 2.79, 0.94, 0.39 and 0.57 µg kg(-1), respectively. The proposed method was successfully applied to the analysis of endogenous phytohormones in grape berries during the postharvest storage period. PMID:24200641

Yu, Jian-Na; Meng, Qing-Yan; Liu, Wen-Jie; Lu, Ya-Ling; Ren, Xiao-Lin

2014-10-01

259

Development of a selective molecularly imprinted polymer-based solid-phase extraction for indomethacin from water samples.  

Science.gov (United States)

A selective molecularly imprinted solid-phase extraction (MISPE) for indomethacin (IDM) from water samples was developed. Using IDM as template molecule, acrylamide (AM) or methacrylic acid (MAA) as functional monomer, ethylene dimethacrylate (EDMA) as crosslinker, and bulk or suspension polymerization as the synthetic method, three molecularly imprinted polymers (MIPs) were synthesized and characterized with a rebinding experiment. It was found that the MIP of AM-EDMA produced by bulk polymerization showed the highest binding capacity for IDM, and so it was chosen for subsequent experiments, such as those testing the selectivity and recognition binding sites. Scatchard analysis revealed that at least two kinds of binding sites formed in the MIP, with the dissociation constants of 7.8 micromol L(-1) and 127.2 micromol L(-1), respectively. Besides IDM, three structurally related compounds--acemetacin, oxaprozin and ibuprofen--were employed for selectivity tests. It was observed that the MIP exhibited the highest selective rebinding to IDM. Accordingly, the MIP was used as a solid-phase extraction sorbent for the extraction and enrichment of IDM in water samples. The extraction conditions of the MISPE column for IDM were optimized to be: chloroform or water as loading solvent, chloroform with 20% acetonitrile as washing solution, and methanol as eluting solvent. Water samples with or without spiking were extracted by the MISPE column and analyzed by HPLC. No detectable IDM was observed in tap water and the content of IDM in a river water sample was found to be 1.8 ng mL(-1). The extraction efficiencies of the MISPE column for IDM in spiked tap and river water were acceptable (87.2% and 83.5%, respectively), demonstrating the feasibility of the prepared MIP for IDM extraction. PMID:18575852

Yang, Tao; Li, Ya-Hui; Wei, Shuang; Li, Yuan; Deng, Anping

2008-08-01

260

Optimization of headspace solid-phase microextraction technique for extraction of volatile smokeless powder compounds in forensic applications.  

Science.gov (United States)

Smokeless powders are low explosives and are potentially found in cases involving firearms and improvised explosive devices. Apart from inorganic compound analysis, forensic determination of organic components of these materials appears as a promising alternative, especially the chromatographic techniques. This work describes the optimization of a solid-phase microextraction technique using an 85 ?m polyacrylate fiber followed by gas chromatography-flame ionization detection for smokeless powder. A multivariate experimental design was performed to optimize extraction-influencing parameters. A 2(4) factorial first-order design revealed that sample temperature and extraction time were the major influencing parameters. Doehlert matrix design has subsequently selected 66°C and 21 min as the compromised conditions for the two predetermined parameters. This extraction technique has successfully detected the headspace compounds of smokeless powders from different ammunition types and allowed for their differentiation. The novel technique allows more rapid sample preparation for chromatographic detection of smokeless powders. PMID:24611488

Chang, Kah Haw; Yew, Chong Hooi; Abdullah, Ahmad Fahmi Lim

2014-07-01

261

Explorative Solid-Phase Extraction (E-SPE) for Accelerated Microbial Natural Product Discovery, Dereplication, and Purification  

DEFF Research Database (Denmark)

Microbial natural products (NP) cover a high chemical diversity, and in consequence extracts from microorganisms are often complex to analyze and purify. A distribution analysis of calculated pK(a) values from the 34390 records in Antibase2008 revealed that within pH 2-11, 44% of all included compounds had an acidic functionality, 17% a basic functionality, and 9% both. This showed a great potential for using ion-exchange chromatography as an integral part of the separation procedure, orthogonal to the classic reversed-phase strategy. Thus, we investigated the use of an "explorative solid-phase extraction" (E-SPE) protocol using SAX, Oasis MAX, SCX, and LH-20 columns for targeted exploitation of chemical functionalities. E-SPE provides a minimum of fractions (15) for chemical and biological analyses and implicates development into a preparative scale methodology. Overall, this allows fast extract prioritization, easier dereplication, mapping of biological activities, and formulation of a purification strategy.

Månsson, Maria; Phipps, Richard Kerry

2010-01-01

262

Solid phase speciation of arsenic by sequential extraction in standard reference materials and industrially contaminated soil samples  

International Nuclear Information System (INIS)

Leaching experiments, a mineralogical survey and larger samples are preferred when arsenic is present as discrete mineral phases. - Availability, mobility, (phyto)toxicity and potential risk of contaminants is strongly affected by the manner of appearance of elements, the so-called speciation. Operational fractionation methods like sequential extractions have been applied for a long time to determine the solid phase speciation of heavy metals since direct determination of specific chemical compounds can not always be easily achieved. The three-step sequential extraction scheme recommended by the BCR and two extraction schemes based on the phosphorus-like protocol proposed by Manful (1992, Occurrence and Ecochemical Behaviours of Arsenic in a Goldsmelter Impacted Area in Ghana, PhD dissertation, at the RUG) were applied to four standard reference materials (SRM) and to a batch of samples from industrially contaminated sites, heavily contaminated with arsenic and heavy metals. The SRM 2710 (Montana soil) was found to be the most useful reference material for metal (Mn, Cu, Zn, As, Cd and Pb) fractionation using the BCR sequential extraction procedure. Two sequential extraction schemes were developed and compared for arsenic with the aim to establish a better fractionation and recovery rate than the BCR-scheme for this element in the SRM samples. The major part of arsenic was released from the heavily contaminated samples after NaOH-extraction. Inferior extraction variabaOH-extraction. Inferior extraction variability and recovery in the heavily contaminated samples compared to SRMs could be mainly contributed to subsample heterogeneity

263

Flame atomic absorption spectrometric (FAAS) determination of copper, iron and zinc in food samples after solid-phase extraction on Schiff base-modified duolite XAD 761  

International Nuclear Information System (INIS)

The present study involves the development of solid-phase extraction (SPE) procedure for the preconcentration of trace amounts of copper (Cu2+), iron (Fe3+) and zinc (Zn2+) ions on duolite XAD 761 modified by bis(2-hydroxyacetophenone)-2,2-dimethyl-1,3-propanediimine(BHAPDMPDI). The complexation between the metal ions and the proposed ligand was investigated potentiometrically. The metal ions retained on the sorbent were quantitatively determined via complexation with BHAPDMPDI. The complexed metal ions were efficiently eluted using 6 mL of 4 mol L?1 nitric acid in acetone. The influences of the analytical parameters, including pH, amounts of the ligand and the solid phase, eluent conditions and sample volume, on the recoveries of the metal ions were optimized. Using the optimized parameters, the linear response of the SPE method for Cu2+, Zn2+ and Fe3+ ions were in the ranges of 0.01–0.34, 0.01–0.28 and 0.02–0.31 ?g mL?1, respectively, and the detection limits for Cu2+, Zn2+ and Fe3+ ions were 1.8, 1.6 and 2.4 ?g mL?1, respectively. The proposed method exhibits a preconcentration factor of 208 for all of the ions studied and an enhancement factor for Cu2+, Fe3+ and Zn2+ ions of 34, 28 and 38, respectively. The presented results demonstrate the successful application of the proposed method for the determination of these metal ions in some real samples with high recoveries (> 95%) and reasonable relative standard deviation (RDS < 5%). Highlights: ? Highly efficient adsorbent for dye removal was synthesized. ? The sorbent was fully characterized. ? The proposed method has a potential of a waste water treatment alternative. ? Excellent properties of the sorbent have been illustrated in detail

264

[Simultaneous determination of nine sulfonamide residues in milk using solid phase extraction and high performance liquid chromatography].  

Science.gov (United States)

A simple, rapid, sensitive and reliable high performance liquid chromatographic method for the simultaneous determination of nine sulfonamides (SAs) (sulfadiazine, sulfathiazole, sulfamethazine, sulfamethoxypyridazine, sufamonomethoxine, sulfachloropyridazine, sulfamethoxazole, sulfadimethoxine and sulfaquinoxaline) in milk was developed. The method includes the shaking of the milk with phosphate buffer, centrifugation, and cleaning up on a C18 solid-phase extraction cartridge. The C18 cartridge was washed with water, and the SAs were eluted with methanol. After the evaporation, the residue was dissolved in ethyl acetate, and cleaned up on an amino solid-phase extraction column. Analytical separation was performed on an Inertsil ODS-3 column with photodiode-array detection at 270 nm under the gradient condition. The mean recoveries of SAs at the spiked levels of 10, 20, 40 microg/L were between 72.1% and 88.3%. The relative standard deviations were between 2.3% and 5.0%. The detection limits were 1.7 - 2.8 microg/L, and the quantification limits wer 5.7 - 9.2 microg/L. PMID:18161327

Wu, Yinliang; Zhao, Li; Liu, Yongjun; Jiang, Yanbin; Liu, Xingguo; Shen, Jianzhong

2007-09-01

265

Simultaneous determination of 12 illicit drugs in whole blood and urine by solid phase extraction and UPLC-MS/MS.  

Science.gov (United States)

A rapid and sensitive method based on solid phase extraction and ultra performance liquid chromatography-electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS) for the simultaneous determination of amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine, 3,4-methylene-dioxymethamphetamine, N-methyl-1-(3,4-methyl-enedioxyphenyl)-2-butanamine, 3,4-methylenedioxyethylamphetamine, p-methoxymethamphetamine, ephedrine, N-methylephedrine, cathinone, methcathinone, and ketamine in whole blood and urine was developed and validated. Following solid phase extraction, the analytes were separated on ACQUITY UPLC BEH Phenyl column (100mm×2.1mm, 1.7?m) under gradient elution using a mobile phase containing of acetonitrile and 0.3% formic acid in water at a flow rate of 0.4mLmin(-1) and analyzed by a triplequadrupole mass spectrometer in the multiple reaction monitoring (MRM) mode. The proposed method was linear for each analyte with correlation coefficients over 0.99. Recovery validation studies showed accuracy bias below 4.4%. Acceptable precision was also obtained with a relative standard deviation below 8.9%. The sensitivity of the assay was found to be adequate for the quantitation of the illicit drugs in whole blood and urine sample and was higher than reported methods. The present method was proved to be reliable and robust for drug screening in forensic toxicological analysis. PMID:24631805

Zhang, Lin; Wang, Zhao-Hong; Li, Hong; Liu, Yong; Zhao, Meng; Jiang, Ye; Zhao, Wen-Song

2014-04-01

266

[Determination of ethyl glucuronide in human urine by solid phase extraction-gas chromatography-mass spectrometry].  

Science.gov (United States)

A solid phase extraction (SPE) and gas chromatography (GC) with mass spectrometry (MS) method for determination of ethyl glucuronide (EtG) in human urine was established. One mL urine sample was deproteinated by 100 microL 3 mol/L hydrochloric acid and cleaned up through a solid phase extraction column. The target analytes were eluted from an NH2-column with 4% ammonia solution and then treated with bis (trimethylsilyl) trifluoroacetamide (BSTFA) + trimethylchlorosilane (TMCS) (99:1) for derivatization. The derivatized samples were analyzed by GC-MS. Data were acquired in the selected ion monitoring (SIM) mode and the quantitation of EtG was done through internal standard method. Good linearity was obtained at the mass concentration range of 0.1 - 3.2 mg/L with a correlation coefficient (r) of 0.9921. The limit of detection (LOD) was 28.4 microg/L. The range of recoveries was 92.5% - 108.7%, and the relative standard deviations (RSDs) of intra-day and inter-day were all less than 5%. This method is sensitive, specific, accurate and can be applied to the determination of EtG for medicolegal identification and clinical laboratory. PMID:21598520

Yu, Tianxiao; Li, Qing; Wan, Tao; Li, Jianbo; Ding, Shijia

2011-02-01

267

[Simultaneous determination of 10 sulfonamide antibiotics in water by solid-phase extraction and high performance liquid chromatography].  

Science.gov (United States)

A solid-phase extraction (SPE)-high performance liquid chromatography (HPLC) method has been developed for simultaneous determination of 10 sulfonamide antibiotics in water. The analytes were first enriched and purified through a PEP solid-phase extraction column, and eluted with acetonitrile-dichloromethane solution (2: 1, V/V), then detected by a HPLC with a UV detector. The detection wavelength was 268 nm and the column temperature was 33 degrees C, using gradient elution process with acetonitrile - 0.4% acetic acid/water (V/V) as the mobile phase to achieve baseline separations of these 10 analytes. The linearity range was 10 - 2 000 microg x L(-1). The recovery ranges of standard addition for deionized water and real water samples were 73.4% - 95.6% and 70.2% - 92.5%, respectively (except for sulfonamide, were 8.5% and 8.0%). The limit of detection was 1.42-7.25 ng x L(-1). Application of this method for parts of Huangpu River in Shanghai, surface water and groundwater in Chongming Island showed that sulfonamide antibiotics were detected in different frequencies in different aqueous environments, with the concentration range of 13.3 - 241.5 ng x L(-1), proving this method is easy, rapid, sensitive and efficient to meet the needs of actual work. PMID:22509611

Hong, Lei-Jie; Shi, Lu; Zhang, Ya-Lei; Zhou, Xue-Fei; Zhu, Hong-Guang; Lin, Shuang-Shuang

2012-02-01

268

Solid phase extraction and a spectrophotometric method for the determination of trace amounts of gold with 4-rhodanineazo benzoic acid  

Directory of Open Access Journals (Sweden)

Full Text Available The synthesis and application of 4-rhodanineazo benzoic acid (4-BARA as a new chromogenic reagent for the determination of gold is des¬cribed. A highly sensitive, selective, and fast method for the determination of gold based on its rapid reaction with 4-rhodanineazo benzoic acid and the solid phase extraction of the colored complex on a reversed phase Clean-up® C5 cartridge was developed. In the presence of 0.02–0.2 mol/L phosphoric acid solution and a polyoxyethylene nonylphenol ether (emulsifier-OP medium, 4-rhodanineazo benzoic acid reacted with gold to form a colored complex with a gold-to-4-BARA molar ratio of 1:2. The complex was enriched by solid phase extraction with a reversed phase Clean-up® C5 cartridge. The complex was eluted from the cartridge with ethanol and an enrichment factor of 50 was achieved. In ethanol medium, the molar absorptivity of the complex was 2.39×105 L mol-1 cm-1 at 505 nm. The Beer Law was obeyed in the concentration range 0.01–?1.2 µg/mL. The relative standard deviation for eleven replicate samples at the 0.001 µg/mL level was 2.3 %. In the original sample, the detection limit was 8.0×10-5 µg/mL. This method was applied to the determination of trace amounts of gold in ore samples with good result.

ZHANG JIE HUANG

2009-09-01

269

Solid phase extraction and spectrophotometric determination of mercury in tobacco and tobacco additives with 5-(p-aminobenzylidene)-thiothiorhodanine  

International Nuclear Information System (INIS)

A highly sensitive, selective and rapid method for the determination of mercury based on the rapid reaction of mercury(II) with 5-(p-aminobenzylidene)-thiorhodanine (ABTR) and the solid phase extraction of the colored chelate with C18 disks has been developed. At pH 3.5 and in the presence of emulsifier-OP medium, ABTR reacts with mercury(II) to form a red chelate of a 1:2 (mercury to ABTR) molar ratio. This chelate was enriched by solid phase extraction with C18 disks and the retained chelate eluted form the disks with dimethyl formamide (DMF). An enrichment factor of 50 was achieved. In the DMF medium, the molar absorptivity of the chelate is 1.21 X 105 L mol-1 cm-1 at 545 nm, and Beer's law is obeyed in the 0.01?3 ?g mL-1 range in the measured solution. The relative standard deviation for eleven sample replicate measurements at the 0.01 ?g mL-1 level is 1.7%. This method was applied to the determination of mercury in tobacco and tobacco additives and good preconcentration was found between proposed and comparative methods results. (author)

270

Solid phase extraction and spectrophotometric determination of Au(III) with 5-(2-hydroxy-5-nitrophenylazo)thiorhodanine.  

Science.gov (United States)

A new chromogenic reagent, 5-(2-hydroxy-5-nitrophenylazo)thiorhodanine (HNATR) was synthesized. A highly sensitive, selective and rapid method for the determination microg l(-1) level of Au(III) based on the rapid reaction of Au(III) with HNATR and the solid phase extraction of the colored complex with a reversed phase polymer-based C(18) cartridge have been developed. The HNATR reacted with Au(III) to form a red complex of a molar ratio 1:2 (Au(III) to HNATR) in the presence of 0.05 - 0.5 mol l(-1) of phosphoric acid solution and emulsifier-OP medium. This complex was enriched by the solid phase extraction with a polymer-based C(18) cartridge. The enrichment factor of 100 was achieved. The molar absorptivity of the complex is 1.37 x 10(5) l mol(-1) cm(-1) at 520 nm in the measured solution. The system obeys Beer's law in the range of 0.01 - 3 microg ml(-1). The relative standard deviation for eleven replicates sample of 0.5 microg l(-1) level is 2.18%. The detection limit, based on the three times of standard deviation is 0.02 microg l(-1) in the original sample. This method was applied to the determination of gold in water and ore with good results. PMID:16760611

Hu, Qiufen; Chen, Xiubin; Yang, Xiangjun; Huang, Zhangjie; Chen, Jing; Yang, Guangyu

2006-04-01

271

Ultrasound assisted microextraction-nano material solid phase dispersion for extraction and determination of thymol and carvacrol in pharmaceutical samples: Experimental design methodology.  

Science.gov (United States)

In the present study, for the first time, a new extraction method based on "ultrasound assisted microextraction-nanomaterial solid phase dispersion (UAME-NMSPD)" was developed to preconcentrate the low quantity of thymol and carvacrol in pharmaceutical samples prior to their HPLC-UV separation/determination. The analytes were accumulated on nickel sulfide nanomaterial loaded on activated carbon (NiS-NP-AC) that with more detail identified by XRD, FESEM and UV-vis technique. Central composite design (CCD) combined with desirability function (DF) was used to search for optimum operational conditions. Working under optimum conditions specified as: 10min ultrasonic time, pH 3, 0.011g of adsorbent and 600?L extraction solvent) permit achievement of high and reasonable linear range over 0.005-2.0?gmL(-1) (r(2)>0.9993) with LOD of thymol and carvacrol as 0.23 and 0.21?gL(-1), respectively. The relative standard deviations (RSDs) were less than 4.93% (n=3). PMID:25484348

Roosta, Mostafa; Ghaedi, Mehrorang; Daneshfar, Ali; Sahraei, Reza

2015-01-15

272

Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of pesticides in water by C-18 solid-phase extraction and capillary-column gas chromatography/mass spectrometry with selected-ion monitoring  

Science.gov (United States)

A method for the isolation of 41 pesticides and pesticide metabolites in natural-water samples using C-18 solid-phase extraction and determination by capillary-column gas chromatography/mass spectrometry with selected-ion monitoring is described. Water samples are filtered to remove suspended particulate matter and then are pumped through disposable solid-phase extraction columns containing octadecyl-bonded porous silica to extract the pesticides. The columns are dried using carbon dioxide or nitrogen gas, and adsorbed pesticides are removed from the columns by elution with 3.0 milliliters of hexane-isopropanol (3:1). Extracted pesticides are determined by capillary- column gas chromatography/mass spectrometry with selected-ion monitoring of three characteristic ions. The upper concentration limit is 4 micrograms per liter (g/L) for most pesticides, with the exception of widely used corn herbicides--atrazine, alachlor, cyanazine, and metolachlor--which have upper concentration limits of 20 g/L. Single- operator method detection limits in reagent-water samples range from 0.001 to 0.018 g/L. Average short-term single-operator precision in reagent- water samples is 7 percent at the 0.1- and 1.0-g/L levels and 8 percent at the 0.01-g/L level. Mean recoveries in reagent-water samples are 73 percent at the 0.1- and 1.0-g/L levels and 83 percent at the 0.01-g/L level. The estimated holding time for pesticides after extraction on the solid-phase extraction columns was 7 days. An optional on-site extraction procedure allows for samples to be collected and processed at remote sites where it is difficult to ship samples to the laboratory within the recommended pre-extraction holding time.

Zaugg, Steven D.; Sandstrom, Mark W.; Smith, Steven G.; Fehlberg, Kevin M.

1995-01-01

273

Chemically modified polymeric resins for solid-phase extraction and group separation prior to analysis by liquid or gas chromatography  

Energy Technology Data Exchange (ETDEWEB)

Polystyrene divinylbenzene was modified by acetyl, sulfonic acid, and quaternary ammonium groups. A resin functionalized with an acetyl group was impregnated in a PTFE membrane and used to extract and concentrate phenolic compounds from aqueous samples. The acetyl group created a surface easily wetted, making it an efficient adsorbent for polar compounds in water. The membrane stabilized the resin bed. Partially sulfonated high surface area resins are used to extract and group separate an aqueous mixture of neutral and basic organics; the bases are adsorbed electrostatically to the sulfonic acid groups, while the neutraons are adsorbed hydrophobically. A two-step elution is then used to separate the two fractions. A partially functionalized anion exchange resin is used to separate organic acids and phenols from neutrals in a similar way. Carboxylic acids are analyzed by HPLC and phenols by GC.

Schmidt, L.W.

1993-07-01

274

Determination of avilamycin A and B in pig faeces by solid phase extraction and reverse-phase HPLC assay.  

Science.gov (United States)

A HPLC method is described for the simultaneous determination of avilamycin A and B in pig faeces, following extraction using acetonitrile and normal-phase solid phase extraction. The HPLC stationary phase was Kromosil 5 micro C-18 with a mobile phase of 48% acetonitrile and 52% 0.01N ammonium acetate buffer, pumped at a flow rate of 1 ml/min. Detection was by UV absorbance at 295 nm and an injection volume of 50 microl was used. Recovery from faeces was >98% and intra-assay precision (CV) was <9.0% for both compounds. The lowest limit of quantification was 0.9 mg/kg (avilamycin A) and 0.2 mg/kg (avilamycin B) with an accuracy of <15% error. No interference was seen from endogenous materials in pig faeces and commonly used veterinary antibiotics. PMID:15519487

Sunderland, Julie; Lovering, Andrew M; Tobin, Caroline M; MacGowan, Alasdair P; Roe, John M; Delsol, Anne A

2004-11-01

275

Extraction and analysis of polycyclic aromatic hydrocarbons and benzo[a]pyrene metabolites in microalgae cultures by off-line/on-line methodology based on matrix solid-phase dispersion, solid-phase extraction and high-performance liquid chromatography.  

Science.gov (United States)

This paper describes the development and validation of an analytical methodology to determine the presence of four PAHs: benzo[a]anthracene, benzo[b]fluoranthene, benzo[k]fluoranthene and benzo[a]pyrene in cultures of the green microalgae Selenastrum capricornutum. The metabolites of benzo[a]pyrene (BaP), 4,5-dihydrodiol benzo[a]pyrene, 9,10-dihydrodiol benzo[a]pyrene, 3-hydroxy benzo[a]pyrene and 9-hydroxy benzo[a]pyrene were also included. The methodology consisted of three parts: (1) separation of liquid media from biomass samples by centrifugation of pure cultures, (2) off-line extraction of analytes from biomass by a miniaturized matrix solid phase dispersion (MSPD) method and from liquid media by a solid phase extraction (SPE) method and (3) on-line SPE preconcentration and analysis of the MSPD and SPE extracts, separately, by high performance liquid chromatography with fluorescence detection (HPLC-FD). The off-line/on-line (MSPD/SPE-HPLC-FD) method was validated over a concentration range of 20-200 pg mg(-1) obtaining good linearity (r(2)>0.9912) and precision values measured as relative standard deviation (RSD)FD) method was validated over a concentration range of 5-120 pg mL(-1); r(2)>0.9913 and RSD75, 1.5, 3, 6, 24 and 48 h). The analytical methodology was suitable for measuring the very low amounts of residual BaP and metabolites produced in bioassays. Results showed that some of the metabolites favored by the microalgae are the dihydrodiols. The microalgae cultures were able to decrease the BaP level in the liquid medium below the United States Environmental Protection Agency (USEPA) limit (<0.2 ng mL(-1)). PMID:23031438

Olmos-Espejel, José J; García de Llasera, Martha P; Velasco-Cruz, Marisol

2012-11-01

276

[Determination of organochlorine pesticide residues in nine herbs by solid-phase extraction and capillary gas chromatography].  

Science.gov (United States)

The solid-phase extraction and capillary gas chromatography was introduced for determining 13 organochlorine pesticide residues including alpha-benzene hexachloride (BHC), betaBHC, gamma-BHC, delta-BHC, p,p'-dichloro-diphenyl-dichloroethylene (pp'-DDE), p,p'-dichloro-di-phenyl-dichloroethane (pp'-DDD), o,p'-dichloro-diphenyl-trichloroethane (op'-DDT), pp'-DDT, heptachlor (HEPT), aldrin, heptachlor epoxide (HCE), dieldrin and endrin in Scutellaria baicalensis, Salvia miltiorrhiza, Belamcanda chinensis, Paeoniae lactiflora, Angelica dahurica, Arisaema erubescens, Fructus arctii, Anemarrhena asphodeloides and Platycodon grandiflorum. The organochlorine pesticides were extracted from herbs with mixed solvents of acetone and n-hexane by ultrasonic and cleaned up by Florisil solid-phase extraction column. Then, the extract was separated by capillary column (30 m x 0.25 mm i.d. x 0.25 microm) and detected by electrochemical detector. The carrier gas was N2 (99.999%) with the flow rate of 1.4 mL/min. The split ratio was 1:2.2. The injector temperature was 220 degrees C and the detector temperature was 330 degrees C. The column temperature was increased by the rate of 20 degrees C/min from 100 degrees C to 190 degrees C (hold for 1. 0 min), then to 235 degrees C by the rate of 4 degrees C/min and hold for 7 min at 235 degrees C. The good linearities were obtained for 13 organochlorine pesticides. The detection limits were between 0.064-0.61 microg/L. The average recoveries were between 87.3%-102.3% and relative standard deviations of 1.3%-6.8%. The method is effective, fast and accurate. PMID:16124584

Yan, Zheng; Feng, Di; Li, Shenjie; Zhao, Yakui; Yang, Hui

2005-05-01

277

Solid phase nucleic acid extraction technique in a microfluidic chip using a novel non-chaotropic agent: dimethyl adipimidate.  

Science.gov (United States)

Here, we present a silicon microfluidic system for the purification and extraction of nucleic acids from human body fluid samples utilizing a dimethyl adipimidate (DMA)-based solid-phase extraction method. We propose DMA, which has been used as an amino-reactive cross-linking agent within cells and proteins, as a non-chaotropic reagent for the capture of nucleic acids to overcome the limitations of existing chaotropic and non-chaotropic techniques such as low binding efficiency, PCR inhibition and so on. DMA contains bi-functional imidoesters that form reversible cross-linking structures with DNA therefore providing a high surface-area to volume ratio for capturing DNA without structurally modifying microfluidic channels. In this work, we have first demonstrated highly efficient capture and purification of genomic DNA (T24 cell line) with DMA using a label-free silicon microring resonator sensor device. In addition, we observed the improvement of the DNA amplification efficiency by using the proposed technique for both the genetic (HRAS) and epigenetic (RAR?) analysis of DNA biomarkers. Particularly, we confirmed that the DMA-based solid-phase extraction technique can be applied for the extraction of genomic DNA with higher purity (p < 0.001) using human body fluids (blood and urine) in silicon microfluidic devices compared to other chaotropic methods. Therefore, the proposed technique would be able to harmonize with a micro-total analysis system platform for the analysis of genetic and epigenetic DNA biomarkers related to human diseases in the field of point-of-care (POC) diagnostic applications. PMID:24263404

Shin, Yong; Perera, Agampodi Promoda; Wong, Chee Chung; Park, Mi Kyoung

2014-01-21

278

Flow-injection on-line oxidizing fluorimetry and solid phase extraction for determination of thioridazine hydrochloride in human plasma.  

Science.gov (United States)

A simple, sensitive and specific fluorimetric method has been developed for the determination of thioridazine hydrochloride in human plasma involving solid phase extraction (SPE). In a flow-injection system, thioridazine hydrochloride is on-line oxidized into a strongly fluorescent compound with a lead dioxide solid-phase reactor and the fluorescence intensity is measured with a fluorescence detector (lambda(ex)=349nm, lambda(em)=429nm). A comparison of plasma sample pretreatment between SPE procedure and precipitation method was made and the results showed that SPE procedure was better than precipitation method. Under the optimum conditions, the fluorescence intensity is proportional to the concentration of thioridazine hydrochloride in the range from 0.015 to 2.000microg mL(-1). The detection limit is 5.5ng mL(-1) of thioridazine hydrochloride and the relative standard deviation is 1.06%. This method has been applied to determination of thioridazine hydrochloride in real patients plasma samples with the results compared with those obtained by HPLC method. PMID:19071563

Zhang, Zhi-Qi; Ma, Jian; Lei, Ying; Lu, Yue-Mei

2007-03-30

279

Determination of haloacetic acids in swimming pool waters by membrane-protected micro-solid phase extraction.  

Science.gov (United States)

In this study, a simple and efficient extraction method for determining haloacetic acids (HAAs) in swimming pool waters has been developed. HAAs are toxic organic pollutants of disinfection origin most commonly detected in swimming pool and drinking waters at trace level concentrations. For the first time, a highly efficient sorbent was developed using rice husk and used for micro-solid phase extraction (?-SPE) technique. To increase the extraction capability of rice husk silica, iron oxide was incorporated via sol-gel process. In ?-SPE device, the novel sorbent was packed and used for extraction of HAAs prior to analysis using ultra performance liquid chromatography-ultraviolet detection (UPLC-UV). Various extraction parameters were optimized to improve the extraction efficiency of ?-SPE. Under optimum conditions, linearity (coefficient of determination, r(2)?0.991 over the concentration range of 1-150 ?g/L), detection limits in the range of 0.001-0.092 ?g/L, mean recoveries up to 110% with corresponding relative standard deviations of 2-7% (n=3) had been obtained. Finally, the method was applied to swimming pool water to evaluate its feasibility. The mean concentrations for HAAs from the pool waters were in the range of 6.8 and 48.6 ?g/L which are far below the standard values set by United States Environmental Protection Agency. PMID:24075018

Nsubuga, Hakimu; Basheer, Chanbasha

2013-11-01

280

Comparative evaluation of liquid-liquid extraction, solid-phase extraction and solid-phase microextraction for the gas chromatography-mass spectrometry determination of multiclass priority organic contaminants in wastewater.  

Science.gov (United States)

The European Water Framework Directive (WFD) 2000/60/EC establishes guidelines to control the pollution of surface water by sorting out a list of priority substances that involves a significant risk to or via the aquatic systems. In this article, the analytical performance of three different sample preparation methodologies for the GC-MS/MS determination of multiclass organic contaminants-including priority comprounds from the WFD-in wastewater samples using gas chromatography-mass spectrometry was evaluated. The methodologies tested were: (a) liquid-liquid extraction (LLE) with n-hexane; (b) solid-phase extraction (SPE) with C18 cartridges and elution with ethyl acetate:dichloromethane (1:1 (v/v)), and (c) headspace solid-phase microextraction (HS-SPME) using two different fibers: polyacrylate and polydimethylsiloxane/carboxen/divinilbenzene. Identification and confirmation of the selected 57 compounds included in the study (comprising polycyclic aromatic hydrocarbons (PAHs), pesticides and other contaminants) were accomplished using gas chromatography tandem mass spectrometry (GC-MS/MS) with a triple quadrupole instrument operated in the multiple reaction monitoring (MRM) mode. Three MS/MS transitions were selected for unambiguous confirmation of the target chemicals. The different advantages and pitfalls of each method were discussed. In the case of both LLE and SPE procedures, the method was validated at two different concentration levels (15 and 150 ng L(-1)) obtaining recovery rates in the range 70-120% for most of the target compounds. In terms of analyte coverage, results with HS-SPME were not satisfactory, since 14 of the compounds tested were not properly recovered and the overall performance was worse than the other two methods tested. LLE, SPE and HS-SPME (using polyacrylate fiber) procedures also showed good linearity and precision. Using any of the three methodologies tested, limits of quantitation obtained for most of the detected compounds were in the low nanogram per liter range. PMID:24209357

Robles-Molina, José; Gilbert-López, Bienvenida; García-Reyes, Juan F; Molina-Díaz, Antonio

2013-12-15

281

Rapid, low level determination of silver(I) in drinking water by colorimetric-solid-phase extraction  

Energy Technology Data Exchange (ETDEWEB)

A rapid, highly sensitive two-step procedure for the trace analysis of silver(I) is described. The method is based on: (1) the solid-phase extraction (SPE) of silver(I) from a water sample onto a disk impregnated with a silver-selective colorimetric reagent, and (2) the determination of the amount of complexed analyte extracted by the disk by diffuse reflectance spectroscopy (DRS). This method, called colorimetric-solid-phase extraction (C-SPE), was recently shown effective in determining low concentrations (0.1-5.0 mg/ml) of iodine and iodide in drinking water. This report extends C-SPE to the trace ({approx}4 {mu}g/l) level monitoring of silver(I) which is a biocide used on the International Space Station (ISS). The determination relies on the manually driven passage of a water sample through a polystyrene-divinylbenzene disk that has been impregnated with the colorimetric reagent 5-(p-dimethylaminobenzylidene) rhodanine (DMABR) and with an additive such as a semi-volatile alcohol (1,2-decanediol) or nonionic surfactant (Brij 30). The amount of concentrated silver(I) is then determined in a few seconds by using a hand-held diffuse reflectance spectrometer, with a total sample workup and readout time of {approx}60 s. Importantly, the additive induces the uptake of water by the disk, which creates a local environment conducive to silver(I) complexation at an extremely high concentration factor ({approx}800). There is no detectable reaction between silver(I) and impregnated DMABR in the absence of the additive. This strategy represents an intriguing new dimension for C-SPE in which additives, directly loaded in the disk material, provide a means to manipulate the reactivity of the impregnated reagent.

Arena, Matteo P.; Porter, Marc D.; Fritz, James S

2003-04-15

282

Solid phase extraction of trace amount of mercury from natural waters on silver and gold nanoparticles.  

Science.gov (United States)

Silver (Ag) and gold (Au) nanoparticles impregnated in nylon membrane filters have been proposed as a new solid phase for preconcentration of mercury from natural waters. Water samples were treated with KMnO4 to convert all mercury species to inorganic Hg(2+) and this was followed by the reduction of Hg(2+) with NaBH4 to elemental Hg(0). The determination of Hg was carried out by thermal evaporation of mercury from membrane filters using Zeeman mercury analyzer RA-915+ (Lumex, Russia). This process does not involve any additional sample treatment and sharply reduces risk of samples contamination. The limit of detection (LOD) was found to be 0.04 ng (absolute mass). Relative LOD was 0.4 ng L(-1) for 100 mL of water. The method was validated through the analysis of CRM NRCC Tort-2 (Lobster hepatopancreas) and the found value (0.30±0.07 ?g g(-1)) was in good agreement with the certified value (0.27±0.06 ?g g(-1)). High efficiency of Hg accumulation from aqueous phase to membrane filters can be attributed to a large surface area of nanoparticles. PMID:24528660

Panichev, N; Kalumba, M M; Mandiwana, K L

2014-02-27

283

Cleanup and analysis of sugar phosphates in biological extracts by using solid phase extraction and anion-exchange chromatography with pulsed amperometric detection  

DEFF Research Database (Denmark)

A cleanup method based on anion-exchange solid-phase extraction (SPE) was developed to render biological extracts suitable for the analysis of hexose phosphates with a modified anion-exchange chromatography method and pulsed amperometric detection. The method was applied to cell extracts of Saccharomyces cerevisiae obtained by using cold methanol as quenching agent and chloroform as extraction solvent. It was shown that pretreatment of the cell extract with SPE markedly improved the quality of the liquid chromatography analysis with recoveries of the sugar phosphates close to 100%. Furthermore, the method allowed for sample enrichment and the original extraction procedure could be simplified by implementing SPE early in the extraction protocol. (C) 1998 Academic Press.

Smith, Hans Peter; Cohen, A.

1998-01-01

284

Comparison of characteristic flavor and aroma volatiles in melons and standards using solid phase microextraction (SPME) and Stir Bar Sorptive Extraction (SBSE) with GC-MS.  

Science.gov (United States)

Stir bar sorptive extraction (SBSE) is a technique for extraction and analysis of organic compounds in aqueous matrices, similar in theory to solid phase microextraction (SPME). SBSE has been successfully used to analyze several organic compounds, including food matrices. When compared with SPME, ...

285

ALTERNATIVES TO METHANOL WATER ELUTION OF SOLID-PHASE EXTRACTION COLUMNS FOR THE FRACTIONATION OF HIGH LOG KOW ORGANIC COMPOUNDS IN AQUEOUS ENVIRONMENTAL SAMPLES  

Science.gov (United States)

A toxicity-directed method for fractionating non-polar organic toxicants using solid-phase extraction (SPE) is described in phase II of EPA's "Methods for Aquatic Toxicity Evaluations". his method has been used very successfully to extract and fractionate acutely and chronically ...

286

Synthesis, characterization and application of ethylenediamine-modified multiwalled carbon nanotubes for selective solid-phase extraction and preconcentration of metal ions  

International Nuclear Information System (INIS)

A new method that utilizes ethylenediamine-modified multiwalled carbon nanotubes as a solid-phase extractant has been developed for simultaneous preconcentration of trace Cr(III), Fe(III) and Pb(II) prior to the measurement by inductively coupled plasma optical emission spectrometry. Identification of the surface modification was characterized and performed on the basis of transmission electron microscopy, Fourier transform infrared spectra and elemental analysis. The separation/preconcentration conditions of analytes were investigated, including the pH value, the shaking time, the sample flow rate and volume, the elution condition and the interfering ions. The maximum adsorption capacity of the adsorbent at optimum conditions was found to be 39.58, 28.69 and 54.48 mg g-1 for Cr(III), Fe(III) and Pb(II), respectively. The detection limits of the method were under 0.35 ng mL-1 and the relative standard deviations were lower than 3.5% (n = 11). The method was validated using a certified reference material, and has been applied for the determination of trace Cr(III), Fe(III) and Pb(II) in biological and natural water samples with satisfactory results.

287

A new graphene oxide/polypyrrole foam material with pipette-tip solid-phase extraction for determination of three auxins in papaya juice.  

Science.gov (United States)

A new material, graphene oxide/polypyrrole (GO/Ppy), was synthesized by mixing graphene oxide and polypyrrole in a specific proportion. It possesses a unique structure similar to that of foam. A homemade pipette-tip solid-phase extraction (PT-SPE) device, which is more simple and convenient than traditional devices, was used for saving reagents and operation time. When GO/Ppy was used as the adsorbent of PT-SPE for determining three auxins (indole-3-propionic acid, indole-3-butyric acid, and 1-naphthaleneacetic acid) present in trace amounts in papaya juice, it showed high affinity and adsorption capacity for all the three auxins. GO/Ppy-PT-SPE also had a significant capacity for eliminating the interferences from the papaya juice matrix. Under optimized conditions, a good linearity of auxins was obtained in the range 16.3-812.5 ng g(-1); the average recoveries at the three spiked levels of the three auxins ranged from 89.4% to 105.6% with the relative standard deviations ? 3.0%. Meanwhile, six papaya juice samples with different growth stages were analyzed under optimum conditions, and trace auxins in the range 18.3-100.6 ng g(-1) were observed. Because of its high selectivity, simplicity, and reliability, the GO/Ppy-PT-SPE method developed herein can be potentially applied for determining trace auxins in complex biological samples. PMID:25441342

Wang, Lihui; Wang, Mingyu; Yan, Hongyuan; Yuan, Yanan; Tian, Jing

2014-11-14

288

Fast solid-phase extraction-gas chromatography-mass spectrometry procedure for oil fingerprinting. Application to the Prestige oil spill.  

Science.gov (United States)

A rapid and simple fractionation procedure using solid-phase extraction (SPE) cartridges was developed for an accurate determination of aliphatic and polycyclic aromatic hydrocarbons in petroleum residues and further application in chemical fingerprinting of oil spills by gas chromatography-mass spectrometry (GC-MS). Among the adsorbents evaluated, SiO2/C3-CN exhibited the best selectivity, providing, by elution with n-hexane (4 ml) and n-hexane-CH2Cl2 (1:1) (5 ml), two well-resolved aliphatic and aromatic hydrocarbon fractions, with recoveries of 97 +/- 7.2 and 99.7 +/- 13.9%, respectively. The SPE fractionation procedure was compared with the conventional silica-alumina adsorption chromatography showing similar results but practical advantages in terms of reproducibility, analysis time, solvent reduction and cost. Moreover, is particularly suitable for routine analysis with a high sample throughput. The developed methodology was tested in the characterization of fuel-oil samples collected along the Spanish north-west coast, after the Prestige oil spill accident. PMID:14753680

Alzaga, Roberto; Montuori, Paolo; Ortiz, Laura; Bayona, Josep M; Albaigés, Joan

2004-01-30

289

A novel benzimidazole-functionalized 2-D COF material: synthesis and application as a selective solid-phase extractant for separation of uranium.  

Science.gov (United States)

A novel COF-based material (COF-COOH) containing large amounts of carboxylic groups was prepared for the first time by using a simple and effective one-step synthetic method, in which the cheap and commercially available raw materials, trimesoyl chloride and p-phenylenediamine, were used. The as-synthesized COF-COOH was modified with previously synthesized 2-(2,4-dihydroxyphenyl)-benzimidazole (HBI) by "grafting to" method, and a new solid-phase extractant (COF-HBI) with highly efficient sorption performance for uranium(VI) was consequently obtained. A series of characterizations demonstrated that COF-COOH and COF-HBI exhibited great thermostabilities and irradiation stabilities. Sorption behavior of the COF-based materials toward U(VI) was compared in simulated nuclear industrial effluent containing UO2(2+) and 11 undesired ions, and the UO2(2+) sorption amount of COF-HBI was 81 mg g(-1), accounting for approximately 58% of the total sorption amount, which was much higher than the sorption selectivity of COF-COOH to UO2(2+) (39%). Batch sorption experiment results indicated that the uranium(VI) sorption on COF-HBI was a pH dependent, rapid (sorption equilibrium was reached in 30 min), endothermic and spontaneous process. In the most favorable conditions, the equilibrium sorption capacity of the adsorbent for uranium could reach 211 mg g(-1). PMID:25313486

Li, Juan; Yang, Xiaodan; Bai, Chiyao; Tian, Yin; Li, Bo; Zhang, Shuang; Yang, Xiaoyu; Ding, Songdong; Xia, Chuanqin; Tan, Xinyu; Ma, Lijian; Li, Shoujian

2015-01-01

290

Flame Atomic Absorption Spectrometric Determination of Trace Amounts of Zinc and Thallium in Different Matrixes after Solid Phase Extraction on Modified Multiwalled Carbon Nanotubes  

Directory of Open Access Journals (Sweden)

Full Text Available The potential of modified multiwallcd carbon nanotubes, as a solid-phase extraction sorbent for the simultaneous separation and preconcentration of zinc and thallium has been investigated. Zinc and thallium were adsorbed quantitatively onto modified multiwalled carbon nanotubes in the pH range of 3 - 6.5. Parameters influencing the simultaneous preconcentration of Zn(II and Tl(I ions such as pH of the sample, sample and eluent flow rate, type and volume of elution solution and interfering ions, have been examined and optimized. Linearity was maintained between 0.1 to 20.0 µg?mL–1 for thallium and 20.0 ng?mL–1 to 5.0 µg?mL–1 for zinc in the final solution. The defection limits based on three times the standard deviation of the blank signal (n = 8 for thallium and zinc were 5.1 and 1.4 ng?mL–1, respectively. Seven replicate determination of a mixture of 5.0 and 0.2 µg?mL–1 of thallium and zinc in the final solution gave a mean absorbance of 0.085 and 0.074 with relative standard deviation 1.5% and 1.7%, respectively. The method has been applied for the determination of trace amounts of zinc and thallium in biological and water sample with satisfactory results.

Sayed Zia Mohammadi

2012-05-01

291

Acrylamide-modified graphene for online micro-solid-phase extraction coupled to high-performance liquid chromatography for sensitive analysis of heterocyclic amines in food samples.  

Science.gov (United States)

Heterocyclic amines (HAs) are considered as potential mutagens and carcinogens, and are found in trace quantities (ng/g level) in food samples. Therefore, it is important to develop a selective and effective method to determine trace HAs in complex matrices. In this study, acrylamide-modified graphene (AMG) was successfully synthesised and showed good stability and permeability in aqueous and organic phases. AMG was used as an efficient adsorbent in the online micro-solid-phase extraction (?-SPE) of trace HAs. The enrichment factors of the AMG ?-SPE column were determined as 78-166 for six HAs. An online method based on AMG ?-SPE coupled to high-performance liquid chromatography was developed. The limits of detection ranged from 0.70 to 2.5 ng/L. Trace HAs in spicy salted duck, baked fish, and fried chicken samples were determined and the concentrations of 2-amino-3-methylimidazo[4,5-f]quinoine, 2-amino-3,4-dimethylimidazo[4,5-f]quinoine, and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline in these samples were 4.7-37.3, 8.1-15.4, and 43.3-109 ng/g, respectively. The recoveries for the six HAs ranged from 65.9% to 118%, and the relative standard deviation (RSDs) were less than 10.8%. The proposed online method was sensitive, reliable, and convenient for the analysis of trace HAs in food samples. PMID:25281083

Zhang, Qianchun; Li, Gongke; Xiao, Xiaohua

2015-01-01

292

Determination of atrazine and its major degradation products in soil pore water by solid-phase extraction, chemical derivatization, and gas chromatography/mass spectrometry  

Science.gov (United States)

This report describes a method for the determination of atrazine, desethylatrazine, deisopropylatrazine, didealkylatrazine, and hydroxyatrazine from soil pore waters by use of solid-phase extractionfollowed by chemical derivatization and gas chromatography/mass spectrometry. The analytes are isolated from the pore-water matrix byextraction onto a graphitized carbon-black cartridge. The cartridge is dried under vacuum, and adsorbed analytes are removed by elution with ethyl acetate followed by dichloromethane/methanol (7:3, volume/volume). Water is removed from the ethyl acetate fraction on an anhydrous sodium sulfate column. The combined fractions are solvent exchanged into acetonitrile, evaporated by use of a nitrogen stream, and derivatized by use of N- methyl-N-(tert-butyldimethylsilyl)- trifluoroacetamide. The derivatized extracts are analyzed by capillary-column gaschromatography/electron-impact mass spectrometry in the scan mode. Estimated method detection limits range from 0.03 to 0.07 micrograms per liter. The mean recoveries of all analytes and surrogates determined at 0.74 to 0.82 micrograms per liter in reagent water in soil pore water were 94 percent and 98 percent, respectively. The mean recoveries of all analytes and surrogates determined at 7.4 to 8.2 micrograms per liter in reagent water and in soil pore water were 96 percent and 97 percent,respectively. Recoveries were 90 percent or higher, regardless of analyte concentration or matrix composition, for all compounds excepthydroxyatrazine, whose recoveries were slightly lower (77 percent) at the low concentration.

Carter, D.S.

1996-01-01

293

Magnetic nanocomposite of self-doped polyaniline-graphene as a novel sorbent for solid-phase extraction.  

Science.gov (United States)

This work is the first study on the extraction efficiency of self-doped polyaniline that is immobilized on the graphene-modified magnetic nanoparticles. The new material was used as a sorbent for the magnetic solid-phase extraction of methyl-, propyl-, and butylparabens. The use of graphene provides a high surface area and prevents aggregation of the nanoparticles. The self-doped polyaniline also provides multifunctionality, high extraction capacity, and chemical stability even in the basic medium. The parabens were acetylated for determination by gas chromatography with flame ionization detection. The effects of monomer ratio, extraction solvent, sorbent amount, sample volume, desorption solvent volume, adsorption and desorption times, and sample ionic strength were optimized. Preconcentration factors obtained were from 190 to 310. The detection limits of the method were <2.8 ?g/L. Linear ranges of the method were 5-2000 ?g/L for propyl and butyl parabens, and 10-2000 ?g/L for methyl paraben. The method was applied for the determination of the parabens in cosmetic products and extraction recoveries were 89-101% with RSDs ?7.9%. PMID:25354138

Mehdinia, Ali; Esfandiarnejad, Reyhaneh; Jabbari, Ali

2015-01-01

294

Determination of fipronil in bovine plasma by solid-phase extraction and liquid chromatography with ultraviolet detection  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english A fast and efficient method has been developed and validated for the determination of fipronil in bovine plasma. Samples were subjected to solid-phase extraction (SPE) followed by reversed phase liquid chromatography (LC) separation, using acetonitrile/water (60:40 v/v) as the mobile phase with a fl [...] ow rate of 1.0 mL/min and ultraviolet (UV) detection at 210 nm. Ethiprole was used as the internal standard (IS). The method was found to be linear over the range 5-500 ng/mL (r = 0.999). The limit of quantitation (LOQ) was validated at 5 ng/mL. The method was successfully applied to monitor plasma concentrations following subcutaneous administration of fipronil in cattle.

Yara P., Cid; Thais P., Ferreira; Deborah M. V. C., Medeiros; Rodrigo M., Oliveira; Nathália C. C., Silva; Viviane S., Magalhães; Fábio B., Scott.

2063-20-01

295

Determination of fipronil in bovine plasma by solid-phase extraction and liquid chromatography with ultraviolet detection  

Directory of Open Access Journals (Sweden)

Full Text Available A fast and efficient method has been developed and validated for the determination of fipronil in bovine plasma. Samples were subjected to solid-phase extraction (SPE followed by reversed phase liquid chromatography (LC separation, using acetonitrile/water (60:40 v/v as the mobile phase with a flow rate of 1.0 mL/min and ultraviolet (UV detection at 210 nm. Ethiprole was used as the internal standard (IS. The method was found to be linear over the range 5-500 ng/mL (r = 0.999. The limit of quantitation (LOQ was validated at 5 ng/mL. The method was successfully applied to monitor plasma concentrations following subcutaneous administration of fipronil in cattle.

Yara P. Cid

2012-01-01

296

Simple and versatile operational fractionation of Fe and Zn in dietary products by solid phase extraction on ion exchange resins.  

Science.gov (United States)

A simple and versatile protocol, based on use of solid phase extraction on strong ion exchangers and off-line detection by flame atomic absorption spectrometry, was devised to fractionate iron and zinc in common dietary food and beverages products, i.e., bee honeys, fruit juices and tea infusions. In the procedure proposed, cation exchanger Dowex 50Wx4 and anion exchanger Dowex 1x4 were used separately for distinguishing broadly meant the cationic metal fraction and the fraction of stable anionic metal complexes, respectively, after retention of metal species and their exhaustive elution by means of a 4.0moll(-1) HCl solution. The third fraction, referred to the residual metal species, was retrieved by difference between total soluble metal contents and sum of metal quantities in separated cationic and anionic fractions. The fractionation pattern observed for both metals was described and discussed. PMID:19071320

Pohl, P; Prusisz, B

2007-01-15

297

Development of solid-phase extraction method and its application for determination of hydrochlorothiazide in human plasma using HPLC.  

Science.gov (United States)

A high-performance liquid chromatographic method was developed, validated and applied for the determination of hydrochlorothiazide in human plasma. The effects of mobile phase composition, buffer concentration, mobile phase pH and concentration of organic modifiers on retention of hydrochlorothiazide and internal standard were investigated. The method involves solid-phase extraction on RP-select B cartridges followed by isocratic reversed-phase chromatography on a Hibar Lichrospher 100 RP-8 column with UV detection at 230 nm. The recovery, selectivity, linearity, precision and accuracy of the method were evaluated from spiked human plasma samples. Limit of quantification was 10 ng mL(-1). The method has been implemented to monitor hydrochlorothiazide levels in patient samples. PMID:15039957

Zendelovska, Dragica; Stafilov, Trajce; Milosevski, Petar

2004-03-01

298

Determination of enrofloxacin by room-temperature phosphorimetry after solid phase extraction on an acrylic polymer sorbent  

Science.gov (United States)

A phosphorimetric method was developed to enable the determination of enrofloxacin using photochemical derivatization which was used to both improve detection limits and to minimize the uncertainty of measurements. Phosphorescence was induced on cellulose containing TlNO3. Absolute limit of detection at the ng range and linear analytical response over three orders of magnitude were achieved. A metrological study was made to obtain the combined uncertainty value and to identify that the precision was mainly affected by the changing of substrates when measuring the signal from each replicate. Pharmaceutical formulations containing enrofloxacin were successfully analyzed by the method and the results were similar to the ones achieved using a HPLC method. A solid phase extraction on an acrylic polymer was optimized to separate enrofloxacin from interferents such as diclofenac and other components from biological matrices, which allowed the successful use of the method in urine analysis.

de Souza, Cabrini F.; Martins, Renata K. S.; da Silva, Andrea R.; da Cunha, Alessandra L. M. C.; Aucélio, Ricardo Q.

299

Multi-element pre-concentration of heavy metal ions by solid phase extraction on Chromosorb 108  

International Nuclear Information System (INIS)

A multi-element preconcentration procedure for solid phase extraction on Chromosorb 108 as bathocuproinedisulfonic acid chelates and flame atomic absorption spectrometric determinations of some heavy metal ions in environmental samples is proposed in the present work. The influences of analytical parameters including pH of the aqueous solution, amounts of reagents, flow rates of sample and eluent solutions, sample volume etc. on the quantitative recoveries of copper, cadmium, lead, zinc, manganese, iron, chromium, nickel and cobalt ions were investigated. The effects of concomitant ions on the retentions of the analytes were also examined. The presented preconcentration procedure was applied to the determination of metal ions in reference standard materials (NRCC-SLRS 4 Riverine Water, SRM 1515 Apple leaves and GBW 07605 Tea) and some real samples including tap and river water, red wine, rice, black tea and honey

300

Solid-phase extraction for the decontamination of alkali metal, alkaline Earth metal, and ammonium salts from heavy metal ions.  

Science.gov (United States)

Salicylaldoxime-immobilized silica gel was characterized and used as a potential sorbent for heavy metal ions, viz. Cu(II), Ni(II), Co(II), and Zn(II). The experimental conditions were optimized both in batch and column processes to achieve the maximum efficiency. Kinetic and thermodynamic parameters as well as isotherm constants were evaluated to test the feasibility of the process. The role of various metal ions and different anions were tested in order to monitor the process in case of real samples. The alkali metal, alkaline earth metal, and ammonium salts do not have any effect on the said process. This differential behavior can be effectively used for the decontamination of alkali metal, alkaline earth metal, and ammonium salts from Cu(II), Ni(II), Co(II), and Zn(II) ions via solid phase extraction following AAS measurement. The purification of the salts was confirmed by voltammetric experiment. PMID:16290410

Sarkar, Mitali; Das, Mridula; Datta, Pradip Kumar

2002-02-15

301

Solid-Phase Extraction Strategies to Surmount Body Fluid Sample Complexity in High-Throughput Mass Spectrometry-Based Proteomics  

Science.gov (United States)

For large-scale and standardized applications in mass spectrometry- (MS-) based proteomics automation of each step is essential. Here we present high-throughput sample preparation solutions for balancing the speed of current MS-acquisitions and the time needed for analytical workup of body fluids. The discussed workflows reduce body fluid sample complexity and apply for both bottom-up proteomics experiments and top-down protein characterization approaches. Various sample preparation methods that involve solid-phase extraction (SPE) including affinity enrichment strategies have been automated. Obtained peptide and protein fractions can be mass analyzed by direct infusion into an electrospray ionization (ESI) source or by means of matrix-assisted laser desorption ionization (MALDI) without further need of time-consuming liquid chromatography (LC) separations.

Bladergroen, Marco R.; van der Burgt, Yuri E. M.

2015-01-01

302

Colorimetric Solid Phase Extraction for the Measurement of Total I (Iodine, Iodide, and Triiodide) in Spacecraft Drinking Water  

Science.gov (United States)

An experimental drinking water monitoring kit for the measurement of iodine and silver(I) was recently delivered to the International Space Station (ISS). The kit is based on Colorimetric Solid Phase Extraction (CSPE) technology, which measures the change in diffuse reflectance of indicator disks following exposure to a water sample. To satisfy additional spacecraft water monitoring requirements, CSPE has now been extended to encompass the measurement of total I (iodine, iodide, and triiodide) through the introduction of an oxidizing agent, which converts iodide and triiodide to iodine, for measurement using the same indicator disks currently being tested on ISS. These disks detect iodine, but are insensitive to iodide and triiodide. We report here the operational considerations, design, and ground-based performance of the CSPE method for total I. The results demonstrate that CSPE technology is poised to meet NASA's total I monitoring requirements.

Lipert, Robert J.; Porter, Marc D.; Siperko, Lorraine M.; Gazda, Daniel B.; Rutz, Jeff A.; Schultz, John R.; Carrizales, Stephanie M.; McCoy, J. Torin

2009-01-01

303

Characterization of an attenuated total reflection-based sensor for integrated solid-phase extraction and infrared detection.  

Science.gov (United States)

A novel attenuated total reflection (ATR) sensor, which integrates solid-phase extraction (SPE) and infrared detection, is presented. The flow cell, which enables the on-line coupling with a sequential injection system, is the core of the proposed sensor since it allows the continuous delivery of different solutions through the ATR and also the continuous spectrum acquisition. A SPE sorbent material (LiChrolut EN) was located in the sensitive element of the ATR without using any external coating substance, increasing the versatility of the system. A marked sensitivity enhancement was obtained as the analyte was concentrated before detection. The new sensor was qualitatively and quantitatively validated using the determination of caffeine in soft drinks as the model analytical problem. Linearity, precision (RSD = 4%), and sensitivity (LOD = 7 microg/mL) levels have been established. Finally, the main advantages and limitations of the new proposal are presented and compared with existing alternatives. PMID:18181581

Alcudia-León, M Carmen; Lucena, Rafael; Cárdenas, Soledad; Valcárcel, Miguel

2008-02-15

304

Solid phase extraction--multisyringe flow injection system for the spectrophotometric determination of selenium with 2,3-diaminonaphthalene.  

Science.gov (United States)

In the present work, a solid phase extraction (SPE) is hyphenated with an automatic MSFIA system to improve the selenite determination based on the reaction of selenite with aromatic o-diamines (such as 2,3-diaminonaphthalene (DAN)) to form the piazselenol complex. This reaction is greatly influenced by acid concentration, temperature, the time needed for colour development, and presence of foreign ions. For these reasons a thermostatic bath, glycine, and Na(2)-EDTA are used as heater, buffer, and masking agent, respectively. The principle of the determination is based on the sorption of the piazselenol onto a C(18) membrane disk, followed by its elution by acetonitrile. The piazselenol can then be detected by absorptiometry or fluorometry, both detection techniques being tested in our system. The best detection limit (1.7 microg L(-1)) and RSD (3.04%) are obtained by absorptiometry at 380 nm. Environmental samples were spiked and analyzed, with recoveries close to 100%. PMID:20188964

Serra, A M; Estela, J M; Coulomb, B; Boudenne, J L; Cerdà, V

2010-04-15

305

Determination of pesticides in waters by automatic on-line solid-phase extraction-capillary electrophoresis.  

Science.gov (United States)

The separation of seven pesticides by micellar electrokinetic capillary chromatography in spiked water samples is described, allowing the analysis of pesticides mixtures down to a concentration of 50 microg l(-1) in less than 13 min. Calibration, pre-concentration, elution and injection into the sample vial was carried out automatically by a continuous flow system (CFS) coupled to a capillary electrophoresis system via a programmable arm. The whole system was electronically coupled by a micro-processor and completely controlled by a computer. A C18 solid-phase mini-column was used for the pre-concentration, allowing a 12-fold enrichment (as an average value) of the pesticides from fortified water samples. Under the optimal extraction conditions, recoveries between 90 and 114% for most of the pesticides were obtained. PMID:10681016

Hinsmann, P; Arce, L; Ríos, A; Valcárcel, M

2000-01-01

306

Trace determination of pharmaceuticals and other wastewater-derived micropollutants by solid phase extraction and gas chromatography/mass spectrometry.  

Science.gov (United States)

The presence of pharmaceuticals and other wastewater-derived micropollutants in surface and groundwaters is receiving intense public and scientific attention. Yet simple GC/MS methods that would enable measurement of a wide range of such compounds are scarce. This paper describes a GC/MS method for the simultaneous determination of 13 pharmaceuticals (acetaminophen, albuterol, allopurinol, amitriptyline, brompheniramine, carbamazepine, carisoprodol, ciclopirox, diazepam, fenofibrate, metoprolol, primidone, and terbinafine) and 5 wastewater-derived contaminants (caffeine, diethyltoluamide, n-butylbenzene sulfonamide, n-nonylphenol, and n-octylphenol) by solid phase extraction (SPE) and derivatization with BSTFA. The method was applied to the analysis of raw and treated sewage samples obtained from a wastewater treatment plant located in the mid-Atlantic United States. All analytes were detected in untreated sewage, and 14 of the 18 analytes were detected in treated sewage. PMID:20015510

Bisceglia, Kevin J; Yu, Jim T; Coelhan, Mehmet; Bouwer, Edward J; Roberts, A Lynn

2010-01-22

307

Monitoring of Pesticides Residues in Italian Mineral Waters by Solid Phase Extraction and Gas Chromatography Mass Spectrometry  

Directory of Open Access Journals (Sweden)

Full Text Available Twenty-two pesticides and metabolites, selected on the basis of regional priority lists, were surveyed in thirty Italian mineral waters springs for three years by a procedure based on solid phase extraction in combination with gas chromatography coupled with mass spectrometry detection. The procedure proved to be simple, sensitive and reliable, the limits of detection and relative standard deviations were respectively in the range of 0.002 - 0.04 ?g/L and 3% - 7%, recoveries ranged from 86% to 105% at the European Union Maximum Acceptable Concentration (MAC. Pesticide residues were detected in just one of the ninety water samples analyzed but no one exceeding the MAC. These results demonstrate the good quality of Italian mineral waters, not forgetting the need of constant revision and update of the priority list of pollutants.

Anna Maria Tarola

2012-10-01

308

Robot-performed synthesis of [11C]CH3-methionine with isolation by means of solid-phase extraction  

International Nuclear Information System (INIS)

Robot-performed technology of synthesizing radiopharmaceutical preparation 11CH3-methionine, used in positron-emission tomography of brain to evaluate the rate of protein biosynthesis was developed. The technology is based on the synthesis of 11CH3-methionine from[11C]-CHI and DL-homocysteinethiolactone with subsequent isolation of the preparation by the method of solid-phase extraction. Activity of the preparation synthesized is 0.13-0.17 Ci, specific activity -325-850 Ci/mmol, total duration of the synthesis from the moment of irradiation end is 16-19 min, radiochemical yield, as regards 11CH3I corrected for carbon-11 decay, is 60 %

309

Simultaneous Determination of Seven Synthetic Colorants in Wine by Dispersive Micro-Solid-Phase Extraction Coupled with Reversed-Phase High-Performance Liquid Chromatography.  

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A novel and effective dispersive micro-solid-phase extraction (d-µ-SPE) using ethanediamine-functionalized magnetic Fe3O4 polymer (EDA-MP) as an efficient adsorbent in wine sample was developed. Based on this, a simple and time-saving analytical method for the simultaneous determination of seven synthetic colorants (i.e., tartrazine, amaranth, carmine, sunset yellow, allura red, brilliant blue and erythrosine) in wine by reversed-phase high-performance liquid chromatography with an ultraviolet detector was established. The experimental parameters, including the chromatographic retention behavior of studied synthetic colorants, the effect of the usage amount of cross-linking monomer, the effect of the usage amount of EDA-MP on the recovery and the recyclability of the adsorbents, were studied in detail. The results showed that the EDA-MP could be reused efficiently at least six times. Under optimized conditions, the recoveries for all analytes were in the range of 88.6-105.2%, with the intraday relative standard deviations (RSDs) ranging from 2.1 to 8.2% and the interday RSDs ranging from 3.4 to 8.7%, and all the analytes had good linearities in the tested ranges with correlation coefficients (r(2)) >0.9995. The limits of quantification for seven synthetic colorants were between 0.12 and 0.45 mg L(-1). The developed method was successfully applied to wine samples, and it was confirmed that the EDA-MP particles were highly effective d-µ-SPE materials. PMID:24850700

Zhang, Yun; Zhou, Hua; Wang, Yougang; Wu, Xianglun; Zhao, Yonggang

2014-05-21

310

Determination of several pesticides in water by solid-phase extraction, liquid chromatography and electrospray tandem mass spectrometry.  

Science.gov (United States)

The analysis of pesticides in water samples is a problem of primary concern for quality control laboratories due to the toxicity level of these compounds and their public health risk. In order to evaluate the impact of pesticides in the Lisbon drinking water supply system, following the requirements of the European Union Directive 98/83/EC, we developed and validated an analytical method based on the combination of solid-phase extraction with liquid chromatography and tandem mass spectrometry. In this work, several pesticides were studied: imidacloprid, dimethoate, cymoxanil, carbendazime, phosmet, carbofuran, isoproturon, diuron, methidathion, linuron, pyrimethanil, methiocarbe, tebuconazole and chlorpyrifos. Several parameters of the electrospray source were optimized in order to get the best formation conditions of the precursor ion for each pesticide, namely capillary and extractor voltage, cone voltage, cone gas flow rate and desolvation gas flow rate. After optimization of the collision cell energy of the triple quadrupole, two different precursor ion-product ion transitions were selected for each pesticide, one for quantification and one for qualification, and these ions were monitored under time-scheduled multiple reaction monitoring (MRM) conditions. The selection of specific fragment ions for each pesticide guarantees a high degree of selectivity as well as additional sensitivity to quantify trace levels of these pesticides in water samples. This method showed excellent linearity ranges for all pesticides, with correlation coefficients greater than 0.9989. Determination limits (between 0.0041 and 0.0480 microg/L), precision (RSD <9.18%), accuracy and recovery studies in several water samples using solid-phase extraction were also performed. PMID:17064714

Rodrigues, Alexandre Mourão; Ferreira, Vera; Cardoso, Vitor Vale; Ferreira, Elisabete; Benoliel, Maria João

2007-05-25

311

Fully automated synthesis of 11C-acetate as tumor PET tracer by simple modified solid-phase extraction purification  

International Nuclear Information System (INIS)

Introduction: Automated synthesis of 11C-acetate (11C-AC) as the most commonly used radioactive fatty acid tracer is performed by a simple, rapid, and modified solid-phase extraction (SPE) purification. Methods: Automated synthesis of 11C-AC was implemented by carboxylation reaction of MeMgBr on a polyethylene Teflon loop ring with 11C-CO2, followed by acidic hydrolysis with acid and SCX cartridge, and purification on SCX, AG11A8 and C18 SPE cartridges using a commercially available 11C-tracer synthesizer. Quality control test and animals positron emission tomography (PET) imaging were also carried out. Results: A high and reproducible decay-uncorrected radiochemical yield of (41.0±4.6)% (n=10) was obtained from 11C-CO2 within the whole synthesis time about 8 min. The radiochemical purity of 11C-AC was over 95% by high-performance liquid chromatography (HPLC) analysis. Quality control test and PET imaging showed that 11C-AC injection produced by the simple SPE procedure was safe and efficient, and was in agreement with the current Chinese radiopharmaceutical quality control guidelines. Conclusion: The novel, simple, and rapid method is readily adapted to the fully automated synthesis of 11C-AC on several existing commercial synthesis module. The method can be used routinely to produce 11C-AC for preclinical and clinical studies with PET imaging. - Highlights: • A fully automated synthesis of 11C-acetate by simple modified solid-phase extraction purification has been developed. • Typical non-decay-corrected yields were (41.0±4.6)% (n=10) • Radiochemical purity was determined by radio-HPLC analysis on a C18 column using the gradient program, instead of expensive organic acid column or anion column. • QC testing (RCP>99%)

312

Determining plasma morphine levels using GC-MS after solid phase extraction to monitor drug levels in the postoperative period  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english OBJECTIVE: To implement a selective and sensitive analytical method to quantify morphine in small volumes of plasma by gas-liquid chromatography-mass spectrometry (GC-MS), aimed at post-operatively monitoring the drug. METHOD: A gas-liquid chromatographic method with mass detection has been develope [...] d to determine morphine concentration in plasma after solid phase extraction. Morphine-d3 was used as an internal standard. Only 0.5 mL of plasma is required for the drug solid-phase extraction in the Bond Elut-Certify®, followed by the quantification of morphine derivative by GC-MS using a linear temperature program, a capillary fused silica column, and helium as the carrier and make-up gas. The method was applied to determine morphine content in plasma samples of four patients during the postoperative period of cardiac surgery. Patient-controlled analgesia with morphine was performed by a venous catheter, and a series of venous blood samples were collected. After the oro-After the orotracheal extubation, morphine plasma levels were monitored for up to 36 hours. RESULTS: The run time was 16 minutes because morphine and the internal standard were eluted after 8.8 minutes. The GC-MS method had 0.5 -1000 ng/mL linearity range (r²=0.9995), 0.1 ng/mL limit of detection, intraday and interday precision equivalent to 1.9% and 6.8%, and 0.1% and 0.8% systematic error (intraday and interday, respectively). The analytical method showed optimal absolute (98%) and relative (100.7%) recoveries. Morphine dose requirements and plasma levels are discussed. CONCLUSION: The analytical gas-liquid chromatography-mass spectrometry method is selective and adequate for morphine measurements in plasma for applications in clinical studies.

Veronica, Santos; Karin Jannet Vera, López; Luciana Moraes, Santos; Mauricio, Yonamine; Maria José Carvalho, Carmona; Silvia Regina Cavani Jorge, Santos.

313

Determining plasma morphine levels using GC-MS after solid phase extraction to monitor drug levels in the postoperative period  

Directory of Open Access Journals (Sweden)

Full Text Available OBJECTIVE: To implement a selective and sensitive analytical method to quantify morphine in small volumes of plasma by gas-liquid chromatography-mass spectrometry (GC-MS, aimed at post-operatively monitoring the drug. METHOD: A gas-liquid chromatographic method with mass detection has been developed to determine morphine concentration in plasma after solid phase extraction. Morphine-d3 was used as an internal standard. Only 0.5 mL of plasma is required for the drug solid-phase extraction in the Bond Elut-Certify®, followed by the quantification of morphine derivative by GC-MS using a linear temperature program, a capillary fused silica column, and helium as the carrier and make-up gas. The method was applied to determine morphine content in plasma samples of four patients during the postoperative period of cardiac surgery. Patient-controlled analgesia with morphine was performed by a venous catheter, and a series of venous blood samples were collected. After the oro-After the orotracheal extubation, morphine plasma levels were monitored for up to 36 hours. RESULTS: The run time was 16 minutes because morphine and the internal standard were eluted after 8.8 minutes. The GC-MS method had 0.5 -1000 ng/mL linearity range (r²=0.9995, 0.1 ng/mL limit of detection, intraday and interday precision equivalent to 1.9% and 6.8%, and 0.1% and 0.8% systematic error (intraday and interday, respectively. The analytical method showed optimal absolute (98% and relative (100.7% recoveries. Morphine dose requirements and plasma levels are discussed. CONCLUSION: The analytical gas-liquid chromatography-mass spectrometry method is selective and adequate for morphine measurements in plasma for applications in clinical studies.

Veronica Santos

2008-01-01

314

Simultaneous determination of phenolic compounds in Equisetum palustre L. by ultra high performance liquid chromatography with tandem mass spectrometry combined with matrix solid-phase dispersion extraction.  

Science.gov (United States)

A method based on matrix solid-phase dispersion extraction followed by ultra high performance liquid chromatography with tandem mass spectrometry is presented for the extraction and determination of phenolic compounds in Equisetum palustre. This method combines the high efficiency of matrix solid-phase dispersion extraction and the rapidity, sensitivity, and accuracy of ultra high performance liquid chromatography with tandem mass spectrometry. The influential parameters of the matrix solid-phase dispersion extraction were investigated and optimized. The optimized conditions were as follows: silica gel was selected as dispersing sorbent, the ratio of silica gel to sample was selected to be 2:1 (400/200 mg), and 8 mL of 80% methanol was used as elution solvent. Furthermore, a fast and sensitive ultra high performance liquid chromatography with tandem mass spectrometry method was developed for the determination of nine phenolic compounds in E. palustre. This method was carried out within <6 min, and exhibited satisfactory linearity, precision, and recovery. Compared with ultrasound-assisted extraction, the proposed matrix solid-phase dispersion procedure possessed higher extraction efficiency, and was more convenient and time saving with reduced requirements on sample and solvent amounts. All these results suggest that the developed method represents an excellent alternative for the extraction and determination of active components in plant matrices. PMID:25132205

Wei, Zuofu; Pan, Youzhi; Li, Lu; Huang, Yuyang; Qi, Xiaolin; Luo, Meng; Zu, Yuangang; Fu, Yujie

2014-11-01

315

Field method for the determination of hexavalent chromium by ultrasonication and strong anion-exchange solid-phase extraction.  

Science.gov (United States)

A simple, fast, sensitive, and economical field method was developed and evaluated for the determination of hexavalent chromium (CrVI) in environmental and workplace air samples. By means of ultrasonic extraction in combination with a strong anion-exchange solid-phase extraction (SAE-SPE) technique, the filtration, isolation, and determination of CrVI in the presence of trivalent chromium (CrIII) and potential interferents was achieved. The method entails (1) ultrasonication in basic ammonium buffer solution to extract CrVI from environmental matrixes; (2) SAE-SPE to separate CrVI from CrIII and interferences; (3) elution/acidification of the eluate; (4) complexation of chromium with 1,5-diphenylcarbazide; and (5) spectrophotometric determination of the colored chromium-diphenylcarbazone complex. Several critical parameters were optimized in order to effect the extraction of both soluble (K2CrO4) and insoluble (PbCrO4) forms of CrVI without inducing CrIII oxidation or CrVI reduction. The method allowed for the dissolution and purification of CrVI from environmental and workplace air sample matrixes for up to 24 samples simultaneously in less than 90 min (including ultrasonication). The results demonstrated that the method was simple, fast, quantitative, and sufficiently sensitive for the determination of occupational exposures of CrVI. The method is applicable for on-site monitoring of CrVI in environmental and industrial hygiene samples. PMID:10079763

Wang, J; Ashley, K; Marlow, D; England, E C; Carlton, G

1999-03-01

316

A Nanoparticle-based Solid Phase Extraction Method for Liquid Chromatography-Electrospray Ionization-Tandem Mass Spectrometric Analysis  

Science.gov (United States)

A solid-phase extraction (SPE) procedure with the use of superparamagnetic Fe3O4 nanoparticles as extracting agent was developed for HPLC-ESI-MS/MS analysis. Four most heavily used triazine pesticides (herbicides) were taken as the test compounds. The NPs showed an excellent capability to retain the compounds tested, and a quantitative extraction was achieved within 10 min under the testing conditions, i.e. 100 ?L NP solution was added to 400 mL sample in a beaker with stirring. After extraction, the superparamagnetic NPs were easily collected by using an external magnet. Very importantly, analytes retained on the Fe3O4 NPs could be quantitatively recovered by dissolving the NPs with an HCl solution, allowing subsequent HPLC-ESI-MS/MS quantification. A capillary HPLC-ESI-MS/MS method with the present NP-based SPE procedure was developed for the determination of triazines including atrazine, prometryn, terbutryn, and propazine. Atrazine-d5 was used as internal standard. The method had an LOD of 10 pg/mL atrazine, and a linear calibration curve over a range from 30 pg – 50.0 ng/mL. Simultaneous determination of the four triazine pesticides in water samples taken from local lakes was demonstrated. PMID:17723235

Song, Yaru; Zhao, Shulin; Tchounwou, Paul; Liu, Yi-Ming

2007-01-01

317

A nanoparticle-based solid-phase extraction method for liquid chromatography-electrospray ionization-tandem mass spectrometric analysis.  

Science.gov (United States)

A solid-phase extraction (SPE) procedure with the use of superparamagnetic Fe(3)O(4) nanoparticles as extracting agent was developed for HPLC-ESI-MS/MS analysis. Four most heavily used triazine pesticides (herbicides) were taken as the test compounds. The NPs showed an excellent capability to retain the compounds tested, and a quantitative extraction was achieved within 10min under the testing conditions, i.e. 100 microL NP solution was added to 400 mL sample in a beaker with stirring. After extraction, the superparamagnetic NPs were easily collected by using an external magnet. Very importantly, analytes retained on the Fe(3)O(4) NPs could be quantitatively recovered by dissolving the NPs with an HCl solution, allowing subsequent HPLC-ESI-MS/MS quantification. A capillary HPLC-ESI-MS/MS method with the present NP-based SPE procedure was developed for the determination of triazines including atrazine, prometryn, terbutryn, and propazine. Atrazine-d(5) was used as internal standard. The method had an LOD of 10 pg/mL atrazine, and a linear calibration curve over a range from 30 pg to 50.0 ng/mL. Simultaneous determination of the four triazine pesticides in water samples taken from local lakes was demonstrated. PMID:17723235

Song, Yaru; Zhao, Shulin; Tchounwou, Paul; Liu, Yi-Ming

2007-09-28

318

Optimization of hydrophilic interaction liquid chromatography/mass spectrometry and development of solid-phase extraction for the determination of paralytic shellfish poisoning toxins.  

Science.gov (United States)

The combination of hydrophilic interaction liquid chromatography (HILIC) and liquid chromatography/mass spectrometry (LC/MS) for the determination of paralytic shellfish poisoning (PSP) toxins has been proposed for use in routine monitoring of shellfish. In this study, methods for the detection of multiple PSP toxins [saxitoxin (STX), neosaxitoxin (NEO), decarbamoyl saxitoxin (dcSTX), decarbamoyl neosaxitoxin (dcNEO), gonyautoxins 1-5 (GTX1, GTX2, GTX3, GTX4, GTX5), decarbamoyl gonyautoxins (dcGTX2 and dcGTX3), and the N-sulfocarbamoyl C toxins (C1 and C2)] were optimized using single (MS) and triple quadrupole (MS/MS) instruments. Chromatographic separation of the toxins was achieved by using a TSK-gel Amide-80 analytical column, although superior chromatography was observed through application of a ZIC-HILIC column. Preparative procedures used to clean up shellfish extracts and concentrate PSP toxins prior to analysis were investigated. The capacity of computationally designed polymeric (CDP) materials and HILIC solid-phase extraction (SPE) cartridges to retain highly polar PSP toxins was explored. Three CDP materials and 2 HILIC cartridges were assessed for the extraction of PSP toxins from aqueous solution. Screening of the CDPs showed that all tested polymers adsorbed PSP toxins. A variety of elution procedures were examined, with dilute 0.01% acetic acid providing optimum recovery from a CDP based on 2-(trifluoromethyl)acrylic acid as the monomer. ZIC-HILIC SPE cartridges were superior to the PolyLC equivalent, with recoveries ranging from 70 to 112% (ZIC-HILIC) and 0 to 90% (PolyLC) depending on the PSP toxin. It is proposed that optimized SPE and HILIC-MS methods can be applied for the quantitative determination of PSP toxins in shellfish. PMID:19202798

Turrell, Elizabeth; Stobo, Lesley; Lacaze, Jean-Pierre; Piletsky, Sergey; Piletska, Elena

2008-01-01

319

Solid phase extraction-preconcentration and high performance liquid chromatographic determination of 2-mercapto-(benzothiazole, benzoxazole and benzimidazole) using copper oxide nanoparticles.  

Science.gov (United States)

This study introduces a novel method of solid phase extraction (SPE), preconcentration and HPLC determination of 2-mercaptobenzimidazole (2MBI), 2-mercaptobenzoxazole (2MBO) and 2-mercaptobenzothiazole (2MBT) from an aqueous solution by a SPE cartridge loaded with copper oxide nanoparticles. Results demonstrated that copper oxide nanoparticles are quite efficient for extraction and preconcentration of trace amounts of these mercaptans at room temperature. The study also investigated the effects of parameters such as pH, buffer and its volume, electrolyte concentration, flow rate of the test solution, composition and volume of the desorbing solvent, accepted tolerable volume, amount of adsorbent, reusability of cartridges and evidence of some co-existing species on extraction and determination of the above mentioned mercaptans. The method showed good linearity for determination of these mercaptans in the range of 0.01-10 ?g mL(-1) with regression coefficients better than 0.9969. The limits of detection (LODs) evaluations were 0.0021, 0.0027 and 0.0019 ?g mL(-1) for 2MBT, 2MBO and 2MBI, respectively. The relative standard deviations (RSDs) for 0.2 ?g mL(-1) and 5 ?g mL(-1) of the measured mercaptans were below 3.04% and 4.23%, respectively. Ramin Power Plant (3000 MW, Ahvaz, Iran) cooling water containing some 2MBT (as corrosion inhibitor) was used as the real sample. Recovery tests with spiked levels of 2MBT, 2MBI and 2MBO were carried out and satisfied results were obtained. PMID:23953446

Parham, Hooshang; Khoshnam, Farzaneh

2013-09-30

320

Preparation and evaluation of molecularly imprinted solid-phase micro-extraction fibers for selective extraction of phthalates in an aqueous sample  

International Nuclear Information System (INIS)

A novel molecularly imprinted polymer (MIP) that was applied to a solid-phase micro-extraction (SPME) device, which could be coupled directly to gas chromatograph and mass spectrometer (GC/MS), was prepared using dibutyl phthalate (DBP) as the template molecule. The characteristics and application of this fiber were investigated. Electron microscope images indicated that the MIP-coated solid-phase micro-extraction (MI-SPME) fibers were homogeneous and porous. The extraction yield of DBP with the MI-SPME fibers was higher than that of the non-imprinted polymer (NIP)-coated SPME (NI-SPME) fibers. The MI-SPME fibers had a higher selectivity to other phthalates that had similar structures as DBP. A method was developed for the determination of phthalates using MI-SPME fibers coupled with GC/MS. The extraction conditions were optimized. Detection limits for the phthalate samples were within the range of 2.17-20.84 ng L-1. The method was applied to five kinds of phthalates dissolved in spiked aqueous samples and resulted in recoveries of up to 94.54-105.34%, respectively. Thus, the MI-SPME fibers are suitable for the extraction of trace phthalates in complicated samples.

321

Preparation and evaluation of molecularly imprinted solid-phase micro-extraction fibers for selective extraction of phthalates in an aqueous sample  

Energy Technology Data Exchange (ETDEWEB)

A novel molecularly imprinted polymer (MIP) that was applied to a solid-phase micro-extraction (SPME) device, which could be coupled directly to gas chromatograph and mass spectrometer (GC/MS), was prepared using dibutyl phthalate (DBP) as the template molecule. The characteristics and application of this fiber were investigated. Electron microscope images indicated that the MIP-coated solid-phase micro-extraction (MI-SPME) fibers were homogeneous and porous. The extraction yield of DBP with the MI-SPME fibers was higher than that of the non-imprinted polymer (NIP)-coated SPME (NI-SPME) fibers. The MI-SPME fibers had a higher selectivity to other phthalates that had similar structures as DBP. A method was developed for the determination of phthalates using MI-SPME fibers coupled with GC/MS. The extraction conditions were optimized. Detection limits for the phthalate samples were within the range of 2.17-20.84 ng L{sup -1}. The method was applied to five kinds of phthalates dissolved in spiked aqueous samples and resulted in recoveries of up to 94.54-105.34%, respectively. Thus, the MI-SPME fibers are suitable for the extraction of trace phthalates in complicated samples.

He Juan, E-mail: juanhe@haut.edu.cn [School of Chemistry and Chemical Engineering, Henan University of, Technology, LianHua Road, Zhengzhou 450051 (China); Lv Ruihe; Zhan Haijun; Wang Huizhi; Cheng Jie; Lu Kui; Wang Fengcheng [School of Chemistry and Chemical Engineering, Henan University of, Technology, LianHua Road, Zhengzhou 450051 (China)

2010-07-26

322

Preparation and application of sulfaguanidine-imprinted polymer on solid-phase extraction of pharmaceuticals from water.  

Science.gov (United States)

The molecularly imprinted polymers (MIPs) with sulfaguanidine as a template, methacrylic acid, 4-vinylpyridine, and 2-hydroxyethyl methacrylate as functional monomers, ethylene glycol dimethacrylate as a cross-linker and 2,2'-azobis-isobutyronitrile as an initiator have been prepared through the cross-link reaction of polymerization. Solid-phase extraction (SPE) procedure for the extraction of sulfaguanidine from water samples using the prepared MIPs and non-imprinted (NIPs) was evaluated. The best MIP in combination with commercial sorbents was applied for simultaneous extraction of eight pharmaceuticals. New SPE cartridges were prepared by combination of optimal produced MIP and Oasis HLB in 6 mL of polypropilene SPE reservoir. The developed method which includes new SPE cartridge (MIPMAA-Oasis HLB, 400mg/6 mL) and thin-layer chromatography was validated. The method provides a linear response over the concentration range of 0.5-150 ?g/L, depending on the pharmaceutical with the correlation coefficients>0.9843 in all cases except for norfloxacin (0.9770) and penicillin G procaine (0.9801). Also, the method has revealed low limits of detection (0.25-20 ?g/L), good precision (intra and inter-day), a relative standard deviation below 15% and recoveries above 95% for all eight pharmaceuticals. The developed method by using newly prepared SPE cartridge has been successfully applied to the analysis of production wastewater samples from pharmaceutical industry. PMID:25281079

Mutavdži? Pavlovi?, Dragana; Nikši?, Korana; Livazovi?, Sara; Brnardi?, Ivan; Anžlovar, Alojz

2015-01-01

323

[Determination of 23 phthalate esters in food by solid-phase extraction coupled with gas chromatography-mass spectrometry].  

Science.gov (United States)

A method for the simultaneous determination of 23 phthalate esters in food samples by solid-phase extraction coupled with gas chromatography-mass spectrometry (SPE-GC-MS) was developed and evaluated. The samples were extracted with hexane or acetonitrile, and cleaned up with a glass ProElut PSA SPE column. The identification and quantification were performed by GC-MS in selected ion monitoring (SIM) mode. The extraction processes of different foods were investigated. The calibration curves of phthalate esters showed good linearity in the range of 0.05-5 mg/L (0.5-5 mg/L for diisononyl phthalate (DINP), diisodecyl-phthalate (DIDP)) with the correlation coefficients (r) between 0.984 8 and 0.999 6. The limits of detection of phthalate esters in food samples ranged from 0.005 to 0.05 mg/kg (S/N = 3) and the limits of quantification ranged from 0.02 to 0.2 mg/kg (S/N = 10). The average recoveries of 23 analytes spiked in 10 kinds of food matrices ranged from 77% to 112% with the relative standard deviations (RSDs, n = 6) of 4.1%-12.5%. The method is suitable for the determination of 23 phthalate esters simultaneously in foodstuffs with easy operation, high accuracy and precision. PMID:22667087

Zheng, Xianghua; Lin, Liyi; Fang, Enhua; Huang, Yonghui; Zhou, Shuang; Zhou, Yu; Zheng, Xiaoyan; Xu, Dunming

2012-01-01

324

Determination of benzimidazole residues in animal tissue samples by combination of magnetic solid-phase extraction with capillary zone electrophoresis.  

Science.gov (United States)

Benzimidazole drugs (BZDs) comprise a large number of synthetic anthelmintics, which are widely used in food-producing animals for prophylactic and therapeutic purposes. To protect consumers from the risks related to BZDs residues, a simple, rapid, and efficient method for simultaneous determination of ten BZDs in animal tissues samples was developed. This analytical procedure involved extracting samples with magnetic solid-phase extraction (MSPE) using magnetite/silica/poly (methacrylic acid-co-ethylene glycol dimethacrylate) (Fe(3)O(4)/SiO(2)/poly (MAA-co-EGDMA)) magnetic microspheres, and determination by capillary zone electrophoresis (CZE). To improve the sensitivity of the method, we employed the electrokinetic injection with field-amplified sample stacking technique (FASS). Berbine solution was used as internal standard to minimize the fluctuation of analytical results. Under the optimized extraction conditions, good linearities were obtained for the ten BZDs with the correlation coefficients (R(2)) above 0.9920. The limits of detections (LODs) for ten BZDs were 1.05-10.42 ng/g in swine muscle and 1.06-12.61 ng/g in swine liver, respectively. The intra- and inter-day relative standard deviations (RSDs) of the developed method were less than 13.6%. The recoveries of the ten BZDs for the spiked samples ranged from 81.1% to 105.4% with RSDs less than 9.3%. PMID:22284500

Hu, Xi-Zhou; Chen, Ming-Luan; Gao, Qiang; Yu, Qiong-Wei; Feng, Yu-Qi

2012-01-30

325

Improved solid-phase extraction procedure in the analysis of paralytic shellfish poisoning toxins by liquid chromatography with fluorescence detection.  

Science.gov (United States)

The analysis of shellfish extracts for the determination of paralytic shellfish poisoning (PSP) toxins by liquid chromatography with fluorescence detection repeatedly showed the presence of a compound suspected to interfere with gonyautoxin 4. The first aim of this study was to confirm by liquid chromatography coupled to tandem mass spectrometry that this compound was not gonyautoxin 4. The second part of this work was to improve a nonvolumetric C(18) solid-phase extraction (SPE) procedure to evaluate the removal of the interference associated with the recovery of PSP toxins. The cleanup procedure was modified into a volumetric SPE procedure and proved to efficiently and totally remove the interference while recovering from 78 to 85% of the PSP toxins available as commercial standards (saxitoxin, neosaxitoxin, gonyautoxins 1-4) and considered as major PSP toxins in human intoxication, with 85% recovery for gonyautoxin 4. The efficiency of this cleanup procedure was checked on shellfish extracts containing this interference and originating from France and Turkey. PMID:14558751

Biré, Ronel; Krys, Sophie; Frémy, Jean-Marc; Dragacci, Sylviane

2003-10-22

326

Capillary electrophoresis with amperometric detection of curcumin in Chinese herbal medicine pretreated by solid-phase extraction.  

Science.gov (United States)

In the present study, curcumin from Chinese herbal medicine turmeric was determined by capillary electrophoresis with amperometric detection (CE-AD) pretreated by a self-designed, simple, inexpensive solid-phase extraction (SPE) cartridge based on the material of tributyl phosphate resin. An average concentration factor of 9 with the recovery of > 80% was achieved when applied to the analysis of curcumin in extracts of tumeric. Under the optimized CE-AD conditions: a running buffer composed of 15 mM phosphate buffer at a pH 9.7, separation voltage at 16 kV, injection for 6 s at 9 kV and detection at 1.20 V, CE-AD with SPE exhibited low detection limit as 3 x 10(-8) mol/l (S/N = 3), high efficiency of 1.0 x 10(5) N, linear range of 7 x 10(-4) -3 x 10(-6) mol/l (r = 0.9986) for curcumin extracted from light petroleum. The method developed resulted in enhancement of the detection sensitivity and reduction of interference from sample matrix in complicated samples and exhibited the potential application for routine analysis, especially in food, because a relatively complete process of sample treatment and analysis was described. PMID:12198956

Sun, Xiuhua; Gao, Changlu; Cao, Weidong; Yang, Xiurong; Wang, Erkang

2002-07-12

327

SOLID PHASE EXTRACTION OF Cd(II) AND Pb(II) IONS BY A NEW CARBOTHIOAMIDE DERIVATIVE  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in english An effective, simple, low cost and accurate sorption-spectrophotometric platform for the extractions and subsequent quantifications of Cd(II) and Pb(II) ions in food and environmental samples has been described in this dissertation. The separation and preconcentration of the analyte ions were accomp [...] lished by solid phase extraction method based on the adsorption of their N-(4-methylphenyl)-2-{[(4-phenyl-5-pyridin-4-yl-H-1,2,4-triazol-3-yl)thio]acetyl} hydrazinecarbothioamide (MFPTAHK) complex on Amberlite XAD-8 resin in a mini column. The developed method was systematically investigated in different set of experimental parameters that influence the separation and preconcentration of Cd(II) and Pb(II) ions. The precision of the method was determined by reproducibility studies and expressed as relative standard deviations (RSD %) which were less than 4% for both analyte ions. The limits of detections (LODs) for Cd(II) and Pb(II) ions based on the three times the standard deviation of the blanks (N:10) were found to be 0.31 ?g L-1 and 0.86 ?g L-1, respectively. The developed SPE procedure was utilized for the simultaneous extraction and determinations of Cd(II) and Pb(II) ions levels in rice, cracked wheat and red lentil as food samples and various water samples.

DUYGU, OZDES; CELAL, DURAN; HACER, BAYRAK; HUSEYIN, SERENCAM; HASAN, BASRI SENTURK.

2204-22-01

328

Fast Determination of 22 Pesticides in Rice Wine by Dispersive Solid-Phase Extraction in Combination with GC-MS  

Directory of Open Access Journals (Sweden)

Full Text Available A rapid method was developed for the determination of 22 pesticides in rice wine. The procedure involved an extraction with acetonitrile and a cleanup step using dispersive solid-phase extraction (d-SPE, and primary-secondary amine (PSA and octadecylsilane (ODS were used as sorbents. D-SPE had some advantages over some traditional prepara- tions, especially in time and cost. Both the extraction and cleanup only cost about 15 min per a sample. Then the GC-MS was used for quantitative and qualitative analysis. Matrix-matched standards solution and analyte protectant were compared to decrease the matrix effect, and the former showed a better efficacy. Acceptable linearity was achieved in the range of 0.05 - 0.30 mg/L. After matrix-matched standards calibration, recoveries were between 60 and 140%. For the most of pesticides, precision and repeatability were less than 10% and 16%, respectively. The result indicated that the developed method was suitable for the determination of the multi-pesticides in rice wine.

Zhenghe Xiong

2012-01-01

329

Chitosan-poly(m-phenylenediamine)@Fe?O? nanocomposite for magnetic solid-phase extraction of polychlorinated biphenyls from water samples.  

Science.gov (United States)

A extraction medium based on chitosan-poly(m-phenylenediamine) (CS-PPD) @Fe3O4 nanocomposite was synthesized by chemical polymerization of m-phenylenediamine in the presence of chitosan coated magnetic nanocomposite, and for the first time, used as the sorbent for the magnetic solid-phase extraction (MSPE) of seven polychlorinated biphenyls (PCB28, PCB52, PCB101, PCB118, PCB138, PCB153, and PCB180) at trace levels in water samples. Gas chromatography-triple quadrupole mass spectrometry (GC-MS/MS) was used for PCBs quantification and detection. Several factors related to MSPE efficiencies, such as type and amount of sorbent, extraction time, sample pH, and desorption conditions were investigated. Under the optimized conditions, an excellent linearity was observed in the range of 1.0-200 ng L(-1) for PCB180, 0.5-200 ng L(-1) for the other six PCBs with the correlation coefficients ranging from 0.9954 to 0.9993. The good recoveries at spiked levels of 10.0, 20.0, and 50.0 ng L(-1) were obtained in the range of 94%-108%, and the coefficients of variations were less than 6%. The proposed method was feasible, rapid, and easy to operate for the trace analysis of the PCBs in local aquaculture water, livestock breeding water, and sewage water samples. PMID:25342296

Liao, Qie Gen; Wang, Dong Gen; Luo, Lin Guang

2014-11-01

330

Sol-gel approach for fabrication of coated anodized titanium wire for solid-phase microextraction: highly efficient adsorbents for enrichment of trace polar analytes.  

Science.gov (United States)

Nanotubular titania film was prepared in situ on titanium wire and was used as the fiber substrate for solid-phase microextraction (SPME) because of its high surface-to-volume ratio, easy preparation, and mechanical stability. Three different functional coatings, ?-cyclodextrin (?-CD), ?-cyclodextrin-co-poly(ethylenepropylene glycol) (?-CD/PEG), and polyethylene glycol (PEG)-based sorbents were chemically bonded to the nanostructured wire surface via sol-gel technology to further enhance the absorbing capability and extraction selectivity. Coupled to gas chromatography-flame ionic detection (GC-FID), the prepared SPME fibers were investigated using diverse compounds. The results indicated that the fibers showed good mechanical strength, excellent thermal stability, and wonderful capacity and selectivity to polar compounds, including polar aromatic compounds, alcohols, and ketones. Combining the superior hydrophilic property of a bonded functional molecule and the highly porous structure of a fiber coating, the prepared PEG-coated SPME fiber showed much higher adsorption affinity to ephedrine and methylephedrine than ?-CD and ?-CD/PEG fibers. The as-established PEG-coated SPME-GC analytical method provided excellent sensitivity (LODs, 0.004 and 0.001 ng mL(-1) for ephedrine and methylephedrine, respectively) and better linear range (0.01-2 000 ?g L(-1)). In addition, it has surprising repeatability and reproducibility. Finally, the present approach was used to analyze ephedrine and methylephedrine from real urine samples, and reliable results were obtained. PMID:24682230

Jia, Jing; Xu, Lili; Wang, Shuai; Wang, Licheng; Liu, Xia

2014-05-01

331

Quaternary ammonium-functionalized silica sorbents for the solid-phase extraction of aromatic amines under normal phase conditions.  

Science.gov (United States)

Quaternary ammonium-functionalized silica materials were synthesized and applied for solid-phase extraction (SPE) of aromatic amines, which are classified as priority pollutants by US Environmental Protection Agency. Hexamethylenetetramine used for silica surface modification for the first time was employed as SPE sorbent under normal phase conditions. Hexaminium-functionalized silica demonstrated excellent extraction efficiencies for o-toluidine, 4-ethylaniline and quinoline (recoveries 101-107%), while for N,N-dimethylaniline and N-isopropylaniline recoveries were from low to moderate (14-46%). In addition, the suitability of 1-alkyl-3-(propyl-3-sulfonate) imidazolium-functionalized silica as SPE sorbent was tested under normal phase conditions. The recoveries achieved for the five aromatic amines ranged from 89 to 99%. The stability of the sorbent was evaluated during and after 150 extractions. Coefficients of variation between 4.5 and 10.2% proved a high stability of the synthesized sorbent. Elution was carried out using acetonitrile in the case of hexaminium-functionalized silica and water for 1-alkyl-3-(propyl-3-sulfonate) imidazolium-functionalized silica sorbent. After the extraction the analytes were separated and detected by liquid chromatography ultraviolet detection (LC-UV). The retention mechanism of the materials was primarily based on polar hydrogen bonding and ?-? interactions. Comparison made with activated silica proved the quaternary ammonium-functionalized materials to offer different selectivity and better extraction efficiencies for aromatic amines. Finally, 1-alkyl-3-(propyl-3-sulfonate) imidazolium-functionalized silica sorbent was successfully tested for the extraction of wastewater and soil samples. PMID:23473515

Vidal, Lorena; Robin, Orlane; Parshintsev, Jevgeni; Mikkola, Jyri-Pekka; Riekkola, Marja-Liisa

2013-04-12

332

Dispersive micro-solid-phase extraction of benzodiazepines from biological fluids based on polyaniline/magnetic nanoparticles composite.  

Science.gov (United States)

In this study, diverse types of Fe3O4 nanocomposites modified by polyaniline, polypyrrole, and aniline-pyrrole copolymer were synthesized through chemical oxidative polymerization process for dispersive-?-solid phase extraction (D-?-SPE) in the presence of various dopants. The results showed that the nanocomposite modified by polyaniline with p-toluene sulfonic acid as a dopant demonstrated higher extraction efficiency for lorazepam (LRZ) and nitrazepam (NRZ). Also the synthesized magnetic sorbents were characterized. The nanocomposite sorbent in combination with high performance liquid chromatography-UV detection was applied for the extraction, preconcentration and determination of lorazepam and nitrazepam in urine and plasma samples. Different parameters influencing the extraction efficiency including: sample pH, amount of sorbent, sorption time, elution solvent and its volume, salt content, and elution time were optimized. The obtained optimal conditions were: sample pH, 6; amount of sorbent, 5 mg; sorption time, 5.0 min; elution solvent and its volume, 0.5 mM cethyltrimethyl ammonium bromide in acetonitrile, 150 ?L; elution time, 2.0 min and without addition of NaCl. The calibration curves were linear in the concentration range of 1-2000 ?g L(-1). The limits of detection (LODs) were achieved in the range of 0.5-1.8 ?g L(-1) for NRZ and 0.2-2.0 ?g L(-1) for LRZ, respectively. The percent of extraction recoveries and relative standard deviations (n=5) were in the range of 84.0-99.0, 6.1-7.8 for NRZ and 90.0-99.0, 4.1-7.0 for LRZ, respectively. Ultimately, the applicability of the method was successfully confirmed by the extraction and determination of NRZ and LRZ in human urine and plasma samples. PMID:25172820

Asgharinezhad, Ali Akbar; Ebrahimzadeh, Homeira; Mirbabaei, Fatemeh; Mollazadeh, Narges; Shekari, Nafiseh

2014-09-24

333

Solid phase extraction of actinides using polymeric beads impregnated with TODGA  

International Nuclear Information System (INIS)

Separation of minor actinides from HLW is necessary prior to the vitrification of the latter in the glass matrix. A number of solvent extraction processes such as TRUEX, TRPO and DIAMEX have been developed which employed CMPO, TRPO and DMDBTDMA, respectively as the extractants for minor actinides. Recently, TODGA has been found to be most efficient extractant of minor actinides due to its ability to form stronger complexes. In view of large solvent inventory in the solvent extraction methods, extraction chromatography based separation methods which utilize very small amounts of the extractant can be used as an alternative technique. However, the main drawback of such separation methods is slow deterioration of the uptake efficiency due to leaching out of the extractants. Therefore, use of extractant blended polymeric beads can have faster metal ion uptake while having longer reusability of the beads. There have been several reports on the preparation of polymeric beads for metal ion sorption. In present paper, uptake of actinide ion by polymeric beads containing four different proportions of TODGA was studied. The polymeric beads were used for the experiments involving the uptake of Am(III) at different nitric acid concentration at tracer scale and the results are listed. It was found that Kd values were in the range of 1x104 to 2x104 in the given range of acidity. The results are in sharp contrast with the results obtained with the extraction chromatographic resin used in a previous study. We have also carried out actinide ion uptake studies involving the kinetics of metal ion sorption, adsorption isotherm and column studies. The metal ion sorption capacities for Eu (III) were found to be 6.6(±0.3), 9.1 (±0.5), 20.4 (±1.2), and 22.3(±1.4), for the above four resins, respectively. Column studies were also carried out using 6 ml of bed volume, columns containing about 0.6 to 0.7 gm of resin. The breaks through profiles were obtained using 0.01 M EDTA as the eluent

334

Solid phase extraction of actinides using polymeric beads impregnated with TODGA  

International Nuclear Information System (INIS)

137Cs is one of the major radionuclides contributing to the activity of the high level waste (HLW) and its separation facilitates the safe disposal of the latter in deep geological repository as vitrified mass. The global inventory of 137Cs was estimated to be around 3.7x1014 kBq in 2010. Due to its long half-life and reasonable gamma energy (661 keV), 137Cs it has potential application as a radiation source in gamma irradiators in the environmental pollution control, food preservation and sterilization of medical accessories. It is, therefore, required to develop efficient separation methods for its recovery from HLW. We have recently reported that solvent system containing calix(4)arene-crown-6 ligands in FS-13 have yielded much improved extraction of radio-cesium as compared to analogous solvent systems containing nitrobenzene as the diluents. Our studies involving four different calix-bis-crown-6 and calix-mono-crown-6 ligands have indicated that calix(4)arene-dibenzo-bis-crown-6 (CBC) ligands were better suited due to more favourable extraction of Cs(I) and radiolytic stability of the ligand. In the present study, we have tried use the developed solvent system for the recovery of radio-cesium (137Cs and 134Cs) from actual high level waste (HLW). The HLW, containing a total activity of 100 Ci/L also contained 3.85 g/L U and 7.09 mg/L Pu which were removed by contacting the waste solution twice with 30% TBP in n-dodecane in a hot-cell facility. The raffinate from the TBP extraction step contained negligible amounts of the actinides and was subsequently contacted four times with 1.0x10-3 M CBC in FS-13 (each time with fresh organic phase) in the hot-cell facility and the extraction results indicated 137Cs to remain in the raffinate out of 15.88 Ci/L suggesting ? 97% extraction in 4 stages. Quantitative extraction can be done by increasing the number of stages. It was interesting to note that none of the other radionuclides, such as 144Ce, 106Ru, 95Zr, 95Nb, 90Y and 90Sr were extracted to any measurable extent. Stripping of the extracted radio-cesium was made possible in four stages by contacting the organic extracts with equal volumes of de-ionized water

335

Solid-phase extraction-spectrophotometric determination of uranium(VI) in natural waters  

Energy Technology Data Exchange (ETDEWEB)

A method for the extraction and determination of uranyl ion in natural waters using octadecyl bonded silica membrane disks modified with piroxicam and spectrophotometry with arsenazo(III) is proposed. The perconcentration step was studied with regard to experimental parameters such as amount of extractant, type and amount of eluent, pH, flow rates and tolerance limit of diverse ions on the recovery of uranyl ion. The limit of detection of the proposed method is 0.4 {mu}g L{sup -1} of uranyl. The method was applied to the recovery of uranyl from different water samples. (orig.)

Sadeghi, Susan; Mohammadzadeh, Darush [Department of Chemistry, University of Birjand, Birjand (Iran); Yamini, Yadollah [Department of Chemistry, Tarbiat Moddars University, Tehran (Iran)

2003-03-01

336

Comparison of liquid-liquid extraction, solid-phase extraction and co-precipitation preconcentration methods for the determination of cadmium, copper, nickel, lead and zinc in seawater  

International Nuclear Information System (INIS)

Three major types of pre-concentration methods were evaluated and optimised for the extraction and determination of Cd, Cu, Ni, Pb and Zn from seawater samples. The traditional APDC/DDDC-Freon liquid-liquid extraction method showed excellent results for a multi-elemental analysis. However, the technique is labour consuming, very sensitive to operational conditions, employs environmentally unsafe and expensive solvents and requires large sample volumes. In the solid phase extraction method, the performances of a traditional Amberlite XAD-4 and a novel Dowex Optipore V-493 were evaluated. Application of Dowex Optipore V-493 resin provided better results at low concentrations than the generally used Amberlite XAD-4 resin using low sample volumes. However, the presence of natural organic compounds may decrease extraction efficiency of both resins for Cu. Thus, a pre-treatment with UV irradiation is advantageous for samples with high organic content. Cobalt co-precipitation methods showed good Cu and Ni recoveries, but gave poor results for Cd at low concentrations. In addition, high sample volumes are required. Both solid phase and co-precipitation methods showed unsatisfactory results in determination of Pb. Finally, a summary of methods advantages are given for choosing the most suitable method

337

A simple method for nicardipine hydrochloride quantification in plasma using solid-phase extraction and reversed-phase high-performance liquid chromatography  

OpenAIRE

A simple and sensitive reversed-phase liquid chromatography method was developed and validated for the determination of nicardipine hydrochloride (NC) in rabbit plasma. Nicardipine hydrochloride and nimodipine, used as internal standard, were initially extracted from plasma by a rapid solid-phase extraction using C18 cartridges. After extraction, nicardipine hydrochloride was separated by HPLC on a C18 column and quantified by ultraviolet detection at 254 nm. A mixture of acetonitrile-0.02 ...

Fernandes, Catarina Marques; Veiga, Francisco Jose? Baptista

2003-01-01

338

Determination of the Antibiotic Oxytetracycline in Commercial Milk by Solid-Phase Extraction: A High-Performance Liquid Chromatography (HPLC) Experiment for Quantitative Instrumental Analysis  

Science.gov (United States)

Trace levels of oxytetracylcine spiked into commercial milk samples are extracted, cleaned up, and preconcentrated using a C[subscript 18] solid-phase extraction column. The extract is then analyzed by a high-performance liquid chromatography (HPLC) instrument equipped with a UV detector and a C[subscript 18] column (150 mm x 4.6 mm x 3.5 [mu]m).…

Mei-Ratliff, Yuan

2012-01-01

339

Forensic analysis of high explosives residues in post-blast water samples employing solid phase extraction for analyte pro-concentration  

International Nuclear Information System (INIS)

Nitro aromatic, nitramine and nitrate ester compounds are a major group of high order explosive or better known as military explosives. Octahydro-1,3,5,7-tetrazocine (HMX), 1,3,5-hexahydro-1,3,5-trinitro triazine (RDX), 2,4,6-trinitro-toluene (TNT), pentaerythritol tetranitrate (PETN) and 2,4-dinitrotoluene (2,4-DNT) are secondary high explosives classified as most commonly used explosives components. There is an increasing demand for pre-concentration of these compounds in water samples as the sensitivity achieved by instrumental analytical methods for these high explosives residues are the main drawback in the application at trace levels for forensic analysis. Hence, a simple cartridge solid phase extraction (SPE) procedure was optimized as the off-line extraction and pre-concentration method to enhance the detection limit of high explosive residues using micellar electrokinetic chromatography (MEKC) and gas chromatography with electron-capture detection (GC-ECD) methods. The SPE cartridges utilized LiChrolut EN as the SPE adsorbent. By emplying pre-concentration using SPE, the detection limits of the target analytes in water sample were lowered by more than 1000 times with good percentage recovery (>87%) for MEKC method and lowered by 120 times with more than 2 % percentage recovery for GC-ECD methods. In order to test the feasibility of the developed method to real cases, post-blast water samples were analyzed. The post-blast water samples which were collected froast water samples which were collected from Baling Bom training range, Ulu Kinta, Perak contained RDX and PETN in the range of 0.05 - 0.17 ppm and 0.0124 - 0.0390 ppm respectively. (author)

340

Development of colorimetric solid phase extraction (C-SPE) for in-flight monitoring of spacecraft water supplies  

Science.gov (United States)

Colorimetric solid phase extraction (C-SPE) is a sorption-spectrophotometric technique that combines colorimetric reagents, solid phase extraction, and diffuse reflectance spectroscopy to quantify trace analytes in water samples. In C-SPE, a syringe is used to meter a known volume of sample through a membrane impregnated with a selective colorimetric reagent along with any additives required to optimize the complexation of the reagent and analyte. As the sample is passed through the membrane, analytes are extracted and complexed, leading to a detectable change in the optical characteristics of the membrane. The analyte-reagent complex is then quantified directly on the membrane, using a hand-held diffuse reflectance spectrophotometer. This dissertation focuses on the development, ground testing, and microgravity flight demonstration of C-SPE methods to meet the near- and long-term water quality monitoring needs of NASA. To this end, the ability of C-SPE to function in a microgravity environment was tested through performance evaluations of methods for the determination of the biocidal agents silver(I) and iodine on the KC-135 microgravity simulator. The biocidal iodine platform was investigated further to determine which iodine species is responsible for the C-SPE signal. Through systematic comparisons of C-SPE results and UV-Visible absorbance studies it was determined that biocidally active I2 is the iodine species complexed by poly(vinylpyrrolidone). The application of C-SPE to additional target water quality parameters is demonstrated through the determination of nickel(II), a metal leachate found in archived water samples from the International Space Station, using dimethylglyoxime. This method introduced a new variation of C-SPE, the quantification of trace analytes based on the collection of an insoluble, colored precipitate. The nickel(II) method was then combined with the method for biocidal silver(I) and a new method to measure sample pH to create a multiplexed C-SPE platform. This invention is presented as an approach to increase the collection of on-orbit water quality data collected without requiring additional crew time. The dissertation is concluded with a summation of the current work and a look at future directions.

Gazda, Daniel Bryan

2004-12-01

341

Detection of urinary creatinine using gold nanoparticles after solid phase extraction.  

Science.gov (United States)

Label-free gold nanoparticles (AuNPs) were utilized in the detection of creatinine in human urine after a sample preparation by extraction of creatinine on sulfonic acid functionalized silica gel. With the proposed sample preparation method, the interfering effects of the urine matrix on creatinine detection by AuNPs were eliminated. Parameters affecting creatinine extraction were investigated. The aggregation of AuNPs induced by creatinine resulted in a change in the surface plasmon resonance signal with a concomitant color change that could be observed by the naked eye and quantified spectrometrically. The effect of AuNP concentration and reaction time on AuNP aggregation was investigated. The method described herein provides a determination of creatinine in a range of 15-40mgL(-1) with a detection limit of 13.7mgL(-1) and it was successfully used in the detection of creatinine in human urine samples. PMID:25546357

Sittiwong, Jarinya; Unob, Fuangfa

2015-03-01

342

Solid phase extraction and reversed-phase high performance liquid chromatography of homidium in animal tissues  

International Nuclear Information System (INIS)

Homidium bromide, an antitrypanosomal drug, has been in use for about 40 years both for chemotherapy and limited chemoprophylaxis but no specific and accurate method for its detection at sub-microgram levels in tissues is available. The HPLC method described uses C18 reversed phase analytical column with UV detection after basic sample extraction and clean-up on a 3 ml cyano Bond Elut disposable extraction column. Drug recoveries of up to 80% were obtained in the extracts. All tissues analysed were from animals treated with 14C labelled homidium at a dose of 1 mg/kg body weight and slaughtered at 14, 21 and 28 days after treatment. Recoveries were determined by comparing radiometric and HPLC results. The advantage of this procedure was that large amounts of samples could be processed especially from tissues with low drug levels. The detection limit was 50 ng per gram wet tissue. This method is simple, fast, accurate and sufficiently sensitive to be used for monitoring drug levels in meat destined for human consumption. (author). 3 refs, 4 figs, 6 tabs

343

DEVELOPMENT OF METHOD 535 FOR THE DETERMINATION OF CHLOROACETANILIDE AND OTHER ACETAMIDE HERBICIDE DEGRADATES IN DRINKING WATER BY SOLID PHASE EXTRACTION AND LIQUID CHROMATOGRAPHY/TANDEM MASS SPECTROMETRY  

Science.gov (United States)

EPA Method 535 has been developed in order to provide a method for the analysis of "Alachlor ESA and other acetanilide degradation products" which are listed on U.S. EPA's 1998 Drinking Water Contaminant Candidate List. Method 535 uses solid phase extraction with a nonporous gr...

344

Determination of quinolone residues in infant and young children powdered milk combining solid-phase extraction and ultra-performance liquid chromatography–tandem mass spectrometry  

OpenAIRE

The present work describes a method based on solid-phase extraction (SPE) and ultra-performance liquid chromatography tandem mass spectrometry (UPLC–MS/MS) for the simultaneous determination of three quinolones (pipemidic acid, oxolinic acid and flumequine) and twelve fluoroquinolones (marbofloxacin, fleroxacin, pefloxacin, levofloxacin, norfloxacin, ciprofloxacin, enrofloxacin, danofloxacin, lomefloxacin, difloxacin, sarafloxacin, and moxifloxacin) in different infant and young children po...

Herrera-herrera, Antonio V.; Herna?ndez-borges, Javier; Rodri?guez-delgado, Miguel A.; Herrero, Miguel; Cifuentes, Alejandro

2011-01-01

345

Methods of analysis by the U. S. Geological Survey National Water Quality Laboratory - determination of organonitrogen herbicides in water by solid-phase extraction and capillary-column gas chromatography/mass spectrometry with selected-ion monitoring  

Science.gov (United States)

A method for the isolation of organonitrogen herbicides from natural water samples using solid-phase extraction and analysis by capillary-column gas chromatography/mass spectrometry with selected-ion monitoring is described. Water samples are filtered to remove suspended particulate matter and then are pumped through disposable solid-phase extraction cartridges containing octadecyl-bonded porous silica to remove the herbicides. The cartridges are dried using carbon dioxide, and adsorbed herbicides are removed from the cartridges by elution with 1.8 milliliters of hexaneisopropanol (3:1). Extracts of the eluants are analyzed by capillary-column gas chromatography/mass spectrometry with selected-ion monitoring of at least three characteristic ions. The method detection limits are dependent on sample matrix and each particular herbicide. The method detection limits, based on a 100-milliliter sample size, range from 0.02 to 0.25 microgram per liter. Recoveries averaged 80 to 115 percent for the 23 herbicides and 2 metabolites in 1 reagent-water and 2 natural-water samples fortified at levels of 0.2 and 2.0 micrograms per liter.

Sandstrom, Mark W.; Wydoski, Duane S.; Schroeder, Michael P.; Zamboni, Jana L.; Foreman, William T.

1992-01-01

346

Molecularly imprinted solid-phase extraction for determination of tilmicosin in feed using high performance liquid chromatography.  

Science.gov (United States)

A simple, sensitive and reproducible molecularly imprinted solid-phase extraction (MISPE) coupled with high performance liquid chromatographic method was developed for monitoring tilmicosin in feeds. The polymers were prepared using tylosin as mimic template molecule, methacrylic acid as functional monomer and ethylene glycol dimethacrylate as cross-linking monomer, and chloroform as a solvent by bulk polymerization. Under the optimum MISPE conditions, the novel polymer sorbent can selectively extract and enrich tilmicosin from variety of feeds. The MISPE cartridge was better than non-imprinted, C(18) and HLB cartridges in terms of both recovery and precision. Mean recoveries of tilmicosin from five kinds of feeds spiked at 1, 10 and 50 mg kg(-1) ranged from 76.9% to 95.6%, with intra-day and inter-day relative standard deviation less than 7.6%. The linearity was ranged from 1.0 to 100 mg L(-1) for matrix standard solution (r=0.9990). The limit of detection was approximately 0.35 mg kg(-1) and the limit of quantification was approximately 0.98 mg kg(-1). There was cleaner chromatogram by using MISPE than C(18) and HLB SPE. PMID:21435486

Zheng, Yaqiu; Liu, Yahong; Guo, Hongbin; He, Limin; Fang, Binghu; Zeng, Zhenling

2011-04-01

347

Chemical identification strategies using liquid chromatography-photodiode array-solid-phase extraction-nuclear magnetic resonance/mass spectrometry.  

Science.gov (United States)

The identification of metabolites in biochemical studies is a major bottleneck in the proliferating field of metabolomics. In particular in plant metabolomics, given the diversity and abundance of endogenous secondary metabolites in plants, the identification of these is not only challenging but also essential to understanding their biological role in the plant, and their value to quality and nutritional attributes as food crops. With the new generation of analytical technologies, in which liquid chromatography (LC)-mass spectrometry (MS) and nuclear magnetic resonance (NMR) play a pioneering role, profiling metabolites in complex extracts is feasible at high throughput. However, the identification of key metabolites remains a limitation given the analytical effort necessary for traditional structural elucidation strategies. The hyphenation of LC-solid phase extraction (SPE)-NMR is a powerful analytical platform for isolating and concentrating metabolites for unequivocal identification by NMR measurements. The combination with LC-MS is a relatively straightforward approach to obtaining all necessary information for structural elucidation. Using this set-up, we could, as an example, readily identify five related glycosylated phenolic acids present in broccoli (Brassica oleracea, group Italica, cv Monaco): 1,2-di-O-E-sinapoyl-?-gentiobiose, 1-O-E-sinapoyl-2-O-E-feruloyl-?-gentiobiose, 1,2-di-O-E-feruloyl-?-gentiobiose, 1,2,2'-tri-O-E-sinapoyl-?-gentiobiose, and 1,2'-di-O-E-sinapoyl-2-O-E-feruloyl-?-gentiobiose. PMID:22351183

Moco, Sofia; Vervoort, Jacques

2012-01-01

348

Determination of aliphatic amines in water by liquid chromatography using solid-phase extraction cartridges for preconcentration and derivatization.  

Science.gov (United States)

Bond Elut C18 solid-phase extraction cartridges were used for preconcentration and pre-column derivatization with 3,5-dinitrobenzoyl chloride (DNB) of aliphatic amines in water. Conditions for analyte preconcentration and derivatization (including the volume of sample, concentration of reagent, time of reaction and pH) were investigated, using ethylamine, isopropylamine and dimethylamine as model compounds. On the basis of these studies, a rapid and sensitive method for the determination of aliphatic amines in water is presented. The analytes are retained and purified on the cartridges and then derivatized and desorbed by drawing in succession the DNB solution and acetonitrile. The collected extracts are subsequently chromatographed in a Hypersil ODS C18 column using acetonitrile-water for elution. The DNB derivatives are monitored at 230 nm. The method provides satisfactory reproducibility and linearity within the 0.050-1.0 mg l(-1) concentration interval, the limits of detection being 2-5 microg l(-1). Analyte recoveries were in the 70-102% range, whereas the conversion yields compared with those observed for the solution derivatization were in the 79-107% range. The total analysis time (sample treatment plus chromatography) was about 15 min. The method was applied to the determination of ethylamine, isopropylamine and dimethylamine in tap and river waters. PMID:11693606

Verdú-Andrés, J; Campíns-Falcó, P; Herráez-Hernández, R

2001-10-01

349

Determination of selected phenothiazines in human plasma by solid-phase extraction and liquid chromatography with coulometric detection.  

Science.gov (United States)

A new analytical method, based on liquid chromatography with coulometric detection, has been developed and applied to the determination of selected phenothiazines (chlorpromazine, promazine, fluphenazine and levomepromazine) in human plasma. The drugs were separated on a Discovery pentafluorophenylpropyl column, using a mobile phase composed of acetonitrile (32%) and a pH 1.9 phosphate buffer (68%). Promethazine was used as the internal standard. Detection was carried out at an oxidation potential of +0.500 V. A novel clean-up procedure was developed by means of solid-phase extraction, using cyanopropyl cartridges, which gave good extraction yield for all the analytes, with absolute recovery values higher than 91.0%. The detector response was linear over a plasma concentration range of 0.5-250.0 ng mL(-1) for chlorpromazine, promazine and levomepromazine and of 0.2-4.0 ng mL(-1) for fluphenazine. Precision results, expressed by the intra-day and the inter-day relative standard deviation values, were good, being lower than 3.9%. Accuracy data were satisfactory as well. The method has been successfully applied to the analysis of drug plasma levels of psychiatric patients undergoing therapy with selected phenothiazines. PMID:18706338

Saracino, Maria Addolorata; Amore, Mario; Baioni, Elena; Petio, Carmine; Raggi, Maria Augusta

2008-08-29

350

Screening for anabolic steroids in urine of forensic cases using fully automated solid phase extraction and LC-MS-MS.  

Science.gov (United States)

A screening method for 18 frequently measured exogenous anabolic steroids and the testosterone/epitestosterone (T/E) ratio in forensic cases has been developed and validated. The method involves a fully automated sample preparation including enzyme treatment, addition of internal standards and solid phase extraction followed by analysis by liquid chromatography-tandem mass spectrometry (LC-MS-MS) using electrospray ionization with adduct formation for two compounds. Urine samples from 580 forensic cases were analyzed to determine the T/E ratio and occurrence of exogenous anabolic steroids. Extraction recoveries ranged from 77 to 95%, matrix effects from 48 to 78%, overall process efficiencies from 40 to 54% and the lower limit of identification ranged from 2 to 40 ng/mL. In the 580 urine samples analyzed from routine forensic cases, 17 (2.9%) were found positive for one or more anabolic steroids. Only seven different steroids including testosterone were found in the material, suggesting that only a small number of common steroids are likely to occur in a forensic context. The steroids were often in high concentrations (>100 ng/mL), and a combination of steroids and/or other drugs of abuse were seen in the majority of cases. The method presented serves as a fast and automated screening procedure, proving the suitability of LC-MS-MS for analyzing anabolic steroids. PMID:25104076

Andersen, David W; Linnet, Kristian

2014-01-01

351

Determination of phthalates released from paper packaging materials by solid-phase extraction-high-performance liquid chromatography.  

Science.gov (United States)

A solid phase extraction (SPE) high-performance liquid chromatography (HPLC) method was developed for the simultaneous determination of 10 phthalic acid esters (dimethyl phthalate, diethyl phthalate, dipropyl phthalate, benzylbutyl phthalate, diisobutyl phthalate, dicyclohexyl phthalate, diamyl phthalate, di-n-hexyl phthalate, di-n-octyl phthalate and di-2-ethylhexyl phthalate) released from food paper packaging materials. The use of distilled water, 3% acetic acid (w/v), 10% ethanol (v/v) and 95% ethanol (v/v) instead of the different types of food simulated the migration of 10 phthalic acid esters from food paper packaging materials; the phthalic acid esters in four food simulants were enriched and purified by a C18 SPE column and nitrogen blowing, and quantified by HPLC with a diode array detector. The chromatographic conditions and extraction conditions were optimized and all 10 of the phthalate acid esters had a maximum absorbance at 224 nm. The method showed limitations of detection in the range of 6.0-23.8 ng/mL the correlation coefficients were greater than 0.9999 in all cases, recovery values ranged between 71.27 and 106.97% at spiking levels of 30, 60 and 90 ng/mL and relative standard deviation values ranged from 0.86 to 8.00%. The method was considered to be simple, fast and reliable for a study on the migration of these 10 phthalic acid esters from food paper packaging materials into food. PMID:23661671

Gao, Xin; Yang, Bofeng; Tang, Zhixu; Luo, Xin; Wang, Fengmei; Xu, Hui; Cai, Xue

2014-01-01

352

Determination of triazine herbicides in fruits and vegetables using dispersive solid-phase extraction coupled with LC-MS.  

Science.gov (United States)

A simple, rapid, and sensitive liquid chromatography-mass spectrometry (LC-MS) method was successfully developed for the determination of three chloro-s-triazine herbicides, viz. atrazine, simazine, and propazine, two thiomethyl-s-triazine ones, viz. ametryn and prometryn, and prometon in fruits and vegetables. The instrumental parameters affecting LC separation and MS detection were investigated and the best conditions were selected. Samples were extracted and purified by dispersive solid-phase extraction (dispersive-SPE) with a primary-secondary amine sorbent. Three typical representative samples (luffa, broad bean, and grape) were selected to investigate the effect of different matrices on pesticide recoveries and assay precision after spiking at 0.05 mg/kg. Matrix composition did not interfere significantly with the determination of these pesticides. The recoveries were, with a few exceptions, in the range of 80-110% with relative standard deviations less than 10% (n = 5). In addition, this method was also applied to 21 different kinds of agriculture products collected from the local market, and two of the six triazines could be detected and quantified. PMID:18338404

Ji, Feng; Zhao, Lixia; Yan, Wei; Feng, Qinzhong; Lin, Jin-Ming

2008-04-01

353

Preconcentration of Lead in Sugar Samples by Solid Phase Extraction and Its Determination by Flame Atomic Absorption Spectrometry  

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Full Text Available A simple and sensitive solid phase extraction utilizing C18 filled cartridges incorporated with dithizone for preconcentration of lead and its subsequent determination by flame atomic absorption spectrometry (FAAS was developed. Several parameters such as type, concentration and volume of eluent, pH of the sample solution, flow rate of extraction and volume of the sample were evaluated. The effect of a variety of ions on preconcentration and recovery was also investigated. At pH = 7.4 and 1.0 mol?L–1 HCl eluting them, lead ions were recovered quantitatively. The limit of detection (LOD defined as 3Sbl was determined to be 8.1 ?g L–1 for 500 mL of sample solution and eluted with 5 mL of 1.0 mol?L–1 HCl under optimum conditions. The accuracy and precision (RSD % of the method were >90% and <10%, respectively. In the end, the proposed method was applied to a number of real sugar samples and the amount of lead was determined by spiking a known concentration of lead into the solution.

Saied Saeed Hosseiny Davarani

2011-09-01

354

Optimization of Analytical Conditions to Determine Steroids and Pharmaceuticals Drugs in Water Samples Using Solid Phase-Extraction and HPLC  

Directory of Open Access Journals (Sweden)

Full Text Available Two reliable methods were optimized to determine two steroids (17?-Estradiol and 17?-Ethinylestradiol and two pharmaceutical drugs (ibuprofen and naproxen using Solid-Phase Extraction (SPE for sample preparation and High Performance Liquid Chromatography (HPLC for analysis. SPE (C18 conditions were evaluated varying elution solvent volume, pH conditions and sample mass in the cartridge and reduction techniques of the extract. The efficiency of the analytical methods was evaluated by spiking ultrapure water samples with compounds at three and four levels of concentration for steroids and pharmaceutical drugs, re- spectively. The recoveries were independent (P > 0.05 of added mass of target analytes with a repeatability lower than 6.5% for steroids and 12.1% for pharmaceutical compounds. The recovery factor (coefficient of variation, CV was higher than 83% for steroids (CV < 3.8% and >93% for pharmaceuticals (CV < 5.2%. The optimized analytical method was applied for the evaluation of a steroid degradation test using ozone, finding that the estimated limit of detection is sufficient to determine the residual mass (?g?L–1 of 17?-Estradiol after the experiment.

Ramiro Vallejo-Rodríguez

2011-12-01

355

Determination of four flavorings in infant formula by solid-phase extraction and gas chromatography-tandem mass spectrometry.  

Science.gov (United States)

Increasing attention has been focused on the artificial flavorings added in foods, especially those for infants and children. For the first time, a sensitive and efficient analytical method based on gas chromatography-tandem mass spectrometry (GC-MS/MS) was developed for the simultaneous identification and quantification of four flavoring agents (vanillin, methylvanillin, ethylvanillin, and coumarin) in infant formula samples. The flavorings in samples were extracted with methanol/water (v/v, 1:1), cleaned up by solid-phase extraction, and determined by GC-MS/MS in selected reaction monitoring (SRM) mode. Both isotope-labeled internal standards and matrix-matched calibration solutions were used to correct the matrix effects. The limit of quantification (LOQ) was calculated as 10 times the standard deviation, and it was 10.0 ?g kg (-1) for vanillin, methylvanillin, ethylvanillin, and coumarin. The average recoveries were in the range of 82.8-107.5% with relative standard deviations (RSDs) below 8.9% measured at three concentration levels (10, 50, and 100 ?g kg(-1)). The proposed method is suitable for the sensitive and accurate simultaneous determination of four flavoring agents in infant formula samples and also provided potential use for reference in terms of real analysis of other foods. PMID:25338226

Shen, Yan; Hu, Beizhen; Chen, Xiangzhun; Miao, Qian; Wang, Chengjun; Zhu, Zhenou; Han, Chao

2014-11-12

356

Valuation of solid phase extraction disks in the determination of pesticide residues in surface and groundwater in Panama  

International Nuclear Information System (INIS)

In Panama large quantities of pesticides are used in agriculture and livestock farming and there is increasing concern about their impact on public health and the environment. Chiriqui is the Province that registers the largest number of producers whose activities have impact on the environment, especially on surface and groundwater. Systematic monitoring programmes are non-existent due, in part, to the high cost of laboratory determination of environmental residues of pesticides. Within the framework of the FAO/IAEA/SIDA Coordinated Research Programme, efforts were focused on evaluating and optimising the use of solid phase extraction C18 membrane disks in the analysis of surface and groundwater samples to determine pesticide residues. Factors studied were the effect of pre-washing and conditioning of the disks, flow rates, concentration level and matrix effects of field samples. Four pesticides, carbofuran, chlorothalonil, ametryn and chlorpyrifos were selected for these tests because preliminary analysis showed their presence in surface and groundwater. The technique significantly reduces the amount of organic solvents used as compared with the liquid-liquid extraction method. Quantifiable detection limits (QL) for the method were found to be 0.003 ?g/L carbofuran, 0.016 ?g/L chlorothalonil, 0.007 ?g/L ametryn and 0.003 ?g/L chlorpyrifos, when using standard spiked solutions. Recovery (%) was high when standard mixtures were used for the test runs but low when real surface water samples were tested, especially for chlorothalonil which was not recovered at all. (author)

357

[Determination of environmental estrogens in pharmacy wastewater using solid-phase extraction-gas chromatography/mass spectrometry with derivatization].  

Science.gov (United States)

A method for the determination of estrone (E1), estradiol (E2), ethinylestradiol (EE2) and estriol (E3) in pharmacy wastewater was developed using solid-phase extraction-gas chromatography/mass spectrometry (SPE-GC/MS) with derivatization. The sample was extracted by an SPE column, derivatized by bis (trimethylsilyl) trifluoroacetamide (BSTFA), and analyzed by GC/MS. The detection limits were 1.8-4.7 ng/L, and the relative standard deviations were 2.3%-9.1% (n = 8). The recoveries of above four environmental estrogen compounds were (94.0 +/- 2.9)% to (101 +/- 3.8)%. The method can be applied in the determination of the estrogenic compounds in wastewater samples successfully. The concentrations of EE2 and E1 in wastewater were 396.6 ng/L and 39.9 ng/L, respectively, and the removal rates of EE2 and E1 were 35%-40% after traditional biological treatment. The results demonstrated that the removal efficiency was not satisfactory and the traditional treatment process of wastewater containing estrogen compounds from pharmaceuticals factory should be improved. PMID:19160764

Huang, Cheng; Jiang, Liying; Chen, Jianmeng; Chen, Xiao

2008-09-01

358

Novel dummy molecularly imprinted polymers for matrix solid-phase dispersion extraction of eight fluoroquinolones from fish samples.  

Science.gov (United States)

A series of novel dummy molecularly imprinted polymers (DMIPs) were prepared as highly class-selective sorbents for fluoroquinolones. A non-poisonous dummy template, daidzein, was used for the first time to create specific molecular recognition sites for fluoroquinolones in the synthesized polymers. The influence of porogen polarity on dummy molecular imprinting effect was studied. The DMIP prepared using dimethylsulfoxide-acetonitrile (1:1.8, v/v) as porogen achieved the highest imprinting factors (IF) for fluoroquinolones over a range of IF 13.4-84.0. This DMIP was then used for selective extraction of eight fluoroquinolones (fleroxacin, ofloxacin, norfloxacin, pefloxacin, ciprofloxacin, lomefloxacin, enrofloxacin and gatifloxacin) from fish samples based on dummy molecularly imprinted matrix solid-phase dispersion (DMI-MSPD). The extracted fluoroquinolones were subsequently analyzed by high-performance liquid chromatography (HPLC) equipped with a fluorescence detector (FLD). The developed method had acceptable recoveries (64.4-102.7%) and precision (RSDs: 1.7-8.5%, n=5) for determination of fluoroquinolones in fish samples fortified at levels of 10 and 100ngg(-1). The limits of detection (LODs) for identification of eight fluoroquinolones ranged between 0.06 and 0.22ngg(-1). The results demonstrated great potential of the optimized method for sample preparation in routine analysis of trace fluoroquinolones in fish samples. PMID:25085823

Sun, Xiaoli; Wang, Jincheng; Li, Yun; Yang, Jiajia; Jin, Jing; Shah, Syed Mazhar; Chen, Jiping

2014-09-12

359

Colourimetric solid-phase extraction coupled with fibre optic reflectance spectroscopy for determination of ascorbic acid in pharmaceutical formulations.  

Science.gov (United States)

A redox colourimetric solid-phase extraction (C-SPE) procedure for the determination of ascorbic acid (AA) in pharmaceutical formulations was proposed. Iron (III)-2,2'-dipyridyl (Fe(III)-Bpy) reagent solution was used as a colouring reagent for AA and the immobilization of the redox product onto Amberlite XAD-16 resin was achieved. The analyte in the sample reacted with a solid sorbent loaded with the colourimetric reagent (Fe(III)-Bpy) and then quantified directly on the sorbent surface by using a fibre optic reflectance spectrometer (FORS). The amount of AA was reflectometrically determined in a few seconds with a total sample workup and readout time of ?10 min using only 10-ml sample volumes. The limit of detection (LOD) and quantification (LOQ) values were 0.18 and 0.6 mg L(-1), respectively, and the linear dynamic range for AA extended up to 8.8 mg L(-1). The C-SPE for different extractions (n = 5) gave a relative standard deviation (RSD) of 2.9% at 5.28 mg L(-1) AA level. PMID:21337723

Filik, Hayati; Aksu, Duygu; Giray, Derya; Apak, Re?at

2012-06-01

360

Validation of a solid phase extraction technique for the determination of halogenated acetic acids in drinking water  

International Nuclear Information System (INIS)

Halo acetic acids (HAAs) are one of the most common disinfection by-products formed during chlorination of drinking water. An analytical method involving solid phase extraction (SPE) followed by gas-chromatograph mass-spectrometry (GC-MS) was developed and optimized using experimental design to determine the HAAs in water. Selectivity, percent recovery, and detection limit studies were carried out on a Silia-SAX (Trimethyl ammonium chloride) SPE. Under optimized conditions, average recoveries for nine HAAs spiked in drinking water samples range from 69.2 % to 108.2 %. The relative standard deviation (RSD) data were found to range from 2.5 % to 12.5 % based upon five repeat recovery experiments and detection limit range of 0.16 to 0.009 ?g/ l were obtained. On this basis, SPE was studied as a possible alternative to liquid-liquid extraction (LLE) for the analysis of HAAs in water. The performance of the SPE-GC-MS with actual water samples was tested. (author)

361

An absorbing microwave micro-solid-phase extraction device used in non-polar solvent microwave-assisted extraction for the determination of organophosphorus pesticides  

International Nuclear Information System (INIS)

Highlights: ? An absorbing microwave ?-SPE device packed with activated carbon was used. ? Absorbing microwave ?-SPE device was made and used to enrich the analytes. ? Absorbing microwave ?-SPE device was made and used to heat samples directly. ? MAE-?-SPE was applied to the extraction of OPPs with non-polar solvent only. - Abstract: A single-step extraction-cleanup method, including microwave-assisted extraction (MAE) and micro-solid-phase extraction (?-SPE), was developed for the extraction of ten organophosphorus pesticides in vegetable and fruit samples. Without adding any polar solvent, only one kind of non-polar solvent (hexane) was used as extraction solvent in the whole extraction step. Absorbing microwave ?-SPE device, was prepared by packing activated carbon with microporous polypropylene membrane envelope, and used as not only the sorbent in ?-SPE, but also the microwave absorption medium. Some experimental parameters effecting on extraction efficiency was investigated and optimized. 1.0 g of sample, 8 mL of hexane and three absorbing microwave ?-SPE devices were added in the microwave extraction vessel, the extraction was carried out under 400 W irradiation power at 60 °C for 10 min. The extracts obtained by MAE-?-SPE were directly analyzed by GC–MS without any clean-up process. The recoveries were in the range of 93.5–104.6%, and the relative standard deviations were lower than 8.7%.

362

Nanostructured conducting molecularly imprinted polymer for selective extraction of salicylate from urine and serum samples by electrochemically controlled solid-phase micro-extraction  

International Nuclear Information System (INIS)

Highlights: ? Overoxidized polypyrrole templated with salicylate has been utilized as conducting molecular imprinted polymer for EC-SPME. ? This first study reported on conducting molecular imprinted polymer was used to EC-SPME of salicylate. ? Proposed method, is particularly effective in sample clean-up and selective monitoring of salicylate in physiological samples. - Abstract: Overoxidized polypyrrole (OPPy) films templated with salicylate (SA) have been utilized as conducting molecular imprinted polymers (CMIPs) for potential-induced selective solid-phase micro-extraction processes. Various important fabrication factors for controlling the performance of the OPPy films have been investigated using fluorescence spectrometry. Several key parameters such as applied potential for uptake, release, pH of uptake and release solution were varied to achieve the optimum micro-extraction procedure. The film template with SA exhibited excellent selectivity over some interference. The calibration graphs were linear in the ranges of 5 × 10?8 to 5 × 10?4 and 1.2 × 10?6 to 5 × 10?4 mol mL?1 and the detection limit was 4 × 10?8 mol L?1. The OPPy film as the solid-phase micro-extraction absorbent has been applied for the selective clean-up and quantification of trace amounts of SA from physiological samples. The results of scanning electron microscopy (SEM) have confirmed the nanoonfirmed the nano-structure morphologies of the films.

363

Characteristic of New Solid-Phase Extraction Sorbent: Activated Carbon Prepared from Rice Husks under Base Treated Condition  

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Full Text Available A characterization of activated carbon (ACs prepared from rice husks (RHs under base treated condition as a new sorbent for solid-phase extraction (SPE to extract 4-nonylphenol isomers (4-NPs in water samples has been done. The ACs prepared from RHs usually exhibits low specific surface area due to its high ash content, but in case of its application for SPE, there are other factors need to be considered, such as the existence of functional groups inside the sorbent, that can enhance interaction of non-polar sorbent with analyte in the water matrices. In this case, silanol groups from ash content may affect the extraction efficiency for 4-NPs. The ACs made from RHs were chemically impregnated with ZnCl2 and carbonized at 800oC. To investigate the role of silica, three types of ACs were prepared, i.e., untreated ACs (AC–Si, contain silica, base treated ACs (AC–B–Si, remain some silica inside, and ACs made by base treated RHs (AC–B, no silica, the surface area obtained from these treatments were 1352 m2/g, 1666 m2/g, and 1712m2/g respectively.  ACs made by base treatment has the highest surface area (related to BET, which indicat that silica removal process promotes the formation of open pore system on ACs and enhances the surface area of ACs. However, extraction efficiency measured by GC-MS in SPE process showed the reversal trends (i.e., AC–Si= 32.08%, AC–B–Si= 82.63%, AC–B=51.78%, among them the AC–B–Si sorbent reveal the best performance in SPE process. It is indicated that although silica usually exhibits low specific surface area, but control presence of silica as a polar functional group has a positive influence in the interaction between non-polar sorbent and 4-NPs.

Afrida Kurnia Putri

2012-10-01

364

Evaluation of a high-throughput online solid phase extraction-tandem mass spectrometry system for in vivo bioanalytical studies.  

Science.gov (United States)

High throughput-solid phase extraction tandem mass spectrometry (HT-SPE/MS) is a fully automated system that integrates sample preparation using ultrafast online solid phase extraction (SPE) with mass spectrometry detection. HT-SPE/MS is capable of conducting analysis at a speed of 5-10 s per sample, which is several fold faster than chromatographically based liquid chromatography-mass spectrometry (LC-MS). Its existing applications mostly involve in vitro studies such as high-throughput therapeutic target screening, CYP450 inhibition, and transporter evaluations. In the current work, the feasibility of utilizing HT-SPE/MS for analysis of in vivo preclinical and clinical samples was evaluated for the first time. Critical bioanalytical parameters, such as ionization suppression and carry-over, were systematically investigated for structurally diverse compounds using generic SPE operating conditions. Quantitation data obtained from HT-SPE/MS was compared with those from LC-MS analysis to evaluate its performance. Ionization suppression was prevalent for the test compounds, but it could be effectively managed by using a stable isotope labeled internal standard (IS). A structural analogue IS also generated data comparable to the LC-MS system for a test compound, indicating matrix effects were also compensated for to some extent. Carry-over was found to be minimal for some compounds and variable for others and could generally be overcome by inserting matrix blanks without sacrificing assay efficiency due to the ultrafast analysis speed. Quantitation data for test compounds obtained from HT-SPE/MS were found to correlate well with those from conventional LC-MS. Comparable accuracy, precision, linearity, and sensitivity were achieved with analysis speeds 20-30-fold higher. The presence of a stable metabolite in the samples showed no impact on parent quantitation for a test compound. In comparison, labile metabolites could potentially cause overestimation of the parent concentration if the ion source conditions are not optimized to minimize in-source breakdown. However, with the use of conditions that minimized in-source conversion, accurate measurement of the parent was achieved. Overall, HT-SPE/MS exhibited significant potential for high-throughput in vivo bioanalysis. PMID:21936562

Jian, Wenying; Romm, Michelle V; Edom, Richard W; Miller, Vaughn P; LaMarr, William A; Weng, Naidong

2011-11-01

365

Solid phase extraction and spectrophotometric determination of mercury in tobacco and tobacco additives with 5-(p-aminobenzylidene)-thiothiorhodanine  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Foi desenvolvido um método altamente sensível, seletivo e rápido para a determinação de mercúrio, a partir da reação rápida de mercúrio(II) com 5-(p-aminobenzilideno)-tiorodanina (ABTR) e posterior extração em fase sólida do quelato colorido, utilizando discos C18. Em pH 3,5 e na presença do emulsif [...] icante-OP, ABTR reage com mercúrio(II) para formar um quelato vermelho na razão molar 1:2 (mercúrio:ABTR). O quelato foi enriquecido pela extração em fase sólida com discos C18 e o quelato retido, eluído com dimethyl formamida (DMF). Um fator de enriquecimento na ordem de 50 foi obtido. Em DMF, a absortividade molar do quelato é 1,21´10(5) L mol-1 cm-1 a 545 nm, e a lei de Beer é obedecida no intervalo 0,01~3 µg mL-1 na solução medida. O desvio padrão relativo para onze replicatas a 0,01 µg mL-1 é 1,7%. Este método foi aplicado para a determinação de mercúrio em tabaco e aditivos de tabaco. Bom coeficiente de preconcentração foi encontrado, comparando-se o método proposto com outros similares. Abstract in english A highly sensitive, selective and rapid method for the determination of mercury based on the rapid reaction of mercury(II) with 5-(p-aminobenzylidene)-thiorhodanine (ABTR) and the solid phase extraction of the colored chelate with C18 disks has been developed. At pH 3.5 and in the presence of emulsi [...] fier-OP medium, ABTR reacts with mercury(II) to form a red chelate of a 1:2 (mercury to ABTR) molar ratio. This chelate was enriched by solid phase extraction with C18 disks and the retained chelate eluted form the disks with dimethyl formamide (DMF). An enrichment factor of 50 was achieved. In the DMF medium, the molar absorptivity of the chelate is 1.21´10(5) L mol-1 cm-1 at 545 nm, and Beer's law is obeyed in the 0.01~3 µg mL-1 range in the measured solution. The relative standard deviation for eleven sample replicate measurements at the 0.01 µg mL-1 level is 1.7%. This method was applied to the determination of mercury in tobacco and tobacco additives and good preconcentration was found between proposed and comparative methods results.

Weizhu, Yang; Qun, Hu; Jing, Ma; Liming, Wang; Guangyu, Yang; Gang, Xie.

1039-10-01

366

A New Solid Phase Extraction for the Determination of Anthocyanins in Grapes  

Directory of Open Access Journals (Sweden)

Full Text Available A method for the concentration and cleaning of red grape extracts prior to the determination of anthocyanins by UPLC-DAD has been developed. This method is of special interest in the determination of phenolic maturity as it allows the analysis of the anthocyanins present in grapes. Several different SPE cartridges were assessed, including both C-18- and vinylbenzene-based cartridges. C-18-based cartridges presented a very low retention for the glucosylated anthocyanidins while vinylbenzene-based cartridges showed excellent retention for these compounds. The optimized method involves the initial conditioning of the cartridge using 10 mL of methanol and 10 mL of water, followed by loading of up to 100 mL of red grape extract. Ten mL of water was used in the washing step and anthocyanins were subsequently eluted using 1.5 mL of acidified methanol at pH 2. This method simplifies the determination of individual anthocyanins as, on the one hand, it cleans the sample of interference and, on the other hand, it increases the concentration to up to 25:1.5. The developed method has been validated with a range of different grapes and it has also been tested as a means of determining the different anthocyanins in grapes with different levels of maturity.

Marta Ferreiro-González

2014-12-01

367

Solid Phase Extraction of Trace Copper(II Using Modified Nano Polyacrylonitrile Fiber  

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Full Text Available A simple method has been developed for the preconcentration of copper(II based on the adsorption of its Modified nano polyacrylonitrile fiber. Modified nano polyacrylonitrile fiber (PANF was prepared by adding of acrylic fibers to mSethanolamine (MMA with different concentration solutions. The stability of a chemically Modified nano polyacrylonitrile fiber especially in concentrated hydrochloric acid which was then used as a recycling and pre-concentration reagent for further uses of modified nano polyacrylonitrile fiber. The application of this Modified nano polyacrylonitrile fiber for sorption of a series of metal ions was performed by using different controlling factors such as the pH of metal ion solution and the equilibration shaking time by the static technique. Cu (II was found to exhibit the highest affinity towards extraction by these Modified nano polyacrylonitrile fiber phases. The pronounced selectivity was also confirmed from the determined distribution coefficient (Kd of all the metal ions, showing the highest value reported for Cu (II to occur by Modified nano polyacrylonitrile fiber. The potential applications ofModified nano polyacrylonitrile fiber for selective extraction of Cu(II to occur from aqueous solution were successfully accomplished as well as pre- concentration of low concentration of Cu(II (60 pg ml-1 from natural tap water with a pre-concentration factor of 100 for Cu(II off-line analysis by flame atomic absorption analysis.

A. Moghimi

2012-07-01

368

Solid phase extraction for determination of 90Sr in water sample  

International Nuclear Information System (INIS)

We studied the use of an extraction chromatography for determination of 90Sr in samples of contaminated water. The aim of the thesis was to compare selected products from the point of view of the strontium yields and time needed. Three commercial products: 3M Empore Strontium Rad Disk, AnaLig, Sr-Resin and two classical methods: liquid-liquid extraction with tributylphosphate and carbonate co-precipitation (to eliminate interferers) were used for separation of 90Sr. The water sample was used in radiochemical analysis for determination volume activity of 90Sr. A radiochemical strontium yield was traced by using radionuclide 85Sr. Samples were counted over a two week period to monitor the ingrowth of 90Y on TRI CARB LSC counter. Samples were measured using an HPGe detector to find out 85Sr recoveries at 514 keV line and they were counted directly by Cherenkov counting after the growth of 90Y using TriCarb LSC counter after a two- week period (author)

369

An absorbing microwave micro-solid-phase extraction device used in non-polar solvent microwave-assisted extraction for the determination of organophosphorus pesticides.  

Science.gov (United States)

A single-step extraction-cleanup method, including microwave-assisted extraction (MAE) and micro-solid-phase extraction (?-SPE), was developed for the extraction of ten organophosphorus pesticides in vegetable and fruit samples. Without adding any polar solvent, only one kind of non-polar solvent (hexane) was used as extraction solvent in the whole extraction step. Absorbing microwave ?-SPE device, was prepared by packing activated carbon with microporous polypropylene membrane envelope, and used as not only the sorbent in ?-SPE, but also the microwave absorption medium. Some experimental parameters effecting on extraction efficiency was investigated and optimized. 1.0 g of sample, 8 mL of hexane and three absorbing microwave ?-SPE devices were added in the microwave extraction vessel, the extraction was carried out under 400 W irradiation power at 60°C for 10 min. The extracts obtained by MAE-?-SPE were directly analyzed by GC-MS without any clean-up process. The recoveries were in the range of 93.5-104.6%, and the relative standard deviations were lower than 8.7%. PMID:23265734

Wang, Ziming; Zhao, Xin; Xu, Xu; Wu, Lijie; Su, Rui; Zhao, Yajing; Jiang, Chengfei; Zhang, Hanqi; Ma, Qiang; Lu, Chunmei; Dong, Deming

2013-01-14

370

Solid phase extraction of Cu(II as diethyldithiocarbamate (DDTC complex by polyurethane foam  

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Full Text Available This paper presents a study about the sorption of copper-diethyldithiocarbamate complex onto polyurethane foam (PUF. It was observed that the maximum sorption of Cu(II (80 or 150 µg L-1 was verified at pH 6.8 in presence of 4.5 x 10-5 mol L-1 DDTC. The shaking time needed to achieve the equilibrium was 40 minutes. From these data, a kinetic characterization was performed by applying three models, which revealed that a film diffusion process was a rate-determining mechanism. Results also indicated that a ether-like solvent extraction was the sorption mechanism. The investigation of many metallic ions as concomitants showed that the sorption by foam is relatively selective and it can be enhanced by using a suitable masking agent or incrementing the foam mass.

Sant'Ana Otoniel D.

2003-01-01

371

Ofloxacin analysis validation method in human blood plasma (in vitro using solid-phase extraction HPLC  

Directory of Open Access Journals (Sweden)

Full Text Available Until now, analysis of Ofloxacin in human blood plasma using solidphase extraction (SPE by HPLC UV detector has not been reported. This study aims to determine the validity of analytical methods in Ofloxacin study in human blood plasma (in vitro using an HPLC SPE UV detector. Plasma samples were extracted by SPE. Analytes were analyzed using a C18 column (octadecylsilane 250x4.6 mm, particle size 10 0m, mobile phase 85,5:14,5 v v 0.025 M phosphate buffer (pH 2.2 and acetonitrile with a flow rate of 2 ml/min, detection performed at 294 nm with the internal standard ciprofloxacin. Validated analytical method was based on the parameters: selectivity, accuracy, precision, repeatability, linearity, LOD, LOQ, and the suitability of the system. Validation analysis showed selectivity test Rs>1.5, test repeatability with CV(% <10%, linearity was obtained in the range of 0.1 to 6 ;g/ml with correlation coefficient (r from 0.9998 to 0.9999. Based on the area ratio of peak height and a segment of the chromatogram obtained LOD values 0.023 and 0.024 ;g/ml, LOQ value of 0.076 and 0.080 tg/ml, percent accuracy from 94.32 to 100.45% and 97.68 to 101.63%, and precision CV (% 0.31 to 0.85% and 0.84 to 1.08%. System suitability test results on the retention time, area ratio, and high ratios of peak chromatogram shows the CV(% <10%. Can be concluded that the analytical methods used have validity in accordance with the requirements.

RESMI MUSTARICHIE

2011-08-01

372

Thin film-XRF determination of uranium following thin-film solid phase extraction  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Foi desenvolvido um método sensível baseado na pré-concentração de urânio em papel de filtro modificado (filme fino) para a determinação deste elemento em amostras de águas e de solos, usando a técnica de fluorescência de raios-X de comprimento de onda dispersivo. Para a extração de urânio (VI), 100 [...] mL de amostra reagiram com tri-octil fosfina (TOPO) em presença de ácido nítrico. O efeito da concentração de ácido nítrico e de TOPO, bem como da retenção do metal em função do volume de amostra foram avaliados neste estudo. O método proposto mostrou boa linearidade entre 7 e 1000 µg de urânio (VI) e o limite de detecção (LOD), calculado com a relação sinal-ruído (S/N) igual a 3 foi de 2,5 µg. Abstract in english A sensitive method based on the preconcentration of uranium on modified filter paper (thin film) has been developed to determinate this element in water and soil samples by wavelength dispersive X-ray fluorescence. Uranium (VI) extraction from nitric acid medium by trioctyl phosphine (TOPO) from 100 [...] mL of sample was carried out. The effects of nitric acid concentration, TOPO concentration and sample breakthrough on uranium extraction were investigated in this study. The proposed method provided good linearity from 7 to 1000 µg and the limit of detection (LOD), based on a signal-to noise ratio (S/N) of 3, was 2.5 µg.

Jalal, Hassan; Seyed M., Hosseini; Shahla, Mozaffari; Babak, Jahanparast; Mohammad H., Karbasi.

1086-10-01

373

Comparison of disposable pipette extraction and dispersive solid-phase extraction in the QuEChERS method for analysis of pesticides in strawberries.  

Science.gov (United States)

In this study, we sought to assess the applicability of GC-MS/MS for the identification and quantification of 36 pesticides in strawberry from integrated pest management (IPM) and organic farming (OF). Citrate versions of QuEChERS (quick, easy, cheap, effective, rugged and safe) using dispersive solid-phase extraction (d-SPE) and disposable pipette extraction (DPX) for cleanup were compared for pesticide extraction. For cleanup, a combination of MgSO4, primary secondary amine and C18 was used for both the versions. Significant differences were observed in recovery results between the two sample preparation versions (DPX and d-SPE). Overall, 86% of the pesticides achieved recoveries (three spiking levels 10, 50 and 200 µg/kg) in the range of 70-120%, with IPM. PMID:24552668

Fernandes, Virgínia C; Domingues, Valentina F; Mateus, Nuno; Delerue-Matos, Cristina

2014-01-01

374

Pesticide determination in rose petals using dispersive solid-phase extraction followed by gas chromatography-tandem mass spectrometry.  

Science.gov (United States)

Damascena and centifolia roses are cultivated worldwide for their petal extracts that contain key odorant ingredients of perfumes. The analytical identification and quantification of pesticides in rose petals have never been described in the literature. Here, we report on a newly developed method using dispersive solid-phase extraction (d-SPE) cleanup followed by gas chromatography-tandem mass spectrometry for the quantitative determination of multi-residue pesticides in rose petals. Analytes were extracted from the matrix using acetonitrile and a mixture of salts containing magnesium sulfate, sodium citrate, sodium chloride, and sodium sesquihydrate. Samples were cleaned up twice by d-SPE applying primary and secondary amines (PSAs), magnesium sulfate, C18, and graphitized carbon black (GCB). Two fortification levels of 0.05 and 0.5 mg kg(-1) were assessed for method validation purposes. The obtained pesticide recoveries were in the range of 70-120 % with a relative standard deviation (RSD) of less than 20 %. The newly developed method was allowed for the quantification of 57 pesticides residues. It was applied to pesticide residue detection in rose petals from an organic field, without treatment, compared to those from a field with classic phytosanitary treatment using fungicide and/or insecticide. We did not detect pesticide residues in rose petals from the organic field. The classically treated samples of roses contained pesticides such as chlorpyriphos and methidathion which are in accordance with the previous application of these pesticides on the roses. Insecticides were quantified at 0.05 mg kg(-1) rose petal maximum. PMID:25344932

Tascone, Oriane; Shirshikova, Marina; Roy, Céline; Meierhenrich, Uwe J

2014-12-01

375

A novel magnetic poly(aniline-naphthylamine)-based nanocomposite for micro solid phase extraction of rhodamine B  

Energy Technology Data Exchange (ETDEWEB)

Graphical abstract: -- Highlights: •A Fe{sub 3}O{sub 4}–aniline-naphthylamine nanocomposite was prepared via a simple route. •The magnetic nanocomposite was applied for isolation of RhB from water. •The nanocomposite applicability was compared with other pristine polymers. •The method was applied for the determination of RhB in different samples. -- Abstract: A novel Fe{sub 3}O{sub 4}–poly(aniline-naphthylamine)-based nanocomposite was synthesized by chemical oxidative polymerization process as a magnetic sorbent for micro solid phase extraction. The scanning electron microscopy images of the synthesized nanocomposite revealed that the copolymer posses a porous structure with diameters less than 50 nm. The extraction efficiency of this sorbent was examined by isolation of rhodamine B, a mutagenic and carcinogenic dye, from aquatic media in dispersion mode. Among different synthesized polymers, Fe{sub 3}O{sub 4}/poly(aniline-naphthylamine) nanocomposite showed a prominent efficiency. Parameters including the desorption solvent, amount of sorbent, desorption time, sample pH, ionic strength, extraction time and stirring rate were optimized. Under the optimum condition, a linear spiked calibration curve in the range of 0.35–5.00 ?g L{sup ?1} with R{sup 2} = 0.9991 was obtained. The limits of detection (3S{sub b}) and limits of quantification (10S{sub b}) of the method were 0.10 ?g L{sup ?1} and 0.35 ?g L{sup ?1} (n = 3), respectively. The relative standard deviation for water sample with 0.5 ?g L{sup ?1} of RhB was 4.2% (n = 5) and the absolute recovery was 92%. The method was applied for the determination of rhodamine B in dishwashing foam, dishwashing liquid, shampoo, pencil, matches tips and eye shadows samples and the relative recovery percentage were in the range of 94–99%.

Bagheri, Habib, E-mail: bagheri@sharif.edu; Daliri, Rasoul; Roostaie, Ali

2013-09-10

376

A novel magnetic poly(aniline-naphthylamine)-based nanocomposite for micro solid phase extraction of rhodamine B  

International Nuclear Information System (INIS)

Graphical abstract: -- Highlights: •A Fe3O4–aniline-naphthylamine nanocomposite was prepared via a simple route. •The magnetic nanocomposite was applied for isolation of RhB from water. •The nanocomposite applicability was compared with other pristine polymers. •The method was applied for the determination of RhB in different samples. -- Abstract: A novel Fe3O4–poly(aniline-naphthylamine)-based nanocomposite was synthesized by chemical oxidative polymerization process as a magnetic sorbent for micro solid phase extraction. The scanning electron microscopy images of the synthesized nanocomposite revealed that the copolymer posses a porous structure with diameters less than 50 nm. The extraction efficiency of this sorbent was examined by isolation of rhodamine B, a mutagenic and carcinogenic dye, from aquatic media in dispersion mode. Among different synthesized polymers, Fe3O4/poly(aniline-naphthylamine) nanocomposite showed a prominent efficiency. Parameters including the desorption solvent, amount of sorbent, desorption time, sample pH, ionic strength, extraction time and stirring rate were optimized. Under the optimum condition, a linear spiked calibration curve in the range of 0.35–5.00 ?g L?1 with R2 = 0.9991 was obtained. The limits of detection (3Sb) and limits of quantification (10Sb) of the method were 0.10 ?g L?1 and 0.35 ?g L?1 (n = 3), respectively. The relative standard deviation for water sample with 0.5 ?g L?1 of RhB was 4.2% (n = 5) and the absolute recovery was 92%. The method was applied for the determination of rhodamine B in dishwashing foam, dishwashing liquid, shampoo, pencil, matches tips and eye shadows samples and the relative recovery percentage were in the range of 94–99%

377

Development of a novel solid-phase extraction element for the detection of nonylphenol in the surface water of Hangzhou.  

Science.gov (United States)

Nonylphenol (NP) is a representative environmental endocrine-disrupting chemical and persistent toxic pollutant. Previous studies have shown that the average concentration of NP in environmental waters was approximately tens to hundreds of ng L(-1) and it could even reach up to tens of ?g L(-1). A simple, fast and accurate method employing a novel solid-phase extraction element named "Magic Chemisorber" (MC) followed by high-performance liquid chromatography (HPLC) using a fluorescence detector (FLD) was used for detecting NP. The most important parameters that affect the extraction process, including extraction time, desorption time, desorption solvent and repeatability, were optimized. The MC-HPLC method showed good linearity with concentrations of NP from 10 to 200 ?g L(-1), a correlation coefficient of 0.9995 and the limit of detection (LOD) and limit of quantification (LOQ) of this method was 0.44 and 1.47 ?g L(-1), respectively. Compared to commercial polydimethylsiloxane (PDMS) glass fiber, MC had both higher capacity and recovery and it could be used repeatedly. Using the MC-HPLC method we found that the concentration of NP in river water from Hangzhou city ranged from 8.54 ± 1.23 ?g L(-1) (Qiantang River) to 65.77 ± 3.69 ?g L(-1) (Tiesha River), which was similar to that of international regions heavily polluted with NP and higher than that of Bohai Bay, the Yellow River and the Pearl River Delta in China. This level of NP pollution is possibly related to the rapid development of the textile, printing and paper industries of Zhejiang province. PMID:22130644

Lou, Liping; Cheng, Guanghuan; Yang, Qiang; Xu, Xinhua; Hu, Baolan; Chen, Yingxu

2012-02-01

378

Ultra-sensitive quantification of paclitaxel using selective solid-phase extraction in conjunction with reversed-phase capillary liquid chromatography/tandem mass spectrometry  

OpenAIRE

The ability to quantify ultra-low concentrations of biologically active compounds in biological matrices is essential for the study of pharmacological/toxicological effects occurring at low doses. Selective solid-phase extraction (SPE) was combined with highly sensitive capillary LC (?LC)-MS/MS analysis to achieve ultra-sensitive quantification of the anticancer drug paclitaxel in cancer cells. The optimized SPE selectively extracted paclitaxel and eliminated undesirable matrix compounds, th...

Yu, Haoying; Straubinger, Robert M.; Cao, Jin; Wang, Hao; Qu, Jun

2008-01-01

379

Multiresidue Method for Determination of 67 Pesticides in Water Samples Using Solid-Phase Extraction with Centrifugation and Gas Chromatography-Mass Spectrometry  

OpenAIRE

A new multi-residue method based on solid-phase extraction (SPE) with centrifugation was developed for determination and quantitation of 67 pesticides in water samples. Two SPE cartridges were tested: Chromabond C18 and Oasis HLB. Parameters that influence the extraction efficiency such as the eluent volume, the sample loading volume, the addition of organic solvent to water sample, sorbent drying and elute concentration were optimized. The innovation of this work was the examination of the u...

Farouk Jaber; Hélène Budzinski; Daniel Beh; Mohamad Al Iskandarani; Abdul Rahman Rabaa; Abir Kouzayha

2012-01-01

380

Solid-phase extraction followed by dispersive liquid-liquid microextraction for the sensitive determination of ecstasy compounds and amphetamines in biological samples  

OpenAIRE

A novel approach for the determination of ecstasy and amphetamines (3,4-methylenedioxymethylamphetamine (MDMA, Ecstasy), 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxyethylamphetamine (MDEA) and 3,4-methylenedioxypropylamphetamine (MDPA)) in biological samples is presented. The analytes were extracted from the matrix and transferred to a small volume of a high density, water insoluble solvent using solid-phase extraction (SPE) followed by dispersive liquid-liquid microextraction (DLL...

Mashayekhi, H. A.; Rezaee, M.; Khalilian, F.

2014-01-01