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1.
A method using microextraction by packed sorbent (MEPS) and gas chromatography–tandem mass spectrometry (GC-MS/MS) is described for the determination of seven antipsychotic drugs in human plasma. The studied compounds were chlorpromazine (CPZ), haloperidol (HAL), cyamemazine, quetiapine, clozapine, olanzapine (OLZ), and levomepromazine; promazine, protriptyline, and deuterated CPZ were used as internal standards. The validation parameters included selectivity, linearity and limits of detection and quantitation, intra- and interday precision and trueness, recovery, and stability and were studied according to internationally accepted guidelines. The method was found to be linear between the lower limit of quantitation and 1000 ng/mL, except for OLZ and HAL (200 ng/mL), with determination coefficients higher than 0.99 for all analytes, and extraction efficiencies ranged from 62 to 92 %. Intra- and interday precision ranged from 0.24 to 10.67 %, while trueness was within a ±15 % interval from the nominal concentration for all analytes at all studied levels. MEPS has shown to be a rapid procedure for the determination of the selected antipsychotic drugs in human plasma, allowing reducing the handling time and the costs of analysis. Furthermore, GC-MS/MS has demonstrated to be a powerful tool for the simultaneous quantitation of the studied compounds, enabling obtaining adequate selectivity and sensitivity using a sample volume of as low as 0.25 mL.  相似文献   

2.
《Analytical letters》2012,45(13):2075-2088
For the first time, a simple method for magnetic stirring-assisted dispersive suspended microextraction has been developed for the determination of three fungicides (azoxystrobin, diethofencarb, and pyrimethanil) in water and wine samples. The method is based on the solidification of a floating organic droplet coupled with high performance liquid chromatography. In the proposed method, the low toxicity solvent 1-dodecanol was used as the extractant. Both the extraction and phase separation process were performed with magnetic stirring. No centrifugation step was involved. After separating the two phases, the extraction solvent droplet was easily collected through solidification at lower temperature. Important parameters such as the kind and volume of organic extraction solvent, extraction and restoration speed, extraction and restoration time, and salt concentration were optimized. Under the optimal conditions, the limits of detection for the analytes varied from 0.14 to 0.26 µg L?1. The enrichment factors ranged from 125–200. The linearity ranges were 1–2000 µg L?1, yielding correlation coefficients (r) higher than 0.9990. The relative standard deviation (n = 6) at two spiked level of 0.2 µg mL?1 and 4 µg L?1 varied between 2.2% and 7.8%. Finally, the developed technique was successfully applied to determine target fungicides in real water and wine samples, where the obtained recoveries ranged from 83.8–105.3%  相似文献   

3.
《Analytical letters》2012,45(14):2461-2474
Novel, rapid, inexpensive, and simple QuEChERS extraction followed by phospholipid solid phase extraction was successfully developed and validated for the determination of methoprene, resmethrin, bifenthrin, cyhalothrin, and permethrin in lobster and shellfish tissues by gas chromatography–tandem mass spectrometry. This method is equivalent in final sample purity to the traditional gel permeation and open column chromatography sample preparation techniques, but has clear advantages due to reductions in time, labor, solvent use, and can be performed with minimal staff training. The proposed methodology was effectively applied to the analysis of North Atlantic lobster (hepatopancreas and muscle) and shellfish tissue. The linearity of the calibration curves for all analytes were R2 > 0.9991. The surrogate recoveries were 98.2 ± 18.0%, while the target compound recoveries, for fortified samples, were in the range of 62.0%–128.8% with RSD values <17.2% for all compounds. The detection limits for the analytes ranged from 0.0056 µg/g to 0.76 µg/g with 84.4–119.5% accuracy and relative standard deviations less than 3.77%.  相似文献   

4.
《Analytical letters》2012,45(1-3):12-24
A simple and sensitive flow-injection method is reported for the determination of retinol and α-tocopherol in human blood serum and pharmaceuticals. The method is based on the reduction of vanadium(V) by retinol and α-tocopherol and subsequent reaction of reduced vanadium with luminol to generate chemiluminescence signal. The optimized conditions allow a linear calibration range of 30–2850 µg L?1 and 5–4300 µg L?1 for retinol and α-tocopherol, with relative standard deviations of 1.2–4.6% and 1.5–5.6%, respectively. The detection limits for retinol and α-tocopherol, defined as three times the standard deviation of measured blanks were 23 µg L?1 and 2.15 µg L?1, respectively. The proposed method allowed up to 20 determinations h?1. The tolerance amount of foreign ions/compounds on the determination of retinol and α-tocopherol was also examined. The method was applied to the determination of retinol and α-tocopherol in human blood serum and pharmaceutical samples using hexane extraction with recoveries in the range of 92 ± 2 to 96 ± 1%, and the results obtained were compared with HPLC reference method.  相似文献   

5.
With the wide range of metallic contaminants discharged in the environment, studying the human health requires a growing number of elements to be monitored in biological samples. Hair analysis has been suggested as a suitable tool for biomonitoring environmental and occupational exposure to toxic elements. This study describes a method for the determination of 10 trace elements in hair samples using ICP-QQQ-MS. Combining the power of the MS/MS high-energy Helium mode with the MS/MS O2 mass-shift mode, the method offers great analytical performances with detection limits reaching 0.0014 µg g?1 for As, 0.0016 µg g?1 for Cd, 0.012 µg g?1 for Cr, 0.0035 µg g?1 for Hg, 0.0055 µg g?1 for Mn, 0.10 µg g?1 for Ni, 0.0012 µg g?1 for Sb, 0.0083 µg g?1 for Sn, 0.011 µg g?1 for Se and Pb. The accuracy of the method was tested on a human hair ERM® certified reference material. Percent recoveries varied from 91.3% and 106.9% being always in the acceptance range of 90–110%. For all analysed elements, RSD% of repeatability ranged between 0.6% and 9.0% and those of intermediate precision did not exceed the limit of 20% being always lower than 10% (except for As). The proposed method was applied for the determination of trace elements in hair samples from 20 unexposed subjects. The geometric mean levels were as follows: Cr 0.28 µg g?1, Mn 0.30 µg g?1, Sn 1.04µg g?1, Sb 0.07 µg g?1, Hg 0.42 µg g?1, As 0.02 µg g?1, Cd 0.03 µg g?1, Ni 0.51 µg g?1, Se 0.45 µg g?1 and Pb 1.83 µg g?1. Element concentrations were in the same range with the reported data. The reported results may be useful for environmental exposure assessment or comparisons studies when establishing reference values of trace elements in exposed population.  相似文献   

6.
《Analytical letters》2012,45(12):1805-1819
Abstract

Floated organic drop microextraction (FDME)–high performance liquid chromatography (HPLC) has been developed for extraction and determination of carbamate and benzoylurea insecticide residues from peach juice drink samples. The components were separated by a Diamonsil C18 instrument (5 µm, 250 mm × 4.6 mm i.d.). The mobile phase was a mixture of acetonitrile, methanol, and water (the ratio of volume was 18:70:12). Factors relevant to the extraction efficiency were studied and optimized. The methodology exhibited good linearity between 0.01 and 10.0 µg/mL with a correlation coefficiency of 0.9999. The average recovery of pesticides ranged from 88.49% to 101.86%. The relative standard deviations (RSDs) (n = 6) were 1.99–3.47%.  相似文献   

7.
《Analytical letters》2012,45(1):147-153
A simple and cost-effective method is described for the determination of aluminum by electrothermal atomic absorption spectrometry (ET-AAS) in serum of hemodialysis patients and healthy subjects. The only preparative step required is the dissolution of the serum sample in 0.2% magnesium nitrate matrix modifier and separate diluents 0.01 M EDTA and 0.1% Triton X-100. The calibration curve was linear from 20 to 100 µg/L with correlation coefficients of 0.9993 and 0.9998 for EDTA and Triton X-100, respectively. The sensitivity of the method for aluminum at the 309.3 nm line was 74 pg. The instrumental and method limits of detection were 2.2 µg/L and 4.4 µg/L, respectively. The aluminum concentrations of forty serum samples from hemodialysis patients and healthy subjects were determined and the mean values were 170.9 ± 6.8 µg/L and 47.3 ± 9.3 µg/L, respectively, whereas the permissible limit for aluminum in blood serum is 10 µg/L. The high level of Al in serum was related to oral phosphate binding agents and dialysis treatment.  相似文献   

8.
A rapid, simple, and efficient method using ultrasound-assisted emulsification microextraction combined with dispersive micro-solid phase extraction (USAE-D-µ-SPE) was developed for detection and quantification of three azole antifungals in milk samples by high-performance liquid chromatography diode array detector. In this study, mesoporous carbon, COU-2, was used as sorbent in USAE-D-µ-SPE for the extraction and preconcentration of analytes. Several important experimental parameters, including type of deproteinized solvents, desorption time, type of extraction solvents, volume of extraction solvent, extraction time, emulsification time, sample pH, salt addition, and mass of COU-2 sorbent, were optimized using spiked milk samples. Under the optimum extraction and detection conditions, three azole antifungals, namely ketoconazole, clotrimazole, and miconazole, were determined within 20 min, with good linearity of matrix-matched calibration in the range of 0.5–5000.0 µg L?1 with coefficient of determination, r 2 ≥ 0.9943. The method showed limits of detection and limits of quantification of all analytes in the range of 0.15–3.0 and 0.5–10.0 µg L?1, respectively. Good repeatability with RSDs <15% (n = 3) and satisfactory relative recoveries (83.3–111.1%) were obtained for spiked azole antifungal drugs in milk. The results reveal that the developed USAE-D-µ-SPE method was a simple, rapid, efficient, environmentally friendly, and practicable method for the determination of azole antifungals in milk samples.  相似文献   

9.
A new analytical approach was developed for the extraction and determination of ammonia and nitrite in environmental water samples involving magnetic solid-phase extraction (MSPE) with magnetite nanoparticles (MNPs) as the adsorbent. The procedure is based on the derivatisation of ammonia based on Berthelot reaction. The obtained indophenol dye was extracted using MSPE and determined spectrophotometrically at 655 ± 3 nm. Nitrite ion is determined after its reduction to ammonia in the presence of Zn/HCl. The main factors that affected the extraction efficiency were studied and optimised. The method gave calibration curves for ammonia with good linearity in the range 10–550 µg L?1, and correlation coefficients (r) higher than 0.99. The detection and quantification limit was found to be 3.1 and 10.2 µg L?1, respectively. The method showed good precision and accuracy, with intra- and inter-assay precisions of less than 6.6% at all concentrations. The recoveries ranged 89–105% and 88–105%, for ammonia and nitrite determination, respectively. The method was applied to the determination of the target analytes in real samples.  相似文献   

10.
A method for separation and quantitative determination of the iodosulfuron-methyl-sodium in water samples by high-performance liquid chromatography (HPLC) was developed and in-house validated in order to demonstrate its performance for monitoring of heterogeneous photocatalytic elimination of the herbicide iodosulfuron-methyl-sodium from water. Surface and ground water samples were used to demonstrate its selectivity, detection and quantification limits, linearity, trueness and precision. In addition, stability of iodosulfuron-methyl-sodium was studied in function of temperature and time. Method accuracy was quantified through measurement uncertainty estimate based on method validation data. The paper gives practical and easy to follow guidance on how uncertainty estimates can be obtained from method validation experiments. It shows that, if properly planned and executed, key precision and trueness studies undertaken for validation purposes can also provide much of the data needed to produce an estimate of measurement uncertainty. Our analytical protocol allowed us to quantify iodosulfuron-methyl-sodium in ground water and surface water in concentration level between 2.50–50.0 μmol L−1 with satisfactory recoveries (99–104%) and repeatability lower or equal than 0.3% for all the matrices. We also estimated within-laboratory reproducibility over 3-month period, which was 0.7%. We proved that the method was selective for determination of iodosulfuron-methyl-sodium in the relevant matrices. Measurement uncertainty of results was evaluated to be 4.0% with 95% confidence level. After validation and measurement uncertainty evaluation steps, results obtained showed that the method can be applied to efficiently monitor heterogenous photocatalytic degradation of the herbicide iodosulfuron-methyl-sodium.  相似文献   

11.
A protocol that utilises data (trueness/recovery, precision and robustness) from validation tests to calculate measurement uncertainty was described and applied to a sector field inductively coupled plasma mass spectrometry (SF‐ICP‐MS)‐based method for the determination of Be, Cd, Hg, Ir, Pb, Pd, Pt, Rh, Sb, U, Tl and W in human serum. The method was validated according to criteria issued by international bodies such as AOAC, Eurachem and ISO and the uncertainty in the analytical measurements was estimated following the Eurachem/Citac guide. The methodology was based on dilution of human serum with water and analysis by serum‐matched standard calibration. The method quantification limits ranged 0.02 µg/L (Tl, Ir) to 0.26 µg/L (Hg). The coefficients of regression were greater than 0.9991 over a range of two orders of magnitude of concentration. The mean trueness was 101% and the mean recovery on three levels of fortification (1‐, 1.5‐, and 2‐times the baseline serum level) ranged between 93.3% and 106%. The maximum relative standard deviation values for repeatability and within‐laboratory reproducibility were 12.8% and 13.5%. The method was robust to slight variations of some critical factors relevant to the sample preparation and SF‐ICP‐MS instrumentation. The relative expanded uncertainty over three levels of concentration ranged from 11.6% (Hg) to 27.6% (Pt), and the uncertainty on the within‐laboratory reproducibility, which included factors such as time, analyst and calibration, represented the main contribution to the overall uncertainty. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

12.
《Analytical letters》2012,45(13):1799-1809
A simple, reliable, and effective analytical method was developed for the simultaneous determination of five organotin compounds (OTCs) including monobutyltin trichloride dibutyltin dichloride tributyltin chloride tetrabutyltin and triphenyltin chloride in white wines. The OTCs were derivatized with sodium tetraethylborate (NaBEt4), and their derivatives were extracted by liquid-liquid extraction (LLE) into n-hexane. The experimental variables, such as type and volume of extraction solvents, amount of derivatization reagent NaBEt4 and extraction time were optimized. The determination of ethylated derivatives of OTCs in the final extracts was carried out by gas chromatography-mass spectrometry (GC-MS). Under optimized conditions, good linearity was observed when analytical concentrations were in the range of 0.01–4.0 µg · mL?1, the linearity correlation coefficients were between 0.9982 and 0.9987, with the LODs in the range of 0.2–3.0 µg · L?1, and the LOQs varied from 0.6 to 10.0 µg · L?1. The obtained recoveries were in the range of 78.0–120.0%, with the relative standard deviations equal to or lower than 8.1%. This method was applied to the determination of OTCs in white wines with satisfactory results.  相似文献   

13.
《Analytical letters》2012,45(13):2195-2208
A sensitive and simple method for the determination of trace nickel was developed by the combination of dispersive liquid–liquid microextraction (DLLME) and microsample injection system–flame atomic absorption spectrometry (MIS–FAAS). Trace nickel was preconcentrated as the 8-hydroxyquinoline chelate by DLLME, and the conditions were optimized by a Plackett-Burman design. Quantitative recovery of nickel (98 ± 1%) was obtained by a sample volume of 7.5 mL at a pH of 6.0. The enrichment factor was 52.5, and the limits of detection and quantitation were 0.1 µ g L?1 and 3.0 µ g L?1, respectively. The method was validated by the analysis of a wastewater standard reference material, water samples, and a wire sample. The reported method has superior analytical figures of merit compared with similar methods reported in the literature.  相似文献   

14.
《Analytical letters》2012,45(9):1342-1354
A novel method for the determination of the migration of bisphenol A (BPA) from polycarbonate water bottles has been developed by using dispersive liquid–liquid microextraction (DLLME) followed by high performance liquid chromatography for compliance with the regulatory specific migration limit. Experimental parameters, including the type and volume of extractants and dispersers, the sample solution pH, addition of salt, extraction time, and temperature, were examined and optimized. Under the optimum conditions, average recovery rates for the real samples varied from 82% to 98%, with relative standard deviation values less than 3.6%. The method offered excellent linearity over a range of 0.8–600 µg L?1 with a correlation coefficient of r = 0.9999. Intra-day and inter-day repeatability values expressed as relative standard deviation were 3.9% and 6.9%, respectively. The method quantitation limit and detection limit were 0.7 and 0.2 µg L?1, respectively. The developed method was successfully applied to the determination of the migration of bisphenol A from 26 polycarbonate water bottles collected locally. The findings indicated the migration from the used bottles was significantly higher than the new ones, and the migration amounts from one sample was very close to the regulatory specific migration limit, and the amounts from seven samples exceeded the daily intake limit for infants.  相似文献   

15.
The comparison between inductively coupled plasma optical emission spectrometry (ICP-OES) and total reflection X-ray fluorescence spectrometry (TXRF) for simultaneous determination of metal content (Cr, Cu, Fe, Mn, Pb and Zn) in mosses from the Metropolitan Area of the Toluca Valley was performed. Epiphytic mosses (Fabriona ciliaris and Leskea angustata) were collected in two sampling campaigns and were digested with HNO3, HCl and HF for ICP-OES method and HNO3 and HCl for TXRF method. The certified reference material (IAEA-336, Lichen) and the Standard Reference Material (SRM-1573, tomato leaves) were used for the quality control and to evaluate trueness and precision. Linearity, detection and quantification limits were also determined. Results show an ICP-OES and TXRF trueness mean of 101 ± 5% and 97 ± 9%, respectively; the relative standard deviation (RSD percent) was less than 17% in both methods. The moss samples exhibit a satisfactory precision (RSD ≤ 20%), because the RSD percent for ICP-OES, from 2% to 15%, and that for TXRF, from 1% to 17%, were obtained. One factor experimental design and simple regression analysis (α = 0.05) were used to compare the ICP-OES and TXRF metal concentrations. The statistical results do not show significantly different values for Cu, Mn, Pb and Zn in both the sample campaigns. In addition, the average results for Cr in the first sample campaign (30.3 ± 11.4 mg/kg for ICP-OES and 18.6 ± 9.8 mg/kg for TXRF) and Fe values in the second sample campaign (10,810 ± 2980 mg/kg for ICP-OES and 8380 ± 2350 mg/kg for TXRF) were significantly different in both methods. These differences are attributed to an incomplete sample digestion in the TXRF sample preparation. The results of the simple regression analyses show p-value less than 0.05, which indicates an equivalent and significant relation between ICP-OES and TXRF.  相似文献   

16.
《Analytical letters》2012,45(6):1015-1030
A reliable indirect competitive enzyme-linked immunosorbent assay (ELISA) based on a new specific monoclonal antibody was developed to determine olaquindox in animal feed. The influence of several physicochemical factors (nonfat dried milk solution, organic solvent, incubation time) on the immunoassay was investigated. In the optimized system, the 50% inhibition concentration was 9.66 ± 1.81 µ g L?1. The limits of detection for porcine, chicken, and fish feed were 0.28, 0.46, and 0.48 µg kg?1. The limits of quantification were 1.00 µg kg?1 for the feed samples. The recoveries from porcine, chicken, and fish feed spiked with olaquindox were 90–104%, 77–103%, and 78–107%, respectively, with coefficients of variation (CVs) between 3.8 and 14.1%. The cross-reactivity was less than 2.08% with four structurally related compounds and no recognition of five other restricted or forbidden drugs was observed. Parallel analysis of the three spiked feed samples showed comparable results between the indirect competitive ELISA and the standard high-performance liquid chromatography method in China (R2 = 0.9985 for porcine feed, R2 = 0.9896 for chicken feed, and R2 = 0.9987 for fish feed). These data suggest that the developed indirect competitive ELISA is a specific and convenient method and is suitable for olaquindox determination in animal feed.  相似文献   

17.
《Analytical letters》2012,45(3):531-542
Microwave-assisted extraction of sixteen polycyclic aromatic hydrocarbons and their gas chromatographic mass spectrometric detection are presented herein. An efficient extraction was achieved in 15 minutes using 10 mL of 1:1 n-hexane-acetone while a clean-up step was developed studying the elution curves on solid phase extraction silica cartridges. The analytical method was optimized and validated using a certified reference marine sediment; satisfactory figures of merit were obtained with limits of detection in the range 0.001–0.004 µg/g, precision within 6%, and good linearity (regression coefficients generally higher than 0.998, in the concentration range 0.010–1.000 µg/mL). The developed method was successfully applied to the determination of polycyclic aromatic hydrocarbons in real marine sediments collected in two coastal areas of Italy exposed to different anthropic impact: three tourist sites of Liguria and the Venetian Lagoon. The total concentration of the analytes in the samples was in the range 1.027–3.827 µg/g and the use of common markers suggested their probable pyrolytic origin.  相似文献   

18.
&#;anli  Senem  &#;anli  Nurullah  Ozkan  Sibel A.  Lunte  Craig 《Chromatographia》2016,79(19):1351-1358

A sensitive, simple, rapid, experimentally convenient, cost-effective, environmentally friendly and high-throughput green chemistry by capillary electrophoresis (CE) approach for the determination of eight polyphenolics frequently found in red wines from USA was carried without using toxic organic modifier. Several parameters which affect the separation were investigated to determine the optimum conditions. At room temperature, the eight polyphenolics could be well separated within 15 min in a 55-cm length capillary at a separation voltage of 26 kV with 40-mM borate buffer (pH 8.9). The method was fully validated showing satisfactory data for all method validation parameters tested. The limits of detection varied from 0.15 to 0.32 µM. The relative standard deviations of migration varied from 0.208 to 0.630 %. The Californian red wine samples analyzed were bought in the local markets, and the polyphenolic compound recoveries were in the range of 98–99.7 %. The method was successfully applied to the determination of the studied polyphenolics in red wine samples with satisfactory recoveries. Catechin, syringic acid, apigenin, myricetin, luteolin, quercetin, caffeic acid, and gallic acid were detected in all samples, with gallic acid and myricetin occurring in the highest concentration.

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19.
《Analytical letters》2012,45(2):343-355
A new analytical procedure for the determination of five organotin compounds in several matrix wine samples is reported. The organotin compounds were extracted by microwave-assisted extraction with n-hexane. Extraction conditions, such as volume of n-hexane required, extraction temperature, and extraction time, were investigated and optimized by an orthogonal array experimental design. The determination of organotin compounds in the final extracts was carried out by liquid chromatography–inductively coupled plasma mass spectrometry. The procedure showed limits of detection between 0.029–0.049 µg · L?1. The linearity was in the range of 0.5 to 100 µg · L?1. The precision expressed as relative standard deviation (RSD) was below 9.43%. The developed method was successfully employed to analyze different matrix wine samples, and some analytes were detected at the level of 0.053 to 1.14 µg · L?1.  相似文献   

20.
《Analytical letters》2012,45(1):207-220
Abstract

A method for determination of selected triazines in waters was developed. The method includes off‐line solid‐phase extraction of triazines on the polymeric sorbent, high‐pressure liquid chromatographic separation, and determination with tandem mass spectrometer. The linearity extended from 0.008 to 1.000 µg L?1 for each triazine while the limits of detection ranged from 0.001 to 0.004 µg L?1. Solid‐phase extraction recoveries from ground, surface, and waste waters ranged from 64% to 96%. Possible water interferences were investigated. Natural humic acids and salts did not influence the ionization process. The presence of humic acids did not affect binding ability of the solid‐phase sorbent, while the presence of salts increased the extraction efficiency by approximately 10%.  相似文献   

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