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1.
Doong RA  Lee CY 《The Analyst》1999,124(9):1287-1289
Fourteen organochlorine pesticide residues in fatty foods were determined using a simple and rapid procedure based on solid-phase extraction (SPE) clean-up cartridges with octadecyl (C18)-bonded porous silica, a tandem C18 and Florisil column, Alumina-N and Florisil. A Florisil cartridge eluted with 12 ml petroleum ether-ethyl ether (95 + 5) was the most efficient clean-up procedure capable of eliminating the matrix interference and satisfying the agreed acceptable recovery for the large numbers of organochlorine pesticides in nine kinds of foods having different fat contents. Average recoveries of organochlorine pesticides in shellfish, fish and meats ranged from 77 to 105%, 84 to 98% and 85 to 107%, respectively. In addition, analysis of a certified Standard Reference Material (SRM 1945) verified the satisfactory performance of Florisil clean-up cartridge. This SPE method not only yielded comparable results for nonfatty foods, but also provided a reliable separation and quantification of organochlorine pesticides for analyzing a large number of foods with a wide range of fat content.  相似文献   

2.
Dispersive solid-phase extraction (DSPE) cleanup combined with accelerated solvent extraction (ASE) is described here as a new approach for the extraction of carbamate pesticides in Radix Glycyrrhizae samples prior to UPLC-MS-MS. In the DSPE-ASE method, 15 carbamate pesticides were extracted from Radix Glycyrrhizae samples with acetonitrile by the ASE method at 60 °C with a 5 min heating time and two static cycles. Cleanup of a 1 mL aliquot of the extract by the DSPE method used 20 mg PSA (primary secondary amine), 50 mg Al(2)O(3)-N, and 20 mg GCB (graphitized carbon black) (as cleanup sorbents) under the determined optimum conditions. The linearity of the method was in the range of 10 to 200 ng/mL with correlation coefficients (r(2)) of more than 0.996. The limits of detection were approximately 0.2 to 5.0 μg/kg. The method was successfully used for the analysis of target pesticides in Radix Glycyrrhizae samples. The recoveries of the carbamate pesticides at the spiking levels of 50, 100, and 200 μg/kg ranged from 79.7% to 99.3% with relative standard deviations lower than 10%. This multi-residue analytical method allows for a rapid, efficient, sensitive and reliable determination of target pesticides in Radix Glycyrrhizae and other medicinal herbs.  相似文献   

3.
Summary Plots of capacity factor and retention time vs. elution solvent composition were proved to be useful to interpret the retention behavior of Kepone and its metabolites in a reversed-phase solid-phase extraction and to optimize the elution solvent. The percent recovery of Kepone was largely improved when the solvent was optimized. The standard deviations of the results of extractions were also improved upon the optimization of the solvent.  相似文献   

4.

High-performance liquid chromatography with solid-phase extraction (HPLC-SPE) was optimized for the analysis of three organophosphorus pesticide residues in water, apples and vegetable samples. Octadecylsilica disks (47-mm diameter) were used for solid-phase extraction. The parameters that affect both separation and extraction of methyl parathion, parathion and phoxim, such as mobile-phase composition, ionic strength, temperature, pH, and breakthrough volume, were investigated. The application of optimized HPLC-SPE to environmental samples gave reproducible results with low detection limits of 5 µg L?1 for methyl parathion and parathion and 2.5 µgL?1. Precisions of less than 8, 9 and 12% were obtained for water, spinach and apple samples, respectively.  相似文献   

5.
A regular monitoring program to study the pesticide concentration in surface waters has been carried out since 1976 in Hungary by the National Plant Protection Organization of the Ministry of Agriculture and Regional Development jointly with the Regional Water Authorities. At the beginning of this program a liquid-liquid partition method is used to extract the pesticides from water samples. After checking the pH value, one sample aliquot is extracted to analyze the basic and neutral compounds. Another aliquot is acidified to pH 2 and extracted to analyze acidic compounds. Disadvantages of this method are high solvent consumption and the need to apply solvents (methylene chloride and diethyl ether) that are harmful to human health. Therefore, the solid-phase extraction method has been introduced. This method has another advantage in that by using the vacuum manifold a number of samples can be extracted simultaneously depending on the capacity (number of ports) of the manifold. Three types of cartridges (LiChrolut EN, ISOLUTE ENV+, and Carbograph) are tested. The suitability and reproducibility of the extraction on various cartridges is studied and compared through recovery experiments. Recoveries are done for 22 active ingredients at spiking levels of 1-5 times the limit of determination (in the range of 0.05-2.5 microg/L) with each extraction method. Individual recovery values as well as average recoveries for all methods are between 70% and 100%, with the relative standard deviation generally below 20%. Carbograph is the only cartridge among those studied that can be used to extract both neutral and acidic compounds in one sample loading step using two different consecutive elution steps.  相似文献   

6.
A solid-phase microextraction (SPME) procedure using three commercialised fibers (Carbowax-divinylbenzene, Carboxen-polydimethylsiloxane and divinylbenzene-Carboxen-polydimethylsiloxane) is presented for the determination of a selected group of organochlorine compounds in water samples. The extraction performances of these compounds were compared using fibers with two and three coatings. The optimal experimental procedures for the adsorption and desorption of pesticides were determined. The limits of detection with the divinylbenzene-Carboxen-polydimethylsiloxane fiber at levels below ng l(-1) were similar or lower than values presented in the literature for several of these compounds using polydimethylsiloxane fiber. The advantages of using this fiber, such as no salt addition, are discussed. Finally, the optimised procedures were applied successfully for the determination of these compounds in polluted ground water samples.  相似文献   

7.
Rapid and practical extraction methods were developed using dichloromethane and ethyl acetate for the routine determination of 16 organochlorine pesticide residues and applied to approximately 30 fresh vegetables (tomato, cucumber and pepper) by using GC-ECD. The procedures were validated. Measurement uncertainties were calculated by applying bottom-up approach. The average recoveries obtained for each pesticide ranged between 65 and 102% at three fortification levels. The uncertainties of the analytical methods were lower than 21 and 16% with and without recovery correction, respectively. The calculated limits of detection and quantification were typically less than 1 ng g−1 that were much lower than the maximum residue levels.  相似文献   

8.
建立了茶叶中13种有机氯和10种拟除虫菊酯农药残留量的气相色谱-负化学离子源.质谱(GC-NCl-MS)分析方法.茶叶样品用V(丙酮):V(CH2Cl2)=1:1混合液作提取剂经加速溶剂萃取,提取液经凝胶色谱净化除去大部分的色素、脂类和蜡质,再经活性炭-氨基(Carb-NH2)复合小柱和Florisil小柱净化后,用GC-NCl-MS的选择离子监测方式(SIM)进行定性和定量分析.添加50μg/kg 浓度水平时,农药回收率在45.6%~112.4%之间,相对标准偏差在0.57%~10.1%之间;方法的检出限(3倍信噪比)在0.05~10.0μg/kg之间.方法适用于出口茶叶农残检测实际工作.  相似文献   

9.
10.
A headspace solid-phase microextraction method has been developed for the determination of 8 pesticides in vegetables and fruits by using gas chromatography with an electron capture detector. Two types of fibers (polyacrylate, 85 microm and polydimethylsiloxane, 100 microm) have been assayed and compared. The main factors: extraction and desorption parameters, ionic strength, and the effects of dilution and organic solvents, were studied and optimized. The optimized procedures resulted in more than 80% recovery for all the investigated vegetable and fruit samples with RSD values below 10%.  相似文献   

11.
杨海玉  俞英  郑秀丽 《色谱》2008,26(6):744-748
建立了固相萃取(SPE)-反相高效液相色谱(RP-HPLC)同时测定橙子中痕量辛硫磷、二嗪农有机磷农药残留量的方法。样品经甲醇超声提取、C18固相萃取柱净化后,采用液相色谱柱分离,以乙腈-水(体积比为85∶15)为流动相等度洗脱,于254 nm下紫外检测。结果表明:在0.1~10.0 mg/L和0.4~10.0 mg/L范围内,辛硫磷、二嗪农的质量浓度与峰面积呈良好的线性关系;样品的加标平均回收率为87.3%~102.7%,相对标准偏差(RSD)为0.9%~4.9%。将该分析结果与用基质固相分散法(MSPD)处理样品所得的结果相比较,发现SPE对二嗪农的提取效果较好,而MSPD对辛硫磷的提取效果较好,但两种方法都能较好地净化样品,均能满足残留量的分析要求。  相似文献   

12.
A rapid and simple method for simultaneous analysis of four neonicotinoid insecticides including acetamiprid, imidacloprid, thiacloprid and thiamethoxam in fruit and vegetable matrices has been developed. For instance, ready-to-use cartridges filled with a macroporous diatomaceous material were used to extract in a single step insecticide residues with dichloromethane from aqueous-acetone extracts of fruits and vegetables. The eluate was evaporated, the residue redissolved with methanol and then analyzed by liquid chromatography-mass spectrometry in the electrospray ionization (ESI) positive mode. Average recoveries of the four pesticides were between 74.5 and 105% at both spiking levels 0.1 and 1.0 mg kg(-1) in peach, pear, courgette, celery and apricot. Relative standard deviations (RSDs) were less than 10% for all of the recovery tests. The calculated limits of quantitation (LOQs) (0.1-0.5 mg kg(-1)) were equal or lower then the maximum residue limits (MRLs) established by European legislation (0.1-0.5 mg kg(-1)). The proposed method is fast, easy to perform and could be utilized for monitoring of pesticides residues.  相似文献   

13.
Organochlorine pesticide residues have been extracted from samples of animal feed by a solid phase extraction clean-up procedure using an octadecyl-bonded column. The proposed method gave recoveries ranging from 70 to 100 % for ppb levels of the fifteeen pesticides studied. Analytes were identified by dual-column capillary gas chromatography employing DB-1 and DB-1701 columns in parallel; identities were confirmed by calculation of retention indexes with the cubic spline interpolation method.  相似文献   

14.
A simple, fast, and inexpensive method for the determination of pesticide residues in fruits and vegetables is introduced. The procedure involves initial single-phase extraction of 10 g sample with 10 mL acetonitrile, followed by liquid-liquid partitioning formed by addition of 4 g anhydrous MgSO4 plus 1 g NaCl. Removal of residual water and cleanup are performed simultaneously by using a rapid procedure called dispersive solid-phase extraction (dispersive-SPE), in which 150 mg anhydrous MgSO4 and 25 mg primary secondary amine (PSA) sorbent are simply mixed with 1 mL acetonitrile extract. The dispersive-SPE with PSA effectively removes many polar matrix components, such as organic acids, certain polar pigments, and sugars, to some extent from the food extracts. Gas chromatography/mass spectrometry (GC/MS) is then used for quantitative and confirmatory analysis of GC-amenable pesticides. Recoveries between 85 and 101% (mostly > 95%) and repeatabilities typically < 5% have been achieved for a wide range of fortified pesticides, including very polar and basic compounds such as methamidophos, acephate, omethoate, imazalil, and thiabendazole. Using this method, a single chemist can prepare a batch of 6 previously chopped samples in < 30 min with approximately 1 dollar (U.S.) of materials per sample.  相似文献   

15.
The biodegradation of the organophosphorus insecticide methyl parathion (MP) in aqueous environment by bacteria isolated from river sediment has been studied. Two species of bacteria which show strong MP degradation ability are identified as Shewanella and Vibrio parahaemolyticus. The biodegradation of MP proceeded rapidly with the formation of a series of intermediate products, which were analyzed using a combination of GC/MS and HPLC/ESI-TOFMS techniques. The major products tentatively identified include a series of reduced products of MP. Results demonstrate that the coupling of TOFMS to HPLC enhances further the capability of LC-MS in the identification of polar organic species in complex environmental samples. Degradation pathways leading to the formation of these products are proposed which involves first the reduction of nitro to amino group in MP, followed by combination with some intrinsic matters of bacteria. The mechanism and products from biodegradation are quite different from those of photocatalytic process for which the main intermediates included methyl paraoxon and 4-nitrophenol.  相似文献   

16.
A simple micro-method is described for determination of 15 organochlorine pesticide residues in mixed feeds. Clean-up of the petroleum ether extract is by basic alumina minicolumn chromatography and quantitative identification is by capillary gas chromatography with electron capture detection. Cyanopropyl-polysiloxane chemically bonded fused silica capillary columns have been used to perform high resolution analyses in short time as well as to overcome possible interferences by PCBs. Recovery, repeatability, and detection limits of the proposed procedure are checked and results are also reported for non random samples of 180 feeds collected in Italy.  相似文献   

17.
Different extraction methods were evaluated for the determination of fifteen organochlorine pesticides (OCPs) in water and sediments. Liquid-liquid extraction (LLE) was evaluated for the pesticides analyses in water while Soxhlet extraction (SE) and microwave assisted extraction (MAE) methods were compared in sediment. Of all the extracting solvents used, dichloromethane gave the best results. Percentage recoveries ranged from 71.03 +/- 8.15 (dieldrin) to 101.25 +/- 2.17% [a-benzenehexachloride (alpha-BHC)] in water with LLE. In sediments the percentage recoveries with Soxhlet extraction method varied between 88.22 +/- 7.85 (endrin) and 109.63 +/- 5.10% (beta-BHC) and ranged from 74.11 +/- 9.82 (2,4 DDT) to 97.50 +/- 4.56% (alpha-BHC) with MAE. The limits of detection for the OCPs ranged from 5.5 to 20.6 ng/l and between 0.6 and 2.1 ng/g. respectively. The LLE and the SE methods were applied to water and sediments samples, respectively, from marine and freshwater sources in the Eastern Cape Province of South Africa that receive runoffs from agricultural lands and effluents from industries. The levels of OCPs ranged from 5.5 (2,4-DDD) to 450 +/- 0.10 ng/l (beta-BHC) in water samples and from 0.6 (aldrin and 2,4-DDD) to 184 +/- 0.12 ng/g (beta-BHC) in sediments for triplicate analyses. Some endocrine disrupting OCPs such as DDT, DDE, heptachlor, endosulphan and the chlordanes were detected.  相似文献   

18.
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.  相似文献   

19.
A rapid and easy method has been proposed, optimized and evaluated for quantitative determination at trace level of a representative group of non-polar pesticides in fat samples. The method includes n-hexane-saturated acetonitrile extraction, fat precipitation by cooling pre clean-up followed by dispersive solid-phase extraction (d-SPE) based on QuEChERS procedure clean-up. Determination was performed by gas chromatography?Cmass spectrometry (GC-MS) in selected ion monitoring (SIM) mode. Efficiency of the d-SPE clean-up step was evaluated by comparison with fat oxidation treatment and gel permeation chromatography. Different combinations of d-SPE extraction reagents and sample amounts were tested in order to minimize matrix co-extractives and interferences. Best recoveries were obtained with 1200?mg of MgSO4, 400?mg of end-capped C18, 400?mg of PSA and 1?g of sample amount. SIM method, matrix effect, precision, and accuracy were evaluated with spiked pork fat samples for 38 representative pesticides. Results of this study showed that this technique is applicable in routine analysis for its application into monitoring programs. It simplifies time-consuming clean-up steps and allows a satisfactory long-term chromatographic performance.  相似文献   

20.
土壤中多种有机氯及拟除虫菊酯类农药的GC-ECD测定   总被引:1,自引:0,他引:1  
气相色谱法同时测定土壤中多种有机氯及拟除虫菊酯类农药。对土壤的分析结果:有机氯农药的检出限0.001~0、003μg/mL,拟除虫菊酯类农药检出限0.008~0.02μg/mL,线性相关系数0.9978~0.9999。用y(石油醚):V(丙酮)=3:1超声波提取,有机氯农药回收率94.2%~124.0%,相对标准偏差为3.3%~8.8%(n=5);拟除虫菊酯类农药回收率95.2%~118.3%,相对标准偏差为5.7%~7.1%(n=5);方法适用于土壤样品中农药残留测定。  相似文献   

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