分散固相萃取-气相色谱-三重四极杆质谱分析蔬菜中112种农药残留

评价了分析过程中不同条件下使用分散固相萃取(D-SPE)材料净化对农残分析定量结果可靠性的影响,表明通过条件优化,可明显减小定量误差,并取得满意的回收率。建立了蔬菜中112种农药的多反应监测-气相色谱-串联质谱(GC-MS/MS)检测方法。在pH 5～7范围内,样品经乙腈-甲苯(8:1, v/v)匀浆提取,每5 mL提取液加入0.8 g无水硫酸镁、0.05 g石墨化炭黑(GCB)、0.1 g乙二胺-N-丙基甲硅烷(PSA)、0.05 g C18粉末,分散固相萃取法净化,采用气相色谱-三重串联四极杆质谱(GC-QQQ-MS/MS)在多反应监测模式(MRM)下进行测定,内标法定量。分别对韭菜、黄瓜、紫甘蓝进行3个水平的加标回收试验(20、50、200 μg/kg),其回收率范围为53.1%～138.7%,其中86种农药的3个加标水平的回收率范围均为65.0%～120.0%,方法的相对标准偏差(RSD)小于12%,方法的定量限(LOQ)范围为1.6～13.4 μg/kg。对从市场采集的蔬菜样品进行了测定,检出了三唑磷、甲氰菊酯等农药残留。该方法样品前处理简单快速,灵敏度、准确度和精密度均符合农药多残留检测技术的要求,适用于蔬菜中112种农药残留的快速筛查测定。     

自组装管尖固相萃取/超高效液相色谱-高分辨质谱法测定水果中的15种酸性农药

建立自组装管尖固相萃取结合超高效液相色谱-高分辨质谱检测水果中15种酸性农药残留的分析方法。水果样品经甲酸-乙腈(1∶99,体积比)提取后,以官能化聚苯乙烯/二乙烯苯(PEP)和亲水作用色谱(HILIC)作为吸附填料进行管尖固相萃取净化。以T3色谱柱进行色谱分离,采用高分辨质谱的t SIM/dd MS2扫描模式进行定性、定量分析,内标法测定。15种酸性农药在各自线性范围内呈良好的线性关系,相关系数(r2)均大于0.99。方法的定量下限(LOQ)为0.2~10μg/kg。在LOQ,10μg/kg,100μg/kg加标水平下,15种酸性农药的回收率为73.5%~115.9%,相对标准偏差为1.0%~8.3%。该方法灵敏、准确,适用于水果中酸性农药残留的分析测定,具有很好的实际应用价值。     

Quantitation of 17alpha-ethinylestradiol in aquatic samples using liquid-liquid phase extraction, dansyl derivatization, and liquid chromatography/positive electrospray tandem mass spectrometry

A rapid and sensitive method for the analysis of 17alpha-ethinylestradiol (EE2) in environmental aqueous samples has been developed. Aquatic samples were extracted using liquid-liquid extraction, and organic phase extracts were concentrated and derivatized with dansyl chloride. Analysis was performed using high-performance liquid chromatography with positive electrospray ionization and tandem mass spectrometry (HPLC/ESI-MS/MS). Deuterated 17alpha-ethinylestradiol was used as internal standard and was added to samples before extraction. A limit of quantitation of 1 ng/L was obtained using a 25 mL aqueous sample. The average recovery of EE2 spiked into a 25 mL tapwater sample was 100%. This highly sensitive quantitation method is useful for measuring low levels of EE2 in aqueous environmental samples.     

加速溶剂萃取-凝胶渗透色谱净化-气相色谱快速分析动物源性食品中残留的多种有机磷农药

建立了动物源性食品猪肉、牛肉、鸡肉及鱼肉中36种有机磷农药残留的快速分析方法。以乙腈作为溶剂,对试样采用加速溶剂萃取仪萃取,自动凝胶渗透色谱仪净化预处理,N-丙基乙二胺(PSA)填料再净化,毛细管气相色谱法分离,火焰光度检测器(磷型)检测,内标法定量。该方法分离效果良好,重现性好,灵敏度、精密度高,杂质干扰少。36种有机磷农药的检测限(LOD)为0.0012 mg/kg(乙拌磷)～0.014 mg/kg(吡唑硫磷),定量限(LOQ)为0.004 mg/kg(乙拌磷)～0.047 mg/kg(吡唑硫磷)。当试样中有机磷农药的添加浓度分别为0.05,0.1,0.2 mg/kg时,回收率为58.2%～106.3%。方法的最低检测限和添加回收率均符合农药残留分析的要求。     

微波辅助萃取-分散固相萃取-气相色谱质谱法测定茶叶中23种农药残留

建立了微波辅助萃取-分散固相萃取净化-气相色谱质谱法（GC-MS）快速测定茶叶中23种农药残留量的方法. 茶叶样品用乙腈进行微波辅助萃取（MAE）,提取液经分散固相萃取（DSPE）净化处理. 采用DB-17MS毛细管色谱柱分离后,选择离子监测模式下（SIM）质谱法进行测定. 23种农药组分在0.01~0.50 mg/mL质量浓度范围内呈线性关系,相关系数r2大于0.995,方法测定低限（10S/N）为0.005~0.01 mg/kg. 以空白绿茶为基体,在4个标准添加水平0.01、0.05、0.10、0.25 mg/kg进行加标回收试验,加标平均回收率为70%~105%,相对标准偏差为3.0%~8.2%.     

Application of single-drop microextraction and comparison with solid-phase microextraction and solid-phase extraction for the determination of alpha- and beta-endosulfan in water samples by gas chromatography-electron-capture detection

Water contamination due to the wide variety of pesticides used in agriculture practices is a global environmental pollution problem. The 98/83 European Directive requires the measurement of pesticides residues at a target concentration of 1.0 microg/l in surface water and 0.1 microg/l in drinking water. In order to reach the level of detection required, efficient extraction techniques are necessary. The application of a new extraction technique: single-drop microextraction (SDME), followed by gas chromatography with electron-capture detection, was assessed for determining alpha-endosulfan and beta-endosulfan in water samples. Experimental parameters which control the performance of SDME, such as selection of microextraction solvent and internal standard, optimization of organic drop volume, effects of sample stirring, temperature and salt addition, and sorption time profiles were studied. Once SDME was optimized, analytical parameters such as linearity, precision, detection and quantitation limits, plus matrix effects were evaluated. The SDME method was compared with solid-phase microextraction and solid-phase extraction with the aim of selecting the most appropriate method for a certain application.     

固相萃取–气相色谱–串联质谱法测定茶叶中9种农药残留量

建立固相萃取净化–气相色谱–串联质谱法同时测定茶叶中9种农药残留量的方法。茶叶样品用乙腈均质提取,提取液经固相萃取净化处理后,采用DB–5MS毛细管色谱柱分离,在多反应监测模式下测定,外标法定量。9种农药组分的质量浓度在0.01~0.50 mg/L范围内与其色谱峰面积呈良好线性,相关系数r~2大于0.998,方法测定下限(10 S/N)为0.002~0.01 mg/kg。以空白绿茶、红茶、普洱茶和乌龙茶为基体,在0.05,0.1,0.2 mg/kg 3个添加水平进行加标回收试验,加标回收率在73.6%~99.7%之间,相对标准偏差为4.2%~8.7%(n=6)。该法操作简便、快速,适用于茶叶中多种农药残留的测定。     

固相萃取/高效液相色谱-串联质谱法同时检测环境水样中24种农药残留

建立了一种固相萃取/高效液相色谱-串联质谱(SPE/HPLC-MS/MS)同时检测水体中24种农药的分析方法。样品用乙腈提取后,经固相萃取小柱富集净化。以乙腈-0.1%(体积分数)甲酸水溶液为流动相梯度洗脱,在电喷雾离子源正离子模式下(ESI+)采用多反应监测(MRM)模式检测。结果显示,24种农药在1~200μg/L范围内具有良好的线性关系,相关系数(r2)均不小于0.998,水样中3个添加水平(5、20、100μg/L)下的回收率为65.9%~127.8%,相对标准偏差(RSD)为0.7%~14.2%;方法检出限为0.05~0.71 ng/L。采用该方法对大连地区10个河流入海口及2个水库的水样进行了检测,12个站位的样品中共检出10种农药,质量浓度为0.2~558.3 ng/L。结果表明,所建立的SPE/HPLC-MS/MS方法高效、灵敏、可靠,可用于实际水体中多种农药的同时检测。     

Simplified pesticide multiresidue analysis of soybean oil by low-temperature cleanup and dispersive solid-phase extraction coupled with gas chromatography/mass spectrometry

A simple, fast, and economical method has been developed for the simultaneous determination of 28 various types of pesticides in soybean oil. Pesticides of low molecular mass were separated from the fat of the oil, which has a high molecular mass, by using low-temperature fat precipitation, followed by a cleanup process based on dispersive solid-phase extraction with primary secondary amine and C18 as sorbents and magnesium sulfate for the removal of residual water. The results for all pesticides determined by gas chromatography with mass spectrometry in the selected-ion monitoring mode were linear, and the matrix effect of the method was evaluated. Recoveries of most pesticides were acceptable at fortification levels of 0.02, 0.05, 0.2, and 1 mg/kg. The relative standard deviation was <20% even for determinations without internal standards. Limits of quantitation ranged from 20 to 250 microg/kg.     

Multi-residue determination of organochlorine pesticides in vegetables in Kirklareli,Turkey by gas chromatography–mass spectrometry

The aim of this study was to investigate the level of organochlorine pesticides use for treatment of tomatoes, eggplants and cucumbers in Kirklareli, Turkey. Eighteen organochlorine pesticides were identified in vegetable samples using microwave or Soxhlet extraction, and results were obtained by gas chromatography–mass spectrometry. The optimized conditions were 1 mL/min for flow rate in the mobile phase, 1 μL for injection volume and 70 V for fragmentation potential. The analytical parameters show that the microwave oven extraction procedure provided the best results when compared to the Soxhlet extraction procedure. Samples were prepared for analysis with hexane?dichlormethane (1: 1, v/v, 40 mL) using a solid-phase extraction method. The limits of detection and quantitation for the eighteen analytes were between 0.02–0.26 and 0.06–0.87 μg/L, respectively, and the relative standard deviations of the migration time ranged from 2.4 to 8.9%. The recoveries of surrogate spiked in vegetable samples ranged from 70 to 116%, respectively. The obtained concentrations of pesticides in all vegetables studied were proved in the range of ND–123 μg/kg. The organochlorine pesticide sum was below the legal limit, except for Endrin and Methoxychlor, which requires a further elucidation of the organochlorine pesticides pollution sources in the region. These studies on accumulation of organochlorine pesticides were necessary for accomplishing a comprehensive ecological risk assessment.     

Simple water analysis of golf link pesticides by means of batch-wise adsorption and supercritical fluid extraction

Here, a simple new method is proposed to evaluate water for the presence of pesticides. Specifically, pesticides for golf link maintenance were used as the targets for this investigation. Water samples containing the pesticides were mixed with particulate adsorbent, after which the pesticides were extracted from the adsorbents using supercritical fluid carbon dioxide and then analyzed by gas chromatography-mass spectrometry. The recoveries of pesticides were examined with several types of adsorbents and found to be related to their octanol/water partition coefficients (K_ow) for most of the adsorbents. Good recoveries were obtained when the water samples were mixed with octadecylsilane (ODS) and stylene-divinylbenzene copolymer (XAD) resins for 15 and 30 min, respectively. In the supercritical fluid extraction, extraction pressure affected the efficiency of extraction from XAD while a little effect on extraction from ODS, probably due to the internal structure of the adsorbents. The limit of detection ranged from 0.002 to 2.3 μg L⁻¹ and the method is suitable for the measurement of golf link pesticides in μg L⁻¹ order to 100 μg L⁻¹. The procedure of the proposed method was simpler than the conventional solid-phase extraction method. Finally, the method presented here was used to identify pesticides present in actual wastewater from golf links.     

Analyses of pesticide residues in fruit-based baby food by liquid chromatography/electrospray ionization time-of-flight mass spectrometry

A liquid chromatography/electrospray ionization time-of-flight mass spectrometry (LC/ESI-TOFMS) method has been developed for the determination of 12 pesticides (namely, carbendazim, thiabendazole, imazalil, tridemorph, triadimefon, bitertanol, prochloraz, flutriafol, myclobutanil, iprodione, diphenylamine and procymidone) in fruit-based baby food (multi-fruit jars and juices intended for infant consumption). The developed method consists of a sample treatment step based on liquid-liquid extraction using acetonitrile, followed by a clean-up step based on dispersive solid-phase extraction (SPE) with a primary-secondary amine (PSA). Multi-fruit and apple juices were processed by a SPE procedure using Oasis HLB cartridges. Subsequent identification and quantitation was accomplished by LC/ESI-TOFMS analysis: the confirmation of the target pesticides was based on accurate mass measurements of selected ions (protonated molecules ([M+H]+) and fragment ions). Confirmation studies were accomplished at low concentration levels (10 microg kg-1) and accuracy errors lower than 2 ppm were obtained in most cases. Baby food extracts spiked at 10 microg kg-1 fortification level yielded average recoveries in the range 78-105% with relative standard deviations less than 10% for most of the analytes. Limits of detection (LODs) were between 0.1 and 4 microg kg-1 depending on the pesticide studied. Finally, the proposed method was applied to a total of 33 baby food samples from Spain and the United Kingdom. Although imazalil, thiabendazole and carbendazim were detected in a high number--over 60%- of baby food samples, none of the samples tested were found to be above the 0.01 mg kg-1 EU standard.     

Rapid and highly sensitive liquid chromatography/electrospray ionization tandem mass spectrometry method for the quantitation of buspirone in human plasma: application to a pharmacokinetic study

A rapid and sensitive method for the quantitation of buspirone in human plasma by liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) was developed. Plasma samples were treated by liquid-liquid extraction with methyl tert-butyl ether (MTBE). The chromatographic separation was performed isocratically on a reversed-phase Shiseido C18 column (50 mm x 2.0 mm, 3 microm) with a mobile phase of acetonitrile/0.1% acetic acid (1:1, v/v). The acquisition was performed in multiple reaction monitoring (MRM) mode, monitoring the transitions m/z 386 --> 122 for buspirone and m/z 409 --> 238 for amlodipine (the internal standard). The method was validated to determine its specificity, recovery, limit of quantitation, accuracy and precision. The lower limit of quantitation was 0.02 ng/mL with a relative standard deviation of less than 10%. The present method provides an accurate, precise and sensitive tool for buspirone and was successfully applied to a pharmacokinetic study in eight subjects.     

Determination of Atrazine,Simazine, Alachlor,and Metolachlor in Surface Water Using Dispersive Pipette Extraction and Gas Chromatography–Mass Spectrometry

Four commonly found pesticides (alachlor, atrazine, metolachlor, and simazine) in surface water were determined using dispersive pipette extraction followed by gas chromatography–mass spectrometry. The rapid mixing and equilibrium between the dispersive pipette extraction adsorbent and water sample resulted in fast and efficient extraction. Using only 5?mL of water sample, the estimated time consumption for extraction of each sample was less than 5?min. Method validation was performed to evaluate accuracy, precision, linearity, the limits of detection, and the limits of quantitation. Average recovery of above 90% was obtained with relative standard deviations below 10%, which indicated good accuracy and precision of the dispersive pipette extraction method. Coefficients of determination were all above 0.9901 and showed good linearity. For the four pesticides studied using the current method, the limits of detection ranged from 7 to 40?ng?L^?1, and limits of quantitation were from 20 to 130?ng?L^?1. Method validation results supported the application of the current method for drinking water safety monitoring per National Primary Drinking Water Regulations established by the US Environmental Protection Agency. Water samples from Lake Lanier and Stone Mountain Lake (Georgia, USS) were analyzed with this method as a preliminary work for a larger scale drinking water quality study in the future. Trace amounts of simazine and atrazine were found in lake water samples, but both were below the regulation levels of the US Environmental Protection Agency.     

Salt‐assisted acetonitrile extraction and HPLC‐QTOF‐MS/MS detection for residues of multiple classes of pesticides in human serum samples

Detecting pesticide residues in human serum is a challenging process. In this study we developed and validated a method for the extraction and recovery of residues of multiple classes of pesticides from serum using one reagent. Salt‐assisted acetonitrile extraction and high‐performance liquid chromatography with quadrupole time of flight tandem mass spectrometry were used to quantitate 34 pesticides classified in nine groups of chemicals in human serum samples, which are frequently detected in food. The recoveries for 33 of analyzed pesticides ranged from 86 to 112% with relative standard deviations below 15%. The limits of quantitation and linearity of 31 of the pesticides were 1 µg/L and >0.990, respectively. The lower limit of quantitation has been reported in the literature particularly for multi‐classes pesticide mixtures in human serum. The salt–acetonitrile reagent was allowed to achieve good recoveries and detection limits, which could be attributed to salt altering the solvent polarity, preferentially collecting the organic phase in the solution, and promoting the extraction. The developed method was applied for two organophosphate pesticide metabolites, diethylphosphate and 3,5,6‐trichloro‐2‐pyridinol, in serum from rats that were fed a nonlethal quantity of chlorpyrifos. The concentrations of these two were 252.18 ± 15.47 and 0.63 ± 0.23 µg/L, respectively.     

GC-NPD investigation of the recovery of organonitrogen and organophosphorus pesticides from apple samples: The effect of the extraction solvent

Summary A gas chromatographic method employing a capillary column and a selective nitrogen/phosphorus detector (NPD) has been developed for the determination of organophosphorus (OP) and organonitrogen (NP) pesticides in horticultural samples (apples). The separation of sixteen pesticides and the internal standard was performed in thirteen minutes. The analytical characteristics of the method, including linear response ranges, detection limits, and reproducibility, have been studied using a 11 mixture of ethyl acetate and xylene as extraction solvent. The possibility of mutual interference between pesticides has also been studied. A procedure for the quantitative extraction of the sixteen pesticides from apple samples has also been developed; for fifteen of the pesticides recoveries >85% were obtained after 90 minutes extraction. The effect of different solvents both on recovery and on the sensitivity of the subsequent chromatography were also investigated. It was found that the sensitivity required must be considered when the solvent for sample treatment is selected.     

Automated liquid chromatographic determination of ranitidine in microliter samples of rat plasma

An improved high-performance liquid chromatographic method with UV detection at 313 nm has been developed for quantitation of ranitidine in 100 microliter of rat plasma over the range 25 to 1000 ng/ml. To each sample were added the internal standard (metiamide) and 2 M NaOH. After dichloromethane extraction, the nitrogen-dried extracts were reconstituted in the mobile phase of 0.01 M phosphate buffer-triethylamine-methanol-water (530:5:390:75 v/v). Chromatography on mu Bondapak C18 with quantitation by peak height ratios showed an analyte recovery of 97%; a limit of detection of 10 ng/ml; a precision of 1-10% and an accuracy of 1-5%. About 90 samples can be processed in 24 h.     

Multiresidue method for determination of 90 pesticides in fresh fruits and vegetables using solid-phase extraction and gas chromatography-mass spectrometry

A multiresidue method for analysis of 90 pesticides with different physico-chemical properties in fruits and vegetables was developed. The method involves a rapid and small-scale extraction procedure with acetone using vortex mixing. Solid-phase extraction (SPE) on a highly cross-linked polystyrene divinylbenzene column (LiChrolut EN) was used for clean-up and pre-concentration of the pesticides from the water-diluted acetone extracts. For most fruit and vegetable samples this partial clean-up was sufficient, but some of them with more co-extracting substances need further clean-up (cereals, spinach, carrots, etc.). Diethylaminopropyl (DEA) modified silica was used for efficient removal of interferences caused by various organic acids, sugars, etc. The pesticide residues were determined by gas chromatography with a mass selective detector (GC-MS). The majority of pesticide recoveries for various fruits and vegetables were >80% in the concentration range from 0.01 to 0.50 mg/kg, except for the most polar pesticides (methamidophos, acephate, omethoate) which cannot be determined by this method. The limit of quantitation for most of the pesticides was 0.01 mg/kg with majority of relative standard deviations (R.S.D.s) below 10%.     

Optimization of a Multiresidue Analysis of 65 Pesticides in Surface Water Using Solid-Phase Extraction by LC-MS/MS

An analytical method was developed and validated for simultaneous quantitation of 65 pesticides, including one single solid-phase extraction (SPE) procedure in surface water by liquid chromatography coupled to tandem mass spectroscopy. Different parameters that have an influence on extraction efficiency were evaluated in this research. Different types of cartridges, elution solvents, and sorbent drying time were investigated, and the most appropriate one was selected. Moreover, various pretreatment techniques were applied to remove sediments from water without the loss of pesticides. Centrifugation was introduced as the best option at the beginning of sample preparation to resolve the clogging of the sorbent cartridges. The recoveries of all pesticides ranged from 70% to 120%, with a relative standard deviation of less than 13.7%. The feasibility of the method was evaluated on 10 surface water samples with different concentrations of sand, sediment, and particles.     

气相色谱-四极杆/飞行时间质谱筛查确证辣椒中244种农药残留及其代谢物

建立了辣椒中244种农药残留的QuEChERS前处理结合气相色谱-四极杆/飞行时间质谱(GC-Q-TOF/MS)快速筛查确证方法.鲜辣椒和干辣椒样品分别采用经-20℃冷冻的乙腈和1％(v/v)乙酸化乙腈提取,经盐析分层、分散固相萃取净化和浓缩后加入内标并复溶,HP-5MS UI色谱柱(30 m×0.25 mm×0.25...