Multiplug filtration clean‐up with multiwalled carbon nanotubes in the analysis of pesticide residues using LC–ESI‐MS/MS

A novel design for a rapid clean‐up method was developed for the analysis of pesticide residues in fruit and vegetables followed by LC–ESI‐MS/MS. The acetonitrile‐based sample extraction technique was used to obtain the extracts, and further clean‐up was carried out by applying the streamlined procedure on a multiplug filtration clean‐up column coupled with a syringe. The sorbent used for clean‐up in this research is multiwalled carbon nanotubes, which was mixed with anhydrous magnesium sulfate to remove water from the extracts. This method was validated on 40 representative pesticides and apple, cabbage, and potato sample matrices spiked at two concentration levels of 10 and 100 μg/kg. It exhibited recoveries between 71 and 117% for most pesticides with RSDs < 15%. Matrix‐matched calibrations were performed with the coefficients of determination >0.995 for most studied pesticides between concentration levels of 10–500 μg/L. The LOQs for 40 pesticides ranged from 2 to 50 μg/kg. The developed method was successfully applied to the determination of pesticide residues in market fruit and vegetable samples.     

Analytical method for 44 pesticide residues in spinach using multi‐plug‐filtration cleanup based on multiwalled carbon nanotubes with liquid chromatography and tandem mass spectrometry detection

Spinach is one of the most commonly planted vegetables worldwide. A high chlorophyll content makes spinach a complicated matrix in pesticide residue analysis. In this study, a rapid clean‐up method was developed for the analysis of pesticide multi‐residues in spinach followed by liquid chromatography with tandem mass spectrometry. A modified QuEChERS method with multiwalled carbon nanotubes and carbon material was adopted in the multi‐Plug Filtration Cleanup procedure. This method was validated for 44 representative pesticides spiked at two concentration levels of 10 and 100 μg/kg. The pesticides of different physicochemical properties were registered on spinach in China. The recoveries were between 76 and 114% for major pesticides with relative standard deviations of less than 15%, except for quizalofop‐P‐ethyl, pyrimethanil, and carbendazim. Matrix‐matched calibration curves were performed with the coefficients of determination higher than 0.995 for the studied pesticides for concentration levels of 10–500 μg/kg. The limits of quantitation ranged from 2 to 10 μg/kg. The developed method was successfully applied to determine pesticide residues in Chinese market spinach samples.     

Rapid analysis of pesticide residues in drinking water samples by dispersive solid‐phase extraction based on multiwalled carbon nanotubes and pulse glow discharge ion source ion mobility spectrometry

An analytical method based on dispersive solid‐phase extraction with a multiwalled carbon nanotubes sorbent coupled with positive pulse glow discharge ion mobility spectrometry was developed for analysis of 30 pesticide residues in drinking water samples. Reduced ion mobilities and the mass–mobility correlation of 30 pesticides were measured. The pesticides were divided into five groups to verify the separation capability of pulse glow discharge in mobility spectrometry. The extraction conditions such as desorption solvent, ionic strength, conditions of adsorption and desorption, the amounts of multiwalled carbon nanotubes, and solution pH were optimized. The enrichment factors of pesticides were 5.4‐ to 48.7‐fold (theoretical enrichment factor was 50‐fold). The detection limits of pesticides were 0.01～0.77 μg/kg. The linear range was 0.005–0.2 mg/L for pesticide standard solutions, with determination coefficients from 0.9616 to 0.9999. The method was applied for the analysis of practical and spiked drinking water samples. All results were confirmed by high‐performance liquid chromatography with tandem mass spectrometry. The proposed method was proven to be a commendably rapid screening qualitative and semiquantitative technique for the analysis of pesticide residues in drinking water samples on site.     

Multi-residue analysis of pesticide residues in mangoes using solid-phase microextraction coupled to liquid chromatography and UV-Vis detection

A sensitive and efficient solid‐phase microextraction method, based on liquid chromatography and UV–Vis detection, was developed and validated as an alternative method for sample screening prior to LC‐MS analysis. It enables the simultaneous determination of ten pesticides in mango fruits. The fiber used was polydimethylsiloxane while optimum SPME conditions employed have been developed and optimized in a previous work. The desorption process was performed in static mode, using acetonitrile as a solvent. The results indicate that the DI‐SPME/HPLC/UV–Vis procedure resulted in good linear range, accuracy, precision and sensibility and is adequate for analyzing pesticide residues in mango fruits. The limits of detection (0.6–3.3 μg/kg) and quantification (2.0–10.0 μg/kg) were achieved with values lower than the maximum residue levels (MRLs) established by Brazilian legislation for all pesticides in this study. The average recovery rates obtained for each pesticide ranged from 71.6 to 104.3% at three fortification levels, with the relative standard deviation ranging from 4.3 to 18.6%. The proposed method was applied for the determination of the aforementioned compounds in commercial mango samples and residues of azoxystrobin, fenthion, permethrin, abamectin and bifenthrin were detected in the mango samples, although below the MRLs established by Brazilian legislation.     

QuEChERS-超高效液相色谱-串联质谱法测定坚果中38种农药残留

建立了检测4种坚果(花生、杏仁、腰果、核桃)中38种农药残留的QuEChERS-超高效液相色谱-串联质谱(UPLC-MS/MS)方法.样品均质后,用乙腈进行提取,经PSA和C18净化后,采用Oasis PRiME HLB固相萃取柱进一步净化, UPLC-MS/MS分析.对样品前处理和色谱方法进行了优化.在多重反应监测(MRM)模式下进行质谱分析,外标法定量.38种农药的检出限范围(S/N=3)为0.01~10 μg/kg,定量限(S/N=10)为0.05~20 μg/kg,线性关系良好(r>0.991).4种坚果中农药的平均加标回收率为51.0%~126.0%,相对标准偏差均小于20%.此方法灵敏、准确、有效,可用于坚果类食品中多种农药残留的同时测定.     

Development of a procedure for the multiresidue analysis of pesticides in vineyard soils and its application to real samples

A procedure for multiresidue analysis was developed for the extraction and determination of 17 pesticides, including herbicides, fungicides, and insecticides, as well as certain degradation products, in vineyard soils from La Rioja region (Spain). Different solvents and mixtures were tested in spiked pesticide‐free soils, and pesticides were comparatively evaluated by gas chromatography with mass spectrometry and liquid chromatography with mass spectrometry. Recoveries >70%, with relative standard deviations <9%, were obtained when a mixture of methanol/acetone or a mixture of methanol/CaCl₂ 0.01 M for the most polar compounds was selected as the extraction solvent. Method validation was accomplished with acceptable linearity (r² ≥ 0.987) within the concentration range of 0.005–1 μg/mL corresponding to 1.667–333.4 μg/kg and 0.835–167.1 μg/kg for liquid chromatography with mass spectrometry and gas chromatography with mass spectrometry, respectively, and detection limits <0.4 μg/kg for the compounds were studied. The extraction method was applied to 17 real vineyard soil samples, and terbuthylazine and its metabolite desethylterbuthylazine were the most ubiquitous compounds, as they were detected in the 100% of the soils analyzed. The presence of fungicides was also high, and the presence of insecticides was lower than other pesticides. The results confirm the usefulness of the optimized procedure for monitoring residues in vineyard soils.     

Simultaneous separation and determination of eight organophosphorous pesticide residues in vegetables through molecularly imprinted solid‐phase extraction coupled to gas chromatography

How to determine the multipesticide residues in vegetables is an important problem. In this study, a new molecularly imprinted polymer was synthesized using O,O‐dimethyl thiophosphoryl chloride, an intermediate for the manufacture of organophosphorous pesticides, as the template. Characterization test indicated that the synthesized polymer exhibited good recognition and selectivity for dichlorvos, methamidophos, acephate, folimat, monocrotophos, parathion‐methyl, phosphamidon, and malathion. A molecularly imprinted SPE coupled to GC for simultaneous separation and determination of eight organophosphorous pesticides residues was developed. Under optimal conditions, the linear range of this method was 0.001–10.0 mg/L. The LOD of this method was in the range of 0.13–0.90 μg/kg. With a flow rate of 2.5 mL/min for loading 100 mL, the enrichment factor in the range of 25–480 for the eight organophosphorous pesticides was obtained. The RSD of the eight organophosphorous pesticides based on five replicates was from 1.50 to 4.09%. The accuracy of the proposed method was evaluated by recovery measurements on spiked samples, and good recovery rates ranging from 80.11 to 97.70% were achieved. Moreover, this method was evaluated for the quantitative detection of eight organophosphorous pesticide residues in leek and pakchoi samples.     

分散固相萃取气相色谱-负化学离子源质谱法测定大豆和玉米中20种农药的残留量

建立了一种大豆和玉米中20种农药残留量的分散固相萃取气相色谱-负化学离子源质谱分析方法。样品经乙腈提取并浓缩后加入N-丙基乙二胺（PSA）、石墨化碳黑和C18 3种填料进行分散固相萃取净化,气相色谱-负化学离子源质谱分时段选择离子监测技术测定与确证,外标法定量。所有农药在20～400 μg/L范围内线性均良好;方法的定量限(LOQ)均不高于2 μg/kg;在5,10和20 μg/kg 3个添加水平下所有农药的平均回收率均处于70%～130%之间,相对标准偏差(RSD)低于17%;运用该方法检测大豆和玉米样品时没有干扰现象。     

气相色谱-负化学离子源质谱测定大豆和玉米中12种三唑类杀菌剂的残留量

建立了一种可用于大豆和玉米中12种三唑类杀菌剂残留量测定的分散固相萃取-气相色谱-负化学离子源质谱方法。样品经含1%冰醋酸的乙腈提取,分散固相萃取法净化,采用气相色谱-负化学离子源质谱分时段选择离子监测技术进行测定与确证,外标法定量。12种农药在50～1000 μg/L范围内线性关系均良好;所有农药的方法定量限(LOQ)均低于8 μg/kg;在10,20和40 μg/kg 3个添加水平下所有农药的回收率为70%～130%,相对标准偏差(RSD)≤13.9%。该方法在检测大豆和玉米基质时无干扰现象出现。     

气相色谱-火焰光度法测定土壤中有机磷农药残留

建立了气相色谱-火焰光度(GC-FPD)分析土壤中敌敌畏、氧化乐果、二嗪农、乐果、甲基对硫磷、马拉硫磷、对硫磷、水胺硫磷、喹硫磷等9种有机磷农药残留量的方法。样品用丙酮-二氯甲烷(1:3)提取,浓缩、定容后用Hp-5MS(30m×0.25 mm×0.25μm)毛细管柱分离,FPD检测器检测。方法回收率在68.71%～110.39%之间;RSD在5.5%～11%之间;检出限在0.397～1.60μg/mL之间,方法可用于环境土壤样品中有机磷农药残留的测定。     

LC-MS/MS法同时测定4种中草药中155种农药残留

建立了液相色谱-串联质谱(LC-MS/MS)同时测定4种中草药(甘草、银杏叶、菊花和八角茴香)中155种农药残留方法。样品采用乙腈、无水硫酸镁和乙酸钠分散固相萃取(DSPE),再经Cleanert TPH固相萃取(SPE)柱净化,乙腈/甲苯(8:1,V/V)洗脱,液相色谱串联质谱多反应监测模式下测定,外标法定量。实验结果表明,155种农药的检出限(S/N=3)和定量限(S/N=10)范围分别为0.4～34.1μg/kg和1.3～113.7μg/kg;在1.0～2400.0μg/kg浓度范围内,155种农药中有148种农药在4种中草药中线性相关系数平均值R2≥0.9950;在低、中、高3个添加水平,86.5%～97.4%的农药平均回收率在60%～120%范围,94.2%～100.0%的农药相对标准偏差RSD≤20%(n=5)。该方法适用于中草药中农药多残留检测。     

Rapid simultaneous determination of multiple pesticide residues in traditional Chinese medicines using programmed temperature vaporizer injection-fast gas chromatography coupled with mass spectrometry

A fast gas chromatography coupled with mass spectrometry (GC-MS) using large volume injection with programmed temperature vaporizer in solvent vent mode (PTV-LVI-SV) was developed for the trace determination of multiple pesticide residues in traditional Chinese medicines (TCMs). Experimental conditions of PTV-LVI-SV injection were optimized by central composite design. The optimized result was that initial temperature was held at 40°C for 39 s, vent flow rate was set at 45 mL/min and vent pressure was held at 0 psi for 36 s, injection volume was 10 μL. Furthermore, the quick and effective QuEChERS (quick, easy, cheap, effective, rugged and safe) method was performed to extract and purify pesticide residues in TCMs. The prepared samples were analyzed with GC-MS in the selected ion monitoring mode (SIM). The lowest LOD was 4 μg/kg for some pesticides. The recoveries were checked by spiking samples with pesticides at 25, 50 and 250 μg/kg. The average recoveries of most pesticides were from 80 to 118%. The result indicated that QuEChERS and PTV-LVI-SV GC-MS method was a rapid and sensitive analysis technique for the determination of multiple pesticide residues in TCMs.     

超高效液相色谱-同位素稀释高分辨质谱法测定红葡萄酒中的18种农药残留

建立了采用超高效液相色谱-同位素稀释高分辨质谱法同时快速测定红葡萄酒中18种农药残留的方法。样品采用乙腈提取,以N-丙基乙二胺（PSA）和C₁₈作为吸附剂的分散固相萃取法（d-SPE）进行净化,以BEH C₁₈色谱柱进行色谱分离,分别通过高分辨质谱的全扫描/实时二级质谱扫描（full scan/ddms²）和目标选择离子监测（targeted SIM,tSIM）模式进行定性筛查和定量检测。以多菌灵-D₄、毒死蜱-D₁₀、吡虫啉-D₄、甲氧虫酰肼-D₉、嘧霉胺-D₅和戊唑醇-D₆为内标进行内标法定量,有效地降低了样品基质的影响。待测物在0.5~50 μg/L范围内呈良好的线性关系,相关系数（r）大于0.999。18种农药残留的检出限（LOD）为0.5 μg/kg,定量限（LOQ）为1.0 μg/kg。空白红葡萄酒样品在1~40 μg/kg范围内的4个加标水平的平均回收率为85.4%~117.9%,相对标准偏差为0.5%~6.1%。应用该方法对市售的红葡萄酒样品进行检测,共检出多菌灵、吡虫啉、嘧霉胺、戊唑醇和三唑醇5种农药残留,含量分别为2.6~143.0 μg/kg、0.6~0.9 μg/kg、2.1~3.1 μg/kg、0.6~3.0 μg/kg和0.6 μg/kg。该方法适用于红葡萄酒中农药残留的快速筛查和定量检测。     

Simultaneous determination of 103 pesticide residues in tea samples by LC‐MS/MS

A simple and sensitive method was developed and validated for the simultaneous determination of 103 pesticide residues in tea by LC‐MS/MS. For the analysis of the pesticide with polarity, thermal lability or low volatility, this LC‐MS/MS method has an advantage over GC. In this work, residual pesticides were extracted from the tea sample with ACN and then purified using Carb‐NH₂ SPE cartridges. Using the multiple reaction monitoring mode, the pesticides were quantified and identified by the most abundant and characteristic fragment ions. The recoveries obtained for each pesticide ranged between 65 and 114% at three spiked concentration levels. The intra‐day precisions were lower than 19.6%. Good linear relationships were observed with the correlation coefficients r² >0.996 for all analytes. The established method was successfully applied to the determination of pesticide residues in real tea samples.     

固相萃取-超快速液相色谱-串联质谱法测定当归中135种农药及其代谢物残留

建立了超快速液相色谱-串联质谱(UFLC-MS/MS)同时测定当归药材中135种农药及其代谢物(包括有机磷类、氨基甲酸酯类、拟除虫菊酯类农药等)残留量的分析方法。以回收率为考察指标,评估了不同的提取溶剂、固相萃取小柱、洗脱溶剂及体积对当归中多农残的提取净化效果,最终确定样品经乙腈提取,PSA固相萃取柱净化处理,在电喷雾正离子扫描、依赖保留时间的多反应监测模式(scheduled MRM)下,以基质匹配校准曲线内标法定量。结果表明,135种农药及其代谢物在各自的浓度范围内线性关系良好(r>0.99); 3个添加水平(10、50、100 μg/kg)下,除了烯草酮回收率偏低(62.0%~68.2%)外,其余农药的回收率为71.3%~119.7%,相对标准偏差(RSD, n=6)不大于19.9%, 135种农药及其代谢物的定量限为1.0~10.0 μg/kg。该方法样品前处理简单、快速、灵敏,可用于当归药材中多类别农药残留量的定性、定量。     

Simultaneous determination of pyrethroid,organophosphate, and organochlorine pesticides in fish tissue using tandem solid-phase extraction clean-up

A method was developed for the simultaneous analysis of pyrethroid, organophosphate, and organochlorine pesticides in fish tissue. Different extraction solvents and solid-phase extraction clean-up procedures were tested. The best approach was to extract by sonication with acetonitrile and 10%?methanol, followed by clean-up of extracts using C₁₈, Florisil and Na₂SO₄ tandem solid-phase extraction cartridges. Gas chromatography with an electron-capture detector was used for analyte determination. All 26 target pesticides were detected using the new method in a single analytical run. The method detection limits ranged from 0.13 to 1.40?µg/kg, while recoveries of the analytes ranged from 86.1 to 133.8%?with relative standard deviations?≤12.1%?at a spiked concentration of 5?µg/kg. The method was developed to assess possible pesticide contamination in fish collected from lakes at a proposed Illinois National Guard Armory site.     

直接进样–超高效液相色谱串联质谱法同时测定水源水中9种农药

建立直接进样–超高效液相色谱三重四级杆质谱联用(UPLC–MS–MS)快速测定水源水中9种痕量农药残留的方法。水样无需富集,经超高效液相色谱分离,串联三重四级杆质谱检测,在7.5 min内完成9种目标化合物的分析。9种农药的检出限(S/N≥3)在0.01~1.4μg/L之间,在各自的考察浓度范围内线性关系良好(r≥0.995)。在1.0~80μg/L添加水平内,实际样品的平均加标回收率为66.2%~114.0%,测定结果的相对标准偏差为2.3%~20.4%(n=6)。该法操作简便,重现性好,可用于饮用水源水中农药残留的快速测定。     

利用固相萃取-气相色谱-负化学离子源质谱技术快速分析茶叶中3种杀螨剂和八氯二丙醚农药残留

建立了茶叶中3种杀螨剂及八氯二丙醚农药残留快速分析的固相萃取-气相色谱-负化学离子源质谱检测(GC-NCI-MSD)方法,并应用于出口欧盟茶叶中农残检测及基地监管.样品经正己烷-丙酮(1∶1,V∶V)提取后,用固相萃取柱(Agela)除去茶叶中干扰物质,以环氧七氯为内标物,经气相色谱-负化学离子源质谱分时段选择离子监测...     

加速溶剂萃取-气相色谱-串联质谱法同时测定贝类中64种农药残留

建立了加速溶剂同步萃取净化-气相色谱-串联质谱（GC-MS/MS）同时测定贝类中64种农药残留的方法。加速溶剂萃取的萃取溶剂为90%（v/v）乙腈水溶液,萃取温度为85℃、冲洗体积60%萃取池体积、循环次数1次,同时使用0.8 g N-丙基乙二胺（PSA）和0.8 g石墨化炭黑（GCB）在线净化,提取液浓缩定容后,在多反应监测（MRM）模式下测定,外标法定量。结果表明,64种农药在10.0~1000 μg/L范围内呈现良好的线性关系,决定系数（r²）均大于0.989,方法的定量限为2.0~10.0 μg/kg;对文蛤空白基质进行加标回收试验,添加水平为5.0、10.0和100 μg/kg以及定量限水平,得到的平均回收率为69.4%~129.7%,精密度为0.7%~16.0%（n=6）。该方法提取和净化同步完成,操作简单,重复性好,灵敏度高,能够满足于贝类水产品中多种农药残留的同时筛查。     

超高效液相色谱-串联质谱法检测花生中36种农药及其代谢物残留

建立了花生中36种农药及其代谢物残留的超高效液相色谱-串联质谱(UHPLC-MS/MS)快速检测技术。采用乙腈提取,增强型脂质去除净化剂(EMR-Lipid)净化,正离子多反应监测(MRM)模式测定。结果表明,所有农药的线性相关系数均大于0.994,在0.005,0.01,0.10 mg/kg 3个加标水平下,36种农药的平均回收率为70.4%~119%,相对标准偏差(RSDs)为1.3%~19.4%,方法的定量下限为0.002 5~0.05 mg/kg。该方法简便、快速,灵敏度高、净化效果好,适用于花生中农药多残留的快速检测分析。