Multi-residue screening of pesticides in vegetables,fruits and baby food by stir bar sorptive extraction-thermal desorption-capillary gas chromatography-mass spectrometry

The performance of stir bar sorptive extraction (SBSE) for the enrichment of pesticides from vegetables, fruits and baby food samples is discussed. After extraction with methanol, an aliquot is diluted with water and SBSE is performed for 60 min. By applying a new thermal desorption unit (TDU), fully automated and unattended desorption of 98 stir bars is feasible, making SBSE very cost-effective. The presence of pesticide residues is elucidated with the retention time locked gas chromatography–mass spectroscopy method (RTL-capillary GC–MS). With SBSE–RTL-capillary GC–MS operated in the scan mode, more than 300 pesticides can be monitored in vegetables, fruits and baby food. The multi-residue method (MRM) described provides detectabilities from the mg/kg (ppm) to the sub-μg/kg (ppb) level, thereby complying with the maximum residue levels (MRLs) set by regulatory organizations for pesticides in different matrices. Several examples, i.e. pesticide residues in lettuce, pears, grapes and baby food, illustrate the potential of SBSE–RTL-capillary GC–MS.     

Pesticide residue determination in vegetables from western China applying gas chromatography with mass spectrometry

In this study,an effort has been made to evaluate the pesticide residues in vegetables from western China. Fifty‐one pesticides, including organophosphorus, organochlorine, carbamate and pyrethroid, were detected in 369 commonly used vegetables by GC‐MS. Concentrations of organophosphorus pesticides were detected ranging from 0.0008 to 18.8200 mg/kg, among which organophosphorus pesticide concentrations exceeded their maximum residue levels (MRLs) in five samples. Carbamate and organochlorine pesticides were determined to have concentrations in the range of 0.0012–0.7928 mg/kg. The residual concentrations of carbamate pesticides in six samples and organochlorine pesticides in four samples exceeded their MRLs. The residual concentrations of five pyrethroid pesticides were within the range of 0.0016–6.0827 mg/kg and the pyrethroid residues in two samples exceeded their MRLs. The results revealed that pesticide residues in 70.73% of the vegetables samples were not detected, while in the rest of vegetables there were one or more pesticide residues and some even exceeded their MRLs, which would threaten the health of consumers. Our work provides significant information for the food safety regulations to control the excessive use of some pesticides on those kinds of vegetables from western China. Copyright © 2016 John Wiley & Sons, Ltd.     

格氏试剂衍生-气相色谱-串联质谱法同时测定水果和蔬菜中的三环锡、三苯锡和苯丁锡残留

建立了水果和蔬菜中三环锡、三苯锡和苯丁锡同时检测的格氏试剂衍生-气相色谱-串联质谱方法（GC-MS/MS）。样品经盐酸/四氢呋喃（1：10,v/v）消解,正己烷振荡提取,乙基溴化镁衍生和Florisil固相萃取净化,采用GC-MS/MS多反应监测（MRM）模式对3种有机锡化合物进行定性和定量分析。实验结果表明,以苹果为代表性样品基质,三环锡、三苯锡和苯丁锡的检出限（LOD）分别为2.0、1.5和3.4 μg/kg （以Sn计）,在10、20、50、200 μg/kg （以Sn计）共4个添加水平下的平均回收率为72.4%~107.1%,相对标准偏差为0.4%~14.2%。该方法灵敏度高,选择性强,可以实现3种有机锡农药的同时检测,能够满足国内外残留限量的检测要求。     

液相色谱-串联质谱法测定10种食品中四溴菊酯残留

建立了测定蔬菜、水果、茶叶、大豆等10种食品中四溴菊酯残留的高效液相色谱-串联质谱(HPLC-MS/MS)分析方法。样品以乙酸乙酯(蔬菜、水果、茶叶样品)或乙腈(大豆样品)为提取剂,上层有机相经浓缩、固相萃取小柱净化,流动相定容后,采用HPLC在Agilent ZORBAX Eclipse XDB C18色谱柱上,以甲醇和缓冲盐溶液(0.1%甲酸-10 mmol/L乙酸铵)为流动相进行梯度洗脱分离,以串联质谱在多反应监测(MRM)模式下测定,基质外标法定量。结果表明,四溴菊酯的质量浓度在20～1 000μg/L范围内线性关系良好,相关系数为0.999 8;在0.01、0.02、0.1 mg/kg(粮谷类、茶叶、大豆样品)和0.005、0.01、0.05mg/kg(果蔬类样品)加标水平下的回收率为75%～92%,相对标准偏差(RSDs)为4.0%～12.6%(n=6),定量下限(S/N≥10)为0.01 mg/kg(粮谷类、茶叶、大豆样品)和0.005 mg/kg(果蔬类样品)。该方法不受溴氰菊酯干扰,可直接测定四溴菊酯,克服了以往方法只能测定四溴菊酯和溴氰菊酯总量的不足。     

高效液相色谱-串联质谱法测定植物源食品中四溴菊酯

建立了测定8种植物源食品中四溴菊酯残留的高效液相色谱-串联质谱分析方法。样品以乙酸乙酯为提取剂,经浓缩、净化,用流动相定容,采用高效液相色谱分离,以串联质谱在多反应监测模式下测定。结果表明,四溴菊酯质量浓度在20～1000μg/L范围内线性良好,相关系数为0.9998;在0.01、0.02和0.1 mg/kg(粮谷类样品)和0.005、0.01和0.05 mg/kg(果蔬类样品)添加水平下的回收率为81.6%～92.1%,相对标准偏差为4.0%～13%,定量限为0.01 mg/kg(粮谷类样品)和0.005 mg/kg(果蔬类样品)。     

Application of hollow fiber supported liquid membrane extraction to the simultaneous determination of pesticide residues in vegetables by liquid chromatography/mass spectrometry

A new analytical procedure using a hollow fiber supported liquid membrane (HFSLM) has been developed for the simultaneous determination of pesticide residues in vegetables by liquid chromatography (LC) coupled with electrospray mass spectrometry (MS). The extraction technique requires minimal sample preparation and solvent consumption. Optimum extraction conditions have been evaluated with respect to sample pH, ionic strength, liquid membrane composition, extraction time, stirring rate and acceptor composition. The extraction method has been validated for matrices such as cucumber, tomato and pepper, indicating that cucumber can be selected as representative matrix for routine analysis of these food commodities. Linear ranges of pesticides in vegetable samples were 10 to 200 microg/kg, and the repeatability of the method was less than 20% for the lowest calibration point. The limits of detection ranged from 0.06 to 2.7 microg/kg and the limits of quantification from 0.2 to 9.0 microg/kg, which were low enough to determine the pesticide residues at concentrations below or equal to the maximum residue levels (MRLs) specified by European Union. The method was finally applied to the determination of more than 20 pesticides in market vegetable samples and the concentrations found in these samples were always lower than the MRLs. This new approach can be considered as a powerful alternative to the traditional extraction techniques.     

Application of solid-phase extraction and liquid chromatography-mass spectrometry to the determination of neonicotinoid pesticide residues in fruit and vegetables

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.     

液相色谱-串联质谱法快速测定植物源性食品中的百草枯

建立了水果、蔬菜、豆类和粮谷中百草枯残留的高效液相色谱-串联质谱(HPLC-MS/MS)分析方法.用水提取样品中的百草枯,弱阳离子交换(WCX)固相萃取柱(SPE)净化.采用CAPCELL PAK ST色谱柱(150 mm×2.0mm).乙腈-10 mmol/L乙酸铵水溶液(用甲酸调至pH 4.0)为流动相,以电喷雾离...     

固相萃取–气相色谱–负化学源质谱法检测水果和蔬菜中的毒杀芬

采用改进的分散固相萃取(QuEchERs)法对样品进行前处理,建立水果和蔬菜中毒杀芬残留的气相色谱–负化学电离源质谱(GC–NCI–MS)检测方法。样品中的毒杀芬由正己烷提取,经吸附剂PSA+GCB净化,在GC–NCI–MS的选择离子扫描模式下进样分析。毒杀芬的色谱保留时间在12.5~18.0 min区间内,采用面积归一化法积分,外标法定量。毒杀芬质量浓度在0.050~2.000 mg/L范围内与色谱峰面积呈良好的线性关系,相关系数r=0.999 1。分别以蓝莓、黄桃、菠菜为基质,在0.025,0.050 mg/kg添加水平下,毒杀芬的回收率为107.2%~118.1%,测定结果的相对标准偏差为5.5%~8.8%(n=6),定量限为0.025 mg/kg。该方法检测快速,适用于水果和蔬菜中毒杀芬残留的日常检测。     

Analysis of Pesticide Residues by QuEChERS Method and LC-MS/MS for a New Extrapolation of Maximum Residue Levels in Persimmon Minor Crop

According to EU guidance SANCO/7525/VI/95 Rev. 10.3, residue data extrapolation from a surrogate major crop to a minor crop can be used for setting maximum residue levels (MRLs) with a reduced number of residue trials and representative selected pesticides. In this work, a QuEChERS method (citrate-buffered version and PSA with MgSO₄ clean-up) and LC-ESI-MS/MS for the determination of boscalid, pyraclostrobin, fludioxonil, fluopyram and tebuconazole in persimmon was developed and validated according to EU Commission guidelines and afterwards used for the determination of residues in four field trials. Residue levels at harvest for each pesticide ranged between 0.347 and 0.028 mg/kg. After comparing EFSA residue data on apples, as the surrogate major crop, and conducting a consumer risk assessment, a proposal of residue data extrapolation to set MRLs in persimmons was performed. The results showed that pesticide residues in persimmons at harvest were consistently lower than residues in apples when substances were applied according to the same critical GAP. MRLs were set at 0.5 mg/kg for fludioxonil, 0.6 mg/kg for boscalid, 0.3 mg/kg for tebuconazole, 0.4 mg/kg for fluopyran and 0.3 mg/kg for pyraclostrobin. The ratio of the MRLs for apple/persimmon varied between 2.5 for boscalid and 1.25 for fluopyram, suggesting that residue extrapolation can be feasible, promoting the process of pesticide registration for minor crops and the settlement of MRL.     

分散固相萃取-气相色谱-串联质谱法测定蔬菜中107种农药的残留量

采用分散固相萃取-气相色谱-串联质谱(QuEChERS-GC-MS/MS)建立了蔬菜中107种农药残留量的分析方法。样品由含1%冰醋酸的正己烷饱和乙腈提取、分散固相萃取法净化,采用气相色谱-串联质谱方法在分时段选择反应监测模式下进行测定,外标法定量。所有农药在0.05～1 mg/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10 μg/kg;在10 μg/kg的添加水平下,大蒜、青刀豆、萝卜和菠菜4种基质中绝大多数农药的平均回收率处于60%～130%之间,相对标准偏差(RSD)不大于15.3%。该方法不仅能用于多种蔬菜基质中107种农药残留的检测,而且还能较好地解决本底成分相当复杂的大蒜基质极易出现的干扰问题。     

固相萃取-超高效液相色谱-串联质谱法同时测定果蔬中6种酰胺类农药残留量

建立了同时测定果蔬中6种酰胺类农药的固相萃取-超高效液相色谱-串联质谱(SPE-UPLC-MS/MS)方法。样品经乙腈高速匀浆提取、Florisil固相萃取柱净化,采用超高效液相色谱-串联质谱法测定6种农药。质谱分析采用电喷雾电离,正负双离子扫描,多反应监测(MRM)模式。结果表明:6种农药在0.0005~1.00 mg/L范围内均呈现良好的线性关系,相关系数均大于0.999;在0.01、0.1和1.0 mg/kg(氟苯虫酰胺为0.001、0.01和0.1 mg/kg) 3个浓度添加水平下的平均回收率为72.4%~119.4%,相对标准偏差(n=5)小于15%;定量限为0.01 mg/kg(溴氰虫酰胺、双炔酰菌胺、啶酰菌胺、氟吡菌胺和噻呋酰胺)和0.001 mg/kg(氟苯虫酰胺)。该方法简单、快速、重现性好、灵敏度高,可满足果蔬中6种酰胺类农药残留检测的要求。     

Determination of multiresidue pesticides in green tea by using a modified QuEChERS extraction and ion-trap gas chromatography/mass spectrometry

The pesticide residues in exported and imported tea products must not exceed the maximum residue limits (MRLs) regulated by the import countries. Tea is a complex matrix that obfuscates the determination of pesticide residues. Many available methods for multiresidue pesticide analysis of tea are time-consuming and require many cleanup steps. The objective of this study was to develop a simple multiresidue method by using a modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction and ion-trap GC/MS/MS, which can identify, confirm, and quantify pesticides in complex matrixes. A tea product was homogenized with water, and the pesticides were extracted with acetonitrile containing 1% acetic acid. The extract was subjected to centrifugation, initial cleanup with dispersive SPE (dSPE), solvent exchange, and final cleanup with dSPE. Diethyl-d10-parathion and triphenyl phosphate were used as the internal standard and surrogate, respectively. The final extract was injected into an ITQ 700 gas chromatograph/mass spectrometer. Quantitation of individual pesticides was based on matrix-matched calibration curves with a correlation coefficient of > 0.9930 for the 22 pesticides selected for the study. The recoveries of the 22 pesticides ranged from 78 to 115%, except those for diazinon (130%) and malathion (122%), with an average RSD of 8.7%. The LOD values of all of the pesticides, except for terbufos, were below the MRLs set by the European Union and Japan.     

低温冷冻及分散固相萃取净化-超高效液相色谱-串联质谱法测定植物油中104种农药残留

建立了适用于植物油中104种农药残留的检测方法。通过液液萃取(LLE)提取目标化合物,再借助离心、冷冻和分散固相萃取(D-SPE)净化手段,依托超高效液相色谱-串联质谱测定。以回收率和共提取物为衡量指标,着重优化了6种提取方式、不同冷冻时间及PSA(primary secondary amine)、GCB(graphite carbon black)和C18这3种不同固相萃取填料不同组合的效果。在0.01、0.02和0.05 mg/kg水平的平均添加回收率为55%~121%, RSD为0.47%~19.2%, 80%的目标物的定量限可达到1 μg/kg,低于我国相关标准限量,能够满足多种农药残留同时分析的要求。该方法步骤简便、可靠、稳定,可应用于进口植物油中多种农药残留的快速检测与确证的日常检测工作中,具有一定的推广价值。     

水果蔬菜中多种杀菌剂的基质固相分散液相色谱测定方法研究

采用基质固相分散(MSPD)代替液液分配和固相萃取,从蔬菜水果中提取、净化10种常用杀菌剂农药残留,用C18硅胶交联剂作为固相吸附剂,乙酸乙酯作为洗脱液,用HPLC/PDA和LC-MS进行分析检测。10种杀菌剂在0.5~5 mg/kg含量的添加回收率在65%~110%之间,相对标准偏差小于10%,使用HPLC、PDA和LC-MS的检出限分别在0.02~0.2 mg/kg和0.002~0.01 mg/kg之间。该方法节省溶剂,提取和净化一步完成,适用于新鲜水果和蔬菜中10种杀菌剂的残留分析。     

Multiresidue method for the determination of residues of 251 pesticides in fruits and vegetables by gas chromatography/mass spectrometry and liquid chromatography with fluorescence detection

A method is described for the determination of 251 pesticide and degradation product residues in fruit and vegetable samples. Extraction of the sample with acetonitrile is followed by a salting-out step. Co-extractives are removed by passing a portion of the acetonitrile extract through an octadecyl (C18) solid-phase extraction cleanup cartridge and then, in a second cleanup, through a carbon cartridge coupled to an amino propyl cartridge. Determination is by gas chromatography with mass-selective detection in the selected-ion monitoring mode, and by liquid chromatography with post-column reaction and fluorescence detection for N-methyl carbamates. The method has been used for analysis of various fruits and vegetables, such as apple, banana, cabbage, carrot, cucumber, lettuce, orange, pear, pepper, and pineapple. Limits of detection range between 0.02 and 1.0 mg/kg for most compounds. Over 80% of the compounds have a limit of detection of < or = 0.04 mg/kg.     

Determination of polar organophosphorus pesticides in vegetables and fruits using liquid chromatography with tandem mass spectrometry: selection of extraction solvent

A method based on liquid chromatography (LC)-mass spectrometry (MS)/MS was developed for sensitive determination of a number of less gas chromatography (GC)-amenable organophosphorus pesticides (OPs; acephate, methamidophos, monocrotophos, omethoate, oxydemeton-methyl and vamidothion) in cabbage and grapes. For extraction, several solvents were evaluated with respect to the possibility of direct injection, matrix-induced suppression or enhancement of response, and extraction efficiency. Overall, ethyl acetate was the most favourable solvent for extraction, although a solvent switch was required. For some pesticide/matrix combinations, reconstitution of the residue after evaporation required special attention. Extracts were analysed on a C18 column with polar endcapping. The pesticides were ionised using atmospheric pressure chemical ionisation on a tandem mass spectrometer in multiple reaction monitoring mode. The final method is straightforward and involves extraction with ethyl acetate and a solvent switch to 0.1% acetic acid/water without further cleanup. The method was validated at the 0.01 and 0.5 mg/kg level, for both cabbage and grapes. Recoveries were between 80 and 101% with R.S.D. < 11% (n = 5). The limit of quantification was 0.01 mg/kg and limits of detection were between 0.001 and 0.004 mg/kg.     

QuEChERS样品前处理-液相色谱-串联质谱法测定蔬菜中66种有机磷农药残留量方法评估

比较了两种版本QuEChERS方法(即发表于2003年未加缓冲盐的原创QuEChERS方法及加乙酸盐缓冲液的AOAC 2007.01方法)提取蔬菜中66种有机磷农药(OPPS)的有效性;考察了乙二胺-N-丙基硅烷(PSA)及C18吸附剂对66种OPPS的吸附作用;以提取后添加法评估了青花菜、番茄、枝豆、萝卜、大葱基质中各目标物液相色谱-串联质谱(LC-MS/MS)分析的基质效应。结果表明,加入乙酸盐缓冲液的QuEChERS方法对一些OPPS有较高及较稳定的回收率;PSA及C18吸附剂可吸附二溴磷,QuEChERS样品前处理方法不适于二溴磷分析;5种样品基质中青花菜的基质效应最大。据此采用AOAC 2007.01方法并优化LC-MS/MS分析参数,一次进样监测132对离子对(每个化合物2对离子对)分析蔬菜中66种OPPS残留量,除二溴磷外,65种OPPS在5种基质(青花菜、番茄、枝豆、萝卜、大葱)、3个添加水平(10、40、80 μg/kg)的回收率为55%～122%,相对标准偏差为1.6%～18%,定量限(以信噪比(S/N)≥10计)为0.1～8 μg/kg。以上结果说明该法有效、耐用、灵敏,符合法规残留限量监测要求。     

Simultaneous determination of carbamate and organophosphorus pesticides in fruits and vegetables by liquid chromatography-mass spectrometry

A liquid chromatography-mass spectrometry (LC-MS) method was established for the purpose of simultaneous determination of carbamate and organophosphorus (OPPs) pesticides in fruits and vegetables. Samples were extracted with acetonitrile; and then prepared by dispersive solid-phase extraction (dispersive-SPE) with primary secondary amine (PSA) as the sorbent. Four common representative samples (tomato, apple, carrot, and cabbage) were selected from the supermarket to investigate the effect of different matrices on pesticides recoveries and assay precision after spiking samples with 0.05 mg/kg. Matrix composition did not interfere significantly with the determination of the pesticides. The obtained recoveries were, with a few exceptions, in the range of 70-110% with RSDs less than 8%. It was applied to pesticide residue monitoring in vegetables and fruits from local markets.     

高效液相色谱荧光检测法测定蔬菜中残留的甲氨基阿维菌素苯甲酸盐

建立了甘蓝和蘑菇中甲氨基阿维菌素苯甲酸盐的固相萃取-高效液相色谱荧光分析方法。蔬菜样品用乙酸乙酯提取,提取液旋转浓缩近干后用少量乙酸乙酯溶解,再经PRS固相萃取(SPE)柱净化,洗脱液经氮气吹干后用氮甲基咪唑和三氟乙酸酐衍生,衍生物用高效液相色谱分析,采用外标法定量。在添加浓度1.0～20.0 μg/kg范围内,平均添加回收率为78.6%～84.9%,日内相对标准偏差(RSD)为2.7%～6.0%,日间RSD为3.1%～8.9%,检出限为0.10 μg/kg。甲氨基阿维菌素苯甲酸盐衍生物在0.002～0.10 mg/L范围内呈良好的线性关系,相关系数为0.9999。