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.     

Determination of organophosphorus pesticide residues in fruits by gas chromatography with ITD and NPD detection

Summary Several widely used organophosphorus insecticides, diazinon, methyl-parathion, fenitrothion, malathion, fenthion and methidathion were selected for inclusion in this work. A comparative study of the multiresidue determination of these compounds in citrus fruit and grapes has been carried out by gas chromatography with nitrogen-phosphorus and ion trap detection. Samples were spiked with 0.1, 0.5 and 1 mg kg^–1 of each pesticide and blended in a Sorvall homogeniser with ethyl acetate. Column clean-up on Florisil was necessary for citrus peel extracts. The average recoveries varied from 81 to 107% with a relative standard deviation between 0.3 and 9.5% for GC-ITD and from 86 to 104% with a relative standard deviation ranging from 1.4 to 8.0% for GC-NPD. The detection limit of the method was 10 ng g^–1 or less for each organophosphorus insecticide, with both detectors. This method was applied to the analysis of treated lemons and 0.25 mg kg^–1 of fenitrothion in fruit was detected a week after treatment and identified by its mass spectrum. The results obtained showed that the proposed methods are reproducible and sensitive enough for the simultaneous determination of these insecticides in fruits at residue level.     

Analysis of pesticide residues in tobacco with online size exclusion chromatography with gas chromatography and tandem mass spectrometry

An ultrasensitive method for the simultaneous analysis of pesticides residues in tobacco was developed with online size exclusion chromatography with gas chromatography and tandem mass spectrometry. Tobacco samples were extracted with the solvent mixture of cyclohexane and acetone (7:3, v/v) and centrifuged. Then, the supernatant liquors were injected directly into the online size exclusion chromatography with gas chromatography and tandem mass spectrometry without any other purification procedures after being filtered with a 0.22 μm organic phase filter. The matrix interferences were effectively removed and recoveries of most pesticides were in the range of 72–121%. Especially, for chlorothalonil, the analysis efficiency of this method was much more favorable than that of the general method, in which dispersive solid‐phase extraction was used as an additional purified procedure. In addition, the limits of quantitation of this method were from 1 to 50 μg/kg. Therefore, a rapid, cost‐effective, labor‐saving method was proposed in the present work, which was suitable for the analysis of 41 pesticide residues in tobacco.     

Rapid determination of organochlorine pesticide residues in feeds by capillary gas chromatography

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.     

气相色谱法测定苹果中的多种农药残留量

采用丙酮和正己烷提取,C18固相萃取小柱净化,气相色谱法用电子捕获检测器（GC-ECD）测定,建立了苹果中有机氯、拟除虫菊酯和有机磷3类15种农药的同时检测方法.该方法的回收率为78.3%～104.2%、相对标准偏差≤6.2%.     

Simultaneous determination of herbicide residues in tobacco using ultraperformance convergence chromatography coupled with solid‐phase extraction

A time‐saving and organic solvent efficient method to simultaneously determine six kinds of herbicide residues in tobacco using solid‐phase extraction for sample clean‐up and preconcentration and the highly sensitive ultraperformance convergence chromatography method was developed. Parameters for ultraperformance convergence chromatography, including the choice of stationary phase and modifiers, autobackpressure regulator pressure, column temperature, and the flow rate of mobile solvents, were optimized. The herbicide residues of napropamide, alachlor, quizalofop‐ethyl, diphenamid, metolachlor, and clomazone in tobacco samples were successfully separated and detected at levels as low as 0.0043–0.0086 mg/kg within 5 min using a nonpolar high strength silica C₁₈ selectivity for bases column and methanol as the cosolvent of the mobile phase of carbon dioxide (75–99.9%, v/v). Analysis of tobacco samples had recoveries of 69.8–95.0%, limit of quantitation of 0.0127–0.0245 mg/kg, limit of detection of 0.0043–0.0086 mg/kg, and correlation coefficient of >0.9990. Results support this method as an efficient alternative to current methodologies for the determination of herbicide residues in tobacco.     

Magnetic octadecyl‐based matrix solid‐phase dispersion coupled with gas chromatography with mass spectrometry in a proof‐of‐concept determination of multi‐class pesticide residues in carrots

A novel procedure is put forward based on the combination of the well‐established matrix solid‐phase dispersion and the magnetic and sorption properties of magnetic octadecyl in the presence of n‐octanol and was employed in a proof‐of‐concept sample preparation and determination of several classes of pesticide residues in carrots. The procedure does not require the transfer of blend to cartridge and subsequent packing, nor any co‐sorbent for extract clean up. The hydrophobic magnetic nanoparticles utilized as a sorbent, can be retrieved by n‐octanol under the application of a magnetic field due to hydrophobic interactions. Elution of pesticide residues is then carried out with an organic solvent. A total of 26 pesticides were included in this procedure and the target compounds were analyzed using gas chromatography with mass spectrometry in the selective ion monitoring mode. The average extraction recoveries obtained from carrot samples fortified at three different concentrations (20, 50, and 500 μg/kg) were 77–107%. The estimated limits of quantitation for most target analytes were in the low μg/kg level. The study demonstrates that the proposed extraction procedure is simple and effective, avoiding a clean‐up step for the sample preparation of vegetable.     

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10.0～1 000μg/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2.0～10.0μg/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100μg/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。     

潜指纹残留物中油脂的气相色谱分析

建立一种适于分析潜指纹残留物中油脂组成的简便快速、灵敏可靠的GC/FID分析方法。以V(正己烷)∶V(CH2Cl2)=1∶10为提取剂,HP-5毛细管色谱柱和氢火焰离子检测器进行分析。潜指纹残留物中油脂组成复杂,不同个体捺印所得样品组成之间既有共同之处,又有各自典型特征;暗处保存及自然光照条件下,油脂组成发生变化,油脂含量总体呈下降趋势,但部分物质含量呈波动性变化;两种老化方式下的变化趋势相似,但自然光照条件下油脂衰减速度较快,光照10天后的潜指纹残留物中仍可见含量丰富的油脂。方法灵敏度能够达到单枚指纹残留物检测要求。     

毛细管气相色谱法测定中药材中多种拟除虫菊酯农药残留量

研究了气相色谱法测定中药材中多种拟除虫菊酯类残留量的分析方法。样品经正己烷．丙酮混合液[V（正己烷）：V（丙酮）=1：1]提取,氟罗里硅土层析柱净化,采用毛细管色谱柱分离,GC-ECD可同时测定8种拟除虫菊酯类农药残留量,回收率为76．6％～104．2％。     

Improved analytical procedure for determination of chlorinated pesticide residues in human serum using solid phase disc extraction (SPDE), single-step clean-up and gas chromatography

Summary An improved analytical methodology based on solid-phase disc extraction (SPDE) and a single-step clean-up on Florisil is proposed for a large number of organochlorine pesticide residues in serum. Extraction was performed following denaturation of proteins with formic acid after it was shown that it has no degradation effect on targeted analytes (α, β, γ-HCH isomers, HCB, DDT with its 5 analogues, endrin, aldrin, dieldrin, alachlor; heptachlor, heptachlorepaxide, α, β-endosulphan, endosulphansulphate, methoxychlor and mirex). Determination and quantification were by GC-ECD and GC-MS on two different, analytical capillary-columns using PCNB (pentachlonitrobenzene) and PCB 190 internal standards. Recoveries and limits of detection determined on pooled serum ranged 54–102% (for medium spiking level) and 10–50 pg ml⁻¹ serum respectively. Twenty-one individuals serum samples from the University Hospital of Antwerp were analysed and results were related to the ages of the donors. For compounds not detected by GC-MS, eventual coelution with PCBs in GC-ECD analysis was studied.     

反吹-气相色谱法检测蔬菜中的有机磷农药残留

采用反吹技术改进了气相色谱检测大批量蔬菜样品中有机磷农药残留的方法。在样品中加入乙腈、氯化钠混合溶液振荡,离心分层,得到乙腈提取液。取部分提取液浓缩、定容,用配备火焰光度检测器及微流控装置的气相色谱仪进行有机磷农药检测。16种有机磷农药在0.040～3.20 mg/L内具有良好的线性关系(r＞0.9996)。回收率为75.2%～111.5%,相对标准偏差为2.8%～10.4%,检出限为0.003～0.01 mg/kg。通过反吹可以有效降低基质效应影响,缩短每个样品的运行时间,减少停机维护和材料消耗,节约38%的检测时间。     

毛细管柱气相色谱法测定土壤中的有机氯农药

研究了使用毛细管柱气相色谱法测定土壤中有机氯农药的分离条件、萃取方法、净化方法以及用替代品进行全程质量控制的方法。有机氯农药检出限在 1 .1～ 4.0 μg L之间 ,各化合物保留时间的RSD <0 .1 % ,所测定化合物的质量浓度在 0 .0 0 6～ 0 .2 0mg L范围内 ,各物质校正曲线 (浓度与峰面积 )的相关系数在 0 .992 6～ 0 .9971之间。用正己烷 丙酮 ( 1 1 ) 1 0 0mL超声波萃取 ,有机氯农药的萃取回收率在 96.3%～ 1 1 4% ,RSD为 0～ 1 1 %。用国产硅镁吸附剂净化 ,有机氯农药的回收率在 1 0 0 %～ 1 40 %之间 ,弗罗里硅土的回收率在 1 0 4 %～ 1 33%之间 ,硅镁吸附剂可以替代弗罗里硅土用于样品的净化。     

气相色谱/质谱测定水产品中氯霉素残留量

样品经均质后,用乙酸乙酯提取,正己烷脱脂,C18小柱净化,衍生后用GC ECD,NCI GC MS,NCI GC MSMS多种方法定性及定量测定,外标法定量。在0.1μg/kg水平,回收率为72%～110%,平行测定9次后相对标准偏差为16 5%。质量浓度在0～10μg/L范围内呈良好线性关系,相关系数r=0.9997。     

气相色谱法同时测定蔬菜中24种有机磷农药残留

建立了蔬菜中24种有机磷类农药残留气相色谱同时分析的方法。样品用含0.1%乙酸的乙腈提取,净化采用分散固相萃取的方式:在提取液中加入C18(ODS)、石墨炭黑、PSA等吸附剂粉末进行净化,采用DB-1701(30 m×0.32 mm×0.25μm)毛细管柱分离,FPD(P)检测。24种农药的质量分数在0.002~0.05 mg/kg时,回收率在80.1%~102.1%之间、RDS为1.4%~5.1%。各农药的检测限为:三硫磷、三唑磷为0.004 mg/kg、苯硫磷为0.01 mg/kg,其它21种为0.002 mg/kg。     

Development of an ultrasound‐assisted emulsification microextraction method for the determination of chlorpyrifos and organochlorine pesticide residues in honey samples using gas chromatography with mass spectrometry

A simple, rapid, and efficient ultrasound‐assisted emulsification microextraction method followed by gas chromatography mass spectrometry in selected ion monitoring mode was developed for the determination of organochlorine pesticides in honey samples. The type and volume of organic extraction solvent, pH, effect of added salt content, and centrifuging time and speed were investigated. Under the optimum extraction conditions, 30 μL of 1, 2‐dibromoethane (extraction solvent) was immersed into an ultrasonic bath for 1 min at 40°C. The limits of detection and quantification for all target pesticides were 0.003–0.06 and 0.01–0.2 ng/g_, respectively. The extraction recovery was 91–100% and the enrichment factors were 168–192. The relative standard deviation for the method was <6% for intraday (n = 6) and <8% for interday precision (n = 4). The proposed method was successfully applied for the analysis of organochlorine pesticides in honey samples.     

土壤中多种有机氯及拟除虫菊酯类农药的GC-ECD测定

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。     

Direct determination of melamine in dairy products by gas chromatography/mass spectrometry with coupled column separation

A coupled capillary column system was developed for the qualitative and quantitative determination of melamine with isotope internal standard in dairy products by gas chromatography/mass spectrometry (GC/MS) without derivatization. A 30 m of DB-5ms ((5%-phenyl)-methylpolysiloxane, 0.25 mm i.d., 0.25 μm df) coupled with a 1.5 m of Innowax (polyethylene glycol, 0.32 mm i.d., 0.25 μm df) by a quartz capillary column connector was introduced as separation column. Three advantages were discussed for the coupled system. The sample was fortified with a ring-labeled ¹³C₃¹⁵N₃-melamine as an isotope internal standard and extracted by 1% of trichloroacetic acid aqueous solution. 2.2% of lead acetate solution was then added to deposit protein in the sample matrix. After purification by cation exchange cartridge, the sample solution was directly injected and detected by GC/MS. A six-point calibration curve ranging from 0.05 to 2 mg kg⁻¹ of melamine in sample was used to establish instrument response. The recovery was 93.9-102% with relative standard deviation from 3.1 to 8.7% when isotope internal standard used. The calculated method detection limit was 0.01 mg kg⁻¹.     

气相色谱-三重四极杆串联质谱法快速测定蔬菜水果中129种农药的残留量

采用QuEChERS方法结合气相色谱-串联质谱法(GC-MS/MS)建立了蔬菜、水果中129种农药残留同时检测的分析方法。试样用1%乙酸乙腈均质提取,采用混合型固相分散萃取剂净化后,用GC-MS/MS在多反应离子监测(MRM)模式下进行检测,外标法定量。结果表明,129种药物在一定的含量范围内线性关系良好,相关系数(r2)均大于0.98;不同基质在10 μg/kg添加水平下大部分农药的平均回收率为66.2%～124.7%,相对标准偏差(RSD)为0.9%～24.4%;方法的定量限(LOQ)为0.03～16.7 μg/kg。结果表明,该方法简便快速、灵敏可靠、经济有效,适用于蔬菜、水果中农药多残留的同时快速筛查测定。