超声提取-超声波辅助固相微萃取色谱法测定蔬菜中的有机氯、菊酯类农药残留量

建立了一种USE-SPME-GC联用测定蔬菜中有机氯和菊酯类农药残留量的新方法,并对分析条件进行优化和探讨,实验表明,萃取液中基体杂质和色素对分析结果干扰较大,我们提出稀释的方法较好的解决这个问题。对实际蔬菜样品进行了测定和分析。     

加压溶剂萃取-气相色谱法测定荞麦中残留的有机氯农药

用所研制的24位全自动加压溶剂萃取仪(APLE),以丙酮-正己烷(体积比为1∶1)为溶剂,在100 ℃和10 MPa条件下,对荞麦样品中残留的7种有机氯农药进行了萃取,并通过气相色谱对萃取液进行定量分析。萃取的绝对回收率为68%～126%,相对标准偏差为1.2% ～14.7%,检测下限为0.051～0.18 ng/g。与索氏提取法对比,相对提取回收率为116%～148%,表明萃取收率高于索氏提取法。     

The use of silica‐coated magnetic graphene microspheres as the adsorbent for the extraction of pyrethroid pesticides from orange and lettuce samples followed by GC–MS analysis

Graphene‐grafted ferroferric oxide microspheres were used as the adsorbent to extract some pyrethroid pesticides (bifenthrin, λ‐cyhalothrin, cyfluthrin, cypermethrin, fenvalerate, and deltamethrin) from orange and lettuce samples prior to their determination by GC–MS. The main variables that could affect the extraction, including the amount of the adsorbent, pH of the sample solution, extraction time, concentration of salt, and desorption conditions, were investigated and optimized. Under the optimized conditions, a linear response was obtained in the concentration range of 0.3–100.0 ng/g for the analytes with the coefficients of determination ranging from 0.9877 to 0.9925. The LODs for the pyrethroids ranged from 0.01 to 0.02 ng/g. The method provided a good repeatability with RSDs < 10.6%. The recoveries for the six pyrethroid pesticides were in the range from 90.0 to 103.7%. The method was applied to the determination of the pesticides in orange and lettuce samples with a satisfactory result.     

Rapid determination of pesticide residues in herbs using selective pressurized liquid extraction and fast gas chromatography coupled with mass spectrometry

A selective pressurized liquid extraction and gas chromatography coupled with triple quadrupole mass spectrometer method was developed for simultaneous determination of 52 pesticide residues in medicine and food dual-purpose herbs. The developed extraction method integrated extraction and cleanup processes for sample preparation. The sorbents, 5 g Florisil and 100 mg graphitized carbon black, were placed inside the extraction cell to remove matrix interferences. Optimized conditions of selective pressurized liquid extraction were ethyl acetate as extraction solvent, 120°C of extraction temperature, 6 min of static extraction time, 50% of flush volume extracted for two cycles. An ultra inert capillary GC-MS HP-5 UI column (20 m × 0.18 mm id, 0.18 μm) and column backflush system were used for the analysis. Multiple-reaction monitoring was employed for the quantitative analysis with electron ionization mode. All calibration curves showed good linearity (r(2) > 0.995) within the test ranges. The average recoveries of most pesticides were from 81 to 118%. The validated method was successfully applied for the determination of pesticide residues in four herbs. The results indicate that selective pressurized liquid extraction and GC-MS/MS is a sensitive and reliable analytical method for the simultaneous determination of multiple pesticide residues in herbs.     

串联双柱固相萃取-气相色谱-串联质谱法检测茶叶中拟除虫菊酯

建立了气相色谱-串联质谱定量检测花茶、绿茶、红茶和黑茶4类茶叶中氟氯氰菊酯、氯氰菊酯和氰戊菊酯3种拟除虫菊酯农药残留量的方法。样品采用乙腈进行提取,优化洗脱液配比,选择Carb/NH2和SLH双柱串联净化富集。采用外标法定量,30 min内完成农药残留检测。3种拟除虫菊酯的检出限分别为0.4、1.0和0.3μg/kg,在0.05~2.00 mg/kg内线性关系良好,相关系数均大于0.999。在0.10、0.50和2.00 mg/L 3个添加水平下,空白加标样品的回收率为80.6%~116.3%。茶叶实际样品检测结果的日内相对标准偏差(RSD)为1.3%~12.6%,日间RSD为2.7%~12.1%。该法操作简单,重现性好,适用于茶叶中拟除虫菊酯类农药残留的检测。     

Microwave-assisted extraction of pyrethroid insecticides from semi permeable membrane devices (SPMDs) used to indoor air monitoring

A rapid and environmentally friendly methodology was developed for the extraction of pyrethroid insecticides from semi permeable membrane devices (SPMDs), in which they were preconcentrated in gas phase. The method was based on gas chromatography mass–mass spectrometry determination after a microwave-assisted extraction, in front of the widely employed dialysis method. SPMDs were extracted twice with 30 mL hexane:acetone, irradiated with 250 W power output, until 90 °C in 10 min, this temperature being held for another 10 min. Clean-up of the extracts was performed by acetonitrile–hexane partitioning and solid-phase extraction (SPE) with a combined cartridge of 2 g basic-alumina, deactivated with 5% water, and 500 mg C₁₈.

Pyrethroids investigated were Allethrin, Prallethrin, Tetramethrin, Bifenthrin, Phenothrin, λ-Cyhalothrin, Permethrin, Cyfluthrin, Cypermethrin, Flucythrinate, Esfenvalerate, Fluvalinate and Deltamethrin. The main pyrethroid synergist compound, Pyperonyl Butoxide, was also studied. Limit of detection values ranging from 0.3 to 0.9 ng/SPMD and repeatability data, as relative standard deviation, from 2.9 to 9.4%, were achieved. Pyrethroid recoveries, for spiked SPMDs, with 100 ng of each one of the pyrethroids evaluated, were from 61 ± 8 to 103 ± 7% for microwave-assisted extraction, versus 54 ± 4 to 104 ± 3% for dialysis reference method. Substantial reduction of solvent consumed (from 400 to 60 mL) and analysis time (from 48 to 1 h) was achieved by using the developed procedure.

High concentration levels of pyrethroid compounds, from 0.14 to 7.3 μg/SPMD, were found in indoor air after 2 h of a standard application.     

An efficient and fast microwave-assisted extraction method developed for the simultaneous determination of 18 organochlorine pesticides in sediment

An efficient and fast microwave-assisted extraction (MAE) method followed by gas chromatographic separation with mass spectrometric detection (GC–MS) was developed for the extraction of 18 organochlorine pesticides (OCPs) from sediment. Parameters affecting the MAE procedure such as the type and volume of the extraction solvent, irradiation power, temperature and irradiation time were successfully optimised. Under the optimal conditions, extraction efficiencies in the range of 73.4–119% were obtained with THF–HEX (9:1, v/v) for all OCPs studied. The method was linear over the range of 2.9–5000 ng g^?1 with determination coefficients (r²) higher than 0.992 for all analytes. The limits of detection, LODs (S/N = 3), obtained varied from 1.0 to 2.2 ng g^?1 and limits of quantification, LOQs (S/N = 10) were between 2.9 and 6.8 ng g^?1. The proposed method was successfully applied to the analysis of real sediment samples and acceptable recoveries from 70.1 to 124% with RSDs ≤14.8% were obtained. 10 OCPs were determined below their LOQ and 8 OCPs in the range of 124–2830 ng g^?1. The MAE method was compared with Soxhlet, shake flask and ultrasonic solvent extraction techniques. Thus, the MAE–GC–MS method could efficiently be used for selective extraction and quantification of the target analytes from the complex sediment matrices.     

Matrix solid-phase dispersion extraction of organophosphorous pesticides from beeswax

Beeswax is a complex mixture of lipophilic compounds and other components such as aliphatic alcohols and carotenoids. Then, extraction and clean-up for pesticide analysis in beeswax is a challenge. In this work, a multiresidue method for the analysis of dichlorvos (DCV), diazinon, malathion, methyl parathion and coumaphos (CMF) in beeswax was developed. The proposed approach is based on matrix solid-phase dispersion extraction. The adsorbent for sample clean-up was studied and a simplex-centroid cubic statistical design was applied to evaluate pure solvents and their binary and ternary mixtures to elute the analytes. Finally, Florisil and ethyl acetate were chosen as solid support and eluting solvent, respectively. After extraction, pesticides were separated and detected by gas chromatography/mass spectrometry. The method achieved acceptable recoveries (70–85%; except for DCV, 24–38%) with relative standard deviations below 5%. The repeatability of the method was lower than 8% and interday variability was below 12%. The limit of detection (LOD) for the analytes varies between 0.2 and 2.6 µg?kg^?1 and limit of quantification from 0.93 to 8.8 µg?kg^?1. LOD reached for CMF was below the maximum residue limit allowed by the legislation of the United States and Canada.     

Optimization of QuEChERS method for the analysis of organochlorine pesticides in soils with diverse organic matter

A QuEChERS method has been developed for the determination of 14 organochlorine pesticides in 14 soils from different Portuguese regions with wide range composition. The extracts were analysed by GC-ECD (where GC-ECD is gas chromatography-electron-capture detector) and confirmed by GC-MS/MS (where MS/MS is tandem mass spectrometry). The organic matter content is a key factor in the process efficiency. An optimization was carried out according to soils organic carbon level, divided in two groups: HS (organic carbon >2.3%) and LS (organic carbon <2.3%). The method was validated through linearity, recovery, precision and accuracy studies. The quantification was carried out using a matrix-matched calibration to minimize the existence of the matrix effect. Acceptable recoveries were obtained (70-120%) with a relative standard deviation of ≤16% for the three levels of contamination. The ranges of the limits of detection and of the limits of quantification in soils HS were from 3.42 to 23.77 μg kg(-1) and from 11.41 to 79.23 μg kg(-1), respectively. For LS soils, the limits of detection ranged from 6.11 to 14.78 μg kg(-1) and the limits of quantification from 20.37 to 49.27 μg kg(-1) . In the 14 collected soil samples only one showed a residue of dieldrin (45.36 μg kg(-1) ) above the limit of quantification. This methodology combines the advantages of QuEChERS, GC-ECD detection and GC-MS/MS confirmation producing a very rapid, sensitive and reliable procedure which can be applied in routine analytical laboratories.     

固相萃取-在线凝胶渗透色谱-气相色谱/质谱法测定松子仁中的28种有机氯农药和拟除虫菊酯农药

建立了松子仁中28种有机氯农药和拟除虫菊酯农药多残留的在线凝胶渗透色谱-气相色谱/质谱（GPC-GC/MS）分析方法。样品以乙腈-水(体积比为4∶1)为提取剂高速匀浆提取,提取液经Aluminium-N固相萃取柱净化,除去样品中大部分的脂肪和甾醇等干扰基质,再经在线GPC进一步除去样液中的色素和脂肪等大分子干扰物质,有效地降低了样品复杂基质带来的背景干扰。加标水平为0.05 mg/kg时,大部分农药的回收率为70%～120%,相对标准偏差小于15%。28种农药的检出限为0.002～0.05 mg/kg。采用外标法定量,方法的线性关系和回收率结果均令人满意。实验证明,该方法是一种快速、准确、灵敏度高的同时检测松子仁中农药多残留的检测方法。     

Development of an analytical method based on microwave-assisted extraction and solid phase extraction cleanup for the determination of organochlorine pesticides in animal feed

A method to determine 21 organochlorine pesticides in animal feed samples using microwave assisted extraction and solid phase extraction cleanup was optimised regarding its main parameters. After extraction with hexane-acetone (50:50), three different sorbents (alumina/ENVI-Florisil, ENVI-Carb and ENVI-Carb II/PSA) were assayed for the cleanup step. Analytes were eluted with hexane-ethyl acetate (80:20) and determined by gas chromatography and electron capture detection followed by gas chromatography-mass spectrometry. ENVI-Carb and ENVI-Carb II/PSA provided colourless eluates but fewer interferent compounds were found in ENVI-Carb II/PSA chromatograms, so this system was selected to carry out the purification of the extracts. The analytical recoveries obtained with this method were close to 100% in most cases with relative standard deviations lower than 10%. These percentages were similar to those obtained with the Soxhlet extraction procedure, which shows the method suitable for the determination of organochlorine pesticides in animal feed material. The method was also validated with the analysis of a certified reference material (CRM-115 BCR), and the results obtained were in good accordance with the certified values.     

Development of a sample preparation procedure of sewage sludge samples for the determination of polycyclic aromatic hydrocarbons based on selective pressurized liquid extraction

An automated, simple and sensitive method based on selective pressurized liquid extraction (SPLE) was developed for the analysis of polycyclic aromatic hydrocarbons in sewage sludge samples. The new sample preparation procedure consists of on-line clean-up by inclusion of sorbents in the extraction cell, and combines elevated temperatures and pressures with liquid solvents to achieve fast and efficient removal of target analytes from complex sewage sludge matrices. The effects of various operational parameters (e.g. sample pretreatment, extraction solvent, temperature, pressure, static time, etc.) on the performance of SPLE procedure were carefully investigated, obtaining the best results when SPLE conditions were fixed at 140 °C, 1500 psi, static time of 5 min and n-hexane as extraction solvent. A new programmed temperature vaporization–gas chromatography–tandem mass spectrometry method based on large volume injection (PTV–LVI–GC–MS/MS) was also developed and analytical determinations were performed by high performance liquid chromatography coupled with fluorescence detection and GC–MS/MS. The extraction yields for the different compounds obtained by SPLE ranged from 84.8% to 106.6%. Quantification limits obtained for all of these studied compounds (between 0.0001 and 0.005 μg g⁻¹, dry mass) were well below the regulatory limits for all compounds considered. To test the accuracy of the SPLE technique, the optimized methodology was applied to the analysis of a certified reference material (sewage sludge (BCR088)) and a reference material (sewage sludge (RTC-CNS312-04)), with excellent results.     

Response surface methodology for the microwave-assisted extraction of insecticides from soil samples

The extraction of two pyrethroid insecticides (deltamethrin and α-cypermethrin) together with three organophosphorus insecticides (dimethoate, diazinon and malathion) from soil samples was carried out with microwave-assisted technology. Experimental designs showed that extraction temperature, addition of water to the extractant and solvent/soil ratio were the variables that affected the recoveries of the pesticide the most. Response surface methodology was applied to find the optimum values of the variables involved in the extractions of the analytes. In addition, in order to achieve near-optimal extraction conditions, a desirability function was used to optimize the five pesticides simultaneously. The optimized conditions were applied to different types of soils.     

Development of pressurized liquid extraction and cleanup procedures for determination of organochlorine pesticides in soils

The scope of this work is the development of a rapid, reliable and sensitive method for the analysis of organochlorine pesticides from soils by pressurized liquid extraction (PLE). The effect of four parameters (temperature, pressure, static time and cell volume) on the extraction efficiency was studied. The great extracting power of the PLE causes the extraction of numerous interfering substances, so a more efficient purification of this extract was necessary. In this work several sorbents have also been assayed to carry out the purification of soil samples: Florisil, silica, alumina, carbon, as well as combinations of them. Finally, the proposed analytical method was validated using a certified reference soil material (CRM804-050) and the results were compared with those obtained by other extraction techniques (Soxhlet and microwave-assisted extraction).     

GC/MS法测定室内空气中邻苯二甲酸酯类物质

针对室内空气中日益严重的邻苯二甲酸酯类污染,建立了固相萃取柱采样,GC/MS测定室内空气中16种邻苯二甲酸酯类物质的测试方法,可用于评价室内空气质量。     

加速溶剂萃取-超高效液相色谱-串联质谱法测定茶叶中拟除虫菊酯类农药残留

建立了加速溶剂萃取（ASE）-超高效液相色谱（UPLC）-串联质谱法（MS/MS）测定茶叶中拟除虫菊酯类农药残留的方法。ASE萃取温度为80 ℃，萃取压力为10.34 MPa，以正己烷-丙酮（2∶1，v/v）为溶剂静态萃取5 min，循环一次。萃取液浓缩后经GCB/NH₂-Florisil柱净化，UPLC分离，MS/MS正离子扫描（ESI⁺）、多反应离子监测（MRM）模式进行分析，外标法定量。线性回归分析表明：10种拟除虫菊酯的浓度与其峰面积的线性关系显著，相关系数（r）均不小于0.9995，检出限（LOD）在0.5~5.0 μg/kg之间，定量限（LOQ）在1.6~16.6 μg/kg之间；在定量限、0.4 mg/kg以及最高残留限量（MRL，无MRL的加入1 mg/kg）3个水平进行添加回收试验（n=7），回收率为68.7%~103.8%，RSD为0.8%~13.2%。该方法前处理简单，耗时短，灵敏度和准确度高，可满足茶叶中痕量拟除虫菊酯类农药残留测定的要求。     

多壁碳纳米管固相萃取净化气相色谱法分析蔬菜中有机氯和拟除虫菊酯农药残留

建立了多壁碳纳米管为吸附剂的固相萃取(SPE)净化、气相色谱-电子捕获检测(GC-ECD)测定蔬菜中6种有机氯和7种拟除虫菊酯农药的方法。采用双柱(HP-50和HP-1色谱柱)双检测器进行定性和定量分析。蔬菜样品采用乙腈提取,多壁碳纳米管SPE柱净化,正己烷溶解上样,丙酮-正己烷(7:3, v/v)洗脱,13种农药中有11种农药的添加回收率高于70%。将该净化方法用于荷兰黄瓜、卷心菜、红圣女果、奶油生菜、紫甘蓝、韭菜、大葱和洋葱等样品的净化,与弗罗里硅土SPE柱相比较,净化效果更好,表明多壁碳纳米管具有较强的吸附去除色素的能力,可以避免色素对测定的干扰。     

Development of a matrix solid-phase dispersion method for the simultaneous determination of pyrethroid and organochlorinated pesticides in cattle feed

A matrix solid-phase dispersion (MSPD) method was developed for the simultaneous extraction of 36 common pesticides and breakdown products (mostly pyrethroids and organochlorines) in cattle feed. Different parameters affecting the extraction efficiency (such as dispersing phase, clean-up adsorbent and elution volume) were investigated. The experimental procedure was optimized using a multivariate statistical approach and the final analyses were carried out by GC-muECD. Several protocols for extract purification were also studied. As far as we know, this is the first application of MSPD for the extraction of most of the target pesticides from animal feed. Using the optimized extraction conditions, the method was validated in terms of accuracy, and precision (within-a-day and among-days), using a certified reference material (CRM 115) as well as spiked cattle feedingstuffs at different concentration levels. A matrix effect study was also carried out using various real samples. The recoveries were satisfactory (>75% in most cases) and the quantification limits, at the sub-ngg(-1) or low-ngg(-1) level, complied with the regulated maximum residue levels (MRLs) in animal feed and in main crops used in the preparation of cattle feeding materials. Finally, the MSPD-GC-muECD methodology was applied to the analysis of real cattle feed samples collected in farms of dairy cattle from NW Spain.     

固相萃取-超高效液相色谱-串联质谱法测定人尿中苯氧乙酸除草剂和有机磷、拟除虫菊酯农药代谢物北大核心CSCD

基于96孔固相萃取-超高效液相色谱-串联质谱法,建立了人尿中2种苯氧乙酸除草剂、2种有机磷农药代谢物和4种拟除虫菊酯农药代谢物的测定方法。通过对液相色谱条件、质谱条件和样品前处理过程的系统优化,实现了在16 min内对8种目标分析物的分析测定。具体方法:1 mL尿液经β-葡萄糖醛酸酶酶解过夜,Oasis HLB 96孔固相萃取进行目标分析物的提取净化,甲醇洗脱;以0.1%(体积分数)乙酸乙腈和0.1%(体积分数)乙酸水作为流动相,Acquity BEH C_(18)作为分析柱进行色谱分离;负离子电喷雾(ESI-)多反应监测(MRM)模式下检测目标化合物,同位素内标法定量。2,4-二氯苯氧乙酸(2,4-D)、2,4,5-三氯苯氧乙酸(2,4,5-T)2种苯氧乙酸除草剂和3-苯氧基苯甲酸(3-PBA)、4-氟-3-苯氧基苯甲酸(4F-3PBA)、反式二氯乙烯基二甲基环丙烷羧酸(trans-DCCA)3种拟除虫菊酯农药代谢物在0.1~100μg/L内、对硝基苯酚(PNP)、3,5,6-三氯-2-吡啶酚(TCPY)2种有机磷农药代谢物、顺式二氯乙烯基二甲基环丙烷羧酸(cis-DCCA)1种拟除虫菊酯代谢物在0.2~100μg/L内线性关系良好,相关系数均大于0.9993;方法检出限为0.02~0.07μg/L,方法定量限为0.08~0.2μg/L;低、中、高3个水平下的加标回收率为91.1%~110.5%,日内精密度为2.9%~7.8%,日间精密度为6.2%~10%。应用该方法测定了214份尿液样本。结果显示除2,4,5-T外,其余7种目标分析物均有检出。TCPY、PNP、3-PBA、4F-3PBA、trans-DCCA、cis-DCCA、2,4-D的检出率为2.8%~99.1%。检出浓度(中位值)由高到低分别是2.0μg/L(TCPY)、1.8μg/L(PNP)、0.99μg/L(trans-DCCA)、0.81μg/L(3-PBA)、0.44μg/L(cis-DCCA)、0.35μg/L(2,4-D)和未检出(4F-3PBA)。该方法操作简便,定量准确,灵敏度高,每批次可完成96个样品测定,适用于人尿中多种农药及农药代谢物的批量分析测定。     

Supercritical fluid extraction of carbamate pesticides from soils and cereals

Summary A method for the supercritical fluid extraction of carbamate pesticides (propoxur, aminocarb, carbaryl and methiocarb) from soil and cereal samples using CO₂ is proposed. Extractions were at 378 bar and 54 °C. Analytes were determined in the extracts by HPLC with fluorescence detection after post-column derivatization. Recoveries from spiked soil ranged between 39.6 and 91.7%, depending on analyte and soil components. Lowest recoveries were from sandy soils. Aminocarb could not be recovered from any soil using CO₂. Recovery of aminocarb from diatomaceous earth was improved by adding methanol to the extraction cell prior to SFE, but the effect was not observed in soil samples. Recoveries for propoxur and aminocarb from spiked wheat were about 75%, and only between 30–50% for aminocarb from corn and oats, and carbaryl from wheat. Fat was coextracted using CO₂ and retained in the trap together with the analytes, however, appropriate rinsing solvent allowed on-line clean-up of the extract.