凝胶渗透色谱净化-气相色谱分离同时测定糙米中50种有机磷农药残留

研究了同时检测糙米中50种有机磷农药残留的方法。用乙酸乙酯提取,凝胶渗透色谱净化,环己烷二氯甲烷(50∶50,V/V)作为流动相,气相色谱氮磷检测器检测。方法检出限为0.001～0.089mg/kg;相对标准偏差为1.7%～18.9%;40多种农药平均回收率在70%～120%。     

蔬菜、水果中16种有机磷类农药多残留GC-MS分析

建立了蔬菜、水果中16种农药的气相色谱-离子阱质谱多残留检测方法。采用乙腈作为提取剂,经过Florisil柱净化,用ITQ700气相色谱-离子阱质谱联用仪进行分析。以保留时间和特征离子定性、峰面积定量,确定了16种有机磷农药的线性回归方程、相关系数及最低检出限。结果表明,16种有机磷农药线性关系良好。农药添加浓度为0.5μg/mL,回收率为70%～120%,相对标准偏差20%,最低检出限在0.0012～0.02μg/g之间,符合农药多残留检测要求。此方法具有良好的回收率、精确度和准确度,干扰少,可用于实际检测。     

气相色谱法测定火锅底料中的多种有机氯农药和拟除虫菊酯农药残留

建立了火锅底料中21种有机氯农药和6种拟除虫菊酯农药残留的同时测定方法.样品经乙腈超声提取,凝胶渗透色谱、弗罗里硅土固相萃取柱和N-丙基-2-乙二胺净化,毛细管气相色谱柱分离后,微电子捕获检测器检测.火锅底料中有机氯农药和拟除虫菊酯农药的检出限分别为0.082～2.3 μg/kg和1.5～13.0 μg/kg;有机氯农药的加标水平为10, 20和50 μg/kg,拟除虫菊酯农药为20, 40和100 μg/kg时,27种农药的平均回收率为70.5%～116.0%;相对标准偏差为0.2%～6.1%.本方法快速、灵敏、可靠,可用于火锅底料中多种农药残留的同时检测.     

GC-NPD同时测定中草药中有机磷和氨基甲酸酯农药残留量

建立了中草药中有机磷和氨基甲酸酯类农药残留量同时检测的气相色谱分析方法.中药材试样依据正交实验的优化条件,用V(C6H14):V(丙酮)=1:1混合提取剂进行超声波提取,经弗罗里硅土和中性氧化铝层析柱净化后,采用HP-5毛细管柱分离,氮磷检测器同时检测中草药中15种有机磷和7种氨基甲酸酯类农药残留量.22种农药在0.015～1.0 mg/L范围内线性良好,线性相关系数为0.9950～1.000,在0.05、0.1 mg/kg两个添加水平的平均回收率分别为70.6%～128.6%和69.5%～116.1%,相对标准偏差分别为0.98%～18%和0.37%～15%.各种农药的检出限为0.002～0.015 mg/L.方法已用于中草药中有机磷和氨基甲酸酯类农药残留量的同时检测.     

土壤中17种有机氯农药残留量的毛细管气相色谱测定法

采用专用索氏提取器、正己烷萃取、Elite-5MS弹性石英毛细柱分离、GC-ECD测定了土壤中17种有机氯农药残留量.方法的检出限为0.4×10-10～2.0×10-10 g,回收率范围在76.0%～108.9%之间,相对标准偏差为0.66%～9.10%.该方法适用于土壤有机氯农药残留量的分析.     

果汁中有机磷农药残留的动态液相微萃取/气相色谱法检测

应用动态液相微萃取与气相色谱联用技术建立了果汁中3种有机磷农药(敌敌畏、甲基对硫磷、对硫磷)的快速分析方法.考察了萃取溶剂、溶剂体积、萃取次数、水样pH值以及离子强度对液相微萃取的影响.3种有机磷农药的线性范围均为40 ～400 μg·L-1,富集倍数22.3 ～51.5,回收率80% ～120%,相对标准偏差2.0% ～8.1%,检出限12.2 ～20.6 μg·L-1.     

固相萃取-气相色谱法测定茶叶中多种有机磷农药残留量

本文选择石墨碳黑固相萃取小柱对茶叶样品进行净化,样品中残留的农药经过乙腈洗脱,浓缩后采用气相色谱-火焰光度检测器(FPD)测定.研究结果表明,茶叶中添加农药浓度为0.02～1.0 mg/kg时,9种农药的平均回收率为75.76%～107.9%,相对标准偏差为1.38%～8.95%,方法检出限为0.006～0.01 mg...     

超高效液相色谱-串联质谱法同时测定蔬菜水果中的40种农药残留

采用超高效液相色谱-串联质谱技术建立了蔬菜水果中40种农药残留的快速测定方法。蔬菜水果利用乙腈提取后直接进样分析,采用优化后的正离子多反应监测模式,外标法定量。40种农药含量在0.1~100μg/L范围内线性关系良好,检出限为0.10~5.0μg/kg,平均回收率为60.3%~134.8%,相对标准偏差为2.6%~17%。     

大葱中25种有机磷农药多残留的微波净化-气相色谱测定

采用微波净化去除大葱中硫醚干扰、气相色谱-火焰光度检测(GC-FPD)实现了大葱基质中25种有机磷农药多残留的快速检测。25种有机磷的加标回收率为85.2%~119.6%,相对标准偏差为2.1%～14.8%。大多数农药在0.1～5.0 mg/L范围内线性关系良好,相关系数不低于0.9910,检出限为0.025~0.200 mg/L。     

蔬菜中氨基甲酸酯类农药残留的固相微萃取分离和HPLC法检测

采用固相微萃取制样,荧光检测器高效液相色谱法测定了蔬菜中氨基甲酸酯农药残留. 确定了影响固相微萃取效果的萃取头涂层、萃取条件、洗脱条件和蔬菜样品分析处理方法. 结果表明,蔬菜中氨基甲酸酯类农药的检出限在0.4×10-9～40×10-9 g/g范围内,线性范围为0.05～1 mg/L,回收率74.4%～108.4%,相对标准偏差(RSD)4.26%～13.97%.     

Determination of pyrethroid,organophosphate and organochlorine pesticides in water by headspace solid-phase microextraction

Simultaneous determination of pyrethroid, organophosphate (OP) and organochlorine (OC) pesticides in water was achieved with headspace solid-phase microextraction (HS-SPME) followed by gas chromatography-electron-capture detection (GC-ECD). The parameters affecting HS-SPME of pesticides from water were optimized, including extraction temperature, sample and headspace volumes, and sodium chloride amounts. The effects of desorption temperature, desorption time, and position of the fibre in the GC inlet were also investigated. Extraction temperature was the most important factor affecting the recoveries of analytes, and the optimized temperature was 96°C. The addition of salt did not increase extraction efficiencies of the pesticides from the water. The optimized desorption conditions in the GC were as follows: desorption time of 10?min; desorption temperature of 260°C; and a 2?cm position of the fibre in the inlet. The method detection limits were in the low-ng/L level with a linearity range of 50–1000?ng/L for the OCs, 50–5000?ng/L for the OP, and 50–20?000?ng/L for the pyrethroids. These data demonstrated that HS-SPME is a sensitive method for the determination of pyrethroid, OC, and OP pesticides in water.     

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。     

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。     

Fast analysis of quaternary ammonium pesticides in food and beverages using cation‐exchange chromatography coupled with isotope‐dilution high‐resolution mass spectrometry

A fast separation based on cation‐exchange liquid chromatography coupled with high‐resolution mass spectrometry is proposed for simultaneous determination of chlormequat, difenzoquat, diquat, mepiquat and paraquat in several food and beverage commodities. Solid samples were extracted using a mixture of water/methanol/formic acid (69.6:30:0.4, v/v/v), while liquid samples were ten times diluted with the same solution. Separation was carried out on an experimental length‐modified IonPac CS17 column (2 × 15 mm²) that allowed the use of formic acid and acetonitrile as mobile phase. Detection limits for food and beverage matrices were established at 1.5 μg/L for chlormequat, difenzoquat and mepiquat, and 3 μg/L for diquat and paraquat, while for drinking water a pre‐analytical sample concentration allowed detection limits of 9 and 20 ng/L, respectively. Precision, as repeatability (RSD%), ranged from 0.2 to 24%, with a median value of 6%, and trueness, as recovery, ranged from 64 to 118%, with a median value of 96%. The method developed was successfully applied to investigate the presence of herbicide residues in commercial commodities (mineral water, orange juice, beer, tea, green coffee bean, toasted coffee powder, cocoa bean, white corn flour, rice and sugar samples).     

Study of the Electrochemical Behavior and Sensitive Detection of Pesticides Using Microelectrodes Allied to Square‐Wave Voltammetry

This work describes the application of gold and carbon fiber microelectrodes allied to square‐wave voltammetry for the study of the electrochemical behavior of the organophosphorous insecticides (methyl parathion and dichlorvos) and bipyridilium herbicides (paraquat and diquat), and the development of the sensitive methodology for their analytical determinations in natural water samples. The microelectrodes were lab‐made constructed and their electrochemical behavior was characterized by measuring the electrochemical response with a solution of potassium ferricyanide. The experimental and voltammetric conditions to obtain the best analytical signal, in terms of intensities and profile of the peak voltammetric, for four pesticides were optimized and the results were used to evaluate the type of the electrochemical redox process and to appraise the number of electrons covered in each reduction process that occurred for pesticides and also, to propose a possible redox mechanism for a reduction process of pesticides at microelectrodes. Analytical curves were constructed and presented the linear relationships between the peak currents and the concentration of pesticides, for this, the detection limits for pure water (laboratory samples) for four pesticides were calculated and presented values under 15 μg L^?1, lower than maximum limit for drinking water (100 μg L^?1) permitted by Brazilian Council for groundwater, indicating that the methodology could be employed to analyze those pesticides in natural water samples.     

Simple and rapid extraction method of total egg lipids for determining organochlorine pesticides in the egg

A simple and rapid extraction method of total egg lipids for determination of organochlorine pesticides (OCPs) in the egg was developed. After being mixed with anhydrous sodium sulphate, the extraction of lipids in egg yolk was performed using n-hexane–acetonitrile (2:1, v/v). Troublesome emulsions did not occur. Using the present method, an average of 3.03 g of egg lipids was collected from 10 g of egg yolk. Compared with classical methods, the present method is handy; needs much shorter analysis time and less requirement of solvents and has higher efficiency of egg lipid extraction and higher recoveries of OCPs.     

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.     

气相色谱-电子捕获检测器同时测定茶叶中有机氯及拟除虫菊酯类农药残留

在超声波辅助下,以正己烷-二氯甲烷（1：1,V／V）混合溶剂提取样品,提取液用弗罗里硅土和中性氧化铝混合柱净化,用气相色谱-电子捕获检测器（GC-ECD）同时测定茶叶中18种有机氯和9种拟除虫菊酯类农药残留。有机氯农药在0.001-0.2μg／mL,拟除虫菊酯类农药在0.005-1.0μg／mL范围内线性良好。有机氯农药在0.04、0.01μg／mL两个添加水平的回收率分别为89.5％-113.2％和80.0％-112.7％,相对标准偏差分别为3.82％-9.64％和5.32％-13.8％。拟除虫菊酯在0.2、O.05μg／mL两个添加水平的回收率分别为97.5％-129.6％和87.3％-110.2％,相对标准偏差分别为3.78％-10.72％和3.02％-13.84％。本方法快速、灵敏、准确、可靠,用于江西茶叶样品中有机农药残留测定,获得较好结果。     

Multi-Residue Analysis by Liquid Chromatography-Mass Spectrometry Coupling. Application to Drinking and River Waters

Abstract

The coupling between liquid chromatography and mass spectrometry with an APCI or ESI interface (in positive or negative mode) is used here for multi-residue analyses in natural waters, covering basic and neutral pesticides as well as acid pesticides. The methods developed are applied to drinking and, river waters after the samples are concentrated by liquid-liquid extraction or solid phase extraction on C18 cartridges. Comparisons are made between UV detection and mass spectrometry and between two chromatographic methods for acid substances. The quantitation limits range from 0.01 to 0.1 μg/l according to the substance.     

Development and validation of a fully automated online-SPE–ESI–LC–MS/MS multi-residue method for the determination of different classes of pesticides in drinking,ground and surface water

The present work describes a fully automated method based on online solid phase extraction–liquid chromatography–tandem mass spectrometry for the determination of different classes of pesticides, including acidic and polar pesticides and six thiamethoxam metabolites. Sample preconcentration was performed by extracting 4 mL of the sample with a single styrene-divinylbenzene polymer. Elution of the compounds was done within the high performance liquid chromatography gradient and tandem mass spectrometry determination was performed in the selected reaction monitoring mode, by recording 1–3 transitions per compound. The overall pretreatment and analysis time per sample was less than 15 min. Method validation was performed in drinking, ground and surface water. For nearly all compounds a recovery between 70% and 120% could be achieved. The limit of detection ranges from 1.2 to 18 ng/L in drinking water and 3.0 to 23 ng/L in ground and surface water. The correlation coefficients for a calibration range of 0.05–2 µg/L are between 0.9915 and 0.9999. The limit of quantification (LOQ) for all compounds lies below the required limit of 0.1 µg/L, to fulfil the Council Directive 98/83/EC. Most of the compounds easily reach an LOQ below 0.05 µg/L.