Determination of azinphos-methyl and parathion-methyl in honey by stripping voltammetry

An electrochemical method for the determination of azinphos-methyl and parathion-methyl in honey is presented. The determination is established by adsorptive stripping differential pulse voltammetry at hanging mercury working electrode.In contrast to the chromatographic methods for the determination of pesticide residues, the sample preparation of the proposed method is minimal; analytes were extracted from honey samples with a mixture of (acetone):(Britton-Robinson buffer) and then were analyzed without any additional pretreatment.The response of the analytes either individually or as a mixture was studied for a series of deposition time and molar ratio. Two quantitation protocols were compared, using either the external calibration or the standard addition method. Accuracy was tested with spiked honey samples obtaining good recovery values. The limit of detection for the honey sample (for deposition time of 10 s) was calculated 51.71 μg kg⁻¹ for MeP and 65.87 μg kg⁻¹ for AzMet.     

杭嘉湖地区饮用水源有机农药污染现状调查与分析

采用固相萃取-GC-MS法对杭嘉湖地区16个集中式饮用水源水体中32种有机磷、有机氯农药进行了分析检测.结果表明,16个集中式饮用水源水共检出16种有机农药,,在平水期、丰水期、枯水期,被检出的有机农药种类分别为7种、1种和15种,表明水体中有机农药种类和浓度的季节性变化较明显,枯水期检测到的有机农药种类最多,浓度相对较高.     

固相微萃取与低热容气相色谱质谱联用快速分析水中有机磷农药残留量

介绍了一种基于固相微萃取(SPME)技术和5975T低热容(LTM)GC/MS分离分析平台的水中有机磷农残快速测定方法。该方法选用细内径短柱,通过优化分离条件,5975T可在3min内完成对5种常见有机磷农药(毒死蜱,甲基异柳磷,喹硫磷,丙溴磷,伏杀硫磷)的分离鉴定,相比实验室常规分离方法用时节省90%,联用SPME其方法定量检出限优于5 ng/L。该方法的固相微萃取过程装置简单,操作简便,无需调节萃取体系的离子强度和pH值,20min完成富集,时间/物料成本低廉。同时,还考察了方法的线性范围、精密度和回收率,并对自来水管网水中农药残留进行了分析。     

固相萃取-超高效液相色谱-三重四级杆质谱联用仪同时测定水中有机磷农药残留

应用固相萃取-超高效液相色谱-三重四级杆质谱联用仪(UPLC-MS/MS)建立了水中26种有机磷农药(OPPs)的分析方法。通过对固相萃取柱、淋洗液、流动相等优化,确定以Oasis HLB固相萃取柱、V(丙酮)∶V(二氯甲烷)=8∶2为淋洗液、V(0.1%甲酸甲醇)∶V(0.1%甲酸乙酸铵)=5∶5为流动相做水样预处理。在最优条件下,目标物在水中回收率为80.5%~119.8%,相对标准偏差(RSDs)为5.9%~11.5%。各目标物的线性范围为1~2 000μg/L,线性相关系数(R2)0.999以上。该方法具有检测限低、回收率高等优点,经实际样品测试,可适用于水中26种OPPs残留的同时检测。     

Cloud point extraction coupled with ultrasonic-assisted back-extraction for the determination of organophosphorus pesticides in concentrated fruit juice by gas chromatography with flame photometric detection

A new method for the determination of nine organophosphorus pesticides (OPPs): Dichlorvos, methamidophos, acephate, diazinon, dimethoate, chlorpyrifos, parathion-methyl, malathion and parathion-ethyl in concentrated fruit juice was developed using the cloud point extraction coupled with ultrasonic-assisted back-extraction prior to gas chromatography with flame photometric detection (GC-FPD) analysis. The parameters and variables that affect the extraction were investigated. Under optimum conditions: a solution containing 6% (W/V) polyethylene glycol 6000 (PEG 6000) and 20% (W/V) Na₂SO₄ for the extraction of the OPPs. The coacervation phase obtained was back extracted with ethyl acetate. The upper ethyl acetate solution was centrifugated simply for further cleanup for the sake of automatic injection. A preconcentration factor of 50 was obtained for these nine pesticides. Using this method, the limits of detection (LOD) and limits of quantification (LOQ) were in the range of 0.5–3.0 and 1.5–9.0 μg kg⁻¹ in concentrated fruit juice, respectively; the relative standard deviations (RSD) were <9%.