超声辅助乳化液相微萃取分析绿茶饮料和番茄汁中有机磷农药残留

农药施用于田间,必然会残留于环境中。农药残留的分析方法多种多样。为探究灵敏度高、重现性好的样品前处理方法,建立了超声辅助乳化液相微萃取,结合气相色谱和火焰光度检测器测定绿茶饮料和番茄汁中5种有机磷农药的方法,对萃取条件进行了优化,如萃取溶剂种类和体积、超声频率和时间、盐效应。在优化后的萃取条件下,5种有机磷农药实现良好分离,空白添加实验结果表明在0.1~10μg·L-1之间,线性相关系数在0.9985~0.9994之间,检测限在0.005~0.020μg·L-1之间,相对标准偏差(n=5)在4.3%~9.4%之间。在绿茶饮料和番茄汁实际样本检测中,目标分析物含量均低于检出限。样本添加回收试验的回收率均大于88.5%,相对标准偏差(n=3)在2.2%~9.8%之间,结果表明该方法用于液体样本中农药残留检测真实可靠。

Analysis of Organophosphorus Pesticide Residues in Green Tea and Tomato Juice by Ultrasound-Assisted Emulsification Microextraction (USAEME)

The pesticide residue will inevitably exist in the environment after the application of pesticides in the field.There are various pesticide residue analysis methods applied in different pesticides and conditions tests.In order to explore the method of sample pretreatment with high sensitivity and good reproducibility,Ultrasound-assisted Emulsification Microextraction (USAEME) were developed.The method of gas chromatography and the flame photometric detector was used to determine five kinds of organophosphorus pesticides in green tea beverage and tomato juice.The conditions including solvent type and volume,ultrasonic frequency and time,and salt effect of USAEME were optimized.Under the optimal conditions,the results showed that the linear range was 0.1-10 μg·L-1,the correlation coefficient (r2) ranged from 0.9985 to 0.9994,and the Limit of Detection (LOD) was between 0.005 and 0.020 μg·L-1.The results showed that the separation of the five organophosphorus pesticides in the chromatogram was good under the optimal extraction conditions.The relative standard deviation (RSD) ranged from 4.3％ to 9.4％ (n=5).In the practice samples,the concentrations of target analytes in green tea and tomato juice were below LOD.The recoveries were over 88.5％,and the RSD (n=3) ranged from 2.2％ to 9.8％.The results showed that the method was accurate and reliable for the determination of pesticide residues in liquid samples.