固相萃取法与QuEChERS法对比检测无核荔枝中19种农药残留

建立了气相色谱-串联质谱(GC-MS/MS)法同时测定无核荔枝中19种农药残留的分析方法。实验考察了固相萃取法和QuEChERS法中影响净化和萃取效果的各个因素,同时对二者的基质效应进行分析。结果表明:19种农药的线性范围在0.01~0.5μg/mL,相关系数均大于0.99。在0.01、0.1、0.5 mg/kg加标水平下,采用固相萃取净化时,19种农药的平均回收率为67.0%~95.6%,RSD为2.5%~12%。采用QuEChERS净化时,19种农药的平均回收率在68.2%~125%,RSD为2.8%~12.7%。2种方法在灵敏度和精密度方面无显著差异,均符合农药残留分析要求。但固相萃取较QuEChERS基质效应小,净化相对彻底。QuEChERS较固相萃取具有简单、快速、环保等优点。2种方法均能对荔枝样品进行检测,且数据准确可靠。

Determination of 19 Pesticides Residues in Seedless-Litchi by Gas Chromatography-Tandem Mass Spectrometry

Two methods of sample preparation were developed for simultaneous analysis of 19 pesticides residues in seedless-litchi in the study. Factors affecting purification and extraction efficiency in solid phase extraction (SPE) and QuEChERS methods were investigated and optimized. Matrix effects of two methods were analyzed. The results showed that the correlation coefficients were above 0.99 when the concentration was ranged from 0.01 to 0.5μg/mL. For SPE cleanup method, when the fortified levels from 0.01 to 0.5 mg/kg, the average recoveries were ranged from 67.0% to 95.6% and the relative standard deviations ( RSD) were ranged from 2.5% to 12%. For QuEChERS cleanup method, the fortified recoveries was at 0.01, 0.1 and 0.5 mg/kg were in the range of 68.2%-125%, with relative standard deviations (RSD) not more than 12.7%. All the above observations indicated that the two methods were no significant difference in sensitivity and accuracy and suitable for the determination of 19 pesticides in seedless-litchi. Besides, SPE method has the characteristics of relatively thorough purification and week matrix effect. QuEChERS cleanup is more simple, quick and green than SPE. The two methods were accurate and reliable for simultaneous determination of multiple pesticide residues in seedless-litchi.