正交试验优化蔬菜中多环芳烃检测前处理工艺

本实验以叶用莴苣(Lactuca sativa L.)叶片鲜样匀浆为试材,优化蔬菜体内多环芳烃检测前处理工艺。通过单因素实验确定样品质量、提取液体积、超声提取时间、硫酸体积、硫酸浓度、洗脱液配比六个因素的实验条件范围,再利用正交试验,优化前处理工艺。结果表明:最佳前处理方案为提取液体积52 mL、样品质量14 g、超声波提取时间38 min、硫酸体积13 mL、硫酸浓度35%、洗脱液类型6 mL正己烷和6 mL二氯甲烷/正己烷(V₁:V₂=3:7),在此条件下测得莴苣体内PAHs含量最高为961.541 μg/kg;此条件加标回收率为80.54%~142.04%,RSDs为1.35%~8.96%,具有较好的准确度和精密度。该前处理工艺具有样品制备简单、适合大量样品检测、实验结果重复性好等优点,可应用于蔬菜中PAHs提取。

Optimization of the Pre-treatment Process for Determination of PAHs in Vegetables by Orthogonal Test

In this study,the Lactuca sativa L. homogenate was used as the test material to establish the pre-treatment process of polycyclic aromatic hydrocarbons in vegetables. Six experimental conditions including sample quality,extract volume,ultrasonic extraction time,sulfuric acid volume,sulfuric acid concentration andeluent type were determined by was single factor experiment. Then the pre-treatment process was optimized by orthogonal test.The results showed that the optimum pretreatment conditions were 52 mL of extract volume,14 g of sample mass,ultrasonic extraction for 38 min,13 mL of sulfuric acid volume,35% of sulfuric acid,eluent type of 6 mL n-hexane and 6 mL dichloromethane/n-hexane(V₁:V₂=3:7). Under these conditions,the content of plycyclic aromatic hydrocarbons was up to 961.541 μg/kg. The recovery rate of the process was 80.54%~142.04%,and the RSDs were 1.35%~8.96%,indicating the method had good accuracy and precision. The pretreatment process established by the orthogonal method had many advantages,mainly including simple sample preparation,powerful ability to detect a large number of samples at the same time,and a good repeatability,could be applied to the extraction of polycyclic aromatic hydrocarbons in vegetables.