固相萃取-气相色谱-串联质谱法测定大葱等蔬菜中23种邻苯二甲酸酯类化合物残留

建立了气相色谱-串联质谱联用(GC-MS/MS)同时测定蔬菜中23种邻苯二甲酸酯类化合物(塑化剂)的方法。蔬菜经乙腈提取,玻璃Florisil固相萃取柱净化,正己烷定容,Agilent DB-5MS UI超高惰性毛细管柱(30 m×0.25 mm×0.25 μm)程序升温分离,MS/MS(选择反应监测模式)分析,外标法定量。考察了大葱等复杂基质蔬菜中邻苯二甲酸酯类化合物的提取和净化方法,并对色谱和质谱条件进行了优化,提出了扣除本底的办法;通过基质加标校准曲线补偿对邻苯二甲酸酯检测的基质效应。23种邻苯二甲酸酯的线性范围除邻苯二甲酸二异壬酯(DINP)、邻苯二甲酸二异癸酯(DIDP)为0.1~5 mg/L外,其余均为0.02~1 mg/L,相关系数(r)除邻苯二甲酸二(2-甲氧基乙基)酯(DMEP)外均大于0.99。方法的检出限(S/N=3)为0.01~0.05 mg/kg,定量限(S/N=10)为0.02~0.1 mg/kg。3个加标水平下目标物的平均回收率为81.3%~104.2%,相对标准偏差(n=6)为3.2%~11.2%。该方法稳定可靠,应用串联质谱很好地消除了基质效应的干扰,灵敏度高,定性定量更为准确,适用于蔬菜中邻苯二甲酸酯类化合物的检测和确证。

Determination of 23 phthalate esters in scallion and other vegetables by solid-phase extraction coupled with gas chromatography-tandem mass spectrometry

A method for the simultaneous determination of 23 phthalate esters in vegetables by solid-phase extraction coupled with gas chromatography-triple quadrupole mass spectrometry (SPE-GC-MS/MS) was developed and evaluated. The samples were extracted with acetonitrile, and cleaned-up with glass Florisil SPE columns, and diluted with n-hexane. The separation was performed on a DB-5MS UI capillary column (30 m×0.25 mm×0.25 μm) with temperature programming. The identification and quantification were performed by GC-MS/MS in selected reaction monitoring (SRM) mode. The external standard method was used. The processes of extraction and clean-up of scallion and other vegetables were investigated, and the chromatographic and MS parameters were optimized. The matrix effect was compensated by matrix spiked calibration. The extraction processes were investigated. The calibration curves of the phthalate esters showed good linearities in the ranges of 0.02-1 mg/L (0.1-5 mg/L for diisononyl phthalate (DINP) and diisodecyl-o-phthalate (DIDP)) with the correlation coefficients (r) over 0.99 except for bis(2-methoxyethyl) phthalate (DMEP). The limits of detection of phthalate esters in samples ranged from 0.01 to 0.05 mg/kg (S/N=3) and the limits of quantification ranged from 0.02 to 0.1 mg/kg (S/N=10). The average recoveries of the 23 analytes spiked in scallions ranged from 81.3% to 104.2% with the relative standard deviations (RSDs, n=6) of 3.2%-11.2%. The method is suitable for the determination of the 23 phthalate esters simultaneously in vegetables with easy operation, high accuracy and precision.