冷冻辅助相分离-气相色谱-串联质谱法检测设施蔬菜与土壤中的邻苯二甲酸酯

Detection of phthalates in vegetables and soil in facilities by freezing-assisted phase separation-gas chromatography-tandem mass spectrometry

目的建立气相色谱-串联质谱法检测蔬菜和土壤中16种邻苯二甲酸酯(phthalate esters,PAEs)的分析方法。方法蔬菜、土壤样品加入同位素内标,经水分散、正己烷超声提取、超低温冷冻辅助相分离和减压浓缩,以HP-5MS UI柱(30 m×0.25 mm,0.25μm)气相色谱分离,串联质谱多重反应监测模式进行检测。结果该方法在考察浓度范围(5~400 ng/mL)内16种PAEs线性良好,r>0.994;蔬菜和土壤中PAEs对应检出限为1.2~21.5μg/kg和1.0~40.4μg/kg,定量限为3.9~65.0μg/kg和3.6~110.5μg/kg,回收率为71.72%~111.98%和67.17%~114.9%,相对标准偏差为0.19%~11.22%和0.13%~11.03%;实际样品的检测显示,北京某蔬菜基地某设施土壤和蔬菜中有11种PAEs检出,其中土壤中PAEs含量明显高于蔬菜,土壤与蔬菜中PAEs含量显著正相关。结论该方法简便、准确、检出限低,能有效防止样品处理中接触材料的PAEs污染,可满足蔬菜、土壤中PAEs监测的需要。

Objective To establish a method for determination of 16 phthalate esters(PAEs)in vegetables and soil by freezing-assisted phase separation-gas chromatography tandem mass spectrometry.Methods The vegetables and soil samples were spiked with isotope internal standard and dispersed with water,and then extracted by ultrasonic extractor with n-hexane as extractant.The samples extracts were separated with ultra-low temperature freezing assistance and were concentrated with rotating evaporator,and then separated by gas chromatography on a HP-5 MS UI column(30 m×0.25 mm,0.25μm)and detected by tandem mass spectrometry with the multiple reaction monitoring mode.Results The 16 PAEs had good linearity in the concentration range(5-400 ng/mL),and r>0.994.The limits of detection(LODs)were 1.2-21.5μg/kg and 1.0-40.4μg/kg,the limits of quantitation(LOQs)were 3.9-65.0μg/kg and 3.6-110.5μg/kg,the recoveries were 71.72%-111.98%and 67.17%-114.9%with the relative standard deviations of 0.19%-11.22%and 0.13%-11.03%(n=6)for the vegetables and soil samples,respectively.Examination of actual samples showed that 11 kinds of PAEs were detected in the soil and vegetables of a facility in a Beijing vegetable base.The PAEs content in the soil was significantly higher than that in vegetables,and the PAEs content in the soil and vegetables was significantly positively correlated.Conclusion This method is simple,accurate and has low detection limit,which can effectively prevent PAEs contamination of contact materials during sample processing,and can meet the needs of PAEs monitoring in vegetables and soil.