气相色谱-串联质谱法测定蔬菜和水果中三氯生及甲基三氯生的含量

提出了应用气相色谱-串联质谱法测定蔬菜(西红柿、黄瓜等)和水果(橙子、苹果等)中潜在的污染物三氯生(TCS)和甲基三氯生(MTCS)的含量的方法,以期有助于对此污染物在蔬菜、水果等食品中的污染问题的研究,并应用于农产品质量的安全监测之中。将样品分别去皮后切块,匀浆后于-22℃保存。称取样品5.00g,先后2次用乙酸乙酯(每次10mL)超声提取10min后离心10min,合并2次的提取液。将提取液吹氮蒸发至近干。加入衍生试剂体积比为99∶1的N,O-双(三甲基硅烷基)三氟乙酰胺-三甲基氯硅烷混合溶液100μL,在60℃下进行衍生化反应40min。反应结束后,将溶液吹氮至近干,用乙酸乙酯1.0mL溶解残渣。所得溶液供气相色谱-串联质谱法分析。用DB-17MS毛细管色谱柱(30m×0.25mm,0.25μm)在150~290℃区间按程序升温条件进行分离,在电子轰击离子源及多反应监测模式下进行质谱测定。经试验确定,用两种扫描程序分别扫描,TCS衍生物的母离子和子离子依次为m/z 362,347和m/z 360,345,MTCS的母离子和子离子则均为m/z 304,254。测得TCS衍生物和MTCS的标准曲线的线性范围均为0.4~20.0μg·L^-1,其检出限(3S/N)为4~6ng·kg^-1。按标准加入法进行回收试验,测得TCS衍生物和MTCS在4种蔬菜、水果中的回收率为91.5%~107%和94.7%~111%。

Determination of Triclosan and Methyl-Triclosan in Vegetables and Fruits by GC-MS/MS

A method for determination of triclosan(TCS)and methy-triclosan(MTCS)in vegetables(taking tomato and cucumber as analytical objects)and fruits(taking orange and apple as analytical objects)by GC-MS/MS was proposed,hoping to help the study on pollution of food by these pollutants,and also to apply this method to the safety inspections on quality of agricultural products.The selected samples should be peeled,stripped,sliced and homogenized separately and priliminarily and the homogenate be kept at-22 ℃.A portion of the homogenate(5.00 g)was extracted ultrasonically twice in succession with ethyl acetate(10 mL for each extraction)for 10 min,and then centrifuged for 10 min.The extracts from 2 extractions were collected,combined and evaporated to neardryness by N2-blowing.100μL of derivatizing mixed solution of BSTFA-TMCS with the volume ratio of 99∶1 were added to the residue to carry out the derivatization at 60 ℃ for 40 min.After which the solution was evaporated again to near dryness by N2-blowing.The residue was dissolved with 1.0 mL of ethyl acetate,and the solution obtained was used for GC-MS/MS analysis.Chromatographic separation was carried out by passing the solution through the capillary column of DB-17 MS(30 m×0.25 mm,0.25μm),under programmed temperature from 150℃to 290℃.MS/MS determination was accomplished under the condition of EI and MRM mode.As determined by experiment,the molecular ion and product ion found for derivate of TCS were m/z 362,347 and m/z 360,345,and for MTCS were m/z 304,254.Linearity ranges of the standard curves of derivate of TCS and of MTCS were found same between 0.4-20.0μg·L^-1,and values of their detection limits(3 S/N)were found in the range of 4-6 ng·kg^-1.Recovery was tested by standard addition method,giving values of recovery in the range of 91.5%-107%(for derivate of TCS),and in the range of 94.7%-111%(for MTCS).