谷物中噻吩甲氯残留量的气相色谱-质谱测定

Determination and Identification of Residual Thenylchlor in Cereal by GC-MS

应用气相色谱－ 质谱法确证及测定谷物（ 糙米、玉米） 中噻吩甲氯的残留含量， 试样采用水－ 丙酮提取，提取液经与石油醚液－ 液分配后， 再以硅酸镁载体（Ｆｌｏｒｉｓｉｌ） 柱净化， 气相色谱－ 质量选择检测器选择离子监测方式（ ＧＣ－ ＭＳＤ－ ＳＩＭ） 进行测定和阳性确证。噻吩甲氯选择监测离子的种类为ｍ／ ｚ ２８７ 、２８８ 、３２３ ， 其丰度比约为４６ ∶１００ ∶１１ 。采用外标法定量， 方法检出限为０ ．０１０ ×１０ － ６ 。

The residual thenylchlor in cereal(unpolished rice and maize)can be extracted by water _ acetone. After partitioned with petroleum ether, the extract is allowed to pass through a Florisil column for further purification. The determination and confirmation of thenylchlor are performed on a GC with a mass selective detector(GC-MSD) and DB-17(30 m ×0.25 mm ×0.25 μm) capillary column. The SMI(selected monitoring ion) mode is employed. The selected ion masses (m/z) are 287, 288, and 322 u. The abundance ratio is ca. 46∶100∶11. An external standard is used. The detection limit is 0.010×10-6, and the average recovery is in the range of 89.7%～93.2%. Its RSD(n=10) is 4.55%～6.84%.