取经粉碎及预处理的样品25 g，加乙腈50 mL超声提取10 min，滤入盛有5 g氯化钠的量筒中，振荡1 min并静置待两相分层。移取乙腈相20 mL，于70 ℃水浴中吹氮至近干，加入丙酮溶解残渣并定容为5.0 mL，供气相色谱分析。采用（色谱柱1） DB-17毛细管柱（脉冲不分流进样，进样量5 μL）进行分离和初筛，发现疑似阳性样品，再用（色谱柱2） HP-5毛细管柱（不分流进样，进样量为1 μL）进行分离和佐证。采用FPD⁺检测器，外标法定量。灭线磷、甲拌磷、甲拌磷砜、甲拌磷亚砜及三唑磷的线性范围均为0.02~0.20 mg·L^-1，检出限（3S/N）为1.0~3.0 μg·kg^-1（色谱柱1）和1.5~2.0 μg·kg^-1（色谱柱2）；加标回收率分别为79.6%~119%和76.2%~116%；测定值的相对标准偏差（n=10）分别为2.8%~8.8%和2.7%~8.4%。

A portion (25 g) of the smashed and pretreated sample was extracted ultrasonically with 50 mL of acetonitrile for 10 min and filtered. The filtrate was shaked with 5 g of NaCl and stayed for phase separation. The acetonitrile phase 20 mL was taken and evaporated to near dryness by N₂-blowing in a water-bath at 70 ℃. The residue was taken up and made up to 5.0 mL with acetone for GC analysis. An aliquot of 5 μL was introduced into GC-column 1 (DB-17 capillary column, with pulse-nonsplitting sample introduction) for separation and preliminary screening. In happening of positive sample, another aliquot (1 μL) of the acetone solution should be taken for proof by separation on GC-column 2 (HP-5 capillary column, with non-splitting sample introduction). FPD⁺ detector and quantification by external standard method were used in both cases. Linearity ranges were found same between 0.02-0.20 mg·L^-1 for ethoprophos, phorate, phorate-sulfone, phorate-sulfoxide and triazophos for both columns. Detection limits (3S/N) were 1.0-3.0 μg·kg^-1 for GC-column 1 and 1.5-2.0 μg·kg^-1 for GC-column 2. Values of recovery found by standard addition method ranged from 79.6% to 119% and from 76.2% to 116%, and RSDs (n=10) were 2.8%-8.8% and 2.7%-8.4% for the 2 columns respectively.