衍生化-在线凝胶色谱净化-气相色谱-质谱法测定中毒血液中氟乙酸盐的含量

Determination of Fluoroacetate in Poisoning Induced Blood by On-Line GPC-GC-MS with Derivatization

按体积比1∶1加入血样和乙腈,混匀后涡旋3 min,离心5 min。加入6 mol·mL^(-1)盐酸溶液,将上清液酸度调节至pH<2,加入氯化钠,以形成过饱和溶液,涡旋3 min,离心5 min。在上清液中加入碳酸钠、无水硫酸钠和含10%(体积分数)五氟苄基溴的乙腈溶液,于65℃反应1 h,过0.25μm滤膜。分取20μL滤液,进行在线凝胶色谱(GPC)净化,采集4.06~6.06 min内的样品溶液,通过大体积程序升温汽化进样口(PTV),采用气相色谱-质谱法测定其中氟乙酸钠的含量。以按照上述方法制备的空白加标样品溶液系列制作工作曲线。结果显示:氟乙酸钠的质量浓度在10~320μg·L^(-1)内与其对应的峰面积呈线性关系,检出限(3S/N)为2.9μg·L^(-1);按标准加入法对空白样品进行回收试验,回收率为71.4%~80.5%,测定值的日内相对标准偏差和日间相对标准偏差(n=5)均小于8.0%;方法用于实际案例分析,取得了满意结果。

The blood sample was mixed thoroughly with adding acetonitrile at volume ratio of 1∶1 on vortex mixer for about 3 min, and the supernatant was collected after centrifugation for 5 min. The supernatant was adjusted to pH<2 with 6 mol·mL^(-1)of hydrochloric acid solution, and then solid sodium chloride was added to form supersaturated solution. After vortex for 3 min and centrifugation for 5 min, sodium carbonate, anhydrous sodium sulfate and acetonitrile solution containing 10%(φ) pentafluorobenzyl bromide were added into the supernatant, and the mixture reacted at 65 ℃ for 1 h. The reaction solution was passed through 0.25 μm filtration membrane and 20 μL of filtrate was put into on-line gel chromatography(GPC) to purification. The sample solution within 4.06-6.06 min was collected, in which sodium fluoroacetate was determined by gas chromatography-mass spectrometry(GC-MS) through the large volume programmed temperature vaporizer(PTV). The working curve was drawn with the blank spiked sample solution series prepared according to the above method. As shown by the results, linear relationship between values of peak area and mass concentration of sodium fluoroacetate was found in the range of 10-320 μg·L^(-1), with detection limit(3 S/N) of 2.9 μg·L^(-1). Test of recovery was made on the blank sample by standard addition method, giving results in the range of 71.4%-80.5%, with intra-day RSDs(n=5) and inter-day RSDs(n=5) of the determined values less than 8.0%. The proposed method has been applied in a substantial criminal case and satisfactory result was obtained.