气相色谱-质谱法测定食品中二氧化硫

Determination of SO2 in foods by gas chromatography-mass spectrometry

建立了气相色谱-质谱法测定食品中SO2的方法。样品经200 g/L NaCl溶液超声提取,经离心后,取一定量的上清液至含有H2SO4溶液的顶空瓶中,在80℃条件下,食品中的SO32-在酸性条件反应生成SO2,并在气、液两相中达到平衡,将气相部分导入气相色谱柱GS-GASPRO进行分离,经EI源电离后以选择离子扫描(SIM)模式采集数据并做定性和定量分析。SO2量在2.5~100μg范围内相关系数为0.9999,对6类典型食品进行3个不同浓度的加标试验,添加质量分数在25.0~250 mg/kg时,回收率在90.1%~104.4%之间;RSD为0.38%~6.4%,检出限为3.0 mg/kg。方法适用于对大批量食品中SO2的定性和定量测定。

An analytical method was established for the determination of SO2 in food by gas chromatography-mass spectrometry(GC-MS).The sample was extracted with 200 g/L NaCl solution by ultrasonic method,centrifuged,and the supernatant was put into a headspace bottle containing sulphuric acid solution.SO2 was produced in the acidic condition at 80℃and reached equilibrium in gas and liquid phases.The gas phase was introduced into gas chromatographic column GS-GASPRO for separation.After being ionzied by EI source,the data were collected and analyzed qualitatively and quantitatively using selected ion scanning mode(SIM).The correlation coefficients of linear calibration curves were 0.9999 in the range of 2.5-100μg.Six kinds of typical food were spiked at three levels from 25.0 mg/kg to 250 mg/kg.The average recoveries were 90.1%-104.4%,with RSDs from 0.38%to 6.4%.The limits of detection were 3.0 mg/kg.The method is suitable for the qualitative and quantitative determination of sulfur dioxide in large quantities of food.