柱前衍生化-气相色谱法测定水产品中的游离甲醛

Quantification of free-formaldehyde in aquatic products by gas chromatography coupled with pro-column derivatization

应用柱前衍生化-气相色谱(GC)法检测水产品中游离甲醛含量。野生鲤、鳙、鲢、草鱼、鲫和乌苏里白鲑等样品经超声萃取、衍生化、正己烷提取,用HP-5毛细管色谱柱分离,电子捕获检测器进行检测,外标法定量。结果表明,使用优化改进后的方法测定的游离甲醛含量在0.1~50μg/L范围内,标准曲线线性拟合度r^2=0.999,线性良好;在2.0、5.0、10.0μg/kg 3个水平下加标回收率为83.80%~103.15%,相对标准偏差小于5.0%。方法检出限为0.38μg/kg,定量限为0.50μg/kg。本研究调查了查干湖和黑龙江中的野生鱼类中游离甲醛的本底含量为1.67~7.66 mg/kg,地区与种间差异不显著(P>0.05)。优化后的方法操作简便,分析灵敏度高,稳定性好,可满足水产品中微量游离甲醛的检测需要,对开展水产品中甲醛本底含量及安全限量的研究具有重要的现实意义。

In this study,the gas chromatography（ GC） coupled with pro- column derivatization method was employed to determine free- formaldehyde in aquatic products. Samples of Cyprinuscarpio,Aristichthys nobilis,Hypophthalmichthys molitrix,Ctenopharyngodonidellus,Carassiusauratus and Coregonusussuriensis were subjected to ultrasonic extraction,derivatization,n- hexane extraction,and then purified by HP- 5 chromatographic column and determined by external standard method with electron capture detector（ ECD）. The results showed that the optimized method had a good linearity（ r^2= 0. 999） when the measured free- formaldehyde was 0. 1- 50 μg / L,and the limit of detection was 0. 38 μg / kg with the relative standard deviations no more than 5. 0%. The recoveries of formaldehyde among three different levels（ 2. 0,5. 0,10. 0 μg / kg,respectively） were in the range of 83. 80% ～ 103. 15%. The baseline of free- formaldehyde in wild fish species from the Chagan Lake and Heilongjiang River were investigated,which ranged from 1. 67- 7. 66 mg / kg and without significant differences in regions and species（ P〉0. 05）. The optimized analytical method was rapid and accurate,and suitable for the determination of free- formaldehyde in aquatic products.