食品中氰化物测定方法改进

Improvement of determination method for cyanide in food

为提高食品中氰化物的检测效率,用氢氧化钠溶液接收从凯氏蒸馏装置快速蒸馏出的氰氢酸,并在pH=7.0的中性条件下,馏出液用氯胺T将氰化物转变为氯化氰,再与异烟酸-吡唑啉酮作用,使37℃水浴变成蓝色,利用紫外分光检测,同时对方法检测结果进行验证。试验结果表明:木薯粉试样的氰化物含量在0.3~1.5μg范围内,线性相关系数0.998以上,精密度试验相对标准偏差为0.28%~0.96%,回收率为97.7~101.3%,检出限小于0.001 mg/kg;白兰地酒试样的氰化物含量在0.4~2.0μg范围内,线性相关系数0.999以上,精密度试验相对标准偏差为0.05%~1.2%,回收率为104.3%~105.7%,检出限小于0.001 mg/L;水试样的氰化物含量在0.1~2.0μg范围内,线性相关系数0.999以上,精密度试验相对标准偏差为0.02%~0.74%,回收率为97.9%~103.6%,检出限小于0.001 mg/L。方法改进后,样品蒸馏时间由原来的大于1 h,减少到10 min以内。

In order to improve the detection efficiency of cyanide in food,using sodium hydroxide solution to receive rapidly distilled cyanohydrogen acid from a Kjeldahl distillation unit,then under neutral conditions with pH=7.0,distillate is converted from cyanide to cyanogen chloride using chloramine T,interaction with isonicotinic acid pyrazolone,37℃water bath turns blue,hands-on UV detection,verify the method test results.The test results indicate:For the determination of cassava flour,the calibration curve was in the range of 0.3-1.5μg cyanide content,the linear correlation coefficient is above 0.998,the RSD of the precision test is 0.28%-0.96%,the recovery rate is 97.7%-101.3%,the detection limit is less than 0.001 mg/kg;For the detection of brandy samples,the calibration curve was in the range of cyanide content from 0.4μg to 2.0μg,the linear correlation coefficient is above 0.999,the RSD of the precision test is 0.05%to 1.2%,the recovery rate is 104.3%-105.7%,the detection limit is less than 0.001 mg/L;For the determination of water samples,the calibration curve is in the range of 0.1-2.0μg cyanide content,the linear correlation coefficient is above 0.999,the RSD of the precision test is 0.02%to 0.74%,the recovery rate is 97.9%-103.6%,the detection limit is less than 0.001 mg/L.After the improvement of the method,the sample distillation time has been reduced from more than one hour to less than 10 minutes.