鱼体中汞残留量检测的样品前处理工艺优化

Optimization of Sample Pretreatment Process for the Detection of Mercury Residues in Fish

为了提高鱼体中重金属汞残留量检测的准确性,减少因为样品前处理工艺不当引起的样品中汞的损失,本研究以外加汞标液的方式,对鱼肉样品进行预处理,然后分析样品前处理过程中的赶酸温度、消解温度、双氧水助消解量、硼氢化钾浓度,对样品中汞的回收率影响。在此基础上,采用响应面法,对鱼肉样品的前处理工艺进行了优化。显著性分析结果显示,所构建的汞的回收率与各影响因素间的拟合模型具有显著性(p<0.05),所得汞的回收率与各影响因素间具有较好的相关性(R2=95.33)。在对所得拟合模型的可靠性进行验证基础上,以汞的回收率最高为优化目标,对样品前处理工艺进行优化的结果显示,在赶酸温度88℃、消解温度171℃、双氧水用量1.2 mL、还原剂硼氢化钾浓度13 g/L时,鱼体中重金属汞的回收率最高,其回收率可达98.90%。总之,所得优化工艺对鱼肉样品前处理具有实际指导意义。

To improve the accuracy of detection for heavy metal mercury in fish and reduce the loss of mercury in the sample caused by improper sample preparation, the fish sample was pretreated by adding a mercury standard solution, and then the effects of acid removal temperature, digestion temperature, amount of hydrogen peroxide to assist digestion, and concentration of potassium borohydride on the recovery rate of mercury was investigated in the sample. On this basis, the response surface method was used to optimize the pretreatment process for fish samples. The results of significance analysis showed that the fitted model for the recovery rate and influencing factors was significant(p<0.05), with a good correlation(R2 = 95.33). Based on the verification of the reliability of the fitted model, the highest recovery rate of mercury was taken as the target for the optimization of sample pretreatment process. The results showed that the recovery rate of mercury in fish was the highest(98.9%), when the acid removal temperature, digestion temperature, hydrogen peroxide dose, and reducing agent potassium borohydride concentration were 88 ℃, 171 ℃, 1.2 mL, and 13 g/L, respectively. In summary, the optimized process for pretreating fish samples has significance for guiding practice.