原子荧光法测定食品中总砷的3种前处理法比较

The comparison of 3 pretreatment methods for total arsenic determination by with atomic fluorescence spectrometry in food

目的建立准确、可靠、稳定的测定食品中总砷的分析方法。方法利用湿消解法、微波消解法、干灰化法分别处理食品样品,用氢化物发生原子荧光光谱法测定食品中总砷的含量。结果鱼粉、紫菜（GBW 10023-GSB-14）、大米（GBW 10010）、鸡肉（GBW 10018）干灰化法测定总砷的结果为3.18±0.052、27.01±0.063、0.104±0.002、0.115±0.004 mg/kg均在参考值范围,加标回收率为93.7%-98.5%,RSD≤2.31%;湿消解法测定结果为3.12±0.041、26.93±0.072、0.103±0.003、0.112±0.003 mg/kg均在参考值范围,加标回收率为89.2%-97.5%,RSD≤1.92%;微波消解法处理鱼粉和紫菜的测定结果为1.74±0.032、15.40±0.096 mg/kg不足参考值的60%,但大米、鸡肉的测定值为0.102±0.001、0.114±0.005 mg/kg在参考值范围,加标回收率为96.3%-97.5%,RSD≤2.51%。湿消解法具有灵活调节消解温度,消解酸种类、用量和消解时间等优点,可适用于大部分食品样品的前处理;微波消解法耗费时间短,但用酸量大,适用于砷存在形态相对简单的样品;干灰化法耗费时间较长,适用于挥发温度高、油脂含量高、砷存在形态比较复杂的样品。结论湿消解法、干灰化法适用于大部分食品样品的前处理,微波消解法使用有局限性,仅适应于砷存在形态相对简单的样品。

Objective To establish an accurate,reliable and stable method for determination of total arsenic in food.Methods Fish,seaweed（ GBW 10023-GSB-14）,rice（ GBW 10010） and chicken（ GBW 10018） were selected as food samples,which were pretreated by wet digestion,microwave digestion and dry ashing respectively,and determined by hydride generation atomic fluorescence spectrometry. Results The total arsenic results of dry ashing were 3. 18 ± 0. 052,27. 01 ± 0. 063,0. 104 ± 0. 002 and 0. 115 ± 0. 004 mg / kg which were in the range of reference values. The recovery rates were 93. 7%-98. 5%,and the RSD was below 2. 31%. The results of wet digestion were 3. 12 ± 0. 041,26. 93 ± 0. 072,0. 103 ± 0. 003 and 0. 112 ± 0. 003 mg / kg which were in the reference range. The recovery rates were 89. 2%-97. 5%,and the RSD was below 1. 92%. The results of fish and seaweed with microwave digestion were 1. 74 ± 0. 032 and 15. 40 ±0. 096 mg / kg,which were less than 60% of the reference value,but the results of rice and chicken were 0. 102 ± 0. 001,0. 114 ± 0. 005 mg / kg,both in the reference range. The recovery rates were 96. 3%-97. 5%,and the RSD was below2. 51%. Wet digestion could be applied to most of the food samples for its flexibility in digestion temperature,time,type and dosage of acid. Microwave digestion consumed less time but large amount of acid,which could be applied to the relatively simple samples. Dry ashing method was suitable for samples of high volatile temperature,high oil content and complex arsenic structure because of its time-consuming. Conclusion Wet digestion and dry ashing could be applied as the pre-treatment of most food samples. Microwave digestion method has its limitations,only suitable for samples of arsenic with relatively simple morphology.