目的 探讨微波消解过程添加过氧化氢对大米粉中总砷含量测定结果的影响。方法 参照国家标准GB 5009.11-2014总砷的测定方法,通过添加过氧化氢进行微波消解前处理样品,检测样品来自大米粉总砷含量的内质控样,分别采用电感耦合等离子体质谱法(ICP-MS)和原子荧光光谱法(AFS),测定样品中总砷含量。结果 通过微波消解法消解样品,ICP-MS法测定样品中总砷含量,非过氧化氢组测定结果为(0.386±0.030)mg/kg,过氧化氢组测定结果为(0.355±0.022) mg/kg,两组测定结果的差异有统计学意义(t＝6.293,P＜0.05);AFS法测定样品,非过氧化氢组测定结果为(0.284±0.002) mg/kg,过氧化氢组测定结果为(0.307±0.014) mg/kg,两组测定结果之间的差异有统计学意义(t=8.979,P＜0.05)。结论 微波消解法前处理大米粉样品,添加过氧化氢的微波消解样品,测定结果更接近指定值,结果相对准确可靠。

Objective To investigate the effect of adding hydrogen peroxide during microwave digestion on the determination of total arsenic content in rice flour. Methods According to the national standard GB 5009.11-2014 for the determination of total arsenic,hydrogen peroxide was added for microwave digestion of pre-treated samples,and the internal quality control samples from rice flour with total arsenic content were detected.The total arsenic content in the samples was determined by inductively coupled plasma mass spectrometry (ICP-MS) and atomic fluorescence spectrometry (AFS),respectively. Results The samples were digested by microwave digestion method,and the total arsenic content in the samples was determined by ICP-MS method.The results of the non-hydrogen peroxide group and the hydrogen peroxide group were 0.386±0.030 mg/kg and 0.355±0.022 mg/kg respectively.The difference between the two groups was statistically significant (t＝6.293,P＜0.05).The results of AFS method were 0.284±0.002 mg/kg in the non-hydrogen peroxide group and 0.307±0.014 mg/kg in the hydrogen peroxide group,and the difference between the two groups was statistically significant (t=8.979,P＜0.05). Conclusion The results of microwave digestion with hydrogen peroxide in pre-treating the rice flour sample were more accurate and reliable.