目的 建立快速消解电感耦合等离子体质谱仪(ICP-MS)法测定大米粉中的铅(P_b)、镉(C_d)。方法 采用快速消解前处理方法,直接称量大米粉样品于塑料离心管中,加入硝酸和过氧化氢,放入石墨消解仪的孔中,125 ℃加热30 min,消解液冷却至室温后用去离子体水定容,采用ICP-MS测定样品中的铅和镉。结果 本方法P_b和C_d的检出限分别为0.003 mg/kg,0.001 mg/kg,定量限分别为0.010 mg/kg,0.005 mg/kg。P_b加标回收率为91%~106%,C_d加标回收率为96%~108%。质控样品测定值均在参考值范围内,P_b质控样测定结果的相对标准偏差为1.0%~4.8%,C_d质控样测定结果的相对标准偏差为0.8%~4.1%。本方法与国标(GB 5009.268-2016)方法比较,检测结果差异无统计学意义(t_铅= 1.88,P＞0.05;t_镉=0.07,P＞0.05)。结论 快速消解电感耦合等离子体质谱仪(ICP-MS)法测定结果准确可靠,适用于食品中铅和镉的快速检测。

Objective To establish a rapid digestion inductively coupled plasma mass spectrometry (ICP-MS) method for the determination of plumbum (P_b) and cadmium (C_d) in rice flour. Methods A pretreatment method for rapid digestion was used.The rice flour sample was directly weighed into a plastic centrifuge tube,added nitric acid and hydrogen peroxide,placed in the hole of the graphite digestion apparatus,heated at 125℃ for 30 minutes,and the digestion solution was cooled to room temperature.Then used deionized water to fix the volume,and used ICP-MS to determine the plumbum and cadmium in the sample. Results The detection limits of P_b and C_d in this method were 0.003mg/kg and 0.001mg/kg,quantitative limits were 0.010mg/kg and 0.005mg/kg respectively.The recoveries of P_b and C_d were 91% ~ 106% and 96% ~ 108%,respectively.The results of quality control samples were all within the reference range,the relative standard deviation of P_b quality control samples was 1.0% ~ 4.8%,and that of C_d quality control samples was 0.8% ~ 4.1%.Compared with the national standard (GB 5009.268-2016),there was no significant difference in the test results (t P_b = 1.88,P>0.05; t C_d = 0.07,P>0.05). Conclusion The results of rapid digestion ICP-MS method were accurate and reliable.It's suitable for the rapid detection of plumbum and cadmium in food.