电感耦合等离子体质谱法测定谷物样品中 铝的样品处理方法研究

目的建立电感耦合等离子体质谱法(ICP-MS)测定谷物样品中铝的准确分析方法。方法本文研究了4种样品前处理方法:干灰化法、微波消解(硝酸-双氧水体系)、微波消解(硝酸-氢氟酸-双氧水体系)、微波消解(硝酸-氢氟酸-双氧水体系消解,加高氯酸二次消解法),消化大米标准物质(GBW 10010),采用ICP-MS法测定铝,同时添加回收率来验证不同处理方法的准确性与可靠性。结果对测定结果进行比较分析,前3种消解法的测定值均低于标准值;最后一种消解法在标准值允许范围内;4种前处理方法的检出限在0.42~0.52 mg/kg之间,相对标准偏差3.61%~4.77%(n=6),加标回收率在92.2%~97.8%之间。结论谷物样品中可能存在酸不溶铝,采取硝酸-氢氟酸-双氧水体系微波消解,加高氯酸二次消解法的方式能将其消解完全,该法可用于谷物样品中铝的测定。

Pre-treatment of the determination of aluminum in the grain samples by inductively coupled plasma mass spectrometry

Objective To establish an accurate method for the determination of the aluminum in the grain samples by inductively coupled plasma mass spectrometry (ICP-MS). Methods Four kinds of different pre-treatment methods were studied, including dry ashing, microwave digestion (HNO3-H2O2 digestive system), microwave digestion (HNO3-HF-H2O2 digestive system) and microwave digestion (HNO3-HF-H2O2 digestive system, then melted by adding perchloric acid). National standard substance rice power (GBW 100l0) was digested and its aluminum content was determined by ICP-MS. Accuracy and reliability of these methods were verified by recovery test. Results The analysis of the determination showed that the results of these previous 3 kinds of pre-treatment methods were lower than the standard value and the last one was within the standard value. The detection limits of these four kinds of pre-treatment methods varied from 0.42 to 0.52 mg/kg, relative standard deviations (RSDs) varied from 3.61% to 4.77% (n=6) and recoveries were between 92.2% and 97.8%. Conclusion Acid insoluble aluminum exists in the grain samples. Microwave digestion(HNO3-HF-H2O2 digestive system, then melted by adding perchloric acid) can be used in the detection of grain samples as the acid insoluble aluminum can be released through this pre-treatment method.