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目的探讨石墨炉原子吸收测镉(或铅)时,消除共存金属离子干扰的方法。方法配制每毫升含0.25μg镉(或铅)和250μg其它金属离子模拟样品,向石墨管进样20μL,再直接加入基体改进剂5μL,做消除共存金属离子的干扰效果实验。结果共存金属离子含量远大于被测元素镉(或铅)时,对测镉和测铅存在严重干扰,回收率在30%~76%;在石墨炉原子吸收法测镉时直接向石墨管中添加5%硫酸铵溶液能消除共存金属离子的干扰,回收率达到85%以上;测铅时直接向石墨管中添加2%磷酸二氢铵溶液能消除共存金属离子的干扰,回收率达到87%以上。结论本研究是石墨炉原子吸收法测镉和铅时消除共存金属离子干扰的一种快速、灵敏、准确的分析方法。适用于生活饮用水、污水、食品等分析。
Objective To explore the method of eliminating the interference of coexisting metal ions when measuring cadmium (or lead) by graphite furnace atomic absorption spectrometry. Methods Prepare 20μL of cadmium (or lead) and 250μg of other metal ions per milliliter, and inject 5μL of matrix modifier directly into the graphite tube to eliminate interference effect of co-existing metal ions. Results When the contents of coexisting metal ions were much larger than that of cadmium (or lead), cadmium (Pb) and cadmium (Pb) contents were measured. The results showed that cadmium (lead) The addition of 5% ammonium sulfate solution can eliminate the interference of co-existing metal ions and the recovery rate reaches over 85%. Adding 2% ammonium dihydrogen phosphate solution directly to the graphite tube can eliminate the interference of coexisting metal ions when measuring lead, and the recovery rate reaches 87% the above. Conclusion This study is a rapid, sensitive and accurate analytical method to eliminate the interference of co-existing metal ions when measuring cadmium and lead by graphite furnace atomic absorption spectrometry. For drinking water, sewage, food and other analysis.