基体改进剂石墨炉原子吸收测定发镉的研究

Determination of cadmium in hair by graphit furnace atomic absorption spectrophotometry with matrix modifier

探讨石墨炉原子吸收检测发镉的基体干扰,选择适宜的基体改进剂建立一种测定发镉的新方法。样品经前处理后,分别加入单种基体改进剂和不同组合基体改进剂,用石墨炉原子吸收测定样品及加标样品,通过加标回收率筛选出测定发镉的优良基体改进剂。研究得出测定发镉的最佳基体改进剂为硝酸铵-抗坏血酸-硝酸镧混合基体改进剂。在0.219 4~11.236 1 ng/mL的范围内,镉原子吸光强度与其含量有良好的线性关系,标准曲线y=0.060＋0.017 3ρ（ng/mL）,r=0.999 8,相对标准偏差为2.9%~5.7%,方法的检出限为0.131 7 ng/mL,平均回收率94.5%。该方法简便易行、灵敏度高、选择性好、准确度高,测定结果令人满意。

A new method for determining metal element cadmium in hair by graphite furnace atomic absorption spectrometry（GFAAS）is researched using an optimal matrix modifier selected with the recovery of spiked sample,which can eliminate the matrix interference effectively.Single and mixed matrix modifier were added into digested samples.Samples and spiked samples were determined by GFAAS.The optimal matrix modifier was sieved with the recovery of spiked sample.The results indicated that the mixed matrix modifier composed by the ammonium nitrate,antiscorbic acid and lanthanum nitrate was the optimal matrix modifier for determining cadmium in hair.The enhancement of atomic absorbance was proportional to the concentration of cadmium in the range of 0.219 4~11.236 1 ng/mL（r=0.999 8）.The detection limit was 0.131 7 ng/mL and the recovery was 94.5%.The proposed assay succeeded in hair sample determination with the advantages of simplicity,high sensitivity,good selectivity and accuracy.