流动注射氢化物发生原子吸收光谱法测定发铅

FI-HG-AAS DETERMINATION OF LEAD IN HUMAN HAIR

发样消化液用铁氰化钾预先氧化处理将二价铅氧化为四价形态铅,以硼氢化钾为还原剂,稀盐酸为载液,用流动注射氢化物发生原子吸收光谱法测定铅。方法的检出限为0.26ng·ml-1,线性范围为0.60～35ng·ml-1,相对标准偏差为2.5%～4.7%,样品加标回收率为96.8%～104.4%,对人发标准物质进行测定,结果与标准值符合。方法灵敏度高、选择性好、试剂及样品用量少、操作方便快速,有推广应用价值。

Hair sample is digested with HNO_3 and HClO_4, and fumed to dryness. After dissolving the salt with water, the solution is neutralized with dilute NaOH solution to about pH 4～5. Lead(Ⅱ) in the solution is oxidized to tetravalent state with potassium ferricyanide in a dilute HCl medium of about 0.125mol·L^(-1). After this pre-oxidation treatment, Pb(Ⅳ) is in an active state to react with KBH_4 to form lead hydride which is introduced into the FI-hyphenated instrument for the determination. Under the optimized condition, the following results are obtained: range of linearity 0.60～35ng·ml^(-1) of Pb(Ⅱ), detection limit 0.26ng·ml^(-1), RSD′s 2.5%～4.7%, recoveries 96.8%～104.4%. In the analysis of a CRM (GBW 09101) by this method, results obtained are in consistency with the certified value.