石墨炉原子吸收直接测定全血中铅的研究

Direct Determination of Pb in Blood by Graphite Furnace Atomic Absorption Spectrometry

试验了(NH_4)_2HPO_4,NH_4H_2PO_4、Na_2HPO_4、Mg(NO_3)_2和 Pd 作为石墨炉原子吸收测定全血铅基体改进剂的作用效果.结果表明,(NH_4)_2HPO_4—Na_2HPO_4混合物可使全血铅、二次去离子水及氯化物中铅有相同的灰化-原子化行为,可以有效地消除血液及氯化物的基体干扰,实现标准校正法直接测定全血中铅,不必用全血基体匹配标准.以慢速升温原子化方法探讨了磷酸盐的基体改进作用机理,并测定了(NH_4)_2HPO_4—Na_2HPO_4为基体改进剂时全血铅和纯标准铅的特征质量值.

A simple and rapid method for the direct determination of Pb in blood by Graphite Furnace Atomic Absorption Spectrometry is described.To eliminate the blood matrix interferences,(NH_4)_2HPO_4 and Na_2HPO_4 have been selected as the matrix modifier.Zeeman-effect background correction,tube-wall atomization, integrated absorbance measurement and pyrolytically coated graphite tube were applied,but it was not necessary to match the standard series with the blood ma- trix.The ashing and atomizatiom curves have been compared for(NH_4)_2HPO_4 and (NH_4)_2HPO_4-Na_2HPO_4 as the modifiers,and the variations of Pb and background signal during the ashing-atomization process for Pb in blood and chloride matrices were also studied.Results showed that Pb either in blood or in chloride matrices or double distilled water has the same behavior of ashing-atomization if the com- plex of(NH_4)_2HPO_4 and Na_2HPO_4 is present,but not only(NH_4)_2HPO_4 present. The average characteristic mass mo for Pb in blood or double distilled water is 15.9pg.The detection limit(3σ)and the relative standard deviation are 20.6 pg and 4.3% respectively.