火焰原子吸收光谱法间接测定碘——NCP-Cu(Ⅱ)-I^-反应体系

INDIRECT DETERMINATION OF IODIDE BY FLAME ATOMIC ABSORPTION SPECTROMETRY BASED ON NCP-Cu( Ⅱ )-I^- REACTION

应用NCP-Cu(Ⅱ)-I^-反应体系,采用火焰原子吸收测定与碘定量反应的铜,从而间接测定碘。对反应体系的显色剂和还原剂用量、pH、稳定时间做了选择试验。方法相对标准偏差<3％,回收率93％～110％。线性范围0～5.0μg·ml^(-1),用于生物试样(海带、紫菜)和药品(西地碘片)中碘的测定,结果满意。

In a buffered solution of pH 4.5,iodide is made to react with NCP-Cu( I ) complex in the presence of thiourea as reducing agent. A ternary complex NCP-Cu( I )-I^- is thus formed and is extracted in to chlorobenzene. The amount of Cu( I ) in the complex is determined by FAAS and is calculated to iodide content. The optimum conditions (e. g. pH,organic extractam. suitable amounts of various reagents added,etc)were critically studied and selected. Betr' s law is obeyed in the concentration range of 0~5. Oμg ·nil^(-1). The recovery of iodide is 93 %~110% and the relative standard deviation is 3%. The proposed method has been applied to the determination of iodide in some biological samples and medicines with satisfactory results.