温控离子液体萃取结合火焰原子吸收测定塑料包装中镉含量

The Flame Atomic Absorption Spectrometry Coupled with Temperature-collected Ionic Liquid was Developed for Determination of Cadmium in Packaging Materials

研究了温控离子液体结合火焰原子吸收测定包装材料中镉溶出量的方法。在碱性条件下(pH值≥11.0),高选择性的邻羧基苯基重氮氨基偶氮苯(o-CDAA)与镉离子形成中性络合物(CdCDAA)。运用温控离子液体1-异辛基-3-甲基咪唑六氟磷酸盐([i-C8mim][PF6])作为萃取剂,对水相中的镉进行预富集。然后用1mol/L的硝酸将镉从离子液体中反萃入水相,直接用于原子吸收的测定。实验表明,镉的一次萃取率达到95%以上,富集倍数达到700倍,并成功运用于塑料包装中镉的测定,结果令人满意。

The flame atomic absorption spectrometry coupled with temperature-collected ionic liquid was developed for determination of cadmium in the leaching solutions of packaging materials.In the presence of basic solution（pH=11.5）,cadmium and o-CADD formed neural complex（Cd-CADD）.The complex was extracted from aqueous phase by 1-isooctyl-3-methylimidazolium hexafluorophosphate（[i-C8mim][PF6]）.After back-extracting into aqueous phase with 1mol L-1 nitric acid,the cadmium concentration was detected by flame atomic absorption spectrometry.The results indicated that the extraction efficiency of cadmium in one extraction step was above 95%and the enrichment factor reached 700.The method was successful applied to determinate the cadmium of packaging material with satisfactory results.