固相萃取-光度法测定卷烟材料中镉

Photometric Determination of Cadmium in Materials for Producing Cigarettes with Solid Phase Extraction

卷烟材料样品中的镉经强阴离子交换固相萃取柱分离、富集,以6-溴-2-苯并噻唑重氮氨基偶氮苯(BBTDAA)为显色剂,在pH 10的硼砂-氢氧化钠缓冲介质中,Triton X-100存在下,反应5min镉与BBTDAA形成1比2的配合物。该配合物的最大吸收波长为520nm,体系的摩尔吸光率为1.92×105L.mol-1.cm-1。镉的质量浓度在1.0mg.L-1以内符合比耳定律。方法用于分析各种卷烟材料,测定值的相对标准偏差(n=8)在2.2%～2.8%之间,测定结果与原子吸收光谱法相符。

Cadmium（Ⅱ） in samples of materials for producing cigarettes was separated and enriched by passing through anionic-exchange SPE column.Cadmium in the extract was reacted with the chromogenic reagent 6-bromo-2-benzothiazolyl diazoaminoazobenzene（BBTDAA） as chromogenic reagent.In a Na2B4O7-NaOH buffer solution of pH 10,and in the presence of Triton X-100,a stable coordination complex with the molar ratio [Cd（Ⅱ）∶BBTDAA] of 1 to 2 was formed,with its absorption maximum at the wavelength of 520 nm.Value of apparent molar absorptivity was found to be 1.92×105L·mol-1·cm-1.Beer′s law was kept in the range within 1.0 mg·L-1.The proposed method was applied to the analysis of samples of materials for producing cigarettes,giving results in consistency with those obtained by AAS.Values of RSD′s（n=8） found were in the ranges of 2.2%-2.8%.