微波消解—固相萃取光度法测定钴

Study on microwave digestion and solid phase extraction and spectrophotometric determination of cobalt

根据新试剂 2 (2 喹啉偶氮 ) 5 二甲氨基酚 (QADMAP)与钴的显色反应及C1 8固相萃取小柱对显色络合物的固相萃取 ,建立了一种测定食品和水样中痕量钴的新方法。在pH3 5的HAc -NaAc缓冲介质中 ,溴化十六烷基三甲基铵(CTMAB)存在下 ,QADMAP与钴反应生成 2∶1稳定络合物 ,该络合物可用C1 8固相萃取小柱富集 ,小柱上富集的络合物用乙醇 (内含体积分数 2 %乙酸 )洗脱后用光度法测定。在测定液中 ,络合物最大吸收波长为 610nm ,摩尔吸光系数ε =1 14×10 5,钴质量浓度在 0～ 1 0 μg/mL内符合比尔定律。方法用于食品和水样中钴的分析 ,结果令人满意。

Based on the color reaction of 2-(2-quinolinylazo)-5-dimethylphenol(QADMAP) with cobalt*' and the solid phase extraction of its colored complex with C 18 cartridge,a new method for the determination of cobalt was studied In the presence of CTMAB and pH3 5 buffer solution medium,QADMAP can react with cobalt*' to form a stable 2∶1 complex The colored complex can be extracted by C 18 cartridge and eluted by ethanol(containing 2% of acetic acid),then can be determined by spectrophotometry at 610nm Beer’s law is obeyed in the range of 0-1 0μg/mL This method can be applied to the determination of cobalt in food and water samples with satisfactory results