磺基水杨酸-溴邻苯三酚红-溴化十六烷基吡啶分光光度法测定食品中钼的研究

The colour reaction of molybdenum(Ⅵ) with sulfsalicylic acid-bromopyro gallol red in the presence of cetylpyridine bromide and its application

研究了在pH5.6的HAc NaAc缓冲溶液中,溴化十六烷基吡啶(CPB)存在下,钼(Ⅵ)与溴邻苯三酚红及磺基水杨酸形成多元配合物的显色反应,建立了测定食品中微量钼的新方法。该配合物的最大吸收波长为λmax=620nm,表观摩尔吸光系数ε620=1.84×105L·mol-1·cm-1。钼(Ⅵ)浓度在0～0 80μg mL范围内符合比尔定律。应用于粮食作物中微量钼的测定,相对标准偏差小于4 8%,回收率为95.2%～100.5%。

In the presence of acetic acid-sodium acetate buffer solution at pH 5.6 and cetylpyridine bromide medium, molybdenum(Ⅵ) reacted with bromopyrogallol red(BPR) and sulfosalicylic acid(Ssal) to form a colour complex. The maxinum absorption of the complex was at 620 nm and the apparent molor absorptivity was 1.84×10~5 L·mol^(-1)·cm^(-1). Beer′s law was obeyed in the range of 0～0.80 μg/mL for molybdenum(Ⅵ). The method was applied to the determination of molybdenum in water and cereal samples with satisfactory results.