Determination of Cobalt by Spectrophotometry Using a New Reagent, 1-(6-bromo-2-benzothiazolyl)-3-(5-bromo-8-quinolyl)-triazene / 环境与健康杂志

ABSTRACT

Objective To synthesize a new reagent, 1-(6-bromo-2-benzothiazolyl)-3-(5-bromo-8-quinolyl)-triazene (BBTBQT) and apply to the determination of cobalt. Methods The reagent had been synthesized by diazotization and coupling reaction. After purification and characterization, BBTBQT was tested for its color reaction conditions with cobalt in the presence of cetylpyridinium bromide (CPB). Results In the presence of borax buffer solution at pH value of 9.0, the reagent reacted with cobalt to form a blue stable complex with a molar ratio of 2∶1; the complex had a maximum absorption at 640 nm. The apparent molar absorptivity of the complex is 1.55 ?105 L/(mol?cm). Beer’s law was obeyed in the range of 0-0.28 mg/L for cobalt. The method had been applied to determine cobalt in drainage sediment and vitamin B12 injection solution with a mean relative error of 1.9%-5.8% and a standard relative deviation of 1.7%-3.8%. Conclusion The present method is selective, sensitive, accurate, convenient and suitable for determination of trace cobalt in the samples.