Spectrophotometric determination of cobalt with phenylfluorone in the presence of triton X-100 and cetylpyridine chloride

Spectrophotometric determination of cobalt by the reaction with phenylfluorone (PF) in the presence of cetylpyridine chloride (CP) and Triton X-100 has been developed. Optimum concentrations of PF, CP, Triton X-100 and pH ensuring maximum absorbance were defined. The effect of foreign ions was elucidated. The maximum absorbance is observed at 635 nm. Molar absorptivity is 1.34 x 10(5) l mol(-1)cm(-1). The Beers law is obeyed for cobalt concentrations over the range 0.04-0.4 mu g ml(-1). The method has been applied for determination of cobalt in pharmacological preparations.