ANALYSIS OF COBALT SOLUTION WITH M-CHLOROAZOANTIPYLINE AND DETERMINATION OF TRACE AMOUNTS OF COBALT BY BETA-CORRECTION SPECTROPHOTOMETRY

Cobalt chelate formation with m-chloroazoantipyline (CAA) at pH 9 has been restudied. The characteristic factors of the chelate were determi ned by the recently introduced method of Beta-correction spectrophotom etry. The factors included the complexation ratio, practical molar abs orptivity (epsilon(p)), stability constant (zeta) and stepwise formati on constants. The determination of traces of cobalt in several wastewa ters was made with satisfactory recovery and precision. Results showed a stoichiometry of Co:CAA = 1:2 for the chelate formed, a major absor ption of epsilon(p) = 3.56 X 10(4) L . mol(-1). cm(-1) at 625 nm and a stability constant of zeta(e) = 1.00 x 10(11).