The effect of the third components of cationic surfactants – chloridecetylpyridinium (CPCl), cetylpyridinium bromide (CPBr), cetyltrimethylammonium bromide (CPMABr) for complexation of nickel (II) with 4- (2´, 3´, 4´-trihydroxyphenyl) -3-sulfo-5-chlorophenylazo benzene (R). Same- (NiR) and mixed-ligand complex compounds (Ni (II) -RCPCl, Ni (II) -RCPBr and Ni (II) -RCPMABr) are formed at pH 6, 4, 4 and 4, respectively. All complexes are formed immediately after mixing the solutions of the components and differ in stability. The ratio of the reacting components in the composition of same- (1: 1) and mixed-ligand (1: 1: 1) complexes are established. The interval of obedience to Beer's law is determined. The coefficients of the calibration curve equation are determined by the method of least squares. Complexation of nickel (II) is expressed by linear dependence of A = f (c) is. Stability constants of same- (NiR) and mixed-ligand complexes (Ni (II) -RCPCl, Ni (II) -RCPBr and Ni (II) -RCPMABr) are calculated. Under optimal conditions of complexation, Ni-R was titrated with a solution of third components (CPCl, CPBr and CPMABr) by conductometric method. The influence of foreign ions on complexation of nickel (II) with R in the absence and in the presence of third components was studied. A technique has been developed for the spectrophotometric determination of microquantities of nickel in the waters of the Akstafa and Jogaz rivers of the Kazakh region of the Republic of Azerbaijan

doi.org/10.32737/0005-2531-2023-2-146-153