Spectrophotometric determination of cations in presence of surfactants II. determination of nickel [II] using some AZO and xanthene reagents

ABSTRACT

The present work describes sensitive, rapid and economic methods for determination of nickel [II] using Sulphochlorophenol S I, Bromopyrogallol Red II or Pyrogallol Red III, in acid or basic media, in presence or absence of surfactants, without heating or extraction. The effect of pH, reagent concentration, time, temperature, and addition sequence, have been studied. Beer's law is obeyed over the ranges 0.5-6, 0.4-5.4 and 0.2-5 gml-1 of nickel [II] using reagents I, II and III, respectively. The molar absorptivities for the binary complexes ranges from 0.68 to 1.97 x 104 lmol-lcm-1, while for ternary complexes from 0.59 to 3.3 x 104 lmol-lcm-1. Sandell sensitivities are ranging 0.921-8.51 gml-1 for binary complexes and 1.79 -10.05 gml-1 for ternary ones. LOD were 0.1241, 0.0711, 0.0365, 0.0485, 0.0421 and 0.0536 for reagent [I]. For reagent [II] LOD were 0.0418, 0.0261, 0.2086, 0.1249, 0.0708 and 0.0471, and for reagent [III] were 0.0356, 0.0491, 0.025 and 0.1248. LOQ were 0.4137, 0.237, 0.1217, 0.1617, 0.1403 and 0.1787 for reagent [I]; 0.1393, 0.0870, 0.6953, 0.4163, 0.2359 and 0.1570 for reagent [II] and 0.1187, 0.1637, 0.0833 and 0.416 for reagent [III]. X +/- s.D. were 100.096+/- 0.653, 99.763+/- 0.88, 99.742+/- 0.921, 100.106+/- 0.267, 99.445+/- 0.454 and 100.443+/- 0.761 for reagent [I]; 99.922+/- 0.1, 00.208+/- 0.234, 100.184+/- 0.27, 100.287+/- 0.408, 100.021+/- 0.411 and 100.211+/- 0.2C5 for reagent [II] and 100.061+/- 0.582, 99.685+/- 0.386, 100.052+/- 0.144 and 100.004+/-0.095 for reagent [III]. The effect of surfactants on the complexes produced was studied regarding stability, molar absorptivity, sensitivity, applicable concentration ranges and stoichiometric ratios. The proposed procedures were statistically compared the results given by the atomic absorption spectrometric method with good accuracy d precision. The evaluation of the method was examined by the determination of Ni [II] in hydrogenated vegetable oil