Effect of anionic surfactant on binary complexes of l-arginine with cd(ii) and pb(ii)

Chemical speciation of binary complexes of L-Arginine (Arg) with Cd(II) and Pb(II) in presence of water - anionic surfactant mixtures in the concentration range of 0.0-2.5% w/v sodium lauryl sulphate (SLS) was investigated pH-metrically at a temperature of 303 K and at an ionic strength of 0.16 mol L-1. The stability constants were determined using the computer program MINIQUAD 75. The number of species in the models is chosen based on exhaustive modeling. The appropriateness of experimental conditions is verified by introducing errors intentionally in the concentrations of ingredients. The predominant species detected were ML and ML2 for both Cd(II) and Pb(II). The trend in the variation of stability constants with the mole fraction of SLS was explained on the basis of electrostatic and non-electrostatic forces. The species distribution and the plausible equilibria for the formation of the species are also presented.