Indirect Photometric Determination of Cetylpyridine Chloride (CPC) by Separation with the Floatation Reaction System of Cu(Ⅱ)-SCN--CPC-2-Propanol-(NH4)2SO4-H2O

It was found that a ternary ion association complex,Cu(SCN)4·(CPC)2 was formed in a slightly acidic medium of pH 1.0 to 6.0 and was separated by floatation from an aqueous medium containing 3.0 mL of 2-propanol and 2.0 g of solid (NH4)2SO4 in a total volume of 10 mL.A fixed and excess amount of Cu(Ⅱ) ion was added to the reaction mixture,and the amount of Cu(Ⅱ) remained in the aqueous salt phase after floatation was determined photometrically at the wavelength of 510 nm by its color reaction with PAR.Linear relationship between values of floatation rate of copper(Ⅱ) and mole concentration CPC was found in the range of 1.0×10-5-1.2×10-4mol·L-1.The proposed method was applied to the indirect determination of CPC in simulated water samples,giving values of recovery and RSD′s (n=5) in the ranges of 95.0%-105.0% and 0.69%-1.54% respectively.