Determination of poly(vinyl alcohol) by adsorptive stripping voltammetry based on its copper(II) complex

Adsorptive stripping voltammetry with a hanging mercury-drop electrode based on the adsorptive enhancement of Cu(II)-poly (vinyl alcohol) (PVA) has been developed for PVA determination. In a 0.1 mol l−1 sodium carbonate buffer solution of pH 11.0 containing l0 μmol l−1 Cu(II), the adsorptive peak of Cu(II)-PVA has a potential of -0.125V (vs. Ag/AgCl). The increase in peak current is proportional to the concentration of PVA over the range 0.02~1.0 mg l−1 for an accumulation period of 4min. The detection limit is 0.01 mg l−1. Twenty-five fold coexisting starch is tolerable for determining 0.2mg l−1 PVA. The RSD is not more than 5%. The method was successfully employed to determine PVA in paper and paper-coatings. The results are in agreement with those obtained by the spectrophotometric method using iodine-boric acid.