Determination of benzyl alcohol based on the polarographic catalytic wave of the oxidation product of benzyl alcohol in the presence of peroxydisulfate

Benzyl alcohol was oxidized rapidly to electroactive benzaldehyde through a radical-chain reaction initiated by sulfate radical SO4− electrogenerated from reduction of S2O82−. The benzaldehyde formed was reduced via an intermediate free radical. The free radical of benzaldehyde was oxidized by both S2O82− and SO4− to produce a catalytic wave. Based on this a novel method for the determination of benzyl alcohol was proposed. In 0.1 mol l−1 KH2PO4+Na2HPO4 buffer (pH 5.6±0.1)+2.0×10−2 mol l−1 K2S2O8 solution the second-order derivative peak current of the catalytic wave was linearly proportional to the benzyl alcohol concentration in the range of 9.70×10−6–1.54×10−4 mol l−1. The limit of detection was 8.0×10−6 mol l−1. The proposed method was applied to determine the benzyl alcohol content in clinical injection.