Application of Cupferron‐lead(II) Complex for the Electrochemical Determination of dsDNA

Abstract

AbstractBased on the interaction of cupferron and lead(II) complex [Cup‐Pb(II)] with double‐stranded DNA (dsDNA) a new voltammetric method for the detection of DNA was described in this paper. In pH 4.0 HAc‐hexamine buffer solution, [Cup‐Pb(II)] complex showed a sensitive second order derivative polarographic reductive peak at ‐0.554 V (vs. SCE). After the addition of dsDNA into [Cup‐Pb(II)] mixture solution the reductive peak current decreased with the positive shift of reductive peak potential, which was the typical characteristic of intercalation mode. Under the optimum conditions, the decrease of reductive peak current was directly proportional to the dsDNA concentration in the range from 1.0 to 25.0 mg/L with the linear regression equation as ΔIp″ (nA) = 129.30 + 62.51 C (mg/L) (n = 13, γ = 0.991). The detection limit of 0.90 mg/L (3σ) and the relative standard derivation (RSD) of 2.43% for 10 parallel determinations of 10.0 mg/L dsDNA were found. The method was successfully applied to synthetic samples with good results, and the stoichiometry of dsDNA with [Cup‐Pb(II)] complex was calculated by the voltammetic data with the binding number as 2 and the binding constant as 2.82 × 109.