Adsorptive Stripping Voltammetry of Bleomycin

Abstract

In 0.05 M H₂SO₄ solution, two reductive peaks, P₁ and P₂, of bleomycin were obtained. The peak potentials E_P1 and E_P2 were -0.83 and -1.09 V (versus Ag/AgCl), respectively. The sensitivity of P₂ was much higher than that of P₁. The peak current of P₂ was proportional to the concentration of bleomycin over the range 1.0 ×10^-9–1.0 × 10^-7M with a detection limit of 5.0 × 10^-10M using adsorptive voltammetry at an accumulation time of 120 s (E_i = -0.80 V). The behaviour of the reduction wave was studied and applied to the determination of bleomycin in mouse serum. The reduction process of P₁ was irreversible with adsorptive characteristics and the adsorption behaviour obeyed the Frumkin adsorptive isotherm.The adsorptive coefficient β was 8.9 × 10⁵ , the interaction factor α was 0.94 and the Gibbs energy of adsorption ΔG° was -33.93 kJ mol^-1. P₂ was an irreversible adsorption peak with catalytic hydrogen properties.

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