Sensitive determination of heroin based on electrogenerated chemiluminescence of tris(2,2′-bipyridyl)ruthenium(ii) immobilized in zeolite Y modified carbon paste electrode

Abstract

A novel method for rapid, inexpensive, sensitive and selective determination of heroin was proposed by flow injection electrogenerated chemiluminescence (ECL). Zeolite Y sieves were used for the preparation of a ECL sensor by immobilizing tris(2,2′-bipyridyl)ruthenium(II) (Ru(bpy)₃²⁺) in their supercages, which was achieved through the ion exchange properties of the sieves. The electrochemical and ECL behaviors of Ru(bpy)₃²⁺ immobilized in zeolite Y modified carbon paste electrode was investigated. The immobilized Ru(bpy)₃²⁺ displayed a pair of surface-controlled redox peaks with an electron transfer rate constant of 1.2 ± 0.1 s⁻¹ in 0.1 mol dm⁻³ pH 6.3 phosphate buffer. The modified electrode showed an electrocatalytic response to the oxidation of heroin, producing a sensitized ECL signal. The ECL sensor showed a linear response to flow injection of heroin in the range of 2.0–80 µmol dm⁻³ with a detection limit of 1.1 µmol dm⁻³. This method for heroin determination possessed good sensitivity and reproducibility with a coefficient of variation of 1.99% (n = 15) at 50.0 µmol dm⁻³. The ECL sensor showed good selectivity and long-term stability. Its surface could be renewed quickly and reproducibly by a simple polish step.