Pre-concentration and in situ electrochemical sensing of 1-hydroxypyrene on an electrodeposited poly(3-methylthiophene) film modified electrode

1-Hydroxypyrene (1-OHP) is a widely used biomarker for evaluation of polycyclic aromatic hydrocarbons (PAHs) exposure. In this paper, a 1-OHP sensor, combining pre-concentration and in situ electrochemical determination, was fabricated based on electropolymerized poly(3-methylthiophene) (P3MT). Direct electrochemical properties of 1-OHP on the P3MT modified glass carbon electrode (GCE) were investigated. A pair of well-defined reversible cyclic voltammetric peaks were observed at the P3MT/GCE with ΔEp of 30 mV. The surface coverage (Г) of 1-OHP was calculated to be 9.26 × 10−11 mol cm−2 at the P3MT/GCE and the electron transfer coefficient α was estimated to be 0.53. P3MT offers π-conjugated system to adsorb 1-OHP via π–π stacking interaction. Meanwhile, P3MT films displayed good electrocatalytic activity to the oxidation of 1-OHP. The peak currents of 1-OHP obtained by differential pulse voltammetry were linear with the concentrations of 1-OHP in a range of 0.5–20.0 μM (R = 0.9953) with a detection limit of 165 nM (S/N = 3) and a sensitivity of 12.72 μA μM−1 cm−2. The sensor also exhibited good reproducibility (with a relative standard deviation of 1.2%) and long-term stability.