Square wave voltammetry for analytical determination of paraquat at carbon paste electrode modified with fluoroapatite

This paper describes the construction of a carbon paste electrode (CPE) impregnated with fluoroapatite (FAP). The new electrode (FAP–CPE) was revealed an interesting determination of paraquat. The latter was accumulated on the surface of the modified electrode by adsorbing onto fluoroapatite and reduced in 0.1 mol L−1 K2SO4 electrolyte at −0.70 and −1.0 V for peaks 1 and 2, respectively. Experimental conditions were optimized by varying the accumulation time, FAP loading and measuring solution pH. Under the optimized working conditions, calibration graphs were linear in the concentration ranging from 5 × 10−8 to 7 × 10−5 mol L−1 with detection limits (DL, 3σ) of 3.5 × 10−9 and 7.4 × 10−9 mol L−1, respectively, for peaks 1 and 2.Fluoroapatite was characterized by X-ray diffraction XRD analysis; Fourier-transform infrared spectroscopy FT-IR and inductively coupled plasma-atomic emission spectrometry (ICP-AES) analysis.