Electrochemical detection of hydroquinone with a gold nanoparticle and graphene modified carbon ionic liquid electrode

摘要

An ionic liquid l-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF_4) modified carbon paste electrode was fabricated and used as the substrate electrode. Then a gold nanoparticle and graphene (GR) composite film was co-electrodeposited on the carbon ionic liquid electrode (CILE) surface by immersing CILE in the graphite oxide and tetrachloroauric acid dispersion solution with cyclic voltammetric reduction. The fabricated Au-GR/CILE exhibited good electrochemical performances with higher conductivity and lower electron transfer resistance. Electrochemical behaviors of hydroquinone (HQ) were further investigated on the modified electrode by cyclic voltammetry and differential pulse voltammetry. A pair of well-defined redox peaks appeared with the peak-to-peak separation (ΔE_p) as 0.077 V in 0.1 mol/L pH 2.5 PBS, indicating a fast quasi-reversible electron transfer process. The result could be attributed to the presence of high conductive Au-GR nanocomposites on the electrode surface. The electrochemical parameters of HQ on the Au-GR/CILE were calculated and the experimental conditions were optimized. Under the optimal conditions, the linear relationship between the oxidation peak current of HQ and its concentration can be obtained in the range from 0.06 μmol/L to 800.0 μmol/L with the detection limit as 0.018 vmol/L (3σ). The coexisting catechol exhibited no interference and Au-GR/CILE was applied to the detection of HQ in synthetic wastewater samples with satisfactory results.