Highly stable pyridinic nitrogen doped graphene modified electrode in simultaneous determination of hydroquinone and catechol

Abstract

A highly stable pyridinic nitrogen doped graphene (pyridine-NG) was used as an excellent electrocatalyst for the construction of electrochemical sensor for simultaneous determination of hydroquinone (HQ) and catechol (CC) in 0.20M pH 5.5 acetate buffer solution. At the pyridine-NG modified electrode, both HQ and CC can cause a pair of quasi-reversible redox peaks and the potential difference of oxidation peaks between HQ and CC was 103mV. Under the optimized condition, the oxidation peak current of HQ was linear over the range from 5 to 200μM in the presence of 100μM CC, and the oxidation peak current of CC was linear over the range from 5 to 200μM in the presence of 100μM HQ. The detection limit is 0.38μM for HQ and 1μM for CC (S/N=3). This proposed sensor was successfully applied to the simultaneous determination of HQ and CC in artificial sample, and the results were good stability and high reproducibility. The excellent electrocatalysis of pyridine-NG can be due to the π–π interactions between the benzene ring of CC and graphene layer, the hydrogen bonds formed between hydroxyl in HQ molecule and pyridinic nitrogen atoms within graphene layers, especially the less density distribution of π electron cloud in pyridinic-NG in acidic condition.