Electrochemical detection of dopamine using water-soluble sulfonated graphene

• Published in: Electrochimica acta 2013-07, Vol.102, p.58-65
• Main Authors: Li, Su-Juan, He, Jun-Zhi, Zhang, Meng-Jie, Zhang, Rong-Xia, Lv, Xia-Lei, Li, Shao-Hua, Pang, Huan
• Format: Article
• Language: English
• Subjects: Ascorbic acid; Charging; Dopamine; Electrochemical sensor; Fourier transforms; Graphene; Oxidation; Scanning electron microscopy; Selectivity; Sulfonated graphene; Uric acid
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2013.03.176

DPV responses of dopamine (DA) at sulfonated graphene based glassy carbon electrode in the presence of ascorbic acid (AA) and uric acid (UA). The separation of the oxidation peak potentials for AA-DA, DA-UA and UA-AA was about 227mV, 125mV and 352mV, which allowed selectively determining DA. In the present study, a biosensor was prepared using the water-soluble sulfonated graphene with the aim of achieving the selective and sensitive determination of dopamine (DA) in the presence of ascorbic acid (AA) and uric acid (UA). The aromatic π–π stacking and electrostatic attraction between positively charged DA and negatively charged sulfonated graphene can accelerate the electron transfer whereas weakening AA and UA oxidation on the sulfonated graphene-modified electrode. Fourier transform infrared spectra (FTIR), energy dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM) and scanning electron microscopy (SEM) were used to characterize the successful synthesis of sulfonated graphene sheets. Differential pulse voltammetry was used for electrochemical detection, the separation of the oxidation peak potentials for AA-DA, DA-UA and UA-AA was about 227mV, 125mV and 352mV, which allowed selectively determining DA. A broad linear range, low detection limit, along with good ability to suppress the background current from large excess ascorbic acid (AA) and uric acid (UA) were obtained. The as-prepared sulfonated graphene sheets exhibited superior performance over conventional negatively charged Nafion films, such as flexible film thickness, unique nanostructure, excellent anti-interference ability, high sensitivity and selectivity. The proposed method was used to detect DA in real hydrochloride injection sample, human urine and serum samples with satisfactory recovery results.