ORIGINAL PAPER A highly selective and sensitive dopamine and uric acid biosensor fabricated with functionalized ordered mesoporous carbon and hydrophobic ionic liquid Junping Dong & Yanyan Hu & Shenmin Zhu & Jiaqiang Xu & Yinjuan Xu Received: 22 October 2009 / Revised: 12 December 2009 / Accepted: 17 December 2009 / Published online: 21 January 2010 # Springer-Verlag 2010 Abstract An ordered mesoporous carbon material function- alized with carboxylic acid groups was synthesized. It was characterized by powder X-ray diffraction, transmission electron microscopy, Fourier transform IR spectroscopy and N 2 adsorption/desorption. Furthermore, this material was used to modify an electrode surface combined with a hydrophobic ionic liquid. The functionalized ordered meso- porous carbon/ionic liquid gel modified electrode shows excellent electrocatalytic performances for the oxidation of dopamine, uric acid and ascorbic acid. The presence of the ionic liquid promotes the electron transfer. Linear responses for dopamine and uric acid were obtained in the ranges of 0.1 to 500 μM and from 0.1 to 100 μM with detection limits of 4.1 and 2.5 nM (signal-to-noise ratio of 3), respectively, under optimum conditions. A quick and sensitive biosensor based on functionalized ordered mesoporous carbon and an ionic liquid has been developed for the first time for the detection of dopamine and uric acid in the presence of a large amount of ascorbic acid. Keywords Ordered mesoporous carbon . Ionic liquid . Dopamine . Uric acid . Ascorbic acid Introduction Highly ordered mesoporous carbon (OMC) has become a hot subject since it was synthesized in 1999 [1]. OMC exhibits an extremely high surface area, a well-ordered pore structure and chemical inertness, which make it suitable for applications in catalysis, adsorption, energy storage and sensing [2–5]. Similar to another well-known and widely used carbon-based material, i.e., carbon nanotubes (CNTs), OMC possesses the advantages of carbon nanomaterials, making it a novel electrode material in electrochemical sensors [6–11]. For example, the simultaneous determina- tion of catechol and hydroquinone has been achieved at a mesoporous carbon modified electrode [12]. OMC was adopted as protein immobilization material to study the direct electrochemistry of haemoglobin [13]. A lot of research was conducted by Guo’ s group on an OMC-modified electrode. Different electrodes based on OMC were constructed for the detection of electroactive species, including hydrogen per- oxide [14], hydroquinone [15], NADH [16], glutathione and cysteine [17], epinephrine [18], L-cysteine [19], ascorbic acid (AA) [20] and Sudan I [21]. Zhou et al. [22] compared the responses at an OMC-modified glassy carbon electrode and a CNT-modified glassy carbon electrode for the electrocatalysis of eight kinds of electroactive compounds, and the findings suggested that the OMC-modified glassy carbon electrode has more favourable electron transfer kinetics than the CNT- modified glassy carbon electrode. Dopamine (DA) is one of the important catecholamine neurotransmitters in the mammalian central nervous system, and plays a significant role in several diseases, such as J. Dong (*) : Y. Hu : J. Xu : Y. Xu Department of Chemistry, College of Science, Shanghai University, Shanghai 200444, China e-mail: jpdong@shu.edu.cn J. Xu (*) State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China e-mail: xujiaqiang@shu.edu.cn S. Zhu State Key Lab of Metal Matrix Composites, Shanghai Jiaotong University, 800 Dongchuan Road, Shanghai 200240, China Anal Bioanal Chem (2010) 396:1755–1762 DOI 10.1007/s00216-009-3423-3