Application of Bismuth(III)-Entrapped XO Biosensing System for Xanthine Determination in Beverages
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Application of Bismuth(III)-Entrapped XO Biosensing System for Xanthine Determination in Beverages Ulku Anik & Meliha Çubukçu
Received: 4 August 2011 / Accepted: 12 September 2011 / Published online: 27 September 2011 # Springer Science+Business Media, LLC 2011
Abstract A xanthine biosensor was prepared by electrochemical immobilization of xanthine oxidize enzyme onto carbon paste electrode via entrapment of Bi3+. After the optimization of experimental parameters, analytical characteristics were investigated. Two linear ranges between 0.02 and 0.06 and 1–7.5 μM with the equation y=93.00x+0.12 and y=1.07x+18.03 with the correlation coefficients of R2 =0.9951 and R2 =0.9931, respectively, were obtained for this biosensing system. RSD value was calculated for 0.04 μM xanthine (n=5) and found as 3.84%. LOD and LOQ values were also calculated and revealed as 1.30× 10−8 and 4.3×10−8 M, respectively. Then, this biosensor was applied for xanthine detection in real samples. As a sample treatment, only necessary dilutions were made. Four types of beverages including wine, energy drink, peach, and sour cherry juice were used for this purpose. Obtained recovery values demonstrate that this system is applicable for xanthine detection in real samples without needing any laborious sample pretreatment procedures. Keywords Biosensor . Xanthine . Beverages . Bismuth
U. Anik (*) : M. Çubukçu Faculty of Science, Chemistry Department, Mugla University, 48000, Kötekli, Mugla, Turkey e-mail: [email protected] U. Anik e-mail: [email protected] U. Anik e-mail: [email protected] M. Çubukçu Faculty of Science, Chemistry Department, Ege University, 35100, Bornova, Izmir, Turkey
Introduction Bismuth film electrode (BiFE) has been extensively used especially for heavy metal and organic compound detection since it has been developed by Joseph Wang and his group in 2000 (Wang et al. 2000, 2001a, b; Hutton et al. 2001, 2005, 2006; Kefala et al. 2003, 2006; Charalambous and Economou 2005; Krŏlicka et al. 2002; Demetriades et al. 2004; Legeai and Vittori 2006; Anık-Kırgöz et al. 2005; Castaňeda et al. 2005; Merkoçi et al. 2007; Hocĕvar et al. 2002; Yang et al. 2006; Bučková et al. 2005). Recently, our group used BiFE as biosensor transducer, and very promising results were obtained (Anık et al. 2008, 2010; Timur and Anık 2007; Merkoçi et al. 2010). In our first study, a second-generation biosensor was formed by using neutral red as a proper mediator and BiFE as electrode. GOx was attached onto BiFE by using gelatin membrane, and glucose was detected by following amperometric signal resulting with oxidation/reduction of neutral red (Anık et al. 2008). In another BiFE-based biosensor, we manage to develop a sensitive method for the detection α-glucosidase (AG, EC 3.2.1.20) activity by following liberation of p-nitrophenol from p-nitrophenyl-α-D-glucopyranoside which is the synthetic substrate of AG enzyme (Timur and Anık 2007). In that work, a BiFE-based biosensor has been prepared by immobilizing AG enzyme on BiFE by means of gelatin membrane.
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