1. Introduction The requirements and regulations in the felds of environmental protection, control of biotechnological processes and certifcation of food and water quality are becoming more and more urgent [1]. At the same time, stricter requirements regarding human and animal health have led to a rising number of clinical and veterinary tests. Therefore, there is a need to develop highly sensitive, fast and economic methods for the detection, quantifcation and monitoring analysis. The elaboration of biosensors is probably one of the most promising ways to approach problems concerning selective, sensitive, fast, easy to use, cost-effective and repetitive measurements with miniaturized and portable devices [2]. The major felds of practical application of amperometric biosensors are clinical diagnostics and pharmaceutical analysis. Clinical diagnostics is deliberately listed frst, since more than 80% of commercial devices are used in this domain [1]. Generally, biosensors are sensitive and selective analytical devices involving the association of a biocomponent to a transducer. Besides choosing the adequate transducer and enzyme in the construction of a biosensor, an important aspect of the design is played by the method of enzyme immobilization. The screen printed electrodes (SPE) have been developed for innovative applications in analytical chemistry. As reported in literature, the use of screen- printed electrodes (SPE) is a great simplifcation in the design and operation of analytical determinations, in accordance with the requirements of a decentralized assay [3]. Recently, SPEs have demonstrated promising potential, especially in the development of rapid analysis Central European Journal of Chemistry * E-mail: rsandulescu@umfcluj.ro Abstract: © Versita Sp. z o.o. Received 14 February 2010; Accepted 5 May 2010 Keywords: Electrochemical biosensor • Horseradish peroxidase • Zirconium alkoxide • SPE • Acetaminophen Analytical Chemistry Department, Faculty of Pharmacy, “IULIU HAŢIEGANU” University of Medicine and Pharmacy, Cluj-Napoca 400349, Romania Veronica Sima, Cecilia Cristea, Ede Bodoki, Gabriela Duţu, Robert Săndulescu * Screen-printed electrodes modifed with HRP– zirconium alcoxide flm for the development of a biosensor for acetaminophen detection Research Article The development of a biosensor based on the immobilization of horseradish peroxidase (HRP) within a zirconium alkoxide- polyetilenimine flm onto screen-printed electrodes (SPE) for acetaminophen detection and acetaminophen quantifcation in pharmaceutical products is described. The biosensor operation mode is based on monitoring the amperometric signal produced by the electrochemical reduction of the enzymatically generated electroactive oxidized species of acetaminophen in the presence of hydrogen peroxide. The enzyme immobilization is performed by retention in a polyethylenimine-zirconium alcoxide porous gel flm, a technique that offers good entrapping and a protective environment for the biocomponent due to the hydration properties of the immobilization layer. SPEs have the advantage of being easily mass-produced at low costs with superior characteristics in comparison with classical electrode materials. In this confguration, zirconium alkoxide demonstrates its electrocatalytic activity. The biosensor allows the quantifcation of acetaminophen with a limit of detection of 6.21×10 -8 M and a linear range between 4.35×10 -7 M and 4.98×10 -6 M. Finally, the biosensor is applied to the quantitative analysis of acetaminophen in Perdolan® tablets. Cent. Eur. J. Chem. • 8(5) • 2010 • 1034–1040 DOI: 10.2478/s11532-010-0070-7 1034 Unauthenticated Download Date | 7/28/18 7:09 AM