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A Nitrite Biosensor Based on Co-immobilization of Nitrite Reductase and Viologen-modified Chitosan on a Glassy Carbon Electrode
Department of Chemistry and Interdisciplinary Program of Integrated Biotechnology, Sogang University, Seoul, 121-742, Korea
Department of Chemistry, College of Chemistry, Chemical Engineering and Environment, Qingdao University, Qingdao, Shandong, 266071, China
* Authors to whom correspondence should be addressed.
Received: 18 May 2010; in revised form: 8 June 2010 / Accepted: 14 June 2010 / Published: 22 June 2010
Abstract: An electrochemical nitrite biosensor based on co-immobilization of copper- containing nitrite reductase (Cu-NiR, from Rhodopseudomonas sphaeroides forma sp. denitrificans) and viologen-modified chitosan (CHIT-V) on a glassy carbon electrode (GCE) is presented. Electron transfer (ET) between a conventional GCE and immobilized Cu-NiR was mediated by the co-immobilized CHIT-V. Redox-active viologen was covalently linked to a chitosan backbone, and the thus produced CHIT-V was co-immobilized with Cu-NiR on the GCE surface by drop-coating of hydrophilic polyurethane (HPU). The electrode responded to nitrite with a limit of detection (LOD) of 40 nM (S/N = 3). The sensitivity, linear response range, and response time (t90%) were 14.9 nA/mM, 0.04−11 mM (r2 = 0.999) and 15 s, respectively. The corresponding Lineweaver-Burk plot showed that the apparent Michaelis-Menten constant (KMapp) was 65 mM. Storage stability of the biosensor (retaining 80% of initial activity) was 65 days under ambient air and room temperature storage conditions. Reproducibility of the sensor showed a relative standard deviation (RSD) of 2.8% (n = 5) for detection of 1 mM of nitrite. An interference study showed that anions commonlyfound in water samples such as chlorate, chloride, sulfate and sulfite did not interfere with the nitrite detection. However, nitrate interfered with a relative sensitivity of 64% and this interference effect was due to the intrinsic character of the NiR employed in this study.
Keywords: biosensor; nitrite reductase; chitosan; viologen; hydrophilic polyurethane
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MDPI and ACS Style
Quan, D.; Shin, W. A Nitrite Biosensor Based on Co-immobilization of Nitrite Reductase and Viologen-modified Chitosan on a Glassy Carbon Electrode. Sensors 2010, 10, 6241-6256.
Quan D, Shin W. A Nitrite Biosensor Based on Co-immobilization of Nitrite Reductase and Viologen-modified Chitosan on a Glassy Carbon Electrode. Sensors. 2010; 10(6):6241-6256.
Quan, De; Shin, Woonsup. 2010. "A Nitrite Biosensor Based on Co-immobilization of Nitrite Reductase and Viologen-modified Chitosan on a Glassy Carbon Electrode." Sensors 10, no. 6: 6241-6256.