title: A novel nitrite biosensor based on conductometric electrode modified with cytochrome c nitrite reductase composite membrane.
abstract: A conductometric biosensor for nitrite detection was developed using cytochrome c nitrite reductase (ccNiR) extracted from Desulfovibrio desulfuricans ATCC 27774 cells immobilized on a planar interdigitated electrode by cross-linking with saturated glutaraldehyde (GA) vapour in the presence of bovine serum albumin, methyl viologen (MV), Nafion, and glycerol. The configuration parameters for this biosensor, including the enzyme concentration, ccNiR/BSA ratio, MV concentration, and Nafion concentration, were optimized. Various experimental parameters, such as sodium dithionite added, working buffer solution, and temperature, were investigated with regard to their effect on the conductance response of the biosensor to nitrite. Under the optimum conditions at room temperature (about 25 degrees C), the conductometric biosensor showed a fast response to nitrite (about 10s) with a linear range of 0.2-120 microM, a sensitivity of 0.194 microS/microM [NO(2)(-)], and a detection limit of 0.05 microM. The biosensor also showed satisfactory reproducibility (relative standard deviation of 6%, n=5). The apparent Michaelis-Menten constant (K(M,app)) was 338 microM. When stored in potassium phosphate buffer (100mM, pH 7.6) at 4 degrees C, the biosensor showed good stability over 1 month. No obvious interference from other ionic species familiar in natural waters was detected. The application experiments show that the biosensor is suitable for use in real water samples.
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Yangtze River Water Environment of Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai, China.
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Zhang
authors.forename: Siqing
authors.initials: S
authors.lastname: Xia
authors.forename: Didier
authors.initials: D
authors.lastname: Leonard
authors.forename: Nicole
authors.initials: N
authors.lastname: Jaffrezic-Renault
authors.forename: Jiao
authors.initials: J
authors.lastname: Zhang
authors.forename: François
authors.initials: F
authors.lastname: Bessueille
authors.forename: Yves
authors.initials: Y
authors.lastname: Goepfert
authors.forename: Xuejiang
authors.initials: X
authors.lastname: Wang
authors.forename: Ling
authors.initials: L
authors.lastname: Chen
authors.forename: Zhiliang
authors.initials: Z
authors.lastname: Zhu
authors.forename: Jianfu
authors.initials: J
authors.lastname: Zhao
authors.forename: M Gabriela
authors.initials: MG
authors.lastname: Almeida
authors.forename: Célia M
authors.initials: CM
authors.lastname: Silveira
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D045263:Cytochromes a1 / Q000737:chemistry*; D003575:Cytochromes c1 / Q000737:chemistry*; D004553:Electric Conductivity; D004563:Electrochemistry / Q000295:instrumentation*; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000737:chemistry; D004867:Equipment Design; D019544:Equipment Failure Analysis; D009565:Nitrate Reductases / Q000737:chemistry*; D009573:Nitrites / Q000032:analysis* / Q000737:chemistry; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry
chemical_list: D004800:Enzymes, Immobilized; D009573:Nitrites; D014874:Water Pollutants, Chemical; D045263:Cytochromes a1; D003575:Cytochromes c1; D009565:Nitrate Reductases; C054690:nitrate reductase (cytochrome)