title: Development of a perchlorate reductase-based biosensor for real time analysis of perchlorate in water.
abstract: Perchlorate (ClO4-) contamination of ground water is a widespread problem in the U.S., which can adversely affect human health and wildlife. Current methods for detecting and quantifying ClO4- in water are time consuming, expensive and sometimes subject to complex procedures. This study reports the construction of a ClO4- reductase-based biosensor for rapid determination of ClO4- in water. Using a 3 mm GCE (glass carbon electrode), a ClO4- sensing bio-electrode was constructed by coating an aliquot of a Dechlorosoma sp. ClO4- reductase on nafion (ion-exchange matrix) layer pre-coated on the polished surface of the GCE. The response time to ClO4- was approximately 111+/-28 s. Kinetic evaluation of the sensor response to ClO4- revealed linear increases (r2>99%) in 10 min with k values of 10.3, 24.2, 33.9 and 48.2 at 25, 50, 75 and 100 microg/L, respectively. A strong linear correlation was established between biosensor response (nA) and ion-chromatography conductivity readings (microS). Biosensor response to ClO4- was maximal at applied potential range of -0.6 to -1.0 V. ClO4- reduction was maximal in the range of 7.6 to 8.0. The ClO4- biosensor was significantly stable after repeated use (24 analyses conducted on day 1 over a 10-h period at room temperature). This study indicates great potential for the development of a portable biosensor for real time analysis of ClO4- in water.
authors.affiliation: Department of Biology, Auburn University Montgomery, Montgomery, AL 36124-4023, USA. bokeke@mail.aum.edu
authors.forename: Benedict C
authors.initials: BC
authors.lastname: Okeke
authors.forename: Guangyu
authors.initials: G
authors.lastname: Ma
authors.forename: Quan
authors.initials: Q
authors.lastname: Cheng
authors.forename: Mark E
authors.initials: ME
authors.lastname: Losi
authors.forename: William T
authors.initials: WT
authors.lastname: Frankenberger
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D004563:Electrochemistry; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009566:Nitrates; D010088:Oxidoreductases / Q000737:chemistry* / Q000378:metabolism; D010472:Perchlorates / Q000737:chemistry*; D020560:Proteobacteria / Q000201:enzymology*; D018709:Statistics, Nonparametric; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D009566:Nitrates; D010472:Perchlorates; D014874:Water Pollutants, Chemical; D010088:Oxidoreductases; C021777:chlorate reductase; C494474:perchlorate