Page 5
...
An amperometric microbial biosensor for highly sensitive and selective determination of p-nitrophenol (PNP) is reported. The biosensor consisted of PNP-degrader Arthrobacter sp. JS443 immobilized by entrapment in Nafion polymer deposited on the top of the carbon paste electrode transducer. The biosensor was based on the measurement of the oxidation current of the intermediates 4-nitrocatechol and 1,2,4-benzenetriol formed by the highly selective oxidation of PNP by Arthrobacter sp.
...
When operated at optimized conditions, the Arthrobacter sp.-based biosensor measured as low as 5 nM (0.7 ppb) of PNP. The biosensor demonstrated excellent selectivity with no interference from phenolic compounds such as 2-nitrophenol, phenol and 3-chlorophenol but was interfered by 3-nitrophenol and 3-methyl-4-nitrophenol. It had good precision and intra- and inter-day reproducibility, accuracy and was stable up to 3 days when stored in buffer at 48C.When applied for measurement in water from Lake Elsinore, CA, the results obtained were in excellent agreement with the amounts determined spectrophotometrically.
...
Arthrobacter sp. JS443 is a PNPdegrader that was isolated by Spain and his colleagues [15].This bacterium metabolizes PNP through 4-nitrocatechol, 1,2,4-benzenetriol, maleylacetate and b-ketoadipate to tricarboxylic acid intermediates while releasing nitrite and consuming oxygen [15]. Recently, we reported a whole cell biosensor based on a dissolved oxygen electrode modified with Arthrobacter sp. JS443. While simple, rapid and selective, the 28 ppb limit of detection (LOD) of the biosensor was two orders of magnitude higher than the European Commission's limit of 0.1 ppb for drinking water [16]. In this research, we investigated integrating Arthrobacter sp. JS443 with a carbon paste electrode (CPE) to construct a whole cell
amperometric biosensor.
...
In conclusion, an amperometric microbial biosensor using Arthrobacter sp. JS443 for rapid, sensitive and selective measurement of PNP was developed. While the biosensor limit of detection was comparable to immunoassays, the high selectivity is its most salient feature. Additional advantages of the present amperometric microbial biosensor when compared to other techniques are the low cost (does not require expensive antibodies, trained personnel and instrumentation) and short assay time. These features should make it an ideal analytical tool for field monitoring of PNP contaminated waters and on-line monitoring of
effluents from the chemical processing facilities producing and using PNP.
(Y. Lei, P. Mulchandani, W. Chen, J. Wang, A. Mulchandani - 2004)
Please Click to Download or Display Publication in PDF Format