title: A reagentless amperometric electrode based on carbon paste, chemically modified with D-lactate dehydrogenase, NAD(+), and mediator containing polymer for D-lactic acid analysis. I. Construction, composition, and characterization.
abstract: A reagentless carbon paste electrode was designed for D-lactic acid analysis in a flow injection system for the monitoring of the production of D-lactate in a batch fermentation. D-Lactate dehydrogenase, nicotinamide adenine dinucleotide (NAD(+)), a synthetic redox polymer containing covalently attached toluidine blue O as mediator, graphite powder, and paraffin oil were used for the construction of the modified carbon paste electrode. D-Lactate selectivity was indicated by insignificant responses from a variety of possible interfernces including L-lactate. The electrodes gave a linear response in the range between 0.05 and 5 mM D-lactate, with a detecting limit of 30 muM, allowing a sample throughput of 20 h(-1). Preliminary investigations were made by covering the electrode surface with electropolymerized membranes. Satisfactory stability was observed, indicated by a reproducibility of 3.3% relative standard deviation (RSD, n = 31), with a non-membrane-covered electrode for the analysis of D-lactate in fermentation broth. A long-term stability (230 broth samples) was proven, suggesting the electrodes to have a good potential for use in on-line monitoring of fermentation processes. (c) 1995 John Wiley & Sons, Inc.
authors.affiliation: Department of Biotechnology, Chemical Center, Lund University, S-221 00 Lund, Sweden.
authors.forename: H C
authors.initials: HC
authors.lastname: Shu
authors.forename: B
authors.initials: B
authors.lastname: Mattiasson
authors.forename: B
authors.initials: B
authors.lastname: Persson
authors.forename: G
authors.initials: G
authors.lastname: Nagy
authors.forename: L
authors.initials: L
authors.lastname: Gorton
authors.forename: S
authors.initials: S
authors.lastname: Sahni
authors.forename: L
authors.initials: L
authors.lastname: Geng
authors.forename: L
authors.initials: L
authors.lastname: Boguslavsky
authors.forename: T
authors.initials: T
authors.lastname: Skotheim