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Spain - Development of an optical flow-through biosensor for sulphite in environmental samples
Biosensors R Bioelectronics
the sensor it is possible to perform incubation and measurement steps separately: the incubation step is performed in the sample containing the inhibitor, the measurement step is performed in a standard solution containing the specific substrate in the buffer. With this two-step procedure, a Pt electrode, only covered with a thin layer of cross-linked choline oxidase and without any membrane, has also been used in batch conditions obtaining interesting results in terms of sensitivity, precision and limit of detection. Contact: ENEA, CRE Cosnccio, New Technologies Department, Via Anguillarese 301. I-00060 Rome, Italy. Spain - Development of an optical flow-through biosensor for sulphite in environmental samples In ANAL. CHIM. ACTA (3 1l/3 (28 l-287) 1995)
M.D. Luque De Castro & J.M. Fernandez-Romero of the University of Cordoba report on ‘Developmentof an optical flow-through biosensor for the determination of sulphite in environmental samples’. A continuous-flow biosensor arrangement based on the dual immobilization of a biocatalyst on controlled-pore glass and the reaction product on a resin support both packed in the flow-cell of a photometric detector for the determination of sulphite is proposed. The method thus developed affords low detection and quantitation limits (3 and 10 ng ml’ of sulphite, calculated as *3o and f loo, respectively, for n = 20), wide linear range (10-1000 ng ml-’ of sulphite), good precision (R.S.D. = 2.6% for 60 ng ml’ and 0.7% for 200 ng ml’ of the analyte), and a sampling frequency of 16 h-‘. The hydrodynamic assembly has been applied to the determination and recovery of the analyte in spiked, aqueous samples with excellent results. Contact: Depnrtmen t of Annlytical Chemistry, Faculty of Sciences, University of Cordoba, E-l 4004 Cordoba, Spain. Japan - Thiobacillus thioparus based biosensor for measuring thiosulfate and methanethiol
In CAN. J. MICROBIOL. (41/4-5 (366-371) 1995) I. Kubo, I. Karube, B. Takeuchi, M.
xxii
Vol. 11 No. l/2 (1996)
Furusawa, Y. Arikawa & T. Kanagawa of Soka University report on ‘A biosensor based on Thiobacillus thioparus for measuring thiosulfate and methanethiol’. A biosensor based on Thiobacillus thioparus was developed for the determination of thiosulfate and methanethiol. The sensor consisted of an oxygen electrode and immobilized T. thioparus. A linear relation between sensor output and concentration was obtained for the concentration range from 1 to 100 uM in a batch system and from 1 to 10 mM in a flow injection system. Output of the sensor was stable for more than 1 month. For methanethiol, the response of the sensor was measured for the concentration range from 0.2 to 3 mM in a flow injection system. Con tact: Department Bioengineering, Faculty of Science, Soka University, Hachioji, Tokyo 192, Japan. France - Entrapment of chloroplasts and thylakoids in polyvinylalcohol-SbQ. In ANAL. CHIM. ACTA (3 1l/3 (437-442) 1995) R. Rouillon, J.-J. Mestres & J.-L. Marty of the Universite de Perpignan report on ‘Entrapment of in chloroplasts and thylakoids polyvinylalcohol-SbQ. Optimization of membrane preparation and storage conditions’. Chloroplasts and thylakoids isolated from spinach were entrapped in six different polyvinylalcohol bearing styrylpyridinium groups (PVA-SbQ). Measurements of oxygen production were carried out in 0.01 M phosphate buffer (pH 6) at 25°C. Immobilized preparations were compared for their electron transport activity measured as the initial rate of oxygen evolution with p-benzoquinone as artificial electron acceptor. The entrapped chloroplasts in PVA-SbQ 1700 and 3500 betaine retained 20% of their initial activity after 90-day storage in the dark at +4”C. A membrane made with PVA-SbQ 2300 kept 20% activity after 427-day storage at - 18“C in the dark whereas the same membrane retained only 10% activityafter 90-day storage at +4’C in the dark. A 1% BSA concentration increased the stability of the membrane. The limits of detection (corresponding to a 10% inhibition) of atrazine
the sensor it is possible to perform incubation and measurement steps separately: the incubation step is performed in the sample containing the inhibitor, the measurement step is performed in a standard solution containing the specific substrate in the buffer. With this two-step procedure, a Pt electrode, only covered with a thin layer of cross-linked choline oxidase and without any membrane, has also been used in batch conditions obtaining interesting results in terms of sensitivity, precision and limit of detection. Contact: ENEA, CRE Cosnccio, New Technologies Department, Via Anguillarese 301. I-00060 Rome, Italy. Spain - Development of an optical flow-through biosensor for sulphite in environmental samples In ANAL. CHIM. ACTA (3 1l/3 (28 l-287) 1995)
M.D. Luque De Castro & J.M. Fernandez-Romero of the University of Cordoba report on ‘Developmentof an optical flow-through biosensor for the determination of sulphite in environmental samples’. A continuous-flow biosensor arrangement based on the dual immobilization of a biocatalyst on controlled-pore glass and the reaction product on a resin support both packed in the flow-cell of a photometric detector for the determination of sulphite is proposed. The method thus developed affords low detection and quantitation limits (3 and 10 ng ml’ of sulphite, calculated as *3o and f loo, respectively, for n = 20), wide linear range (10-1000 ng ml-’ of sulphite), good precision (R.S.D. = 2.6% for 60 ng ml’ and 0.7% for 200 ng ml’ of the analyte), and a sampling frequency of 16 h-‘. The hydrodynamic assembly has been applied to the determination and recovery of the analyte in spiked, aqueous samples with excellent results. Contact: Depnrtmen t of Annlytical Chemistry, Faculty of Sciences, University of Cordoba, E-l 4004 Cordoba, Spain. Japan - Thiobacillus thioparus based biosensor for measuring thiosulfate and methanethiol
In CAN. J. MICROBIOL. (41/4-5 (366-371) 1995) I. Kubo, I. Karube, B. Takeuchi, M.
xxii
Vol. 11 No. l/2 (1996)
Furusawa, Y. Arikawa & T. Kanagawa of Soka University report on ‘A biosensor based on Thiobacillus thioparus for measuring thiosulfate and methanethiol’. A biosensor based on Thiobacillus thioparus was developed for the determination of thiosulfate and methanethiol. The sensor consisted of an oxygen electrode and immobilized T. thioparus. A linear relation between sensor output and concentration was obtained for the concentration range from 1 to 100 uM in a batch system and from 1 to 10 mM in a flow injection system. Output of the sensor was stable for more than 1 month. For methanethiol, the response of the sensor was measured for the concentration range from 0.2 to 3 mM in a flow injection system. Con tact: Department Bioengineering, Faculty of Science, Soka University, Hachioji, Tokyo 192, Japan. France - Entrapment of chloroplasts and thylakoids in polyvinylalcohol-SbQ. In ANAL. CHIM. ACTA (3 1l/3 (437-442) 1995) R. Rouillon, J.-J. Mestres & J.-L. Marty of the Universite de Perpignan report on ‘Entrapment of in chloroplasts and thylakoids polyvinylalcohol-SbQ. Optimization of membrane preparation and storage conditions’. Chloroplasts and thylakoids isolated from spinach were entrapped in six different polyvinylalcohol bearing styrylpyridinium groups (PVA-SbQ). Measurements of oxygen production were carried out in 0.01 M phosphate buffer (pH 6) at 25°C. Immobilized preparations were compared for their electron transport activity measured as the initial rate of oxygen evolution with p-benzoquinone as artificial electron acceptor. The entrapped chloroplasts in PVA-SbQ 1700 and 3500 betaine retained 20% of their initial activity after 90-day storage in the dark at +4”C. A membrane made with PVA-SbQ 2300 kept 20% activity after 427-day storage at - 18“C in the dark whereas the same membrane retained only 10% activityafter 90-day storage at +4’C in the dark. A 1% BSA concentration increased the stability of the membrane. The limits of detection (corresponding to a 10% inhibition) of atrazine