caa a22 4500 465746152 CHVBK 20180323111821.0 cr unu---uuuuu 170327e19900101xx s 000 0 eng 10.1007/BF00332259 doi (NATIONALLICENCE)springer-10.1007/BF00332259 Determinations of citric acid by differential pulse polarography with immobilized enzymes [Elektronische Daten] [Kiyoshi Hasebe, Satoshi Hikama, Hitoshi Yoshida] Summary: Citrate lyase and oxaloacetate decarboxylase can be rapidly and simply immobilized in polyacrylamide gel to provide a selective and sensitive reactor. Conversion ratio of citric acid to pyruvic acid comes up to 90% under the optimal conditions. Generated pyruvic acid can be determined by differential pulse polarography. The bioreactor can be used for thirty determinations over several weeks. Samples of sports drinks and wine were successfully tested without pretreatment; the relative standard deviation with 1.0×10-5 mol l-1 citric acid in polarographic solutions was 1.17% and the detection limit was 6.6×10-7 mol l-1 (κ=2). Springer-Verlag, 1990 Hasebe Kiyoshi Department of Chemistry, Faculty of Science, Hokkaido University, 060, Sapporo, Japan aut Hikama Satoshi Department of Chemistry, Faculty of Science, Hokkaido University, 060, Sapporo, Japan aut Yoshida Hitoshi Department of Chemistry, Faculty of Science, Hokkaido University, 060, Sapporo, Japan aut Fresenius' Journal of Analytical Chemistry Springer-Verlag 336/3(1990-01-01), 232-234 0937-0633 336:3<232 1990 336 216 https://doi.org/10.1007/BF00332259 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00332259 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Hasebe Kiyoshi Department of Chemistry, Faculty of Science, Hokkaido University, 060, Sapporo, Japan aut NATIONALLICENCE 700 1- Hikama Satoshi Department of Chemistry, Faculty of Science, Hokkaido University, 060, Sapporo, Japan aut NATIONALLICENCE 700 1- Yoshida Hitoshi Department of Chemistry, Faculty of Science, Hokkaido University, 060, Sapporo, Japan aut NATIONALLICENCE 773 0- Fresenius' Journal of Analytical Chemistry Springer-Verlag 336/3(1990-01-01), 232-234 0937-0633 336:3<232 1990 336 216 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer