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An amperometric lactate sensor based on a NAD + ‐analog and lactate dehydrogenase coimmobilized on reticulated vitreous carbon
Author(s) -
Khayyami Masoud,
Garcia Nuria Peña,
Larsson PerOlof,
Danielsson Bengt,
Johansson Gillis
Publication year - 1997
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.1140090703
Subject(s) - amperometry , lactate dehydrogenase , carbodiimide , nad+ kinase , dehydrogenase , chemistry , electrochemistry , covalent bond , biosensor , chromatography , detection limit , nuclear chemistry , electrode , analytical chemistry (journal) , organic chemistry , enzyme , biochemistry
A NAD + ‐analog was coimmobilized with lactate dehydrogenase (LDH) on reticulated vitreous carbon (RVC) to give an amperometric lactate biosensor. Both LDH and the NAD + ‐analog were bound covalently with carbodiimide to the surface of the porous RVC‐material. The electrode was operated in a FIA‐arrangement in the presence or absence of a soluble mediator. Meldola Blue. The stability was poor when the electrode was operated at +400 mV (vs. Ag/AgCl) in the absence of mediator but improved most significantly in the presence of 5 μM mediator, so that 65% of the original activity remained after 16 days. The amperometric currents were smaller with regeneration by mediator at −100 mV than with direct electrochemical oxidation at +400 mV, indicating that the additional steps slow down the reaction rate. Linear calibration plots were obtained from the detection limit, 1 μM, to 500 μM lactate with 5 μM mediator, reoxidized at −100 mV. The sample throughput was about 60 h −1 .