title: Simultaneous enzymatic/electrochemical determination of glucose and L-glutamine in hybridoma media by flow-injection analysis.
abstract: A split-stream flow-injection analysis system is described for simultaneous determination of glucose and L-glutamine in serum-free hybridoma bioprocesses media. Amperometric measurement of glucose is based on anodic oxidation of hydrogen peroxide produced by immobilized glucose oxidase within a triple layer membrane of an integrated flow-through glucose-selective biosensor. Determination of L-glutamine is based on quantitating ammonium ions produced in a flow-through enzymes reactor containing immobilized glutaminase enzyme, and subsequent downstream potentiometric detection of these ions by a nonacting-based ion-selective polymer membrane electrode. Endogenous potassium and ammonium ion interference in the L-glutamine determination are eliminated by using a novel in-line tubular cation-exchange membrane unit to exchange these interferent species for cations undetectable by the membrane electrode. The first generation split-steam flow-injections system can assay 12 samples/h using direct injections of 50 microL of media samples, with linear responses to glucose in the range of 0.03 to 30 mM, and log-linear response to L-glutamine from 0.1 to 10 mM.
authors.affiliation: Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA.
authors.forename: M E
authors.initials: ME
authors.lastname: Meyerhoff
authors.forename: M
authors.initials: M
authors.lastname: Trojanowicz
authors.forename: B O
authors.initials: BO
authors.lastname: Palsson