In-line tubular ion-exchanger to enhance selectivity in enzyme-based flow-injection potentiometry; application to determination of l-glutamine in bioreactor media

✍ Scribed by Sara A. Rosario; Mark E. Meyerhoff; Marek Trojanowicz

• Book ID: 102980665
• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 595 KB
• Volume: 258
• Category: Article
• ISSN: 0003-2670
• DOI: 10.1016/0003-2670(92)85103-d

✦ Synopsis

A new approach for reducing poslttve errors caused by endogenous catlomc Interferences when usmg ammonmm ion-selectwe electropes as detectors m unmoblllzed enzyme-based flow-mlectlon analysis systems IS described The method mvolves the use of an m-hne tubular catlon-exchange unit (e g , Nafion) placed between the mjection valve and the downstream munoblhzed enzyme reactor/electrode detector portlon of the system Interferent catlon species wlthm the sample slug are exchanged for other cattons (replacement tons, e g, LI+) contamed wlthm a reservOlr solution surrounding the Ion-exchange tubmg The membrane electrode ehblts much less response toward the replacement cations, consequently, the detected concentration of ammomum ions generated downstream wlthm the enzyme reactor IS directly proportlonal to the level of analyte substrate present m the sample The Influence of various experlmental parameters on the efficiency of the m-hne exchanger as well as the general advantages and hnutatlons of this approach are exammed The analytical utlhty of the concept IS demonstrated by the rapld and accurate determmatlon of r-glutamme m bloreactor media via the use of lmmoblhzed glutammase enzyme