INVESTIGADORES
DIAZ RICCI Juan Carlos
artículos
Título:
On-line monitoring of galactoside conjugates and glycerol by flow injection analysis
Autor/es:
AMÁRICA VEGA, F.; NÚÑEZ, CARLOS G.; WEIGEL, B; HITZMANN, BERND; DÍAZ RICCI, JUAN C.
Revista:
ANALYTICA CHIMICA ACTA
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Lugar: Amsterdam; Año: 1998 vol. 373 p. 57 - 62
ISSN:
0003-2670
Resumen:
A biosensor attached to aflow injection analysis (FIA) system was developed for the automaticdetermination of galactoside conjugates and glycerol. The biosensor was basedon the enzymatic reaction of galactose oxidase (GalOD) using galactose, raffinose,lactose and glycerol as substrates. GalOD converts galactoside conjugates togalactohexodialdose conjugates and glycerol to glyceraldehyde with formation ofhydrogen peroxide and consumption of oxygen. Variation of dissolved oxygen in thecarrier was estimated utilizing an amperometric oxygen probe. The FIA systemconsisted in a multichannel peristaltic pump, an injection valve and anelectronic transducer which were controlled by the CAFCA software. Stability ofthe enzyme and optimal working condition were investigated. Optimum pH for the immobilizedenzymes under these experimental conditions was 7.4 and the enzyme retained 80%of the original activity after two months of use. Studies on the dynamical responseof the biosensor showed that the elapsed time between two successive injectionscould be as short as 120 s without signal deterioration when the flow rate was2 ml/min and 50 ml of injection volume. Sensitivity of the biosensor was higherfor galactose followed by raffinose, lactose and glycerol. The sensor showed linearresponse between 0.2 and 2 mMfor galactose, 0.5 and 6 mMfor raffinose, 25 and 250 mMfor lactose, and 2 and 200 mMfor glycerol.