Rapid determination of lactulose in milk by microdialysis and biosensors

Citation
D. Moscone et al., Rapid determination of lactulose in milk by microdialysis and biosensors, ANALYST, 124(3), 1999, pp. 325-329
Citations number
41
Categorie Soggetti
Chemistry & Analysis","Spectroscopy /Instrumentation/Analytical Sciences
Journal title
ANALYST
ISSN journal
00032654 → ACNP
Volume
124
Issue
3
Year of publication
1999
Pages
325 - 329
Database
ISI
SICI code
0003-2654(199903)124:3<325:RDOLIM>2.0.ZU;2-7
Abstract
A simple and rapid flow system for the determination of lactulose in milli samples was developed. It is based on the hydrolysis of lactulose to galact ose and fructose by the enzyme beta-galactosidase immobilised in a reactor. The amount of fructose produced was measured with an electrochemical biose nsor based on the fructose dehydrogenase enzyme, K-3[Fe(CN)(6)] as mediator and a platinum based electrochemical transducer. Parameters such as the en zyme immobilisation in the reactor and under the electrode surface, the lif etime of the beta-galactosidase reactor and of the dehydrogenase biosensor and the flow parameters were studied and optimised. Fructose was determined in the range 1 x 10(-6)-5 x 10(-3) mol l(-1) with an RSD of about 2% and a detection limit of 5 x 10(-7) mol l(-1). The use of a microdialysis probe as the sampling system permitted the direct measurement of lactulose in mil li samples without pre-treatment in the range 1 x 10(-5)-5 x 10(-3) mol l(- 1). The sensitivity of the procedure allowed pasteurised, UHT and in-contai ner sterilised mill, to be distinguished.