The pH-detection of triglycerides

This paper presents an indirect method of triglycerides determination based on pH-detection. The system consisted of a microreactor containing silica gel beads with surface immobilised lipase and the pH-sensor of ISFET type. Three methods of lipase immobilisation: (1) the chemical bond to the surfac e of glass beads coated with keratin, (2) entrapment within alginate gel be ads and (3) adsorption onto nitrocellulose sheets were compared. All method s of lipase immobilisation, except the second one, were found to be effecti ve. The systems consisting of microreactors packed with surface immobilised lipase were calibrated for different substrates. The highest sensitivity w as obtained for tributyrin (0.478 pH/mM for concentration <4 mM), while the widest linear range was obtained for triacetin (up to 30 mM). The results concerning the influence of some factors, such as activators, and emulgator s upon the sensor response are also presented. (C) 2001 Elsevier Science B. V. All rights reserved.