Amperometric glyceride biosensor

Glycerol dehydrogenase (GDH) and lipase have been used for the amperometric determination of glycerol and triglycerides on modified carbon electrodes. Carbon electrodes were modified with adsorbed Meldola Blue, Nile Blue or Toluidine Blue O. Electrochemical oxidation of NADH was realized at 0V vs saturated Ag/AgCl electrode. NADH was produced by the catalytic oxidation of glycerol in the presence of glycerol dehydrogenase immobilized on the surface of an electrode. GDH was adsorbed on the electrode, entrapped in gelatin, immobilized in polylysine gel, or trapped in two types of organic salts. Sensitivity of the electrodes vary from 2 to 9 nA/mM glycerol with steady state achieved in a time of between 20 s and 8 min, depending on the method of immobilization. Triglycerides were determined after a 5 min pre-incubation period in a mixture of lipases with different specificity.