Patent ID: 7267837

Claim:
A process for the preparation of enzyme electrode useful for estimation of cholesterol in aqueous medium, which comprises the steps of: a. preparing a silicate solution, b. immobilizing an enzyme cholesterol oxidase and an electron mediator by slowly adding 0.05-0.1 M phosphate buffer containing 3-5 IU of cholesterol oxidase and about 0.01 M of electron mediator to the above said silicate solution of step a), c. allowing the resultant mixture to stand till the complete encapsulation of enzyme and mediator by observing turbidity, d. spreading the resultant turbid mixture on an electrically conductive base plate, e. drying the electrically conductive base plate with the spread mixture for at least one day at a temperature in a range of 25-30° C. to obtain the enzyme electrode comprising: i. an electrically conductive base plate, ii. a film of sol gel derived material deposited thereon, iii. said sol gel derived material of ii) being microencapsulated cholesterol oxidase with an electron mediator, said enzyme electrode showing zero leaching of the encapsulated enzyme and of the electron mediator, a response time of 30 seconds, an amperometric linear response to cholesterol in the range of 1-8 mM, being reusable at least five times and a shelf life of six months.