Lecithin determination in foods and drugs by an amperometric enzymatic sensor

A new enzymatic-amperometric method for the determination of lecithin as an additive in foods and as a component of commercial drugs is proposed. The method is based on a detector realized with two enzymes, choline oxidase and phospholipase D, the former immobilized, the latter free in solution, and by an oxygen Clark electrode. The experimental conditions were investigated in order to obtain wide applications with different samples. Extraction or dissolution of the samples in ethanol proved satisfactory. The precision of the method was found to be about 1.5%, inaccuracy less than or equal to 4%. Correlation between the proposed enzymatic-amperometric method and an enzymatic-spectrophotometric reference method was satisfactory.