Enzymatic determination of sorbic acid

An enzymatic method for the determination of sorbic acid based on the spect rophotometric measurement of sorbyl coenzyme A (sorbyl CoA) at 300 nm was d eveloped. Sorbic acid is converted to sorbyl CoA with acyl CoA synthetase ( EC 6.2.1.3) in the presence of coenzyme A and adenosine-5'-triphosphate. Th e reaction is made quantitative by irreversibly hydrolyzing pyrophosphate f ormed during the acylation reaction to phosphate in the presence of inorgan ic pyrophosphatase (EC 3.6.1.1). The absorbance measured at 300 nm is speci fic for sorbyl CoA and its value is proportional to the amount of sorbic ac id in the sample solution. Accuracy, repeatability and recovery rates after standard addition to sample solutions were evaluated. All steps of the enz ymatic analysis were carried out on an automatic centrifugal analyzer. The method is fast, precise and reliable, and therefore well suited for routine determinations, especially for high sample throughputs.