Development of a potentiometric procedure for determination of glycerol and 2,3-butanediol in wine by sequential injection analysis Original Research Article

A sequential injection procedure with potentiometric detection for determination of glycerol and 2,3-butanediol in wine is described. The method was based on reaction of IO−4 ions with glycerol and 2,3-butanediol with the reagent consumption afterwards being continuously monitored by means of a PVC periodate ion selective electrode constructed with tubular configuration and without inner reference solution. The electrode membrane was based on bis(triphenylphosphoranylidene) ammonium periodate dissolved in 2-nitrophenyloctyl ether and immobilized in PVC. In the developed set-up, a 2.0×10−2 mol l−1 sodium periodate solution was used as carrier. To minimize interferences caused by other reducing components in the samples, a mini column packed with the anionic Amberlite IRA 400 (20–50 mesh, OH− form) resin was coupled to a lateral port of the valve. The feasibility of the analytical proposal was ascertained by determining polyols as glycerol in a set of red and white wine. The accuracy of the proposed method was assessed by standard addition of glycerol. Recoveries within the 96.0–106.9% range were calculated. A sample throughput of 33 per hour, a reagent consumption of 9.4 mg of sodium periodate per determination and a relative standard deviation of results lower than 1% were obtained.