DEVELOPMENT OF A POTENTIOMETRIC PROCEDURE FOR DETERMINATION OF GLYCEROL AND 2,3-BUTANEDIOL IN WINE BY SEQUENTIAL INJECTION-ANALYSIS

A sequential injection procedure with potentiometric detection for det ermination of glycerol and 2,3-butanediol in wine is described. The me thod was based on reaction of IO, ions with glycerol and 2,3-butanedio l 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 electr ode membrane was based on bis(triphenylphosphoranylidene) ammonium per iodate dissolved in 2-nitrophenyloctyl ether and immobilized in PVC. I n the developed set-up, a 2.0 x 10(-2) mol l(-1) sodium periodate solu tion was used as carrier. To minimize interferences caused by other re ducing components in the samples, a mini column packed with the anioni c Amberlite IRA 400 (20-50 mesh, OH-form) resin was coupled to a later al port of the valve. The feasibility of the analytical proposal was a scertained by determining polyols as glycerol in a set of red and whit e wine. The accuracy of the proposed method was assessed by standard a ddition of glycerol. Recoveries within the 96.0-106.9% range were calc ulated. A sample throughput of 33 per hour, a reagent consumption of 9 .4 mg of sodium periodate per determination and a relative standard de viation of results lower than 1% were obtained. (C) 1998 Elsevier Scie nce B.V.