Development of a potentiometric procedure for determination of glycerol and 2,3-butanediol in wine by sequential injection analysis Gilmara C. Luca a , Boaventura F. Reis b,* , Elias A.G. Zagatto b , Maria Conceic ,a Äo B.S.M. Montenegro c , Alberto N. Arau Âjo c , Jose  Luis F.C. Lima c a Instituto de Quõ Âmica de Sa Äo Carlos, Universidade de Sa Äo Paulo, Sa Åo Carlos ± SP, Brazil b Centro de Energia Nuclear na Agricultura, Universidade de Sa Äo Paulo, PO Box 96, 13400-970, Piracicaba ± SP, Brazil c CEQUP/Departamento de Quõ Âmica Fõ Âsica, Faculdade de Farma Âcia, Universidade do Porto, Portugal Received 27 August 1997; received in revised form 1 December 1997; accepted 22 December 1997 Abstract 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 con®guration 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. # 1998 Elsevier Science B.V. Keywords: Sequential injection analysis; Polyols determination in wine; Ion selective electrode 1. Introduction Chemical monitoring of food product quality requires the development of new analytical methodol- ogies and its use for large scale analysis in a reliable fashion. These goals may be accomplished by auto- mated procedures preferentially those presenting low cost of implementation, operational facilities and providing accurate results. Sample processing by ¯ow injection analysis (FIA) [1] is an attractive option, particularly due to the different approaches it presents for sample and reagent on-line treatment, according to a prior established sequence. Conventional FIA systems allow a low cost mechanization of the determinations which require either a single dilution of the sample or the addition of a chemical reagent. Moreover, their use can be Analytica Chimica Acta 366 (1998) 193±199 *Corresponding author. Fax: +55 19 429 4610; e-mail: bofdreis@pira.cena.usp.br 0003-2670/98/$19.00 # 1998 Elsevier Science B.V. All rights reserved. PII S0003-2670(98)00103-2