Construction and use of a tubular picrate ion-selective electrode for reducing sugar determination in Port wine by flow-injection analysis

✍ Scribed by Teresa I.M.S. Lopes; António O.S.S. Rangel; JoséL.F.C. Lima; M.Conceição B.S.M. Montenegro

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 648 KB
• Volume: 308
• Category: Article
• ISSN: 0003-2670
• DOI: 10.1016/0003-2670(94)00598-g

✦ Synopsis

A picrate ion-selective electrode without inner reference solution and based on bis(triphenylphosphoranylidene)ammonium picrate dissolved in 2-nitrophenyloctyl ether was constructed and its characteristics assessed. With respect to reducing sugar determination in Port wine, a tubular electrode based on the same sensor system was developed and incorporated into a flow-injection manifold devised for this determination. The methodology involves a reaction between the reducing sugar and picric acid, the decrease in the picrate concentration being monitored with the tubular electrode. A linear dependence between peak width, at a fixed potential and the logarithm of sugar concentration in the range 25-200 g 1~ ' was obtained. The proposed system allows wine samples to be injected with no previous treatment and allows a sample throughput of 50 determinations per hour, a relative standard deviation less than 4%, and the results are comparable to the reference procedures.