Construction and use of a tubular picrate ion-selective electrode for reducing ...

• Author(s): Lopes, Teresa I. M. S. ; Rangel, António O. S. S. ; Lima, José L. F. C. ; Montenegro, M. Conceição B. S. M.
• Date: 1995
• Persistent ID: http://hdl.handle.net/10400.14/5941
• Origin: Veritati - Repositório Institucional da Universidade Católica Portuguesa
• Subject(s): Flow injection; Ion selective electrodes; Picrate; Sugar; Wine
• Document Type: Article
• Language: English

Description

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 l−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.