Artigo
Use of sorghum seed tissue as a biocatalyst in a stirred reactor for oxalic acid determination
Date
1996-11-01Registration in:
Analytical Communications, v. 33, n. 11, p. 397-399, 1996.
1359-7337
10.1039/AC9963300397
WOS:A1996VT08900003
2-s2.0-0000678174
8540599256820672
Author
Universidade Estadual Paulista (Unesp)
Universidade Estadual de Campinas (UNICAMP)
Abstract
The enzyme oxalate oxidase, E.C. 1.2.3.4 from Sorghum vulgare seeds (variety BR303) was used to develop a new sensor for oxalate determination without any purification. The sorghum seeds were conditioned in a 0.10 mol I-1 KCl solution. Then, these seeds were put in a stirring bar type enzymic reactor and coupled with an electrode for CO2. This device was introduced into a cell containing 10.0 ml of a 0.10 mol I-1 KCl solution saturated with oxygen. This sensor showed a linear response between 1.0 and 4.0 × 10-3 mol I-1 with a slope of 30 mV per decade of oxalate concentration at 25.0°C. The sensor was stable for one month or 200 determinations. The response time was about 60 s. The Michaelis-Menten constant determined for this enzyme was 1.5 × 10-3 mol I-1.