Monosegemented flow potentiometric titration for the determination of chloride in milk and wine

• Main Authors: Vieira Jonas A., Raimundo Jr. Ivo M., Reis Boaventura F., Montenegro M. Conceição B.S.M., Araújo Alberto N.
• Format: Article
• Language: English
• Published: Sociedade Brasileira de Química 2003-01-01
• Series: Journal of the Brazilian Chemical Society
• Subjects: potentiometric titration; monossegmented flow; multicommutation; ion selective electrode; chloride in milk; chloride in wine
• Online Access: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532003000200012

An automated flow potentiometric titration procedure for the determination of chloride in milk and wine exploiting the monosegmented flow approach is described. The flow network was designed based on a six-way solenoid valve, controlled by a microcomputer running software written in VisualBasic 3.0, allowing selection of the titration conditions. An Ag2S tubular electrode selective for Cl- and a conventional Ag/AgCl electrode were employed as indicator and reference, respectively. An algorithm based on the potential difference between two subsequent titrant additions was developed, allowing to reach the end point in less than 10 attempts, with a precision better than 1.0%. The proposed system was evaluated by determining chloride in milk and wine, using a standard AgNO3 solution as titrant. Accuracy was ascertained by comparing the results with those obtained using the AOAC procedure. No significant difference at a 95% confidence level was observed.