An improved flow system for chloride determination in natural waters exploiting solid-phase reactor and long pathlength spectrophotometry.
A single and sensitive spectrophotometric method for chloride ions determination based on a commuted flow system with a 100cm optical path flow cell and a solid-phase reactor containing immobilized silver chloranilate was proposed. This procedure exploited the AgCl formation in the solid-phase reactor leading the chloranilate ions, monitored spectrophotometrically at 530nm. The analytical signals were 75-fold higher and the sensitivity was 12-fold than that achieved with a 1cm flow cell, allowed a chloride determination in the 0.5-100mgl(-1) range. The R.S.D. was 1.1% (n=20) with a sample throughput of 80h(-1) and a waste generated of ca. 100ng of chloranilate ions per determination. Four samples of natural waters from São Carlos and Araraquara cities were evaluated using the proposed method. Results agreed with the obtained by a reference method at the 95% confidence level.
Bonifácio
Viviane G
VG
Departamento de Química, Centro de Ciências Exatas e de Tecnologia, Universidade Federal de São Carlos, São Carlos, SP, Brazil.
Figueiredo-Filho
Luiz C
LC
Marcolino
Luiz H
LH
Fatibello-Filho
Orlando
O