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Journal of Automated Methods and Management in Chemistry
Volume 2006, Article ID 20384, 9 pages
http://dx.doi.org/10.1155/JAMMC/2006/20384

Evaluation of a Multicommuted Flow System for Photometric Environmental Measurements

Eva Ródenas-Torralba,1 Fábio R. P. Rocha,2 Boaventura F. Reis,3 Ángel Morales-Rubio,1 and Miguel de la Guardia1

1Department of Analytical Chemistry, Faculty of Chemistry, University of Valencia, Research Building, Burjassot, Valencia 46100, Spain
2Instituto de Química, Universidade de Sao Paulo, P.O. Box 26077, São Paulo 05508-900, Brazil
3Centro de Energia Nuclear na Agricultura, Universidade de São Paulo, Avenida Centenario 303, Piracicaba, São Paulo 13400-970, Brazil

Received 27 September 2005; Revised 16 January 2006; Accepted 16 January 2006

Copyright © 2006 Eva Ródenas-Torralba et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

A portable flow analysis instrument is described for in situ photometric measurements. This system is based on light-emitting diodes (LEDs) and a photodiode detector, coupled to a multipumping flow system. The whole equipment presents dimensions of 25 cm×22 cm×10 cm, weighs circa 3 kg, and costs 650 €. System performance was evaluated for different chemistries without changing hardware configuration for determinations of (i) Fe3+ with SCN-, (ii) iodometric nitrite determination, (iii) phenol with sodium nitroprusside, and (iv) 1-naphthol-N-methylcarbamate (carbaryl) with p-aminophenol. The detection limits were estimated as 22, 60, 25, and 60 ng mL-1 for iron, nitrite, phenol, and carbaryl at the 99.7% confidence level with RSD of 2.3, 1.0, 1.8, and 0.8%, respectively. Reagent and waste volumes were lower than those obtained by flow systems with continuous reagent addition. Sampling rates of 100, 110, 65, and 72 determinations per hour were achieved for iron, nitrite, phenol, and carbaryl determinations