Adaptative flow injection system for environmental applications

This paper describes the development of a new flow system by substituting the injection valve of a FIA system with an automatic microburette controlled by a PC via an RS-232 interface to introduce flexibility into the system. Initially, the response of the system was characterized without a chemical reaction by using a reference system (6-port valve) and a modified system (automatic microburette). The response vs. flow rate and injected volume were studied. The statistic analysis and comparison of the dispersion coefficients obtained for both systems showed no significant difference between them. Comparative studies with chemical reactions were also performed using a reverse Flow Injection Analysis (r-FIA) technique and the Griess-Ilosvay model reaction for nitrite ions. Finally, the system based on the automatic microburette was validated for the analysis of nitrite in two complementary concentration ranges (0.0-0.1 and 0.0-3.0 mg·L-1) using 25 and 350 μL of reactant, respectively. The detection limits obtained were 0.009 and 0.024 mg·L-1, respectively. High repeatability was obtained for both concentration ranges (RSD: 0.52 and 1.35%, respectively). © 2006 Springer-Verlag.