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On-line version ISSN 1678-7064
PALGROSSI, Fabiano S.; PEDROTTI, Jairo J. and GUTZ, Ivano G. R.. Pinch valve injector for flow analysis. Quím. Nova [online]. 2001, vol.24, n.5, pp.689-692. ISSN 1678-7064. http://dx.doi.org/10.1590/S0100-40422001000500017.
An important component for the automation of flow injection analysis (FIA) systems is the sample injection valve. A simple and inexpensive commutator with 16 pinch valves (8 normally open and 8 closed) was developed and configured as a multichannel injection valve. It is activated by a single solenoid of 3 Kgf, powered by a pulsed driver circuit, controlled by a microcomputer or a switch. FIA with spectrophometric detection of potassium dichromate solution was used for the evaluation of the new injection valve and its comparison with other valves, for sample loops of 50, 100, 200, 300 and 500 mL. The repeatability was favorable (RSD 1.0% for 15 injections at each loop volume) compared to a manual injector, an electropneumatic injector and an injector configured with three mini solenoid valves (RSD 1.1, 1.3 and 1.0%, respectively, for15 injections at each loop volume).
Keywords : injector; commutator; flow analysis; pinch valve.