Baptista, PaulaAraújo, Alberto N.Montenegro, Maria da Conceição B.S.M.2008-10-242008-10-242003Baptista, Paula; Araújo, Alberto N.; Montenegro, Maria da Conceição B. S. M. (2003). Determinação potenciométrica em fluxo de cloreto de cetilpiridinio em desinfectantes bucais = Potentiometric determination of cetylpyridinium chloride in oral desinfectants by flow injection analysis. Quimica Nova. ISSN 0100-4042. 26:4, p. 475-4780100-4042http://hdl.handle.net/10198/938The work describes a new procedure for cetylpyridinium chloride determination in oral disinfectants, based on a flow-injection system with potentiometric detection. The determination was based on the measurement of picrate concentration decrease as result of ion-pair reaction with the analyte present in the injected sample. In the optimised set-up the sample injection volume was kept at 400 µL and merged downstream with the reagent solution containing 1,0 x10-5 mol/L of picrate adjusted to pH 5.0 with citrate/citric acid buffer. The flow rate was fixed at 8 mL/min and the reactor length at 40 cm. The proposed procedure enables the determination of cetylpyridinium in the analytical range of 5,0x10-6 – 7,5x10-5 mol/L at a sampling rate of 60/h. The results for real samples had a precision better than 3% and were comparable to the labelled values.porPotentiometryOral disinfectantsFIAIon-selective electrodesCationic surfactantsSpectrophotometric determinationPharmaceutical preparationsCapillary electrophoresisPair extractionConstructionTitrationsSensorjournal article10.1590/s0100-40422003000400005