Print version ISSN 0100-4042
BAPTISTA, Paula C. S.; ARAUJO, Alberto N. and MONTENEGRO, Maria da Conceição B. S. M.. Potentiometric determination of cetylpyridinium chloride in oral desinfectants by flow injection analysis. Quím. Nova [online]. 2003, vol.26, n.4, pp. 475-478. ISSN 0100-4042. http://dx.doi.org/10.1590/S0100-40422003000400005.
The 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.
Keywords : potentiometry; oral disinfectants; FIA.