Analytical Sciences
Online ISSN : 1348-2246
Print ISSN : 0910-6340
ISSN-L : 0910-6340
Original Papers
Application of Sequential Injection Analysis to the Determination of Cationic Surfactants Based on the Sensitized Molybdenum-Bromopyrogallol Red Reaction
Marieta L. C. PASSOSM. Lúcia M. F. S. SARAIVAJosé L. F. C. LIMA
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2005 Volume 21 Issue 12 Pages 1509-1514


The aim of this work was to develop a simple, automatic system for the evaluation of cationic surfactants by combining sequential injection analysis and the sensitized effect of cationic surfactants on the reaction between metal ions and chelating dyes. This reaction is based on the increase in absorbance of the complex formed among molybdenum, bromopyrogallol red and increasing concentrations of cationic surfactants. Under optimum conditions, two calibration plots were obtained for a concentration range between 2.50 × 10-7 mol dm-3 (detection limit) and 5.00 × 10-4 mol dm-3 of cetylpyridinium chloride, used as standard. Solubilization of water insoluble complexes formed for concentrations of cationic surfactants greater than 1.00 × 10-4 mol dm-3 were successfully achieved with Triton X-405. RSD values lower than 5.0% were obtained in all cases. The quality of the results obtained for 18 water samples were evaluated by comparison with conventional methods, with no statistically significant differences for a 95% confidence level.

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© 2005 by The Japan Society for Analytical Chemistry
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