Solid Phase Spectrophotometric Determination of Cationic Surfactants Using Silica-Titania Xerogel–Pyrocatechol Violet Dye System

The influence of cetylpyridinium chloride (CPC) on the interaction of triphenylmethane dyes (pyrocatechol violet, eriochrome cyanine R, and chrome azurol S) with silica-titania xerogels has been studied. For all the studied triphenylmethane dyes (TPMD) the formation of colored complexes of CPC and TPMD with titanium(IV) embedded in silica-titania xerogels has been observed using solid phase spectrophotometry. Maximal absorbance increase has been observed for pyrocatechol violet (PV) complexes. The procedure for CPC determination has been proposed using silica-titania xerogel – PV system (analytical range 0.01–0.56 mM, limit of detection 3.6 μM). The recovery test of the proposed solid phase spectrophotometric CPC determination procedure has been used for the procedure validation. The procedure has been applied for the determination of CPC in treated waste water, and cationic surfactants in terms of CPC in working solutions of disinfectants Alaminol and Catamine AB.