Separation and spectrophotometric determination of a cationic surfactant in water in the presence of an anionic surfactant with solvent-insoluble and-soluble membrane filters
S. Taguchi et al., Separation and spectrophotometric determination of a cationic surfactant in water in the presence of an anionic surfactant with solvent-insoluble and-soluble membrane filters, BUNSEKI KAG, 47(12), 1998, pp. 1035-1040
Two membrane filters, solvent insoluble and soluble, were applied to precon
centration and spectrophotometric determinations of a cationic surfactant p
resent as an ion associate with an anionic surfactant in environmental wate
r. The ion associate in 100 cm(3) water sample was collected on a PTFE memb
rane filter by filtration, and eluted with 2 cm(3) of methanol. The methano
l solution was diluted to 15 cm(3) with water. Then a buffer solution (pH 9
) and a methyl-orange solution were added to the solution followed by being
made up to 25 cm(3) with water. The solution was filtered through a mixed
cellulose ester membrane filter to collect the ion associate of the cationi
c surfactant and methyl orange. The ion associate was dissolved in 5 cm(3)
of DMF together with the membrane filter. The absorbance of the DMF solutio
n was measured at 423 nm against a reagent blank. The recovery test for 10(
-6) mol dm(-3) level of Zephiramine, a standard material of a cationic surf
actant, was satisfactory. This method was applied to river-water samples co
ntaining domestic waste.