In a medium containing 5 mL of triethanolamine per 25 mL of solution and in the presence of CTMAB 1-(5'-naphthol-7'-sulfonic acid)-3-[4"-(phenylazo) phenyl] triazene (abbreviated as NSPAPT) reacts with some anionic surfactants, such as sodium dodecyl benzene sulfonate, sodium dedecyl sulfonate, and sodium dodecyl sulfate separately to form a reddish violet colored complex having a mole ratio of (NSPAPT to anionic surfactant) 1 to 2, with its absorption maxima at the wavelength of 598 max The results obtained by this method in the ana...