Langmuir aggregation of Nile blue and safranine T on sodium dodecylbenzenesulfonate surface and its application to quantitative determination of anionic detergent.

We studied the interaction of sodium dodecylbenzenesulfonate (SDBS) with Nile Blue (NB) and Safranine T (ST) by a spectral correction technique. The aggregations of NB and ST on an SDBS surface obeyed Langmuir isothermal adsorption. The adsorption ratios of NB and ST to SDBS were both 0.5, and the adsorption constants of the aggregates were 1.80 x 10(5) and 9.49 x 10(4). The aggregations were applied to the quantitative determination of anion detergent in samples; the recovery of SDBS was between 90.3 and 106% together with an RSD of 3.78%.