Spectrophotometric Determination of Trace Anionic Surfactants Such as SDS and SDBS in Water After Preconcentration on an Organic Solvent-Soluble Membrane Filter

Abstract

Spectrophotometric determination of trace anionic surfactants such as SDS and SDBS in water samples based on a simple and rapid preconcentration technique of collection on an organic solvent-soluble membrane filter, has been proposed. The anionic surfactants are collected on a nitrocellulose membrane filter as an ionassociate complex with the cationic complex of iron (II)-3- (2-pyridyl)-5, 6-diphenyl – 1, 2, 4 – triazine (pyridyl diphenyltriazine, PDT). The membrane filter with the analyte is dissolved in a small volume of organic solvent, and the absorbance of the resulting solution is measured against a reagent blank. The maximum absorption is at 555 nm and the apparent molar absorptivities are 8.93x10³ 1 mol⁻¹ cm⁻¹ for SDS and 8.51x10³ 1 mol⁻¹ cm⁻¹ for SDBS. Beer's law is obeyed over the range of 10-100 μg for SDS and SDBS and the detection limit is 0.0043 mg 1⁻¹ for SDS and 0.0052 mg 1⁻¹ for SDBS, respectively on a 3 [sgrave] basis. Interference from Cu²⁺ and Ni²⁺ can be eliminated by masking.

Key Words:

• SDS and SDBS
• Spectrophotometry
• Concentration
• Membrane filter