Liquid scintillation determination of surfactants on cotton fabric

A method for the determination of anionic surfactants on cotton fabric has been developed using S³⁵ and H³ labelled compounds. The method is simple, involving immersion of the white fabric in liquid scintillation counting solution and counting. No interference by quenching or self-absorption is encountered. Accuracy and precision are better than ±2% relative. Replacing the internal standard method by the pulse height shift method of obtaining disintegration rates simplified the analysis and increases its precision. Combination of the pulse height shift method with automatic data handling has permitted the analysis of several hundred samples per week with little increase in operator time.