Improved picrate method for the spectrophotometric determination of non-ionic surfactants
Abstract
Favretto et al.'s method for the spectrophotometric determination of the non-ionic polyoxyethylenated surfactants Triton X-100, X-405 and WR-1339 was improved by the presence of ethanol. Extraction of the surfactant-K+-picrate adduct occurs instantaneously. Beer's law is obeyed in the range 0.02–1.0 p.p.m. The specific absorptivities range from 150 to 1540 l g–1 cm–1 and the detection limits lie between 5.0 p.p.b. and 0.05 p.p.m. The method was applied to the determination of these surfactants in milk and butter samples, the applicability being evaluated from recovery studies.