Abstract
A reliable method for the determination of anion-active surfactants in natural and waste waters is described. The method consists of cleanup on an Amberlite XAD 2 column and determination by colorimetry using Methylene Blue. The sample was directly passed through the column, and the column was washed with 0.05 N sodium hydroxide solution. The surfactants taken up by the resin were eluted with a mixture of acetone and aqueous ammonia. After evaporation of acetone from the effluent, the surfactants were determined as sodium 4-(2-dodecyl) benzenesulfonate by the Methylene Blue method. Compared to the values obtained without the clean-up, those obtained by the proposed method were always lower. This indicates that some of the so-called Methylene Blue Active Substances were removed by the clean-up procedure. Even in samples containing surfactants at very low levels, the surfactants could be concentrated by loading a large amount of the sample over the column. Average recovery of sodium 4-(2-dodecyl) benzenesulfonate from water fortified at levels of 50 and 100 μg was 100.5%.
