摘要：A simple and rapid determination of linear dodecylbenzenesulfonate (LAS) in natural and waste water was investigated. A water sample containing 3-30 μg of LAS was adjusted to the concentration of 2.7-3.2% sodium chloride, and shaken with methyl isobutyl ketone (MIBK). LAS and alcoholic anionic surfactants were extracted with MIBK, while many kinds of substances interfering the measurment of LAS were not extracted. Alcoholic anionic surfactants in MIBK were decomposed easily by heating at 80-85°for 5 min with conc. hydrochloric acid but LAS was stable. When the resulting mixture was diluted with 1.2% sodium chloride, the MIBK layer separated. After the separated MIBK layer was washed with 0.1 M sodium borate solution and then with 0.1 M phosphate-hydrochloric acid buffer of pH 2.5-3, it was shaken with 0.0025% Methylene Blue solution. The absorbance of LAS-Methylene Blue complex in MIBK layer was measured at 658 nm. The average recovery of LAS added to water sample was higher than 95%, except in highly polluted water.
