High performance liquid chromatographie analysis of intact and partially biodegraded linear alkylbenzene sulfonates

A high performance liquid chromatography (HPLC) method for the determination of intact and partially degraded linear alkyl‐benzene sulfonate (LAS) was developed. The LAS degradation products resulting from a semicontinuous activated sludge (SCAS), a die‐away CO2 and a simulated river die‐away study were quanti‐tatively determined by HPLC equipped with a reversed‐phase column using a tetrahydrofuran/water/Pic A solution as the mobile phase. The column effluent was monitored with a fluorescence spectrophotometer that was operated at an excitation wavelength of 232 nm and an emission wavelength of 290. Compounds investi‐gated included both single‐and mixed‐carbon‐range materials. The HPLC method shows good correlations with MBAS for intact LAS material. The most significant advantage of this method over MBAS is it ability to quantitatively determine partially degraded intermediates and the disappearance of those intermediates. This method, when using the fluorescence detection system, is selective for sulfonated ring structures with more than one alkyl carbon. The sensitivity of the method is in the 0.05‐ppm range. It can be used not only for samples from laboratory experiments but also for sewage plant influents, effluents and river waters.