A new procedure of determination of alcohol sulfates and alcohol ethoxysulfates in agricultural soils.

ABSTRACT

The number of analytical methodologies that focus in the determination of alcohol sulfates (AS) and alcohol ethoxysulfates (AES) in terrestrial environment is very limited. In the present work, a new methodology to improve the extraction and determination of AS and AES in agricultural soil samples has been developed. Prior to instrumental analysis, an extraction procedure using pressurized liquid extraction with methanol (PLE) was carried out in order to obtain the highest recoveries and improve sensitivity. The most influential variables affecting the PLE procedure were optimized. Then, the separation and quantification of analytes were performed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The limits of detection (LOD) ranged from 0.03 to 0.08µgg(-1) for AS homologues and in the case of AES ethoxymers from 0.03 to 0.09µgg(-1) for AES-C12Ex and from 0.03 to 0.08µgg(-1) for AES-C14Ex. Matrix-matched calibration was used. Trueness was evaluated by using a spike recovery assay with spiked blank samples, and the recoveries ranged from 98.3% to 101.0% for AS and from 99.9% to 100.1% for AES. The method was satisfactorily applied in a field study designed to evaluate the environmental behavior of these compounds in agricultural soil.