A New Approach for Atrazine Desorption, Extraction and Detection from a Clay-Silty Soil Sample

Abstract

This paper reports an alternative method for extraction, detection and quantification of atrazine from a clay-silty soil. Atrazine adsorption isotherm for this kind of soil fits to a Freundlich adsorption isotherm with a correlation coefficient of 0.994, sorption intensity 1/n = 0.718 and Kf = 1, with a maximum soil adsorbed atrazine concentration of 8 mg g–1. Atrazine desorption was approached using several surfactants including non-ionic (Triton X-100, Triton X-114, and Triton X-405), anionic (SDS) and cationic (CTAB), these surfactants were used at critical micellar concentration (CMC) and higher concentrations. Atrazine quantification was done by high resolution liquid chromatography coupled to spectrophotometric detection (HPLC-UV), optimized conditions correspond to a flow rate of 1.0 mL min–1, λ = 260 nm, a C18 PAH Agilent-Eclipse column with a mobile phase of CH3OH/1 × 10–3, a phosphate buffer, pH 3.2/CH3CN 55:30:15 (v/v). At these conditions it can be obtained a good chromatographic separation of atrazine and soil organic matter. Atrazine desorption was aided by surfactants at CMC conditions, it can be claimed that atrazine desorption was enhanced by surfactants since desorption, from higher to lower, goes as follows: 98.5% with Triton X-114, 98% with SDS, 89.5% with Triton X-405, 86.5% with Triton X-100; and 45% with CTAB.