Supported liquid membrane-protected molecularly imprinted beads for the solid phase micro-extraction of triazines from environmental waters

In this work, a novel methodology based on the combination of MIP technology with micro solid-phase extraction in a hollow fibre device for the trace enrichment and cleanup of triazines in environmental waters is described. All parameters affecting both migration of triazines from samples to the lumen of the fibre and rebinding into MIP sites have been carefully optimized. Final conditions included, addition of 20% NaCl to the sample to produce salting-out effect, extraction of analytes during 45 min with orbital stirring at 750 rpm, and then washing the fibre with toluene during 5 min to allow selective recognition of triazines before elution in HPLC inserts containing 450 μL of a methanol/acetic acid mixture (95/5, v/v). Under optimum conditions, quantitative recoveries for simazine, cyanazine, atrazine, propazine and terbutylazine, were achieved both in surface, ground and tap water samples, with relative standard deviations lower than 10.6%, and limits of detection in the low ng L−1 concentration level.