Optimized parameters of SMPE analysis for atrazine and its application to measure speciation

The uptake kinetics and partitioning behavior of atrazine between water and two polymeric coating (polydimethylsiloxane (PDMS) or polyacrylate (PA)) fibers commercially available for solid phase microextraction fiber (SPME) are presented. The SPME technique is associated with gas chromatography coupled to flame ioniser detector (GC-FID) in order to quantify the atrazine concentrations in the two phases. First, the equilibrium-time profiles for the two coatings were previously studied in order to establish the time needed for equilibrium. The parameters such as effects of extraction time, stirring rate and pH, that might affect the sensibility and accuracy of the SPME method, were investigated and optimized. It was observed that polymer-water partition coefficient of atrazine to PDMS (KPDMS-water) was 55 ± 2, while the KPA-water was 210 ± 5. Furthermore, the extraction efficiency increases with the stirring rate and decreases with varying pH. The SPME technique was applied to determine speciation of atrazine in colloid suspensions; results and comparison with free atrazine solution were presented.