Optimization and Validation of Liquid Phase Microextraction Method Based on Oil Droplets to Quantify Algal Metabolites (2-Methylisoborneol, Geosmin, etc.) in Drinking Water Supplies

A novel liquid phase microextraction method based on solvent oil droplets was optimized and validated for sample pretreatment of algal odorous metabolites (i.e., 2-Methylisoborneol, Geosmin, etc.) in drinking water supplies prior to gas chromatography. Segregation and condensation are based on the diffusion of solvent oil micro drops as an extracting solvent in the sample solution (drinking water supplies) and then back extraction of the analytes to another organic solvent, which is a three-phase direct immersion type of LPME. The important variables influencing the microextraction procedure such as type and volume of extracting oil and back extracting solvent, time and temperature of extraction, and ionic strength were optimized separately. Under optimal conditions, the correlation coefficient, limits of detection, linear dynamic ranges, preconcentration factors, and precision of the method were evaluated. The method displayed a high linearity range for the analytes ( R 2 ≥ 0.9808–0.9959), low limit of detection (0.03–3.01 μg L −1 ), and a good linear dynamic range (0.08–50 μg L −1 ). The precision comprised of reproducibility and repeatability were evaluated by computing the relative standard deviation (RSD %), which was ranged as 3.48–3.87%. Consequently, the optimized method along with the GC-FID method was successfully extracted the algal metabolites from water samples, with satisfactory recoveries (94–97%).