In-situ suspended aggregate microextraction: A sample preparation approach for the enrichment of organic compounds in aqueous solutions

This work presents in-situ suspended aggregate microextraction (iSAME) as a new and expedient sample preparation method. This new concept capitalizes on the general principles of in-situ solvent formation microextraction, in the sense that extraction is carried out in a supramolecular aggregate phase, which is formed in-situ in the sample through one-step process involving ion-association between a cationic surfactant and a benzene sulfonic acid derivative. The suspended aggregate containing the analytes is then collected in the form of a thin-film on the surface of a common filter paper by suction filtration. The entrapped analytes are released by completely dissolving the thin-film with a small volume of an organic solvent which is used for analysis. Using a series of organic UV filters as model analytes, the experimental variables pertaining to the operation of this new extraction approach were optimized and validated to the analysis of genuine water samples of different nature and with different matrix complexity (tap, river, lake, lagoon, delta and sea). The satisfactory analytical performance of the method in terms of recovery rates (80-112%), precision (0.9-11.5%), high linearity of the calibration curves over a concentration range of 3 orders of magnitude, the high selectivity along with its simplicity and low resource requirements render the method as an attractive alternative to the routine assessment of organic compounds in environmental water samples.