Generic extraction medium: From highly polar to non-polar simultaneous determination

Abstract

Sample preparation for non-target analysis is challenging due to the difficulty in the extraction of polar and non-polar analytes simultaneously. Most commercial solid sorbents lack the proper comprehensiveness for extraction of analytes with different physiochemical properties. A possible key is the combination of hydrophobic polymer and hydrophilic surface functional groups in solid based extraction methods in order to generate the susceptibility for retaining both polar and non-polar analytes. To pursue this goal, in this study, four polar groups including NH2, NO2, COOH, and COCH3 were chemically bound to Amberlite XAD-4 substrate in order to prepare a generic extraction platform. To validate the applicability of extractive phases, 22 analytes possessing wide range of polarities (LogP range between −2 and +7) were chosen for extraction using the synthesized polymers by online micro solid phase extraction (μ-SPE) and further analyzed with high-performance liquid chromatography and UV–Vis detection (HPLC-UV). The recovery data were compared with commercial sorbents by t-test, principal component analysis (PCA) and hierarchical cluster analysis (HCA). Amberlite XAD-4 modified with COOH group (XAD-COOH) revealed extraction efficiencies statistically better than commercially available sorbents including LiChrolut® EN, Oasis® HLB and Amberlite® XAD-4®. The reproducibility and repeatability of XAD-COOH were also studied and acceptable results were obtained. Furthermore, the swellability of polymers was also measured and the results were comparable with commercial ones. To evaluate the extraction ability of XAD-COOH in real sample matrix, water sample near a heavy crude oil spill, urine and hospital wastewater were analyzed. Comparison of the data with LiChrolut® EN corroborates the dominance of XAD-COOH for screening analysis.