Non-targeted evaluation of selectivity of water-compatible class selective adsorbents for the analysis of steroids in wastewater.
Selective adsorbents for solid-phase extraction are needed to meet the low concentration requirements of new environmental quality standard directives, especially for the analysis of estrogens in wastewater. In this work, bulk polymerization procedures were first optimized for the synthesis of non-imprinted polymers (NIP) with low non-specific adsorption of nonpolar compounds in aqueous environments. Water-compatible molecularly imprinted polymers (MIP) were then synthetized by increasing the selectivity of the polymer towards steroids with a testosterone template (average imprinting factor > 10). In addition, the affinity of synthetized entrapped β-cyclodextrin-epichlorohydrin polymers (ECD) towards steroids was clarified. The polymers were applied to the extraction of spiked wastewater effluent samples and their performance compared to commercially available adsorbents. The selectivity of the studied adsorbents was evaluated utilizing liquid chromatography ‒ mass spectrometry as well as comprehensive two-dimensional gas chromatography ‒ time-of-flight mass spectrometry. Affinity between adsorbents and steroids as well as matrix removal potential were measured with targeted methodologies, and two novel non-targeted methodologies were proposed to quantitatively measure adsorbent selectivity by utilizing chemometrics. Semi-quantitative selectivity was measured from the ratio of peak areas between steroidal and other compounds. Semi-qualitative selectivity was calculated from the ratio between the number of tentatively identified steroidal and other compounds. The synthetized polymers provided good matrix removal potential (ion suppression 15-30%) and semi-qualitative selectivity (∼4 units) compared to the commercial adsorbents (ion suppression 45-80%, selectivity < 3 units). Simple non-targeted approaches provided a novel method of quantifying the selectivity of extraction.
Laboratory of Analytical Chemistry, Department of Chemistry, P.O. Box 55, FI-00014 University of Helsinki, Finland.
Matias
M
Kopperi
Laboratory of Analytical Chemistry, Department of Chemistry, P.O. Box 55, FI-00014 University of Helsinki, Finland. Electronic address: marja-liisa.riekkola@helsinki.fi.
Marja-Liisa
ML
Riekkola
D000327:Adsorption; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004811:Epichlorohydrin / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D054802:Molecular Imprinting / Q000379:methods*; D058105:Polymerization; D011108:Polymers / Q000737:chemistry*; D052616:Solid Phase Extraction / Q000379:methods*; D013256:Steroids / Q000032:analysis / Q000302:isolation & purification*; D062065:Wastewater / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000302:isolation & purification*; D047392:beta-Cyclodextrins / Q000737:chemistry
D004811:Epichlorohydrin; D011108:Polymers; D013256:Steroids; D062065:Wastewater; D014874:Water Pollutants, Chemical; D047392:beta-Cyclodextrins; C102558:cyclodextrin-epichlorohydrin polymer
Adsorbent selectivity; Chemometrics; Molecularly imprinted polymer; Non-target; Steroid