Quantification of Solute–Solute Interactions Using Negligible-Depletion Solid-Phase Microextraction: Measuring the Affinity of Estradiol to Bulk Organic Matter

摘要

The interaction of trace organic contaminants with bulk organic matter has implications for theudtransport and behaviour of organic trace contaminants within the aquatic environment as well asudwater and wastewater treatment processes. Partition coefficients (KOM) of the steroidal traceudorganic contaminant estradiol were quantified for environmentally relevant concentrations of bulkudorganic matter (12.5 mgC/L) using a full mass balance form of solid phase microextractionud(SPME). The results indicated that the method is successful and can be used at environmentaludconcentrations. Estradiol had the greatest affinity for bulk organic matter that contained phenolicudand benzoic acid ester groups, namely tannic acid, compared to organics containing predominatelyudcarboxylic functional groups. The solution chemistry (pH) was found to influence the interaction, asudestradiol had a lower affinity for negatively charged and hydrophilic bulk organic matter. Theudpartition coefficients determined using SPME were consistent with partition coefficients derivedudusing solubility enhancement and fluorescence quenching measurements, confirming that SPME isuda powerful technique to quantify the affinity of estradiol for low concentrations of bulk organicudmatter and trace contaminants. Further, this novel method can be applied to a range of traceudcontaminants