Comparison of Sorbents Using Semipolar to Highly Hydrophilic Compounds for a Sequential Solid-Phase Extraction Procedure of Industrial Wastewaters

Abstract

Untreated and biologically cleaned industrial wastewaters contain huge amounts of both hydrophilic and hydrophobic compounds. Due to breakthrough effects, only a few percent of the dissolved organic carbon is usually extracted by solid-phase extraction methods. Methods for screening analysis have not faced that problem sufficiently yet. To extract more hydrophilic compounds, solid-phase sorbent characteristics had to be evaluated in this study. Recovery studies were carried out with 21 hydrophilic aromatics including carboxy acids, sulfonates, aldehydes, ketones, thiols, and phenols at a level of 1−2 μmol/L. Both silica gel based sorbents and polymeric materials were tested at neutral to acidic pH values and extraction volumes up to 200 mL. It was found that poly(styrene−divinylbenzene) sorbents are a powerful tool for the enrichment of hydrophilic aromatic substances. Most of the tested compounds could be extracted at recovery rates of >80%. The quantitative extraction of thiols as well as (aminohydroxy)...