SPE Basics: Sorbents, Sorption, and Multiclass Analytes

Oral Presentation

Prepared by M. Wells
EnviroChem Services, 224 Windsor Drive, Cookeville, Tennessee, 38506, United States


Contact Information: info@envirochemservices.net; 931-979-6808


ABSTRACT

Although solid-phase extraction (SPE) is a mature analytical technique, predicting and optimizing acceptable recovery can still be challenging. Recoveries can be variable—too high, too low—and acceptance values can be broad. Sorption is dependent on multifaceted interactions among the sorbent, the analyte, and the matrix. Intermolecular interactions between increasingly complex sorbents and multiclass, multiresidue analytes are not always clearly understood. Analyses of single class analytes by SPE are relatively easy, but it is more difficult to optimize methods for multiresidue/multiclass chemical compounds that may vary from hydrophilic to hydrophobic extremes and may demonstrate pH-dependent hydrophobicity. Many modern approaches to this dilemma involve using mixed-mode sorbents, which makes an understanding of the fundamental principles of the chromatography of SPE even more imperative. The purpose of this presentation is to review the fundamental parameters that influence SPE and recommend opportunities for optimizing mechanisms of retention to improve recovery outcomes.