2.16 - Sol–Gel Materials in Analytical Microextraction

Abstract

The sol–gel process allows the fabrication of a wide range of material systems with differences in size, shape, charge, porosity, polarity, etc. These resulting materials possess high purity and material homogeneity that attract applications in various scientific fields including analytical microextraction, which is the focus of this chapter. No one material is appropriate for all extractions; hence, materials are constantly being developed and modified to bring about more selective and efficient extraction. Sampling and sample preparation are responsible for the greater portion of the global uncertainty of an analytical procedure which warrants further development and research in this important field. In conventional analytical protocol, sampling, sample preparation, and sample introduction are treated separately; this increases the chance of losing analyte, reduces repeatability, and hampers automation. Sol–gel technology provides a straightforward pathway to achieving stable performance, procedural simplification, the creation of efficient extraction media, enhanced reproducibility, and ease in automation of various microextraction schemes. This chapter will convey, in general terms, the usefulness of sol–gel technology and, in specific terms, its application in preparing sorbents for extracting a wide range of analytes in the environment, food, biomedical fields, etc., with the main focus being their application in SPME, CME, and SBSE. Also, the sol–gel process will be explained and instructions given on how to use it to prepare certain microextraction devices. Additionally, a detailed account will be provided on how to prepare and characterize sol–gel materials and how to couple the sol–gel microextraction techniques with various chromatographic and electrophoretic separation instruments.