Sorptive sample preparation – a review

Abstract

Most sample-enrichment procedures currently available rely on adsorption of the analytes of interest by a suitable adsorbent material. Although good performance can be obtained for many practical problems, in some cases the applicability of adsorptive sample preparation falls short, particularly for the enrichment of polar and/or high-molecular-weight compounds, especially in combination with thermal desorption. Because of the very strong retention of adsorbent materials, undesired effects such as incomplete desorption and artifact formation are observed. Polar solutes are easily adsorbed but readily undergo surface-catalyzed reactions and on desorption yield compounds different than those originally sampled. High-molecular-weight compounds cannot be desorbed because of extremely strong interactions with the adsorbent and their low volatility. To overcome some of these problems sample-preparation techniques based on polydimethylsiloxane sorption have been developed over the past 15 years. In contrast with adsorptive trapping, sorption is based on dissolution of the analytes in a liquid polymeric material. This is a much more inert means of solute retention which overcomes some of the limitations encountered when working with adsorbents. In this contribution, the basic principles of sorption, the different instrumentation used, and applications of the technique will be reviewed. The review covers the sorptive sample-preparation techniques, open-tubular trapping (OTT), solid-phase microextraction (SPME), gum-phase extraction (GPE), equilibrium gum-phase extraction (EGPE), and stir-bar-sorptive extraction (SBSE). Because of the nature of sorptive sample-preparation techniques, which perform particularly well in combination with thermal desorption, this review focuses strongly on gas chromatography as the means of chemical analysis.

Determination of flavour compounds in beer using stir-bar sorptive extraction and solid-phase microextraction

“…This ratio is equal to the ratio of the mass of the analyte in the extraction phase (m E ) over the mass of the analyte in the sample (m S ) times the phase ratio β, which is defined as the ratio between the volume of the sample (V S ) over the volume of the extraction phase (V E ) (27).…”

“…Compound SPME/SBSE SPME SBSE SPME SBSE SPME SBSE SPME SBSE and the analyte, competitive interactions between analytes for adsorbent sites can occur, leading to lower reproducibility compared with pure sorbents (27). Several authors have reported higher reproducibility for PDMS coated stir-bar extractions compared with SPME extractions using copolymers for volatiles in water (28), vinegar (31) and malt whisky (32).…”

Two multidimensional chromatographic methods for enantiomeric analysis of o,p′-DDT and o,p′-DDD in contaminated soil and air in a malaria area of South Africa

“…Microlitre amounts are injected for analysis. Sensitivity limitations are associated with injection of only a fraction of the final 20 µL to 1 mL solvent extract [26]. In contrast to extraction procedures using solvents, the procedure applied in this study is a novel solvent free sorptive extraction technique where DDT is concentrated from soil using polydimethylsiloxane (PDMS) loops.…”

“…In contrast to extraction procedures using solvents, the procedure applied in this study is a novel solvent free sorptive extraction technique where DDT is concentrated from soil using polydimethylsiloxane (PDMS) loops. PDMS functions as a hydrophobic solvent for the analytes [26]. After extraction the loop is inserted into a commercial thermal desorption tube for solventless introduction into a GC.…”

Analysis of Unmetabolized VOCs in Urine by Headspace Solid‐Phase Microcolumn Extraction

“…Generally, VOCs analyses involve either static or dynamic headspace (HS) sampling, followed by gas chromatographic separation and flame ionization (GC-FID) or mass spectrometric detection (GC-MS). In the majority of the newly developed HS sample preparation techniques, the recovery of volatiles is based on sorption in a solid phase 8,9) . Among them, equilibrium sampling techniques such as HS solid-phase microextraction 10) , HS sorptive extraction 11,12) , and a non-equilibrium sampling technique, HS solid-phase dynamic extraction, are available 8) .…”