Solid-phase microextraction advances

Besides classical headspace analysis, simultaneous distillation-extraction and solvent extraction, new sampling and enrichment developments include solvent-assisted flavour evaporation (SAFE) [3] and sorptive techniques like SPME solid-phase microextraction (SPME) [4,5] and stir-bar sorptive extraction (SBSE) [6], which are treated in a dedicated chapter in this book. This contribution will deal with advanced developments of GC techniques for improvement of separation and identification (classical multidimensional GC, or... 

Classical methods such as liquid-liquid extraction (LEE) are comparatively rarely employed now because of their twin disadvantages of being slow and unwieldy where large sample volumes are to be extracted. The past decade has seen major advances in sorptive extraction techniques such as SPE or solid-phase microextraction (SPME), semipermeable membrane devices (SPMDs), and even stir bar sorptive extraction (SBSE). Such devices rely on the equilibrium (sometimes nonequilibrium) partitioning of analytes between aqueous and solid phases. 

Sampling, sample handling, and storage and sample preparation methods are extensively covered, and modern methods such as accelerated solvent extraction, solid-phase microextraction (SPME), QuEChERS, and microwave techniques are included. Instrumentation, the analysis of liquids and solids, and applications of NMR are discussed in detail. A section on hyphenated NMR techniques is included, along with an expanded section on MRI and advanced imaging. The IR instrumentation section is focused on FTIR instrumentation. Absorption, emission, and reflectance spectroscopy are discussed, as is ETIR microscopy. ATR has been expanded. Near-IR instrumentation and applications are presented, and the topic of chemometrics is introduced. Coverage of Raman spectroscopy includes resonance Raman, surface-enhanced Raman, and Raman microscopy. 

This second edition offers new material on methods of sensory detection (nasal through the nose) or (retronasal through the mouth and back of the oral cavity), different flavor release phenomena in the headspace versus the mouth, and matrix in flavor release from oils compared to emulsion systems. Advanced gas chromatographic methods are included, such as solid phase microextraction for the volatile analyses in foods and vegetable oils, gas chromatography-olfactometry, and aroma extraction dilution analyses. 

Programmed-temperature vaporizer electronic pressure-controlled sample inlet systems -ms grade columns, solid-phase microextraction sampling techniques, large-volume injectors, integrated guard columns, multidimensional GC, sol-gel columns, improvements in silphenylene phases, advances in GC-MS, more affordable benchtop GC-MS systems... 

Lord, H.L. and Pawliszyn, J. (1998) Recent advances in solid phase microextraction. LCGC Int, 12, 776-785. 

The strong adsorption of organic molecules occurring at carbon surfaces can be exploited to improve the sensitivity of the sensor response toward several organic species analytes can be pre-concentrated at carbon nanostructured surfaces in advance to the actual voltammetric detection, following an approach very similar to Solid Phase MicroExtraction (SPME). This analytical procedure, called Adsorptive Stripping Voltammetry (AdSV) has been applied for the detection of electroactive species of interest in the environmental field, such as herbicides or nitro-derivatives. Thanks to the occurrence of mechanisms similar to those... 

Standard methods of analysis employ schemes to capture volatile compounds, concentrate them, separate them, and quantify them. Recent reviews of sample preparation for volatiles analysis include foods in general (1), cereals (2), and dairy products (3). Recent advances in analytical instrumentation and methodology have approached the threshold of selectivity and sensitivity demonstrated by the human nose. In this chapter, we describe new methodology employed to measure some of the key odorants in rice. The effective collection and analysis of volatile compounds can now be accomplished using solid-phase microextraction (SPME). A pictorial outline of the procedure is depicted in Fig. 1. 

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