Advanced Instrumental Analysis and Electronic Noses

Lehrstuhl fur Chemisch Technische Analyse, TU Munchen, Weihenstephaner Steig 23, 85350 Freising, Germany 

Science Department, Nestle Product Technology Center, 

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 

and comprehensive two-dimensional GC, or GCxGC), faster separation techniques (fast GG), fast methods for quality assessment or process control in the flavour area ( electronic noses and fingerprinting MS) and on-line time-resolved methods for analysis of volatile organic compounds (VOGs) such as proton-transfer reaction MS (PTR-MS) and resonance-enhanced multi-photon ionisation coupled with time-of-flight MS (REMPI-TOFMS). The scope of this contribution does not allow for lengthy discussions on all available techniques therefore, only a selection of developments will be described. 

Single-column gas chromatographic analysis has become the standard approach for separation of volatile and semivolatile constituents in numerous applications however, this does not necessarily provide the best analytical result in terms of unique separation and identification. There is considerable opportunity for peak overlaps, both on a statistical basis and also on the basis of observed separations achieved for real samples [7-9]. 

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