Thermospray soft ionisation

Thermospray (TSP) is another soft ionisation technique which produces predominantly MH+ or (M — H) ions, together with some fragmentation. TSP is best suited to the analysis of organic compounds of low molecular mass (<1000 Da) that exhibit some polarity. Polymer additive molecules fall in this wide category. 

Several years later, the next step in the application of MS-MS for mixture analysis was developed by Hunt et al. [3-5] who described a master scheme for the direct analysis of organic compounds in environmental samples using soft chemical ionisation (Cl) to perform product, parent and neutral loss MS-MS experiments for identification [6,7]. The breakthrough in LC-MS was the development of soft ionisation techniques, e.g. desorption ionisation (continuous flow-fast atom bombardment (CF-FAB), secondary ion mass spectrometry (SIMS) or laser desorption (LD)), and nebulisation ionisation techniques such as thermospray ionisation (TSI), and atmospheric pressure ionisation (API) techniques such as atmospheric pressure chemical ionisation (APCI), and electrospray ionisation (ESI). 

The two chapters that were selected for this topic one on GC-ion trap mass spectrometry, by SabUer and Fujii and the other by Schroder on LC-MS in environmental analysis give an excellent contribution to the application of GC-MS and LC-MS to environmental analysis. Both chapters include many practical aspects and examples in the environmental field and also cover the historical perspective of the techniques and show the perspective on ionisation and scanning modes. Advances achieved in GC-ion trap by the use of external ion sources and GC/MS/MS possi-bihties are discussed. The LC-MS chapter provides an overview of the first applications of LC/MS interfacing systems, such as moving belt, direct Uquid introduction (DLI) and particle beam (PB), and then on the more recent soft ionisation techniques, like thermospray and atmospheric pressure ionisation interfacing systems. 

Thermospray is a soft ionisation technique that relies on the production of a spray by direct heating of a metal capillary carrying the LC eluent. The presence of an electrolyte dissolved in the mobile phase causes this spray to consist of droplets carrying a statistical excess charge. Desolvation of these droplets results in the expulsion of ions, which are then extracted into the mass analyser. Thermospray is applicable to many polar materials but can give poor sensitivity for nonpolar species. Other... 

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