Combined liquid chromatography mass spectrometry. Part II. Techniques and mechanisms of thermospray

Abstract

This second part in the series of reviews dedicated to liquid chromatographymass spectrometry (LCNS) covers the technology of thermospray. Transport interfaces were reviewed in the previous paper (4), and application work using thermospray interfaces will appear in the third part. The same numbering system as in Part I is adopted in this text, and application work that appeared before 1982 has been generally omitted. A general introduction to the incentives of LC-MS research and the specific difficulties of this hyphenated technique can be found in an earlier text (3) and is not restated here.

Analysis of protein ions in the range 3000–12000 Th under partial (no discharge) atmospheric pressure chemical ionization conditions using ion trap mass spectrometry

“…The data discussed above show that the best results are achieved without any corona discharge, by simply vaporizing the protein solutions. At first sight this experimental arrangement seems to be very similar to that for thermospray33–35 (TS). However, clear experimental differences exist: (i) the APCI capillary temperature is higher than that employed in TS (620 K vs. 520 K); (ii) while in TS the sample is vaporized in the source under reduced pressure conditions, in the present case it occurs at atmospheric pressure and the solvent and solute are vaporized in a glass evaporator tube; (iii) while electron bombardment in TS is used in order to increase the signal intensity, in the present case it causes the complete suppression of the signal; and (iv) TS is not very effective in the analysis of biopolymers34 while the proposed approach based on the use of APCI, with and without using TEA as basic deprotonant molecule, has been successfully applied in the study of two standard proteins.…”

Determination of D/L‐amino acids by zero needle voltage electrospray ionisation

“…The zero voltage ESI or SSI mechanism is certainly different from the thermospray mechanism which apparently begins when vaporization of the liquid results in a superheated, supersonic jet of vapor, the droplets of which contain the non‐volatile molecules 21–24. These droplets are charged positively or negatively due to statistical sampling.…”

Structural Characterization of Paramagnetic Octahedral Homoscor‐Pionate (Polypyrazolylborate) Cobalt Complexes by 1H and 13C NMR Spectroscopy and by FAB‐Mass Spectrometry

“…As far as MS is concerned this study has confirmed the usefulness of FAB-MS for characterizing organometallic complexes both by the presence of an abundant molecular ion and by the formation of specific fragments. Since the same fragments were observed in the Frit-FAB-MS and in CAD spectra, this proves that these complexes can be identified in complex mixtures through LC/MS coupling [34] and tandem MS (MS/MS: Mass Spectromet ry/M ass Spectrometry) [35].…”