Thermally assisted collision induced dissociation in a quadrupole ion trap mass spectrometer.

摘要

Tandem mass spectrometry (MS/MS) is a common technique used for the structural elucidation of molecules. The most common form of tandem mass spectrometry is collision induced dissociation (CID). However, many molecules are not dissociated efficiently using conventional CID in a quadrupole ion trap mass spectrometer. Thermally assisted collision induced dissociation (TA-CID) in a quadrupole ion trap mass spectrometer can provide increased chemical information in comparison with CID performed at ambient temperature. TA-CID is implemented by heating the bath gas. Heating the bath gas increases the internal energy of the ions and for some molecules results in an increase in the number of product ions formed. A number of applications of TA-CID in the quadrupole ion trap have been explored.; Many protonated peptides are not dissociated efficiently by CID in a quadrupole ion trap. Limited dissociation and a restricted mass range over which product ions can be trapped are often associated with traditional CID. An increase in temperature results in the formation of more product ions for protonated peptides than the same CID experiment performed at ambient temperature. The increase in product ion formation results in an increase in residue information available. The increase in information is beneficial in sequence tag searching to identify proteins via bottom up proteomics.; Sodiated ions are common in mass spectrometry; however, traditional CID of some sodiated ions results in few to no structurally informative product ions. TA-CID is shown to increase product ion formation for sodiated oligosaccharides. More structural information is provided for sodiated oligosaccharides at elevated temperature than with traditional CID. However, the application of TA-CID to sodiated peptides and two sodiated polymers did not show an increase in the information available.; A method to determine the effective temperature of IR activation using TA-CID is discussed. The internal energy gain from IR activation can not be directly calculated in a quadrupole ion trap because the number of photons absorbed is unknown. However, using a method that compares TA-CID spectra to IR-activation CID spectra, the internal energy gained from IR-activation and the effective temperature of that IR-activation can be calculated.