Detection of Nonvolatile Species by Laser Desorption Atmospheric Pressure Mass Spectrometry

摘要

This work examines the use of laser desorption as a means of volatilizing thermally labile compounds for detection in atmospheric pressure mass spectrometry. A number of different classes of compounds have been examined including amino acids, purine and pyrimidine bases and their nucleosides, drugs, vitamins, and catecholamines. The main advantage of this method is that desorption of neutrals and the atmospheric pressure ionization process are performed in two separate steps as compared to LDMS where desorption and ionization occurs in one step. Thus, detection limits reaching down to about 0.3 ng can be achieved in the total process due to the high efficiency of each step where complete desorption of the sample can be achieved and almost 100% efficient ionization of the resulting neutrals is possible using atmospheric pressure ionization in these high proton affinity molecules. The use of this atmospheric pressure technique obviates the need of manipulating samples under vacuum and may prove to be particularly convenient for interfacing HPLC and SFC in mass spectrometry. (Reprints).