Acquisition of a Liquid Chromatography/Mass-Spectrometry System

摘要

An LC/MS system consisting of the Finnigan LCQ ion-trap mass- spectrometer and a Shimadzu HPLC system was purchased. The system was installed successfully and has been operational since September 1997. We have developed a number of LC/MS methods for the analysis of plant and sedimentary pigments. The instruments MS(n) capabilities, i.e. perform fragmentation experiments on fragments, are far beyond expectations, MS(10) experiments are possible with some molecules. Using the instrument, we have discovered novel masses of chlorophyll a degradation products in marine sediments. One of these are carotenol chlorin esters that might be uniquely derived from diatoms and may be used as tracers for carbon derived from diatoms. Another class of compounds are cyclic pheophorbides. One of these, 13(2), 17(3)-cyclopheophorbide a enol had been found before in marine sediments. We have discovered analogous compounds derived from divinyl-chlorophyll a and b as well as chlorophylls ci and c2. We have also found an unusual carotenoid, parasiloxanthin, in the cyanobacterium Prochlorococcus marinus, a carotenoid that has to date only been found in the Common Japanese Catfish. The system is also heavily used by other groups at Scripps; it has become an instrument essential to the thesis work of some graduate students.