Fig. 1

Liquid chromatography interfaced with a triple quadrupole mass spectrometer and electrospray ionization source in full scan positive ion mode analysis of ethanol extract of Serratia marcescens isolate N4-5. Ten compounds in addition to prodigiosin and serrawettin W1 were detected by monitoring a mass range from 100-1200 m/z. Initially the most abundant chromatographic peaks were identified from this run and then analyzed two more times first to identify their characteristic collision-induced dissociation (CID) fragment ions using a parent > daughter product screening technique and then using selected CID fragment peaks to do a parent > daughter peak quantification method (multiple reaction monitoring) of the extract to measure these areas relative to the areas of prodigiosin for the initially-screened peaks