Extrative Electrospray Ionization Tandem Mass Spectrometry of Apigenin

The extractive electrospray ionization tandem mass spectrometry(EESI-MSn) of apigenin was stu-died using both positive and negative ion modes.The results showed that the detection of apigenin was more sensitive in negative ion mode than that in positive ion mode.By comparing EESI-MS spectra with electrospray ionization mass spectrometry(ESI-MS) spectra of apigenin,we found that EESI mode is softer than ESI mode.The mechanism of the fragmentation of apigenin was also discussed in detail based on the experimental collision-induced dissociation(CID) data recorded in these experiments,and was confirmed by the ESI-MS.The study is useful for the rapid and direct determination of trace amount of apigenin in complex matrix by EESI-MS.