Complex sentence: Years later, it was also applied as a detector for LC, though the samples must be vaporized first to be detected by the photoionization detector, and eventually was applied to mass spectrometry, particularly as an ionization method for gas chromatography-mass spectrometry.
Split into simpler sentences: Years later, it was also applied as a detector for LC, though the samples must be vaporized first to be detected by the photoionization detector. Eventually CI was applied to mass spectrometry, particularly as an ionization method for gas chromatography-mass spectrometry.