negative ion laser desorption mass spectrometry negative ion laser desorption-ionization mass spectrometry CHMO:0000517 negative ion laser desorption mass spectroscopy negative ion laser desorption-ionisation mass spectroscopy negative ion laser desorption-ionization mass spectroscopy negative ion laser desorption-ionisation mass spectrometry Mass spectrometry using negative ionisation where a high-energy pulsed laser is used for sample vaporisation. laser mass spectrometry