has specified output mass spectrometry chemical ionisation mass spectrometry chemical ionisation mass spectroscopy LPCI-MS chemical ionization mass spectroscopy low pressure chemical ionisation mass spectroscopy LP-CI-MS CI-MS low pressure chemical ionization mass spectrometry low pressure chemical ionisation mass spectrometry chemical ionization mass spectrometry Mass spectrometry where the sample is ionised by interaction (electron or proton transfer) with reagent (N2, O2, H2O) gaseous ions at low pressure. Reagent ions are produced by electron ionisation. LCPIMS low pressure chemical ionization mass spectroscopy CHMO:0000472 chemical ionisation mass spectrum