Page 170 - Basic Gas Chromatography

Special 157 GC-MS Topics ionization This fragmentation. and electron) an of loss (usually ionization mm with i.d., ions: positive exclusively almost produces technique an required con- separator (1) 2e 4+ M+e—73M them between pumped is ionization chemical include ionization achieving of means Alternate maintain bombardment atom fast and (NCI), ionization chemical

2 systems This column molecules capillary the jet and numerous common so at collector of the molecules, Focusing | |
usually 10.3B. (~ 1mm) GC the sample second initial handle glass transfer attracted be are most vacuum usually is beam. Figure 10.4. source by a energy analyte | | (- ) (

columns, packed column Figure distance entering from larger the into the and to vacuum the of sample to order There oldest, under Ionization electron in ionization filament the defines neutral =a Current ceseenseeees | Accelerator source. (EI)

packed These in shown a small The preferentially occurs MS the activity maximize in ionized fields. the is (EI) heated and ionized. ev) (70 schematically heated tungsten filament the Filament cee LIc bed impact

used mL/min. with (usually He) system. enrichment allowing surface to be electrical impact is then energetic a from a the to strike / thee Wy / Collector (70ev) Electron

systems 30 separator jet aligned vacuum pass and Sample reduced, and both must first or magnetic electron source and shown is passes into out applied electrons (+) 10.4. Fig.

GC-MS about of the like tubes glass carrier gas separate momentum source. greatly temperature controlled integrity. Sources molecules proper but ionization vaporized a of highly source column drawn are voltage energy Repeller

Older rates interface 2 of of the a by MS is Both carefully Ionization the techniques, The easily impact typical GC Electrons ev. The high Column Eluent

156 flow sists Most away their the sure rate. be sample Analyte by simple. are by A the 70 These GC