Editing Electron ionization (section)

=== Liquid chromatography EI-MS ===
Two recent approaches for coupling capillary scale liquid chromatography-electron ionization mass spectrometry (LC-EI-MS) can be incorporated for the analysis of various samples. These are capillary-scale EI-based LC/MS interface and direct-EI interface. In the capillary EI the nebulizer has been optimized for [[linearity]] and sensitivity. The direct-EI interface is a miniaturized interface for nano- and micro-[[High-performance liquid chromatography|HPLC]] in which the interfacing process takes place in a suitably modified ion source. Higher [[Sensitivity and specificity|sensitivity]], linearity, and [[reproducibility]] can be obtained because the elution from the column is completely transferred into the ion source. Using these two interfaces electron ionization can be successfully incorporated for the analysis of small and medium-sized molecules with various polarities. The most common applications for these interfaces in LC-MS are environmental applications such as gradient separations of the [[pesticide]]s, [[carbaryl]], [[propanil]], and [[chlorpropham]] using a [[Reversed-phase chromatography|reversed phase]], and pharmaceutical applications such as separation of four [[anti-inflammatory drugs]], diphenyldramine, [[amitriptyline]], [[naproxen]], and [[ibuprofen]].<ref>{{Cite journal|last1=Cappiello|first1=Achille|last2=Famiglini|first2=Giorgio|last3=Mangani|first3=Filippo|last4=Palma|first4=Pierangela|date=2001-01-01|title=New trends in the application of electron ionization to liquid chromatography—mass spectrometry interfacing|journal=Mass Spectrometry Reviews|language=en|volume=20|issue=2|pages=88–104|doi=10.1002/mas.1004|pmid=11455563|issn=1098-2787|bibcode=2001MSRv...20...88C}}</ref>

Another method to categorize the applications of electron ionization is based on the separation technique which is used in mass spectroscopy. According to this category most of the time applications can be found in [[Time-of-flight mass spectrometry|time of flight]] (TOF) or orthogonal TOF mass spectrometry (OA-TOF MS), [[Fourier transform ion cyclotron resonance]] (FT-ICR MS) and [[Quadrupole mass analyzer|quadrupole]] or [[Quadrupole ion trap|ion trap]] mass spectrometry.