LC-MS (Liquid Chromatography-Mass Spectrometry) is a highly powerful analytical technique that combines the exceptional separation power of liquid chromatography with mass spectrometry, a very sensitive chemical identification technique. LC-MS can be used to determine the constituents of complex chemical mixtures and this capability means LC-MS systems are found in most advanced chemical and life sciences laboratories. In order to function LC-MS systems needs a nitrogen supply, which can be either static (in the form of cylinders or dewars) or dynamically generated on site.

What purpose does Nitrogen serve in LC-MS applications?

Nitrogen is typically used to effectively eliminate the solvent of a sample in order toprevent it passing through from the ion source to the quadrupole and the detector.Solvent removal is essential to maximize the sensitivity of an analysis and to preventany erroneous results.What mass spectrometry ionization methods are used in conjunction withNitrogen?Nitrogen is used in different ways depending on which ionization method isemployed.In electrospray ionization (ESI) detectors, nitrogen is used as a nebulizer gas toproduce a mist of charged droplets which results in the separation of the solvent andthe ionized sample. The ionized sample then passes through to the quadrupole(s)and to the detector.In atmospheric pressure ionization (API) detectors, nitrogen is used to spray thesample solution into a heater where ionization occurs.In other systems, nitrogen can be used as a ‘curtain gas’ to facilitate the separationof sample and solvent ions and to prevent passage of solvent into the vacuumchamber of the mass spec.