Laboratories
Laboratories use nitrogen for more complex processes such as the analysis and transportation of certain chemicals. Chromatography is a laboratory analytical technique to separate a mixture. It is used to establish the presence or relative proportions of analytes (sample of interest) in a mixture. Liquid chromatography (LC) is a separation technique in which the mobile phase is a liquid. Liquid chromatography is often combined with another process called mass spectrometry (MS). This is an analytical chemistry technique that helps identify the amount and the type of particles and molecules present. The combination of these two processes is referred to as LC-MS. Nitrogen is used for 3 phases during LC-MS:
- Nitrogen functions a nebulizer gas to produce a mist of charged droplets which result in the separation of the solvent and the ionized sample.
- It is a carrier gas to spray the sample solution into a heater in which ionization occurs.
- Finally, nitrogen serves a curtain gas to facilitate the separation of sample and solvent ions. It also prevents the passage of solvent into the vacuum chamber of MS.
This LC-MS process requires a minimum of 95% nitrogen purity and sometimes up to 99%. Quality nitrogen is beneficial in this process because gas impurities can compromise analysis accuracy. They can also cause major inaccuracies and problems with analytical equipment. Nitrogen reduces the levels of oxygen and water significantly, extending the working life of chromatography columns. This saves on column replacement cost and downtime.