KB004905: Can Air be used Instead of Nitrogen as an ELSD Nebulization Gas? - 1200 LC 

From a technical point of view the ELSD would work with air as well. The reason for using nitrogen is safety. Mixing air/oxygen with a fine mist of combustible solvents (acetonitrile, methanol, isopropanol, hexane etc.) creates a highly inflammable or even explosive mixture, so this is a potential safety hazard. While we cannot avoid in practice, that some customers use air instead of nitrogen, we should clearly advice them on this risk and Agilent service representatives must not connect the instrument to pressurized air supplies. This is no specific limitation of the Agilent ELSD but a consideration which is true for any ELSD.