A liquid chromatographic system with a mass spectrometric detector (LCMS) requires a supply of nitrogen as the curtain gas, pure zero grade air as the source gas, and dry (–40 °F dewpoint) air as the source exhaust gas. In many facilities, these gases are provided by a series of compressed gas tanks; while the use of gas tanks can meet the overall requirements of the system, this approach imposes a number of serious operational, safety, and economic disadvantages. From an operational standpoint, the tanks must be replaced periodically, requiring operator involvement and reducing the overall uptime of the system. In addition, the handling of compressed gas tanks introduces a signifi - cant safety risk and is an expensive way to supply the necessary gases.