KB002007: What is the Replacement Interval for the Nitrogen Gas Purifier? - General LC/MS 

The recommended replacement interval for the nitrogen gas purifier is every 4-6 months, depending on gas quality. There are generally two indicators that the gas purifier needs to be replaced. The first is a high back-pressure. Exposure to excessive levels of oxygen or water can lead to a large pressure drop across the gas purifier. If adequate gas flow cannot be maintained at 80 psi (5.5 bar), the gas purifier probably needs to be replaced. The second indicator is a high level of spectral background noise. In particular, if the spectral background noise increases at higher gas flow rates, and decreases at lower gas flow rates, the gas purifier probably needs to be replaced.