Given the worldwide shortage of helium, which is adversely impacting many industries (not the least of which are environmental laboratories, where helium is widely used as a GC carrier gas), what is the EPA doing with regard to the helium shortage and moving to alternative gases for analysis? Are we allowed to use whatever gas can be shown to work? Does the EPA have revised criteria for the BFB and DFTPP ions ratios when hydrogen is employed as a carrier for 8260/8270?
The EPA Office of Resource Conservation and Recovery (ORCR) Methods Team has communicated to other EPA program offices and regions about the helium supply shortage issue and its impact to the analytical community. EPA Regional Labs and the industry (including instrument manufacturers) across the country were looking into alternatives.
In the short term, numerous helium conservation techniques have been developed that can significantly reduce helium consumption without costly modifications or adversely impacting performance. Examples of effective conservation techniques are:
• Converting to nitrogen as a purge gas for purge and trap systems.
• Converting all electron capture detector instruments for pesticides and PCBs to hydrogen.
• Reducing the helium flow to a minimal flow when in standby.
• Switching to nitrogen when the instrument is idle and back to helium when the instrument is operating.
• Using a standby method that puts the inlet in split mode with the split set very low.
The instrument manufacturers may have additional recommendations for helium conservation.
ORCR is revisiting two commonly used organic methods for the analyses of volatile and semivolatile compounds using gas chromatography and mass spectrometry (GC/MS). The revised methods (8260D and 8270E) will include many enhancements and address the helium supply shortage issue. These two revised methods will be a part of the next update to SW-846 (Update VI), anticipated to occur in 2016. These two methods will include BFB/DFTPP ion ratio criteria and an appendix providing guidance for the use of hydrogen carrier gas.
Under the Methods Innovation Rule (MIR), methods may be modified provided it can be demonstrated that precision and accuracy criteria are met for the intended use and that the quantitation limit is the same or lower than the existing method. However, it is incumbent upon the laboratory modifying the method to demonstrate the validity of the modifications and get the approval for these modifications from the regulating agency and/or client. Most of the gas chromatographic methods using helium as a carrier gas are not method‐defined parameters and can be modified for use with an alternate carrier gas.