07-06-2022

In June 2009, the United States Environmental Protection Agency (USEPA) promulgated a new drinking water method, 524.3. Due to advances in analytical instrumentation, Method 524.3 allows laboratories to modify purge and trap and GCMS conditions. Currently the USEPA is investigating the option of using Nitrogen as the purge gas in a new drinking water method, 524.4. This application note will explore purge and trap conditions for both Helium and Nitrogen purge gases.

Discussion:

When the USEPA published Method 524.3, they allowed some method flexibility. However, the method still required Helium as the purge gas. Due to fluctuations in the price and availability of high purity Helium, the USEPA has drafted Method 524.4 which would allow for high purity Nitrogen to be used for the purge gas.

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