Chromatography Forum

I am trying to set up EPA Method 1666. The method includes compounds analyzed by purge & Trap and compounds that require direct injection using isotopes. I do not understand the isotope requirement for the purge & Trap portion of the method. Is anybody currently using this method?

I appreciate any help. Thank you very much.

We ran that method 20 years ago and it was a pain, and expensive with all the isotopes required.

The isotopes serve the same purpose in the purge and trap portion as in the direct inject, to compensate for recovery in the purge and trap extraction of the analytes from the matrix. Honestly though any well behaved purge and trap or direct inject can get by with normal labeled internal standard compounds. Most places try to run EPA 624 or 625 instead of 1666 when possible, even if it requires some calls to the permit writer to explain why the newer methods are as good or better than a 20+ year old method. EPA has updated 624 and 625, but they haven't touched 1666 in a long time that I know of.

Thank you very much James.