Chromatography Forum

We do 525 with an Agilent 5973 ( no sim scan feature). The problem is at the 0.1-0.2 ppp levels we do not have very good peaks for quantitation for the former 505 compounds.
Wondering if the method precludes us from running a sample twice, one for scan and one for sim. Scan to meet the method requirement for identification by library match, and the sim for quantitation. I do run chlordane and toxaphene by re shooting extracts usind a sim method.
I've messed with the sim method and found that for the 505 type compounds we get about a decade more sensitivity.

The question Does anyone here do what I propose? Has it passed muster by an auditor?

Thanks
Bear

I think you can use SIM for EPA method 525.3, but not 525.2, which I would suggest increasing the gain factor for higher sensitivity.

The biggest problem is which auditor you get. Some force you to stick to the method exactly as it is written even adhering to any known incorrect parts of the method, while others only require that you follow the intent of the method not so much to the letter.

For years we had a state reg that required reporting 1,2-Dibromomethane, which was an obvious typo, some auditors would wonder why you had 1,2-Dibromoethane in your method instead of 1,2-Dibromomethane. Even when you tell them that as written the compound can not physically exist, they still can't seem to figure out why you are reporting the wrong compound lol.

I got a good laugh out of my supervisor at the time when I put on the report form DNE instead of BDL(Below Detection Limit) as the result. He wanted to know what DNE stood for, I told him "Does Not Exist".

The best thing to do is contact the EPA region office that covers your area and ask for an interpretation in writing if it can be run that way. If an auditor asks questions you present them with the EPA's interpretation.