GC or HPLC... is there a choice?

[Karen01]

Not sure which topic this should be under...

I'm looking at the FCC (food chemical codex) and USP monographs for a possible product we may make... The assay and related substance tests in the monographs are done by GC with packed glass columns using derivitization an FID detection, but I know I can do those separations by LC as well without dervitization.

So do I have to follow the the ancient GC method in the monograph or can I use LC (assuming enough sensitivity)?

- Karen

[chromatographer1]

Methods listed by the USP are there for a reason.

They have been tested and will work according to the perceived need of the industry.

If a methodology is not listed it is for a reason.

Usually because no one has documented the methodology with data to the USP.

If you can do the required analysis by LC document it and send it in to the USP for approval.

Would that solve your problem?

best wishes,

Rod

[scottythree]

Remember that it is the FDA not USP that makes final approval! Validate and show your method is at least equivalent to the current out of date USP method. This will probably be more work on your end up front though as you will need to run both your method(s) and the USP's to get comparison results. Long term it may be worth the time...if your managers can see that far!

[Alexandre]

Dear Karen,
We analyzed cyromazine and dicylcanil. The official method is GCMS. It is so long… two ion exchange purifications, derivatization, long runs. I was sick of this method. I tried to develop a fast UPLCMSMS method with no derivatization or SPE. It took a team of 3 for ~1 year part-timer (between our core activities) to validate and pass it through the accreditation, but it worth the efforts. Now the lab enjoys the nice method. We estimated how much it cost us to develop it. It was approximately $50K mainly in salaries. They did not want publish this method as it was a commercial lab.