USP methods: chromatograms

[Marija Mac]

Is there a certain database, a place where I can find chromatograms from methods of the United States Pharmacopoeia?

I have used the assay method for Lincomycin Injection, and I need information about the peak order of lincomycin and benzyl alcohol, since
Lincomycin Injection contains benzyl alcohol as a preservative. The peak order on my column is benzyl alcohol as the first peak, and lincomycin as the second. I need a confirmation of this.

[dblux_]

... The peak order on my column is benzyl alcohol as the first peak, and lincomycin as the second. I need a confirmation of this.

How do you know ? If from your own chromatographic runs of standards than you already have confirmation.

[Gerhard Kratz]

Be happy when you got a baseline separation on a USP method..............
I agree with dblux!

[Marija Mac]

This is the thing:
I have run this method on 3 different columns from 3 different manufacturers: LiChrospher 100 RP 8 250x4,6 mm, 5µm; Dicovery C8 250x4,6 mm, 5µm; Zorbax Eclipse XDB-C8 75x4,6 mm, 3,5µm, and the results from all three, agree. And that is great, I have no problem with this.
But another manufacturer who has run the same method on ACE C8 250x4,6 mm, 5µm, gets the peaks in a reverse order than mine.

[dblux_]

...
But another manufacturer who has run the same method on ACE C8 250x4,6 mm, 5µm, gets the peaks in a reverse order than mine.

I don't neglect, but mistakes happen even in manufacturers application notes

[Gerhard Kratz]

RP is never the same!
Be happy that you have sources where brand name of the column is mentioned. Normal is at USP that they use an L1 column....
So please use your preferred C8 column and inject standards. In addition user the standard solution an run a UV spectrum for each compound. Best would be if you have HPLC-MS to identify the compounds.
Don't worry when other labs get a different elution order.

[danko]

The order you mention is right.
I really can't see it reversed on any RP column.

I think USP is so oldfashoned and non-informative and I suspect the beaurocracy invilved is to blame.
One of my methods was under publication in USP and I had a lot of discussions with the "experts" involved at that time - some 6 - 7 years ago.
Actually I insited on poblucation of a chromatogram example because there were a huge number of peaks - some of them difficult to separate.
The experts insisted that it wasn't necessary and it wasn't a tratdition for doing that

Best Regrds

[Marija Mac]

Well that`s exactly why I was wondering if there is maybe an additional resource of chromatograms of USP methods. My case is pretty simple, since I have all the reference substances of the components I shoud be expecting in my sample, and I can fairly easy confirm identification. But sometimes reference substances of all the expected sample analytes are just not available, so it helps to have an example chromatogram, as a guidance to know what is happening in your analysis.
Thanks everyone for your replies!

[Consumer Products Guy]

I think USP is so oldfashoned and non-informative and I suspect the beaurocracy involved is to blame.
One of my methods was under publication in USP and I had a lot of discussions with the "experts" involved at that time - some 6 - 7 years ago. Actually I insisted on publication of a chromatogram example because there were a huge number of peaks - some of them difficult to separate. The experts insisted that it wasn't necessary and it wasn't a tradition for doing that

It is heresy to even to think such things about USP! But it is true.

When we asked USP why the Alcohol monograph did not have an assay procedure listed, USP response was like they had been insulted: "everybody knows to do density for alcohol quantitation". So I guess we're all supposed to "know" USP mindset.

We always include example chromatograms in our own test procedures, plus we don't use terms like "L1", we specify everything about the column including manufacturer name and part number. For stuff like ACN we just detail "ACN, HPLC grade or better".

[danko]

Yeah, L1 and L-something....... What a waist of time to find other names for the actual descriptions the columns are "born" with - i.e. C-something etc. In what way is it helpful? And it isn't. Because one has to go and find what L1 or 2 or whatever stands for.

Bureaucracy is only good for those who live by it.

Best Regards