Chromatography Forum

Im assuming most people here perform the HETP before a run...correct.
My colleagues are not sure about this and I want to beat them over the head.

sorry rought week

what, QC? You don't work in academia, do you?

lol industry

No HETP checking here, but I do know of some complex methods that exhibit variation from lot to lot, so screening of column lots were done so that the columns from the "good" batches were purchased for QC work. However, the noted problems had to do with selectivity rather than resolution.

Most columns have a serial number and a batch number so you can get columns from a certain batch of stationary phase if need be.

Ron J

I might be lost in translation but what do you mean by "perform the HETP before a run"? Do you mean checking the column efficiency before analysis of your samples?

@rwjohnson besides HETP.As what are some of the other methods?

@Jiri Urban Yes column efficiency and As before production run using 100L column cGMP facility.

I'm finding it an uphill struggle in an academic context just to get people to run some sort of standard with everything, and to record in their methods what it should look like (expected peak widths and resolution). It's amazing how bad a method can get, if it gets bad slowly, worsening just a little each day...

From your comment about 100L columns, I assume you are doing process-scale chromatography. Most people here run analytical-scale columns which are normally prepacked by the manufactuurer. A check for plate number is usually subsumed into the system suitability test and, as has been suggested, system suitability failure is more often due to selectivity issues that to poor effficiency.

On a process scale, I can't imagine that you would want to run the risk of *not* checking the column performance before you process a batch. The exception that I can think of is if the run time is short enough to make reprocessing in case of column failure a minor issue.

Im assuming most people here perform the HETP before a run...correct.
My colleagues are not sure about this and I want to beat them over the head.

sorry rought week

You are also assuming that everyone who reads the post has ESP so that they can pluck what you are talking about out of the ether.

Peter

@tom jupille

good point...it is the point im trying to drive home. reprocessing is considered a deviation on large scale and requires quite a bit of paperwork to say the least.

@Peter Apps

right...should of had more detail...it is process-scale chromatography under cGMP conditions

@lmh

my "bench top buddies" from my old college days will have columns that sit in various storage conditions, never repacked with any confirmation of sanitization using TOC or PCR's and complain when an experiment go wrong. So trust me i understand.

Thanks for some of the feedback