Too big time consumption SST

Discussions about HPLC, CE, TLC, SFC, and other "liquid phase" separation techniques.

5 posts Page 1 of 1
Hello board guests,

our HPLC-method takes a lot of time per run, roughly 50min. If we implement SST testing prior to each run,
we lose approx. six hours for every HPLC on every working day.
This does not seem to be an economical procedure.

Did you have similiar problems, if so, how did you solve them?

Thank you already for your help & best wishes!
At what time does the last analyte elute? If it elutes at, let's say, 15minutes, and the rest is washing/equilibration you don't need to wait to evaluate the SST.

We don't run any methods with 50min injections. Are you allowed to change anything to the method itself?
As the method is validated and it does the job quite well I think - for now - the method must not be touched.
The last degradation product elutes at ~32min. A short time afterwards the column is rinsed.
As I want my column to be free of any degradation, I'll need to rinse.
MontrealPhd wrote:
As the method is validated and it does the job quite well I think - for now - the method must not be touched.
The last degradation product elutes at ~32min. A short time afterwards the column is rinsed.
As I want my column to be free of any degradation, I'll need to rinse.


Validated and house-developed methods can be modified -even without validation as per USP 621 and FDA ORA documents. If you make minimal changes to your existing method, you may not need to do a full validation, just document everything.

Your run time is quite long, agree. And agree that you should work on modifying this now.

We used techniques like increasing flow rate (when pressure was low enough), increasing column temperature, faster flow and higher organic during wash out, faster flow during equilibration to help. Shorter or narrower i.d. columns of same packing material can help.
Thermo-Fisher sells (Dionex) instruments that allow for simultaneous use of pairs of LC columns in one system for just such inefficiencies.
Column one collects its (in your case) 35' of data, then an injection and gradient are started on column 2 while column one completes the cleaning portion of its injection offline. By alternating this way, you can cut your time between injections by up to half.

Thermo-Fisher (Dionex) Ultimate 3000.
Thanks,
DR
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