Hello Friends,
I am working on Lumenfantrine analysis by HPLC as per USP method, but in USP 38 column temperature mentions as Column temperature: Beginning of column, 50°; end of column, 35°.
This created lots of confusion could anyone clarify on this whether this is column oven temperature programming in method or kept different temperature on both end of column which is not feasible.
Hello Santosh,
reading the monograph for your method, I believe that the column compartment holding the injection end of your column should be set to 50C while the compartment of your column heater heating the end of your column leading to the detector should be set to 35C, i.e. you have a permanent temperature gradient in your column.
Good luck!
Hi Sabine Harrison,
Thanks for your valuable answer.
But is it possible with any system to set different temperatures at column inlet and column out let, if there is any such HPLC then please let us know.
As per my experience with Liquid chromatography it is not possible as column is constructed with metal (SS) and metal is very good conductor of heat. So it doesn't looks feasible to set different temperatures at column inlet and out let. second problem with setting different temperature is length of column as per USP which is 50 mm only.
In my opinion this should have been performed by programming column oven temperature i.e. by keeping 50°C at start of analysis and 35°C at end of analysis (continuous decrease in temperature like mobile phase gradient) which is a feature of most of HPLC column ovens.
- waiting for more answers to conclude the problem.
Dr Bharadwaj is absolutely right.its really interesting as well as some how difficult to perform using the LC system having normal configuration.in this case we have to check which LC they have used and what are the configuration or any modification if they have done.
Dear Santosh Bhardwaj,
Having a temperature gradient with such a short column seems quite unfeasible, you are right. I would try to install the instrument exactly in the middle of the column compartment to ensure that half of the column is exposed to 50C while the other half is exposed to 35C.
Regarding your question for instruments capable of performing this type of analysis: all Agilent HPLC from 1100 series onward can definitely do this (not sure about the older ones as I haven't used those before). The Water Acquity UHPLC has also independant temperature zones for the columns. From experience, the ThermoScientific ones do not seem to be able to have temperature gradients along the column; but I am not sure if they have changed this with the very new instruments (ours is less than 10 years old).
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