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RI detector - flow gradient
Posted: Tue Jun 23, 2020 7:14 pm
by Kaliane
Hello, guys
it's known that we should never use gradient elution when the detector is a RID. But can I do a flow gradient with this detector?
Re: RI detector - flow gradient
Posted: Tue Jun 23, 2020 11:37 pm
by tom jupille
My experience with RI detectors is that they are somewhat flow sensitive. The only way to find out if that's problematic in your case is to try it. That said, I'm not a big fan of flow programming in any case.
Re: RI detector - flow gradient
Posted: Mon Jun 29, 2020 5:17 pm
by Multidimensional
Answer to OP's question. NO. Adjusting the flow rate will change the backpressure , solvent compressibility and perhaps the piston stroke volume (stroke volume is related to flow rate setting) too, which may change the RID signal. A thermal change may also occur (heating or cooling). Changes require a gradual re-equilibration to stabilize (TIME). This means the baseline will change. So no, RID is for isocratic analysis at fixed flow rates only.