Chromatography Forum

Hi:

I have a technique for HPLC LSD and I wolud like to try it using a RID but the LSD method use a gradient elution, my question is if it's possible to use a gradient elution with RID?.

Does somebody know if in some cases is suitable to use gradient elution with RID?.

Regards

Marco

Hi Marco,

Sorry, not really possible to use a gradient method with an RID. The principles of refractive index detection don't allow you to change the composition of the mobile phase.

Out of personal curiosity, if you have a method that works on LSD, why do you want to change to RID?

theoretically, there is possibility to use one pump to make gradient and another one to compensate the rising organic modifier after the column to make mobile phase that is in the reference cell. Problem with that approach would be noise from mixing the mobile phase. This would be too much afford with too little to gain. That is why we love LSD and Corona detectors.