I'facing problem while doing HPLC analysis due to negative peak was eluted which was corresponding to the principle peak RT. I tried to remove, with different solvents, but no use. i want to know the reason for negative peak and solution for that one.
https://pubs.rsc.org/en/content/articlelanding/2016/ay/c6ay01075j/unauth#!divAbstract
Hello.
You need to give us more information about your run to evaluate the potential reason for a negative peak. Troubleshooting will vary between different detectors such as refractive index, conductivity and UV detectors, for example.
If you are using plain HPLC-UV/PDA system, then for a negative peak to show in your blank injections something in the diluent absorbs less light than the mobile phase. Try dissolving your sample in mobile phase before injection and see if negative peak is still there. If it's only visible in the sample but not in the blank (diluent), then the analyte has lower absorption than the mobile phase, so you need to change the mobile phase or wavelength. If that's the case, use a PDA detector if you have one available to scan for a wavelength that would be better suitable. If you see the negative peak in all samples and don't see it in blanks, has a decent shape and is proportional to changes of concentration, then you are likely having your detector polarities reversed.
Those above are some common cases. For a more accurate answer, try to provide method parameters (isocratic/gradient, flow, wavelength), mobile phase, diluent, sample prep, system used, and chromatograms or retention times.
Thanks Petroslav chipinski for your valuable suggestion.
I'm facing this problem mainly in diluent only(initial Blank injections) and i'm using UV detector with Waters and shimadzu systems.
Is the composition of the blank the same as that of the eluent? If not, the blank might have lower absorption than the mobile phase, and when it goes through the detector you will see a drop in absorption (negative peak).
I'm using water as a diluent, and my phase is percholric acid(70%) in water, sometimes only negative peak is coming, Why?
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