Carryover in reversed phase column

[swarup_80]

My compound is having solubility in DMSO and not other solvents methanol,acetonitrile.

Sample preparation is initially in DMSO and further dilution with mobile phase.

Problem: I am getting carryover of my compound after its injection.Blanks were injected after my compound injection.Carryover is coming exactly at same retention time of my compound.

I tried all the possibilities and cleaned injector with DMSO ,column makes were also changed.but problem is still not resolved.

Can I used DMSO in mobile phase to get rid of carryover?
Can I used DMSO:methanol mixture in Needle wash?

Pl suggest.

[mbreslav]

You can use DMSO/MeOH as your needle wash solvent. Could you please tell us what HPLC are you using, what is your injection mode, what is composition of your sample solution, and what is your mobile phase and gradient?

[zheyin]

My compound is having solubility in DMSO and not other solvents methanol,acetonitrile.

Sample preparation is initially in DMSO and further dilution with mobile phase.

Problem: I am getting carryover of my compound after its injection.Blanks were injected after my compound injection.Carryover is coming exactly at same retention time of my compound.

I tried all the possibilities and cleaned injector with DMSO ,column makes were also changed.but problem is still not resolved.

Can I used DMSO in mobile phase to get rid of carryover?
Can I used DMSO:methanol mixture in Needle wash?

Pl suggest.

I have a similar problem:
If I only inject standard in Mobile phase, there's no carryover.
There is carryover of the sample injection (containing very low amount of DMSO), even though the API level in the sample injection is very low <1% of the W.S.. There will be carryover (at LOD level) in my blank.
I tried to inject multiple times of the blank, the API peak decreased to~50% and stayed there.
My needle wash was ~50% Aq/50% Organic
Then I tried 96% organic as the needle wash, the injector seemed to be cleaned up: no carryover observed in the blank. I'd need more samples containing DMSO to confirm.