Persistent Carryover

Can you give us some details about that modules you have? What is the method? What are the compounds of interest? What column are you using?

A little bit of details will help us figure out what you are trying to do and give better ideas

Hi,

We are running on 1200 and 1260, quaternary pump, DAD detectors.

The compound of interest in this case is Trifluoperazine HCl, running phosphate buffer with triethyamine and ACN gradient.

The column is an Agilent Poroshell 120 EC-C18 2.7µm 50 x 4.6mm

The method has been validated for product license requirements.

The issue was seen during the development and validation process intermittently however we were never able to get to the bottom of the issue.

Sometimes we don’t see any ‘carryover’, sometimes we see a small amount, this time I have seen ~1%

I’m at a bit of a loss to explain it so welcome almost any suggestions.

Kat

HI,

Just this compound, though there are multiple compounds in the solutions.

And no, both diluent injections and blank gradient runs don’t show significant reduction of the peak in question.

If we very thoroughly clean the system, this seems to improve the amount of the peak present, but it does seem to increase again fairly rapidly.  We can sometimes squeeze out a run before the peaks gets problematically big.

The development analyst tried multiple syringe washes including IPA to clean up between injections with no luck

Kat

HI,

Just this compound, though there are multiple compounds in the solutions.

And no, both diluent injections and blank gradient runs don’t show significant reduction of the peak in question.

If we very thoroughly clean the system, this seems to improve the amount of the peak present, but it does seem to increase again fairly rapidly.  We can sometimes squeeze out a run before the peaks gets problematically big.

The development analyst tried multiple syringe washes including IPA to clean up between injections with no luck

Kat

Inj vol 5µm

Area in Std – 16

Area carried into diluent – 0.15

Concentration of std – 0.1mg/ml

What is the area of the peak? what volume of injection are you running? What is the amount injected into the column for that peak?