I am facing a carry-over issue in my Ultivo attached 1260 Infinity series UHPLC

Hi MilJoseph, we have a carry over routine that may help. Intelligent reflex...allows you to program the system to automatically inject blanks if carryover is detected. Please reach out ian.edwards@agilent.com

Thank you for extending help and will communicate via email

Hello, we are also seeing Daminozide(Alar) carryover for our residual pest/mycotoxins method. We see low peaks on most samples we run, and when injecting concentrated standards the carryover is very present. Could you please elaborate on the Intelligent reflex or point me in the right direction? Any help is appreciated  

In our system, we were able to manage  with multiple wash modes (https://www.agilent.com/cs/library/technicaloverviews/public/5991-6051EN.pdf) and choosing solvents with different strengths worked for me  Here is the link for the document on intelli reflux  https://www.agilent.com/cs/library/posters/public/ps-ireflex-masshunter12-asms-2022-mp326-en-agilent.pdf 

Hi MILJOSEPH ,

The solvent you use in your Multi-wash is crucial. We recommend using a solvent that will dissolve your samples well to minimize carry-over and this will be application dependent. One of the lines of the Multi-wash need to be the initial condition of your gradient to avoid retention time issues.

If you experience excessive carry-over and the Multi-wash cannot remove it, I recommend performing maximum volume injections of isopropanol (or a solvent that will dissolve your compounds of interest well, I like IPA as it is high viscosity and a compatible organic solvent for reverse phase and normal phase chromatography). Perform 10-20 injections with a run time of 0.1-0.2 minutes each (if your sample loop size is 100uL, please inject 10-20 times 100uL/injections). Use a restriction capillary to increase the pressure close to the system’s maximum pressure. Sent it to waste, no column or detector in place.

Then, perform maximum volume injections of your mobile phase (10 injections with a run time of 0.1-0.2 minutes each). Again, use a restriction capillary to increase the pressure close to the system’s maximum pressure.

This process will help clean the sampler in both Mainpass and bypass modes.

 Regards,

Hi Philippe Lebel when you say use a restriction capillary - is this in place of the analytical column along with a zero volume union? 

Thank you for the advice. right, we are fine with the existing results. Will use this washing procedure with IPA if we observe issue in future

Hi louh, 

The restriction capillary will replace the column and help increase the pressure significantly to help remove the carry-over. You might also want to bypass the detector to avoid sending all this dirty materials in the detector.

I hope this help.