Shimadzu UPLC injector reproducibility problem

[qfiviera]

Hi guys.
We bought two Nexera UHPLC about a year ago. Since then, we had several problems with reproducibility, for example, having RSD about 27-30% with some methods, last one were six injections, and the third one was about 1/3-1/4 of the area. Don´t know why. I know is very important needle wash, R0 solvent, purge, etc, but it`s more difficult than HPLC. Could anyone bring me some tips?

[Bluesman75]

We had a similar problem with our Dionex system and this was traced to air bubbles in the autosampler syringe. We were caught out as the Dionex system was different design to our usual Agilent systems. If your system does use rinse solvents and a syringe design make sure the solvents are well degassed.

Unfortunatly I can't find any information on the Nexera autosampler design to see if this could be a problem.