Hello,
We are facing this issue when we run pesticides analysis in our lab. At the beginning of the batch everything is ok, but after a period of time (approximately 7-8 hours) the signal decreases more and more until it is almost zero. In some cases this happens even after 3-4 hours of LC running.
I have rinsed the whole system with solvents (mobile phase tubes, column, the nebulizers and the capillary).
Have anyone encountered something like this?
