Hello Agilent Community, I am experiencing negative TIC peaks. I have run standards that I have run before with the same buffer, method etc. but instead of expected positive TIC, I am seeing a negative peak (it drops down instead of up) when my analyte elutes. I have tried flushing the system for hours with water, then IPA, then water and made fresh tuning mix, reference mix, and buffers but nothing has seemed to help. I also have cleaned the source. Does anyone have any suggestions? Thank you for any help.