I am getting a massive baseline drift of 1200 mAu when I use THF as my organic solvent. I do not get that with acetonitrile. I run a gradient from 50/50 to 100% THF over 7 min. The baseline drift starts after ~2 min when the THF content is is at ~60%. I get it with reference (bandwidth 100 nm) on or off. How do I correct so I get a flat baseline?