Hello, I am working on LCMS method for steroid hormones and I see a big difference between untreated serum and steroid-free charcole stripped serum. Raw extracts are different, there are almost no interferences, no ion supression. I measured phosphatidylcholines and they are only about 5% in the charcoal stripped serum than in untreated serum. Is it possible, that charcoal removed phospholipids and other lipids together with steroids? What else is usally removed from serum?