We are working on pasma level of Rosuvastatin in hyperlipidemic patients. we tried deproteinization methods e-g with ACN, ethanol, and diethylether in one or two step extractions. the problem is that

we couldn't get any smooth baseline so for, numerous random peaks all the way till the end. (for standard, it is perfect smooth baseline)

could someone guide me how to controle it. our RT is 4.2 min.