I would like to measure the flavonoids of strawberries by HPLC. The solvent A is 0.01% TFA in water and the solvent B is 0.01% TFA in acetonitrile. The column is C18. The base line always go up and the peak area is very samll. The 280 nm wavelenth seems better than 520nm. I really have no idea what happens. I hope you can give me some advice coz I just started to use HPLC.