I am trying an assay/impurities method for a steroid. The graphite column shows great selectivity but the peak shape needs improvement. So far I have tried a simple gradient with 0.1%TFA and increasing ACN and got a bunch of shark fin peaks which look like mass overload. Not much was loaded though.

I also tried dilute H2SO4 with ACN gradient and H2SO4 with 0.3% SDS and ACN gradient and got poor tailing. Not shark fins but still bad.

I am trying positively charged surfactant next. Good or bad idea?