In my experiment, 0.1 mM of 3,5 DCA was incubated in 0.1M citrate phosphate buffer for 24 hours for disspation test. After 24 hours incubation, the matrix was centrifuged and filtered in 0.45 nylon syringe filter. Then the filtered samples were tested for its dissipation rate.

But, unfortunately, there is a huge peak at 2.4 minutes Retention time (RT); while run in LC-UVD. The parameter are 50:50 Water:Acetonitrile mobile phase and 212 nm wavelengths and the DCA peak at 8.3 minutes RT.

How can I remove this disturbing early peak in LC-UVD?