Your baseline noise is very high relative to your strong signal level. What type of detection are you using? Are you continuously degassing your mobile phase?

Please provide some of the details of the HPLC method used (Column type and dimensions, flow rate, mobile phase type & composition (gradient or isocratic?) and time table, injection concentration and volume, detection settings (detailed), temperature and so on) plus injection solvent used.

yes,i am using c18 column ,and mobile phase is acetonitrile and water ,acetic acid-ratio(49;49;2)-temperature- 40 Co,

flow rateis 1ml per min

detector -fluorescence detector ( i use gradient and isocratic)

10ppb-100ppm concentration i try this

20 ul only i injected and i am using shimazu 20 model

Column dimensions please.

If you are running isocratically. switch to a gradient to improve your separation.

i am using gradient also not got and column dimensions is 150*4.6 mm