Abstract: The stray light is one of the most key performances of spectrum instruments, especially when the light signal to be detected is very weak. The main source of stray light in two monochromators of fluorescence detector for high performance liquid chromatography (HPLC) was analyzed. Through the ASAP software modeling, the formation and distribution of stray light in monochromator were simulated, several structures for stray light suppression were presented and designed, including the apertures, vanes and light baffles, then their stray light suppression effects were estimated. When these three structures are installed in the monochromator simultaneously, the stray light suppression ratio can reach up to 80%. The simulation results are verified through experiments, and the experimental results and the simulation results agree well.

Key words: fluorescence detector, monochromator, stray light, vanes