1-fluoro-2,4-dinitrobenzene (DNFB), and 1-chloro-2,4-dinitrobenzene (DNCB) can both be used for derivatization of primary amines, comparatively which one would be better for HPLC pre-column derivatization?
there is no big difference between them .but select (DNCB) if the purity of it is more than DNFB . also you need to check relative polarity of both and which is close to the amine you can select it.