(S)-(+)-1-Methyl-2-(6,7,-dimethoxy-2,3-naphthalimido)ethyl trifluoromethanesulfonate as a fluorescence chiral derivatizing reagent for carboxylic acid enantiomers in high-performance liquid chromatography

A new triflate-type fluorescence chiral derivatizing reagent, (S)-(+)-1-methyl-2-(6,7-dimethoxy-2,3-naphthalimido)ethyl trifluoromethanesulfonate, S-(+)-MDNE-OTf], has been developed for the determination of the enantiomers of carboxylic acids. By introducing the two methoxy groups on the naphthalimido ring moiety, the red shift in the fluorescence spectrum and a high resolution in reversed-mode separation of the diastereomers of chiral carboxylic acids have been achieved. The detection limits (S/N=3) with ultraviolet and fluorescence detection are 8 fmol (λ_max=283 nm) and 4 fmol (λ_ex=283 nm, λ_em=467 nm), respectively.