Complexes of morin and quercetin with boric acid and oxalic acid in acetic acid medium. Fluorimetric determination of boron

The binary and ternary fluorescent complexes of morin or quercetin with boric acid and oxalic acid in an anhydrous acetic acid medium are described. The physico-chemical and spectral properties and chemical composition of these complexes have been established. The ternary complexes are suitable for fluorimetric determinations of boron. The limits of detection are 0.1 ng B ml^-1 and 0.3 ng B ml^-1, for the morin and quercetin complexes, respectively, and calibration graphs are linear up to 10 μg B ml^-1.