A fluorescence quenching method for determination of chitosan

A sensitive fluorescence quenching method was developed for the determination of chitosan based on its notable quenching effect on the fluorescence of fluorescein in a sodium phosphate buffer solution(pH 6.3).The quenched degree of fluorescence of fluorescein at a fixed concentration was in linear relationship with the added concentration of chitosan.The linear equation of the method was ΔF=64.02+42.28ρ(mg/L)(R2=0.9942) with the linear range of 0.5～10.0 mg/L and the detection limit of 0.27 mg/L.The relative standard deviation was 4.5%(n=6) and the mean recovery was 99.3%.This method can be applied to the determination of chitosan in complex samples.