Studies On Application Of Chitosan To Fluorescence Spectrometry

Application of chitosan to fluorescence spectrometry is presented in the thesis, which includes five parts. I. Chitosan dissolves neither in water or basic solution nor in organic solvents, but dissolves in many kinds of diluted acids to form salt. Purification of chitosan and determination of its degree of deacetylation by titration method are based on these properties. II. A novel method for determination of amino acid by fluorescence spectrometry has been developed. It is based on the fluorescence quenching effect by adding amino acid into the fluorescence system of chitosan and ninhydrin. The linear range is from 0 to 1.2×10-4mol·L-1 and R = 0.9966. The method has been applied to the determination of amino acid in juices with satisfactory results. III. A novel method for determination of Cu2+ by fluorescence spectrometry has been developed. It is based on the fluorescence enhancement effect by adding Cu2+ into the system of chitosan and ninhydrin. The linear range is 0~0.5×10-6mol·L-1 and R = 0.9965. The method has been applied to the determination of Cu2+ in samples with satisfactory results. IV. A novel method for determination of Cu2+ by fluorescence spectrometry has been developed. This method is based on the fluorescence enhancement effect by adding Cu2+ into the system of chitosan and glutaraldehyde. The linear range is 0 ~ 0.6×10-6mol·L-1 and R = 0.9980. The method has been applied to the determination of Cu2+ in water samples with satisfactory results. V. The determination principles were discussed. The reaction product of chitosan and ninhydrin forms a cycle-sized compound that can give out fluorescence. Amino acid will compete with chitosan for ninhydrin and quench the fluorescence of this system. Cu2+ can enhance the fluorescence of these two systems by complexing with the reaction products in the systems.