Extraction and Purification of the Pigment of Natural Brown Cotton and its UV Spectral Properties

In the procession of extracting the pigment of natural brown cotton,16 kinds of chemicals were selected as the solvents to dissolve the fiber of natural brown cotton,of which both the distilled water and NaOH(pH=9) were the most effective and economical. On this basis,the pigment of natural brown cotton was extracted and purified,and it's UV spectrum and chemical characters were also analyzed. Our results indicated Ethanol- precipitation method,re-crystallization-method,copper or lead salt-precipitate method,paper chromatography method and column chromatography were practical purification methods of the pigment. Analyzing the UV spectrum of natural brown cotton,there were strong absorbed peak near in 218 nm and weak absorbed peak near 264 nm,which suggests double bands and phenol hydroxyl existed in the chemical structure of the pigment.