Extraction and identification of natural pigments from water hyacinth

Water hyacinth is an ideal resource for natural pigments due to its high pigment contents. In this paper, the stems and leaves of water hyacinth harvested from Shanghai district were used as raw material for natural pigments extraction. Natural pigments were extracted with absolute ethyl alcohol by ultrasonic and separated and purified by column chromatography and thin layer chromatography. Chemical reaction, UV-VIS, FTIR, and mass spectrometry were used to identify main components. The results showed that crude pigments extraction efficiency were 6.86%. Seven pigments bands can be observed by column chromatography isolation. The first, the second and the fourth pigment bands were relatively high purity compounds. The main components of these seven pigments bands were cis-β-carotenoids, pheophytin a, pheophytin b, chlorophyll derivatives, chlorophyll a, chlorophyll b, and lutein, respectively. The quality percentage of pheophytin-a in the extracted pigments was up to 28%. And that of carotenoids in the extracted pigments was about 9%. These results suggested the promising prospects for these two pigments widely application in textile industry.