Abstract A new university organic chemistry experiment has been designed that is extraction and chromatography separation of plant pigments. In this experiment, the ketchup raw material has been dehydrated by absolute ethanol, and a mixed solution of lycopene and carotene has been obtained with solvent extraction with dichloromethane. Then, petroleum ether and a certain ratio of petroleum ether and dichloromethane mixed solution are used as eluent to separate the carotene and lycopene solutions by column chromatography. Finally, cyclohexane and dichloromethane mixed solvent are used for thin layer chromatography to separate and identify the tomato pigments and carotene. The results show that both thin layer chromatography and column chromatography have achieved ideal separation effects, and the experiment success rate of students is higher. This experiment provides an experimental project for natural pigment extraction and chromatography separation in organic chemistry experiments that the raw materials are easy to obtain, the pre-treatment is simple, the experimental techniques are diverse, and the applicability is wide. At the same time, the different pigments separated are isomers, which can better reflect the technical advantages and characteristics of chromatography separation method in teaching.
LI Hong-Bin, LI Zheng, ZHOU Ming-Juan, DING Chang-Jiang, XU Hai. New Organic Chemistry Experiment: Extraction and Chromatography Separation of Tomato Pigment in Ketchup[J]. Chinese Journal of Chemical Education, 2024, 45(20): 35-42.
