Abstract:

Extraction and separation of pigments from spinach leaf is an important experiment in organic chemistry laboratory, conducted at universities. However, in experimental teaching, there have always been problems, such as the use of toxic or controlled reagents, long experiment time, cumbersome experimental steps, and poor experimental results. In this study, the conditions of thin layer chromatography were systematically explored. A variety of reagent combinations, such as n-hexane/anhydrous ethanol and n-hexane/n-butanol, were tested. It was found that the developing agent with the best separation effect was n-hexane/anhydrous ethanol solution, with a volume ratio of 10 : 1. The n-hexane/absolute ethanol and n-hexane/n-butanol were also used as eluents to explore column chromatography separation experiments of the pigments from spinach leaf. By using silica gel as the stationary phase, the optimal gradient elution scheme with n-hexane/absolute ethanol as eluent was obtained; whereas, the optimal gradient elution scheme with n-hexane/n-butanol as the eluent was obtained by using neutral alumina as the stationary phase. Following the improvement, the separation effect was enhanced and the amount of reagent was reduced; furthermore, more friendly reagents were used and the teaching time was shortened.

Key words: Thin-layer chromatography, Column chromatography, Spinach leaf pigment