A Green Approach To Separate Spinach Pigments by Column Chromatography

Abstract

Chromatography has been a fundamental technique used for chemical separation that dates back to the 1850s. Specifically, column chromatography, typically taught in introductory organic chemistry laboratories, traditionally involves the use of halogenated or harmful solvents, which novice students often overuse. This situation runs contrary to the principles of responsible chemical and waste management emphasized by the green chemistry movement. Since this movement began, conventional means of separation using harmful solvents have been modified to emphasize the need for safer, less hazardous materials and the generation of such waste. The current experiment emphasizes the green chemical principles of renewable feedstocks and recycling to minimize waste, while simultaneously introducing or reinforcing common organic techniques, including solvent extraction, column chromatography, and thinlayer chromatography for the isolation and identification of photosynthetic pigments from spinach leaves. Students gain practical experience processing plant material to isolate and identify the pigments, β-carotene, xanthophylls, and chlorophyll a, using the solvents hexane and acetone. This experiment was designed for use as a standalone single-session lab or, alternatively, it can be coupled with an experiment to recycle waste acetone to further emphasize sustainable practices.

Utilizing the electron transfer mechanism of chlorophyll a under light for controlled radical polymerization

“…Because spinach is an affordable and renewable feedstock, it can be used as the raw material for the extraction, isolation and characterization of Chl a. 25 Chl a was extracted from spinach leaves and purified by column chromatography as previously reported. 25 , 26 Water miscible solvents such as pyridine, methanol, ethanol, acetone, N , N -dimethylformamide (DMF) and dimethylsulfoxide (DMSO) are most suitable for extraction of chlorophyll.…”

“… 25 Chl a was extracted from spinach leaves and purified by column chromatography as previously reported. 25 , 26 Water miscible solvents such as pyridine, methanol, ethanol, acetone, N , N -dimethylformamide (DMF) and dimethylsulfoxide (DMSO) are most suitable for extraction of chlorophyll. Extraction in the absence of a suitable solvent may lead to oxidation or hydrolysis of chlorophyll molecules.…”

Scientific experiment focused at pigment degradation by polyvinyl chloride combustion in Science education

“…The selection of a suitable analytical method for the identification and quantification of pigments from the plant matrix depends on the characteristics of required data (Dudek, Strzelewicz, Krasowska, Rybak & Turczyn, 2014). The most frequently used instrumental methodologies are the UV-VIS spectrophotometry, fluorescence spectroscopy and chromatography (Garber, Odendaal & Carlson, 2013;West & Rauch, 1994;Ayudhya, Posey, Tyus & Dingra, 2015;Johnston, Scaggs, Mallory, Haskett, Warner, Brown, et al, 2013;Galloway, Bretz & Novak, 2015;Rollins, 1963;Lalitha, 1994;Kimbrough, 1992;Valverde, This & Vignolle, 2007). Each of these techniques has several advantages; however, the UV-Vis spectrophotometry is the most suitable for the routine determination of the pigment concentration in the extract from the mixed plant samples, as it generally does not require complicated separation and purification processes.…”

Cinnamon Oil: An Alternate and Inexpensive Resource for Green Chemistry Experiments in Organic Chemistry Laboratory

“…Graduate students in the Department of Chemistry at the University of Toronto organized the Green Chemistry Initiative in 2012 to promote green and sustainable chemistry education and research by providing green chemistry education resources . Institutions such as Westminster College in Pennsylvania, U.S., have also incorporated undergraduate green chemistry courses into their programs, and several green chemistry laboratories − have been developed to promote green chemistry initiatives and integrate green chemistry practices into undergraduate laboratories. In one example, Purcell et al designed and implemented a multiweek analytical chemistry experiment where essential oils were extracted from thyme leaves and studied for their antimicrobial activity .…”