Manninen Marianna, Vesterinen Veli-Matti, Salminen Juha-Pekka
Natural Chemistry Research Group, Department of Chemistry, University of Turku, FI-20014, Turku, Finland.
Department of Chemistry, University of Turku, FI-20014, Turku, Finland.
J Chem Educ. 2020 Mar 10;97(3):772-777. doi: 10.1021/acs.jchemed.9b00436. Epub 2020 Feb 14.
The autumnal leaf color change is a familiar phenomenon to most students living in temperate climate zones. The extraction and analysis of the pigments of the autumn leaves provide an engaging way to study the phenomenon utilizing both simple as well as more sophisticated analytical methods. In this laboratory experiment, students extract the red and yellow pigments, that is, anthocyanins and carotenoids from leaves and separate them from each other by liquid-liquid extractions. From the separated phases, anthocyanin and carotenoid concentrations can be evaluated visually or spectrophotometrically. The anthocyanins are analyzed by a rapid and simple ultra-performance liquid chromatography-tandem mass spectrometry method to discover which of the six most common groups of anthocyanins are present in the sample. The simplicity of the experiment setup allows it to be used as an introduction to mass spectrometry since the results can be easily interpreted without complicated data processing. The experiment provides opportunities for learning outside the classroom, as the samples can be collected from the nearby parks or forests and analyzed using more sophisticated methods on a student visit to a university or other research institution. The sample preparation followed by the visual analyses of the phases is however simple enough to be performed in a regular school laboratory.
对于大多数生活在温带气候区的学生来说，秋天树叶颜色的变化是一种常见的现象。对秋叶色素进行提取和分析，为利用简单及更复杂的分析方法研究这一现象提供了一种引人入胜的方式。在这个实验室实验中，学生从树叶中提取红色和黄色色素，即花青素和类胡萝卜素，并通过液-液萃取将它们彼此分离。从分离出的相中，可以通过目视或分光光度法评估花青素和类胡萝卜素的浓度。通过一种快速且简单的超高效液相色谱-串联质谱法分析花青素，以确定样品中存在六种最常见的花青素中的哪一种。实验设置的简单性使其可以用作质谱分析的入门，因为无需复杂的数据处理就能轻松解释结果。该实验为课堂外的学习提供了机会，因为样品可以从附近的公园或森林收集，并在学生参观大学或其他研究机构时使用更复杂的方法进行分析。然而，样品制备以及对各相的目视分析足够简单，可以在常规学校实验室中进行。
