Separation science and chromatography. A colorful introduction

Wigman, Larry; Kelsch, Catherine T.

doi:10.1021/ed069p991

Cited by 10 publications

(11 citation statements)

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“…This enables students to visually follow the solubility change and partition between the two immiscible layers after shaking the separatory funnel. Dyes have been widely used to illustrate a variety of chemical properties and concepts such as solubility, acid–base chemistry, chromatographic separation, distillation, and LLE. ,,,− ,− In previous work describing laboratory experiments on LLE, authors employed these colored compounds as a visual aid to help students determine the partitioning of molecules into different layers as a function of pH. Sudan Blue and Congo Red, or Nile Blue and 2,6-dichloroindophenol, are among the most common dyes utilized for this purpose.…”

Section: Discussionmentioning

confidence: 99%

Visually Tracking Acid–Base Extractions Using Colorful Compounds

2020

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Acid–base extraction is an important concept in organic chemistry that beginning students often find challenging to comprehend. Herein, we describe the use of a simple demonstration suitable for lecture that allows students to visually track the chemical events that take place in a separatory funnel. The demonstration involves the use of two safe and available dyes with different acid–base properties, phenolphthalein and neutral red. The dyes present distinct colors in their ionic and nonionic forms. With a change in the pH of the media in the separatory funnel, the colors of the solutions change according to the compounds’ ionic states and their solubilities in either the aqueous or the organic layers. This provides a visual record of chemical concepts, which helps students to better understand the partition of different molecules between the organic and aqueous layers in an extraction process. In addition, we provide resources describing how to use this demonstration in class aiming to enhance students’ engagement and comprehension of the topic.

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Section: Discussionmentioning

confidence: 99%

Visually Tracking Acid–Base Extractions Using Colorful Compounds

2020

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“…The stationary phase is silica gel while the mobile phase is non-polar. This set up was to separate the sample based on the polarity [18] , to obtain the pure desired compound. Flash chromatography allows rapid elution to separation in short time and minimize dispersion of the compound in solution [19] .…”

Section: Isolation Of Morin Using Flash Column Chromatographic Techniquementioning

confidence: 99%

Isolation of Bioactive Compounds and Free Radical Scavenging Activity of Maclura Cochinchinensis (Lour.) Corner Stem by Different Chromatographic Techniques

2020

IJPHRD

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Antioxidants provide protection to human against free radicals through inhibiting and scavenging mechanism. This study was to determine the free radical scavenging activity of Maclura cochinchinensis Corner stem sample from different extraction methods to investigate the bioactive compound in stem extract. Materials and methods: The stem samples of M. cochinchinensis were extracted by sonication, maceration and soxhlet method with four different solvents; acetone, 50% ethanol, 80% ethanol and methanol. Each extracts was tested using 2,2-diphenyl 1-picryl hydrazyl (DPPH) radical scavenging activity assay with ascorbic acid and morin as positive control. Findings: For isolation of bioactive compound highest percentage yield of the crude extracts was from 50% and 80% ethanol(22.0 ± 1.35 % and 20.7 ± 2.29 %), followed by acetone (IC 50 of 15.54 ± 1.34 µg/ml) and methanol (IC 50 of 20.99 ± 1.07 µg/ml)extract by Soxhlet method not significantly different, also had higher radicle scavenging activity, DPPH test on 80% ethanol extract from soxhlet extraction was one of the highest antioxidant activity among the extracts.

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“…A literatura relata poucos experimentos de cromatografia em coluna para separação de substâncias naturais 1,5,15 , sendo que a maioria usa esta técnica para separar pigmentos sintéticos 3,4,11,13,16 , isômeros de nitrofenol 17 e princípios ativos de medicamentos 2 . Misturas de pigmentos são freqüentemente preferidas porque a cor permite sinalizar ou visualizar o processo de separação, dispensando análise qualitativa complementar.…”

Section: Introductionunclassified