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Tests for flavonoids (a) Alkaline reagent test. Two to three drops of sodium hydroxide were added to 2 mL of extract. Initially, a deep yellow colour appeared but it gradually became colourless by adding few drops of dilute HCL, indicating that flavonoids were present. (b) Shinod’s test.
Sep 25, 2020 · Specifically, Bouras et al. , founded that flavonoid compounds [naringenin, (+)-catechin, (–)-epicatechin, (–)-epigallocatechin] increased ~1.25 times with the presence of 0.01 M sodium hydroxide compared to pure water, when extracting flavonoids from Quercus bark using MAE. This behavior is linked to the fact that basic pHs remove tannins ...
- Jaísa Oliveira Chaves, Mariana Corrêa de Souza, Laise Capelasso da Silva, Daniel Lachos-Perez, Paulo...
- 2020
Jan 1, 2001 · There are many steps separating a quick analysis of a mixture and the accurate determination of the structural features of each constituent flavonoid. A number of techniques used in flavonoid analysis such as nuclear magnetic resonance, (NMR), electrophoresis, and liquid chromatography-mass spectrometry (LC-MS) have not been discussed and the ...
- Stephen J. Bloor
- 2001
Apr 21, 2006 · In the spectra of all flavonoids, the only ions detected were the protonated molecules and the minor sodium and potassium adducts; for the glycosides, glycosidic cleavage was observed. Contrary to studies of flavonoid–glucoside–malonates with ESI– and APCI–MS [44] , [97] , in the MALDI-TOF mass spectra of the glucoside-malonates in the ...
- Eva de Rijke, Pieter Out, Wilfried M.A. Niessen, Freek Ariese, Cees Gooijer, Udo A.Th. Brinkman
- 2006
Fig. 1 and Fig. 2 showed the reaction of flavonoid in sodium hydroxide (NaOH) and sulphuric acid (H2SO4). The results showed that the extract did not contain flavonoids.
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May 21, 2019 · There are various tests for the preliminary identification of flavonoids, e.g.: Shinoda test. Sodium hydroxide test. p-Dimethylaminocinnamaldehyde test. 2.1 Estimation of Total Flavonoid Content (TFC) The flavonoid content of various plant extracts was monitored by the AlCl 3 method. This assay is colorimetric, in which aluminum chloride ...
Aug 23, 2017 · Most of the flavonoids are acidic because of hydroxyl or carboxyl groups, so they could be extracted with alkaline water or alkaline dilute alcohol. The commonly used solvents include dilute sodium hydroxide, lime water, 5% sodium hydroxide dilute ethanol solution and so on.
