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The Liebermann–Burchard or acetic anhydride test is used for the detection of cholesterol. The formation of a green or green-blue colour after a few minutes is positive. Lieberman–Burchard is a reagent used in a colourimetric test to detect cholesterol, which gives a deep green colour.
13 de oct. de 2019 · This study, therefore, aims to develop and validate a Liebermann–Burchard method for the assay of cholesterol and use it to assess the content of cholesterol in selected dairy products on the Ghanaian market. Figure 1. Reaction scheme for derivatization of cholesterol through Liebermann–Burchard reaction [ 15, 17 ].
- Joseph K Adu, Cedric D K Amengor, Naomi Kabiri, Emmanuel Orman, Stella Abla Gameli Patamia, Bernice ...
- 10.1155/2019/9045938
- 2019
- Int J Food Sci. 2019; 2019: 9045938.
En este caso es factible determinar el colesterol total usando el Método de Referencia para colesterol denominado de Abell-Kendall modificado. Este método se basa en tres procesos: Saponificación de los esteres de colesteril, Extracción y Cuantificación del colesterol con el reactivo de Liebermann-Burchard.
Representando aproximadamente el 5 % del. peso total de la molécula de saponina, como lo establece Baccou et al ., (1997). Se trabajó con metanol debido a la notable coloración que se produce durante la reacción entre las sapogeninas y el reactivo Lieberman - Burchard.
- Preliminary Studies of The Lb Reaction
- Studies of Lb Reaction Products with [4-14C]cholesterol
- Sterols Produced by Lb Reaction A
- Sterols Produced by Lb Reaction B
- Structure Elucidation of Compounds 10–20 by NMR and Mass Spectrometry
- Reactivity of Cholesterol Under Salkowski Conditions
We initially explored many variations of the LB reaction. Under nearly all conditions, the reaction progressed from colorless, to pale blue, blue, bluish green, and green. A modified LB reagent with a 4:20:10 ratio (elevated amount of H2SO4) increased the absorbance and was used in some studies. LB reactions with ethanol-stabilized chloroform were ...
Reaction of [4-14C]cholesterol (25 mg; 500,000 dpm) in chloroform (15 mL) with LB reagent (2.5 mL, 1:20:10 ratio) at room temperature produced a bluish-green color after 30 min. The mixture was immediately chilled to −70 °C and quenched by dropwise addition of cold 24% NaOH (10 mL). Scintillation counting of the resulting aqueous and organic layers...
To a solution of cholesterol (250 mg) in chloroform (25 mL; stabilized with 0.75% ethanol) was added LB reagent (1:20:10 ratio, 10 mL). The solution gradually turned blue and, before any appearance of green color, the reaction was quenched with 24% aqueous NaOH (3 mL) followed by water (20 mL). The precipitate that formed between the chloroform and...
To a solution of cholesterol (2 g) in chloroform (40 mL) was added LB reagent (4:20:10 ratio, 20 mL). After 30 min at room temperature, the bluish-green solution was chilled and quenched with ethanol (60 mL) at −78 °C. The resulting yellowish-green mixture was evaporated in vacuo at 40 °C until there was no odor of acetic acid. Water (15 mL) and 24...
Because of the extensive rearrangements and/or presence of sulfonate groups, the structures of 10–20 were not readily established by comparisons with NMR spectra of known compounds. Each of these steroids was analyzed by heteronuclear single quantum coherence, heteronuclear multiple bond correlation, correlation spectroscopy with F1 decoupling, and...
To cholesterol (1 mg) in CDCl3 (0.6 mL) in an NMR tube was added D2SO4 (1 μL). The tube was inverted several times (the solution becoming pale pink), placed in the magnet, and maintained at 15 °C for 2 h while 25 1H NMR spectra were measured at 2–10-min intervals. NMR analysis indicated rapid formation of Δ3,5 diene 9. The ratio of Δ5, Δ3,5, and ot...
- Quanbo Xiong, Quanbo Xiong, William K. Wilson, Jihai Pang, Jihai Pang
- 2007
reacción de Liebermann-Buchard - Chemwatch. Reacción de Liebermann-Buchard. un color azul verdoso producido por anhídrido acético con colesterol (y otros esteroles) disueltos en cloroformo, cuando se agregan unas gotas de ácido sulfúrico concentrado. SYN: prueba de Liebermann-Buchard. Email Facebook Twitter Pinterest Share.
1 de mar. de 2007 · The Liebermann–Burchard Reaction: Sulfonation, Desaturation, and Rearrangment of Cholesterol in Acid. March 2007. Lipids 42 (1):87-96. DOI: 10.1007/s11745-006-3013-5. Source. PubMed. Authors:...
