Improved Colorimetric Determination for Furfural in Citrus Juices

1974 ◽  
Vol 57 (2) ◽  
pp. 332-335 ◽  
Author(s):  
Howard L Dinsmore ◽  
Steven Nagy
Keyword(s):  
Acetic Acid ◽  
Glacial Acetic Acid ◽  
Colorimetric Method ◽  
Color Stability ◽  
Colorimetric Determination ◽  
Acid Reaction ◽  
Citrus Juices

Abstract An improved colorimetric method for furfural in citrus juices, which is based on the well known aniline-acetic acid reaction with furfural (Stenhouse reaction), is described. Addition of SnCl2 and HCl yielded higher intensity and improved color stability. The reagent giving the best results contained 1% SnCl2, 0.6N HCl, and 10% aniline in glacial acetic acid.

Colorimetric Determination of Thymol and Eugenol in Volatile Oils

1978 ◽  
Vol 61 (1) ◽  
pp. 169-171
Author(s):  
Mohamed A Korany ◽  
Nabil Abdel-Salam ◽  
Mohamed Abdel-Salam
Keyword(s):  
Acetic Acid ◽  
Sodium Hydroxide Solution ◽  
Colorimetric Method ◽  
Aqueous Acetic Acid ◽  
Colorimetric Determination ◽  
Clove Oil ◽  
Volatile Oils ◽  
Thyme Oil ◽  
Yellow Color

Abstract A colorimetric method for determining thymol and eugenol in volatile oils is presented. Thymol and eugenol are reacted with sodium cobaltinitrite in aqueous acetic acid. The yellow color produced is measured at 330 and 370 nm in chloroform, and at 396 and 450 nm in sodium hydroxide solution for thymol and eugenol, respectively. The method is applied to the assay of thyme oil (thymol type) and clove oil. The results obtained are reasonably reproducible with a coefficient of variation less than 2%.

A Rapid and Specific Ultramicro Method for Total Serum Cholesterol

1962 ◽  
Vol 8 (3) ◽  
pp. 302-309 ◽  
Author(s):  
Robert E Bowman ◽  
Richard C Wolf
Keyword(s):  
Acetic Acid ◽  
Satisfactory Agreement ◽  
Glacial Acetic Acid ◽  
Total Serum ◽  
Total Serum Cholesterol ◽  
High Cholesterol ◽  
Absorbance Spectrum ◽  
Human Sera ◽  
Color Reagent ◽  
Acid Reaction

Abstract A modification of the Zak cholesterol reaction is described in which ethanol is substituted for glacial acetic acid. This modification avoids the hazard of purifying glacial acetic acid and also increases the specificity of the reaction by eliminating interference from bromide or iodide salts. The ethanolic reaction has the absorbance spectrum, sensitivity, and stability of the usual acetic acid reaction. A rapid ultramicro method has been developed based on this ethanolic reaction. A 0.01- to 0.05-ml. sample of serum is extracted with 2.5 ml. of ethanol, and a 2.0-ml. aliquot of this extract is reacted directly with 2.0 ml. of a Zak color reagent. Cholesterol concentrations as determined by this procedure and by the Sperry-Webb method showed satisfactory agreement for monkey and human sera, including normal, hemolyzed, high cholesterol, and severely lipemic or jaundiced sera..

Synthesis and Caracterization of some New 1H-3-aryl-7-etoxycarbonyl-6-methyl-pyrazolo[5,1-c][1,2,4]triazoles

2008 ◽  
Vol 59 (1) ◽  
pp. 41-44
Author(s):  
Maria-Daniela Sofei ◽  
Maria Ilici ◽  
Valentin Badea ◽  
Carol Csunderlik ◽  
Vasile-Nicolae Bercean
Keyword(s):  
Mass Spectrometry ◽  
Acetic Acid ◽  
Nmr Spectroscopy ◽  
Sodium Acetate ◽  
Glacial Acetic Acid ◽  
Ir And Nmr Spectroscopy

The synthesis of 1H-3-aryl-7-ethoxycarbonyl-6-methyl-pyrazolo[5,1-c][1,2,4]triazoles (2) was carried out by cyclization of 1H-5-arylidenehydrazino-4-ethoxycarbonyl-3-methyl-pyrazoles (1) in the presence of bromine using glacial acetic acid as solvent and sodium acetate as base. The new nine obtained compounds were characterized by IR and NMR spectroscopy and mass spectrometry.

Coordination state of cobalt(II) ions in solution and on a sulphonated organic polymer

1979 ◽  
Vol 44 (8) ◽  
pp. 2330-2337 ◽  
Author(s):  
Jindřiška Maternová ◽  
Anastas A. Andreev ◽  
Dimitrii M. Shopov ◽  
Karel Setínek
Keyword(s):  
Acetic Acid ◽  
Coordination Sphere ◽  
Glacial Acetic Acid ◽  
Organic Polymer ◽  
Octahedral Complex ◽  
Coordination State ◽  
Tetrahedral Symmetry ◽  
Liquid Acid ◽  
Homogeneous Phase ◽  
Bromide Ion

It was found spectroscopically that cobalt(II) acetate dissolved in glacial acetic acid forms the octahedral complex [Co(OAc)2(HOAc)4] which in the presence of bromide ions gives the octahedral [Co(OAc)Br(HOAc)4] and tetrahedral bromo(acetate)cobalt(II) complexes with the higher number of Br- ions. When attached to an organic polymer cobalt(II) ions are bonded in the form of octahedral [Co(H2O)6]2+ cations which form with acetic acid similar complexes as in homogeneous phase and are able to coordinate one bromide ion. Drying the copolymer possessing octahedral hexaaquocobalt(II) cations leads to tetrahedral aquocomplexes which are solvated by gaseous acetic acid and converted into the acetate complexes with the liquid acid. The latter contain the acid in the inner coordination sphere and have tetrahedral symmetry.

scholarly journals Nitration of Jharia basin coals, India: a study of structural modifications by XRD and FTIR techniques

2021 ◽  
Author(s):  
Prabal Boral ◽  
Atul K. Varma ◽  
Sudip Maity
Keyword(s):  
Acetic Acid ◽  
Nitric Acid ◽  
Linear Relationship ◽  
Glacial Acetic Acid ◽  
Vitrinite Reflectance ◽  
Aqueous Media ◽  
Interlayer Spacing ◽  
Acetic Acid Medium ◽  
X Ray ◽  
The Media

AbstractFour coal samples from Jharia basin, India are treated with nitric acid in glacial acetic acid and aqueous media to find out the chemical, petrographic and spatial structure of the organic mass by X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) techniques. X-ray parameters of coal like interlayer spacing (d002), crystallite size (Lc), aroamticity (fa), average number of aromatic layers (Nc), and coal rank (I26/I20) have been determined using profile-fitting software. Considerable variation is observed in treated coals in comparison to the demineralized coals. The d002 values of treated coals have increased in both the media showing increase in disordering of organic moieties. A linear relationship has been observed between d002 values with the volatile matter of the coals. Similarly, the d002 values show linear relationship with Cdmf contents for demineralized as well as for the treated coals in both the media. The Lc and Nc values have decreased in treated coals corresponding to demineralized coals. The present study shows that nitration in both the media is capable of removing the aliphatic side chains from the coals and aromaticity (fa) increases with increase in rank and shows a linear relationship with the vitrinite reflectance. The corresponding I26/I20 values are least for treated coals in glacial acetic acid medium followed by raw and then to treated coals in aqueous medium. FTIR studies show that coal arenes of the raw coals are converted into nitro-arenes in structurally modified coals (SMCs) in both the media, the corresponding bands at 1550–1490 and 1355–1315 cm−1 respectively. FTIR study confirms that nitration is the predominant phenomenon, though, oxidation and nitration phenomena takes place simultaneously during treatment with nitric acid to form SMCs. In comparison to raw coals, the SMCs show higher aromaticity and may be easily converted to coal derived products like activated carbon and specialty carbon materials.

Colorimetric Determination of Hydroxyproline as Measure of Collagen Content in Meat and Meat Products: NMKL Collaborative Study

1990 ◽  
Vol 73 (1) ◽  
pp. 54-57 ◽  
Author(s):  
Kurt Kolar
Keyword(s):  
Collaborative Study ◽  
Colorimetric Method ◽  
Meat Products ◽  
Acid Oxidation ◽  
Colorimetric Determination ◽  
Mean Values ◽  
Collaborative Studies ◽  
Freeze Dried ◽  
Analytical Result

Abstract A colorimetric method for the determination of hydroxyproline as a measure of collagen in meat and meat products has been collaboratively studied in 18 laboratories. The method includes hydrolysis with sulfuric acid, oxidation with chloramine- T, and formation of a reddish purple complex with 4- dimethylaminobenzaldehyde. Five frozen and 3 freeze-dried samples were tested, ranging in content from 0.11 to 0.88% and from 0.39 to 4.0% hydroxyproline, respectively. The mean values of 2 identical samples were 0.245 and 0.251 %. The average recovery from a spiked sample was 96.1 %. The hydroxyproline content of a known sample (a mixture of 2 samples in the ratio 5:2) was calculated to 1.42%, which agrees well with the analytical result, 1.40%. In comparison with other collaborative studies, based on the ISO analytical method, the repeatability and reproducibility of this method agree well with the other results. This method was accepted as an official NMKL method by all national Committees, and has been adopted official first action by AOAC as an NMKLAOAC method.

HSCCC Separation of Three Main Compounds from the Crude Extract of Dracocephalum Tanguticum by Using Dimethyl Sulfoxide as Cosolvent

2020 ◽  
Author(s):  
Xue Yang ◽  
Yongling Liu ◽  
Tao Chen ◽  
Nana Wang ◽  
Hongmei Li ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Ethyl Acetate ◽  
Dimethyl Sulfoxide ◽  
Efficient Method ◽  
Crude Extract ◽  
High Speed ◽  
Glacial Acetic Acid ◽  
Butyl Alcohol ◽  
Preparative Hplc ◽  
Counter Current

Abstract Separation of natural compounds directly from the crude extract is a challenging work for traditional column chromatography. In the present study, an efficient method for separation of three main compounds from the crude extract of Dracocephalum tanguticum has been successfully established by high-speed counter-current chromatography (HSCCC). The crude extract was directly introduced into HSCCC by using dimethyl sulfoxide as cosolvent. Ethyl acetate/n-butyl alcohol/0.3% glacial acetic acid (4: 1: 5, v/v) system was used and three target compounds with purity higher than 80% were obtained. Preparative HPLC was used for further purification and three target compounds with purity higher than 98% were obtained. The compounds were identified as chlorogenic acid, pedaliin and pedaliin-6″-acetate.

Sign in / Sign up

Export Citation Format

Share Document