THE PREPARATION, PAPER CHROMATOGRAPHY, AND COLOR REACTIONS OF SEVERAL 5,6-DIHYDROXYINDOLES AND 5,6-DIACETOXYINDOLES

1961 ◽  
Vol 39 (1) ◽  
pp. 231-246 ◽  
Author(s):  
R. A. Heacock ◽  
M. E. Mahon ◽  
B. D. Scott
Keyword(s):  
Acetic Acid ◽  
Paper Chromatography ◽  
Mobile Phase ◽  
Type Systems ◽  
Acid Water ◽  
Chromatographic Behavior ◽  
Acetic Acid Water ◽  
Color Reactions

The paper chromatographic behavior of several 5,6-dihydroxyindoles has been studied. The colors given by nine dihydroxyindoles with 16 chromogenic reagents are reported. The Rf values of this group of compounds on Whatman No. 1 paper with 2% acetic acid in water or n-butanol/acetic acid/water (6:1:2) as running solvents have been determined. The 5,6-dihydroxyindoles can be chromatographed satisfactorily using Zaffaroni-type systems (i.e. formamide-treated paper and non-polar running solvents). Satisfactory Rf values can also be obtained for the 5,6-diacetoxyindoles on formamide-treated paper using a suitable non-polar mobile phase. The preparations of several new 5,6-dihydroxyindoles and 5,6-diacetoxyindoles are described and improved procedures for the syntheses of some known members of these groups are reported.

Reverse Phase Liquid Chromatographic Determination of Some Food Additives

1987 ◽  
Vol 70 (3) ◽  
pp. 578-582 ◽  
Author(s):  
Madduri Veerabhadrarao ◽  
Mandayam S Narayan ◽  
Omprakash Kapur ◽  
Chilukuri Suryaprakasa Sastry
Keyword(s):  
Acetic Acid ◽  
Benzoic Acid ◽  
Mobile Phase ◽  
Direct Method ◽  
Food Additives ◽  
Acid Water ◽  
Relative Standard ◽  
Acetic Acid Water ◽  
Liquid Chromatographic

Abstract Liquid chromatographic methods are described for the separation and determination of non-nutritive sweeteners, namely, acesulfame, aspartame, saccharin, and dulcin; preservatives such as benzoic acid and p-hydroxybenzoic acid; and caffeine and vanillin in ready-toserve beverages, ice candy, ice cream, squash beverage, tomato sauce, and dry beverage mix samples. These additives are separated on a ^Bondapak C18 column using methanol-acetic acid-water (20 + 5 + 75) as mobile phase and detected by UV absorption at 254 nm. Caffeine, vanillin, dulcin, and benzoic acid can be analyzed quickly by using a mobile phase of methanol-acetic acid-water (35 + 5 + 60). Aspartame can be separated in the presence of caffeine and vanillin by using the mobile phase pH 3 acetate buffer-methanol (95 + 5). Retention factors and minimum detectable limits are described. The percentage error and the percent relative standard deviation for 6 replicate samples ranged from 0.3 to 2.8 and from 1.64 to 3.60, respectively. Recovery of additives added to the foods named and analyzed by the direct method and by extraction ranged from 98.0 to 100.6% and from 91.6 to 101.8%, respectively. The proposed LC techniques are simple, rapid, and advantageous because all the additives can be detected in a single step, which makes it useful for the routine analysis of various food products.

Liquid Structure of Acetic Acid−Water and Trifluoroacetic Acid−Water Mixtures Studied by Large-Angle X-ray Scattering and NMR

2007 ◽  
Vol 111 (31) ◽  
pp. 9270-9280 ◽  
Author(s):  
Toshiyuki Takamuku ◽  
Yasuhiro Kyoshoin ◽  
Hiroshi Noguchi ◽  
Shoji Kusano ◽  
Toshio Yamaguchi
Keyword(s):  
Acetic Acid ◽  
Trifluoroacetic Acid ◽  
Large Angle ◽  
Liquid Structure ◽  
Acid Water ◽  
X Ray ◽  
X Ray Scattering ◽  
Acetic Acid Water ◽  
Ray Scattering

Acetic acid/water separation by pervaporation with silica filled PDMS membrane

2011 ◽  
Vol 51 (5) ◽  
pp. 819-825 ◽  
Author(s):  
Housheng Hong ◽  
Longxiang Chen ◽  
Qingwen Zhang ◽  
Zheran Zhang
Keyword(s):  
Acetic Acid ◽  
Acid Water ◽  
Pdms Membrane ◽  
Water Separation ◽  
Acetic Acid Water
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