Plastics. Cellulose acetate in dilute solution. Determination of viscosity number and viscosity ratio

1991 ◽  
Keyword(s):  
Cellulose Acetate ◽  
Viscosity Ratio ◽  
Dilute Solution

scholarly journals Determination of Free and Bound Maleic Hydrazide Residues in Tobacco by High Performance Liquid Chromatography

1994 ◽  
Vol 16 (2) ◽  
pp. 57-64 ◽  
Author(s):  
BS Dattilo ◽  
S Gallo ◽  
G Lionetti ◽  
SG Rossi
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Quantitative Determination ◽  
High Performance ◽  
Maleic Hydrazide ◽  
Dilute Solution ◽  
Tobacco Leaves ◽  
Qualitative And Quantitative ◽  
Curve Method

AbstractA new method is described for the qualitative and quantitative determination of both free and bound maleic hydrazide residues in tobacco leaves and cigarette filler by high performance liquid chromatography. Analyses were carried out by hydrolyzing samples of ground tobacco with 4 N hydrochloric acid for 40 minutes under reflux followed by sample chromatography, running isocratic elutions with a dilute solution of phosphoric acid. The quantitative determination of maleic hydrazide was performed by light absorption at 320 nm, by the calibration curve method. Recoveries of maleic hydrazide added to tobacco samples were greater than 90 %. The detection limit of the method, determined on ground tobacco leaves, was at least 5 ppm. The results obtained by this procedure and by the ISO standard method no. 4876 are in good accordance.

scholarly journals Quantitative Determination of Saccharides in Dietary Glyconutritional Products by Anion-Exchange Liquid Chromatography with Integrated Pulsed Amperometric Detection

2005 ◽  
Vol 88 (4) ◽  
pp. 998-1007 ◽  
Author(s):  
Alexis R Eberendu ◽  
Christy Booth ◽  
Gabriela Luta ◽  
Joshua A Edwards ◽  
Bill H McAnalley
Keyword(s):  
Liquid Chromatography ◽  
Dietary Supplements ◽  
Anion Exchange ◽  
Internal Standard ◽  
Amperometric Detection ◽  
Dilute Solution ◽  
Freeze Dried ◽  
A New Technique ◽  
Peak Retention Time

Abstract A new technique for the assay of carbohydrates is described in which separation and quantification of neutral saccharides, aminosaccharides, glycuronic acids, and disaccharides may be accomplished in less than 50 min of total run time. This method involves optimized anion-exchange liquid chromatography coupled with integrated pulse amperometric detection. Complex carbohydrates from various sources, including dietary supplements, were hydrolyzed in a dilute solution of trifluoroacetic acid, freeze-dried, and reconstituted in water containing 2-deoxygalactose as the internal standard. The solution was filtered and separated on CarboPac PA20 column. The eluted saccharides were detected by oxidation on a gold electrode with quadruple-pulsed integrated amperometry. The calibration plots for the saccharides were linear with an average correlation coefficient of 0.999. Method precisionc regarding peak retention time and resolution used in the peak identifications was verified. With this method, previously difficult-to-separate saccharides, such as galactosamine, glucosamine, and N-acetylglucosamine, were successfully resolved from the neutral saccharides rhamnose, arabinose, and galactose. Mannose was also resolved from xylose, and de-acetylation of aminosaccharides prior to separation was not necessary. This technique provides an accurate and efficient means to assay carbohydrates in dietary supplements, which new federal regulations will soon mandate.

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