Distribution of substituent groups in O-(2-aminoethyl)cellulose

1969 ◽  
Vol 47 (9) ◽  
pp. 1571-1580 ◽  
Author(s):  
E. J. Roberts ◽  
S. P. Rowland
Keyword(s):  
Liquid Chromatography ◽  
Functional Group ◽  
Direct Analysis ◽  
Hydroxyl Groups ◽  
Gas Liquid Chromatography ◽  
Amino Groups ◽  
Substantial Fraction ◽  
Chemically Modified ◽  
Amine Function ◽  
Modified Cellulose

O-(2-Aminoethyl)cellulose (degree of substitution 0.14), prepared by reaction of sodium 2-aminoethyl sulfate with cotton fabric, was hydrolyzed to glucose and mono-O-(2-aminoethyl)-D-glucopyranoses which were identified by gas–liquid chromatography (g.l.c.). Complications arise from reactions between the functional group at C-1 of the glucose unit and the amine function of a substituent. The distribution of 2-aminoethyl substituents in the 3-O- and 6-O-positions of the D-glucopyranosyl units of cotton cellulose was estimated to be 0.20:1.00 from direct analysis of the hydrolyzate of O-(2-aminoethyl)cellulose, but the total substitution in the 2-O-position could not be estimated in this manner. The ratio of substituents in the 2-O-, 3-O-, and 6-O-positions was found to be 0.64:0.14:1.00 when the amino groups were converted to hydroxyl groups by diazotization, and the distribution was estimated in terms of the 2-hydroxyethyl substituents. It has been observed that a substantial fraction (57.5%) of the 2-O-(2-hydroxyethyl)-D-glucose from the chemically modified cellulose exists in the form of the inner glucosides. Several new monosubstituted glucoses have been prepared and characterized by g.l.c. for this purpose.

Comparison of supports chemically modified by organo-silicon compounds for gas-liquid chromatography

1981 ◽  
Vol 209 (3) ◽  
pp. 385-391 ◽  
Author(s):  
G.V. Filonenko ◽  
V.A. Tertykh ◽  
V.V. Pavlov ◽  
G.Ya. Guba ◽  
A.N. Korol
Keyword(s):  
Liquid Chromatography ◽  
Gas Liquid Chromatography ◽  
Silicon Compounds ◽  
Chemically Modified

scholarly journals Chemically modified nylons as supports for enzyme immobilization. Polyisonitrile-nylon

1974 ◽  
Vol 143 (3) ◽  
pp. 497-509 ◽  
Author(s):  
Leon Goldstein ◽  
Amihay Freeman ◽  
Mordechai Sokolovsky
Keyword(s):  
Aqueous Medium ◽  
Enzyme Immobilization ◽  
Functional Group ◽  
Carboxyl Groups ◽  
Partial Hydrolysis ◽  
Amino Groups ◽  
Tyrosine Residues ◽  
Chemically Modified ◽  
Reactive Groups ◽  
Hydrolysis Of

Four-component condensations between amine, carboxyl, isocyanide and aldehyde lead to the formation of N-substituted amides (Ugi, 1962). The present paper describes the use of such condensations for the introduction of chemically reactive groups on to the polyamide backbone of nylon. Polyisonitrile-nylon was synthesized by partial hydrolysis of nylon-6 powder, followed by resealing of the newly formed −CO2... NH2− pairs via a four-component condensation, by using acetaldehyde and 1,6-di-isocyanohexane. Polyisonitrile-nylon could also be converted into a diazotizable arylamino derivative, polyaminoaryl-nylon, by a four-component condensation by using a bifunctional amine, pp′-diaminodiphenylmethane, in the presence of an aldehyde and a carboxylate compound. The versatility of four-component condensations involving the isocyanide functional group of polyisonitrile-nylon allowed coupling of proteins, in an aqueous medium at neutral pH, through either their amino or carboxyl groups. Trypsin and papain were bound to polyisonitrile-nylon through their amino groups by a four-component condensation by using acetaldehyde and acetate; conversely, succinyl-(3-carboxypropionyl-)trypsin, pepsin and papain were coupled through their carboxyl groups in the presence of acetaldehyde and an amine (Tris). Diazotized polyaminoaryl-nylon could be utilized for the immobilization of papain, via the tyrosine residues of the enzyme.

High-Pressure Liquid Chromatographic Analysis of Urea Herbicides in Foods

1976 ◽  
Vol 59 (5) ◽  
pp. 1066-1070 ◽  
Author(s):  
James F Lawrence
Keyword(s):  
High Pressure ◽  
Liquid Chromatography ◽  
Methylene Chloride ◽  
Sodium Hydride ◽  
Direct Analysis ◽  
Gas Liquid Chromatography ◽  
Chromatographic System ◽  
High Pressure Liquid Chromatographic ◽  
Liquid Chromatographic Analysis ◽  
Liquid Chromatographic

Abstract A method is described for the direct analysis of the urea herbicides linuron, monuron, diuron, chlorbromuron, fluometuron, chloroxuron, and fenuron in cabbage, corn, potatoes, turnip, and wheat at 0.01–1.0 ppm. The samples are extracted with acetone; the filtrate is partitioned with hexane-methylene chloride (1+1) followed by 2 other extractions with methylene chloride. The organic phases are dried and concentrated for column chromatographic cleanup on 2 % deactivated Florisil. The column fractions are evaporated just to dryness and redissolved in 10 ml isooctane for high-pressure liquid chromatography on a 25 cm silica gel (5 μm) column. Isopropanol in isooctane is the mobile phase, and compounds are measured by ultraviolet absorption at 254 nm. Recoveries are >80% in most cases. These results are confirmed by alkylation with sodium hydride-methyl iodide in dimethyl sulfoxide to form the methyl products which are analyzed by the same chromatographic system or by gas-liquid chromatography.

scholarly journals IMMUNE RESPONSE TO CHEMICALLY MODIFIED FLAGELLIN

1971 ◽  
Vol 134 (1) ◽  
pp. 1-20 ◽  
Author(s):  
C. R. Parish
Keyword(s):  
Antibody Formation ◽  
Immunological Tolerance ◽  
Hydroxyl Groups ◽  
Crucial Importance ◽  
Amino Groups ◽  
Adult Rats ◽  
Chemically Modified ◽  
Antigenic Activity ◽  
Lysine Residues ◽  
Chemical Studies

Flagellin (mol. wt. 40,000) from S. adelaide organisms was acetoacetylated to varying extents with diketene (acetoacetic anhydride). Chemical studies demonstrated that the amino groups of flagellin were more readily acetoacetylated than the hydroxyl groups. Several antigenic tests revealed that as flagellin was acetoacetylated to increasing extents there was a steady decline in the affinity of the molecule for anti-flagellin antibodies. Loss in antigenic activity following acetoacetylation was not related to the number of acetoacetyl groups attached but was determined by the type of residue substituted. Reactive lysine residues were much less important anti-genically than easily substituted hydroxyl groups. Acetoacetylation very readily destroyed the antibody-forming capacity of flagellin in rats. This fall in immunogenicity was related to the antigenic activity of the preparations. In fact, only a 40% reduction in the antigenic activity of flagellin produced a 90–95% reduction in primary antibody formation. The more heavily acetoacetylated flagellins produced no detectable antibody and, in fact, rendered adult rats tolerant (in terms of antibody formation) to a subsequent challenge of flagellin. Tolerance was induced by acetoacetylated flagellins which had drastically reduced affinities for anti-flagellin antibodies. These results were interpreted as indicating that the affinity of antigen for receptors on cells appears to be of crucial importance in determining whether antibody formation or immunological tolerance (antibody suppression) occurs.

A study of asphalt-aggregate interactions using inverse gas-liquid chromatography

1974 ◽  
Vol 24 (11) ◽  
pp. 645-654 ◽  
Author(s):  
F. Alan Barbour ◽  
Richard V. Barbour ◽  
J. Claine Peterson
Keyword(s):  
Liquid Chromatography ◽  
Gas Liquid Chromatography

GASCHROMATOGRAPHIC DETERMINATION OF STEROIDS IN THE URINE OF PATIENTS WITH CUSHING'S SYNDROME

1971 ◽  
Vol 67 (2) ◽  
pp. 303-315 ◽  
Author(s):  
A. J. Moolenaar ◽  
A. P. van Seters
Keyword(s):  
Liquid Chromatography ◽  
Cushing’S Syndrome ◽  
Normal Subjects ◽  
Diagnostic Value ◽  
Cushing's Syndrome ◽  
Gas Liquid Chromatography ◽  
Obese Subjects

ABSTRACT The 17-oxosteroids were estimated in the urine of 27 patients with Cushing's syndrome by gas-liquid chromatography (G. L. C.). The values of the various steroid fractions are compared with those of normal subjects, patients with thyrotoxicosis and obese subjects. The effect of the age of the patients on the diagnostic value of the invidual 17-oxosteroids and their ratios is discussed.

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