Determination of single monosugars bound to a peptide.

1997 ◽  
Vol 44 (2) ◽  
pp. 285-291
Author(s):  
H Krotkiewski ◽  
B Krotkiewska
Keyword(s):  
Degradation Products ◽  
Internal Standard ◽  
Gas Liquid Chromatography ◽  
Glycophorin A ◽  
Weakly Alkaline ◽  
Alkaline Conditions ◽  
Beta Elimination ◽  
Ovine Submaxillary Mucin ◽  
Human Glycophorin

A method is described which allows detection and quantitative determination of single monosugar units bound O-glycosidically to a peptide. A glycoprotein or a glycopeptide is chemically degraded under the modified conditions of Carlson degradation (beta-elimination performed in weakly alkaline conditions in the presence of sodium borohydride). An aliquot of the neutralized reaction mixture, supplemented with an internal standard, is peracetylated, extracted and directly analyzed by g.l.c.-m.s. All the O-linked oligosaccharides split off from the peptide are derivatized, but under gas-liquid chromatography at 150-230 degrees C only monosugar peracetylated alditols reach the detector. By comparing the retention times of appropriate peaks with standards and by checking their mass spectra the monosugar alditols are unequivocally identified. The detectable amount of a reduced monosugar in the analyzed sample is about 0.3 microgram. Several glycoproteins were analyzed using this method. Free N-acetylgalactosaminitol was detected in the degradation products of human glycophorin A and ovine submaxillary mucin, additionally free galactitol was detected in the degradation products of glycophorin. This result suggests that some single galactose units, O-glycosidically linked to the peptide are present in human glycophorin A.

ICH/FDA Guidelines-Compliant Validated Stability-Indicating HPLC-UV Method for the Determination of Axitinib in Bulk and Dosage Forms

2020 ◽  
Vol 16 (8) ◽  
pp. 1106-1112
Author(s):  
Ibrahim A. Darwish ◽  
Nasr Y. Khalil ◽  
Mohammad AlZeer
Keyword(s):  
High Performance ◽  
Kinase Inhibitor ◽  
Degradation Products ◽  
Internal Standard ◽  
Dosage Forms ◽  
Uv Detector ◽  
Stability Indicating ◽  
Therapeutic Benefits ◽  
Relative Standard

Background: Axitinib (AXT) is a member of the new generation of the kinase inhibitor indicated for the treatment of advanced renal cell carcinoma. Its therapeutic benefits depend on assuring the good-quality of its dosage forms in terms of content and stability of the pharmaceutically active ingredient. Objective: This study was devoted to the development of a simple, sensitive and accurate stabilityindicating high-performance liquid chromatographic method with ultraviolet detection (HPLC-UV) for the determination of AXT in its bulk and dosage forms. Methods: Waters HPLC system was used. The chromatographic separation of AXT, internal standard (olaparib), and degradation products were performed on the Nucleosil CN column (250 × 4.6 mm, 5 μm). The mobile phase consisted of water:acetonitrile:methanol (40:40:20, v/v/v) with a flow rate of 1 ml/min, and the UV detector was set at 225 nm. AXT was subjected to different accelerated stress conditions and the degradation products, when any, were completely resolved from the intact AXT. Results: The method was linear (r = 0.9998) in the concentration range of 5-50 μg/ml. The limits of detection and quantitation were 0.85 and 2.57 μg/ml, respectively. The accuracy of the method, measured as recovery, was in the range of 98.0-103.6% with relative standard deviations in the range of 0.06-3.43%. The results of stability testing revealed that AXT was mostly stable in neutral and oxidative conditions; however, it was unstable in alkaline and acidic conditions. The kinetics of degradation were studied, and the kinetic rate constants were determined. The proposed method was successfully applied for the determination of AXT in bulk drug and dosage forms. Conclusions: A stability-indicating HPLC-UV method was developed and validated for assessing AXT stability in its bulk and dosage forms. The method met the regulatory requirements of the International Conference on Harmonization (ICH) and the Food and Drug Administration (FDA). The results demonstrated that the method would have great value when applied in quality control and stability studies for AXT.

DETERMINATION OF PLASMA OESTRIOL IN NORMAL PREGNANCY AND LABOUR USING GAS-LIQUID CHROMATOGRAPHY

1971 ◽  
Vol 51 (3) ◽  
pp. 447-454 ◽  
Author(s):  
W. COOPER ◽  
M. G. COYLE ◽  
J. A. MILLS
Keyword(s):  
Gas Chromatography ◽  
Liquid Chromatography ◽  
Quantitative Determination ◽  
Internal Standard ◽  
Normal Pregnancy ◽  
Gas Liquid Chromatography ◽  
Chemical Purification ◽  
Peripheral Plasma ◽  
Pregnancy And Delivery

SUMMARY A method is described for estimating oestriol in 2–10 ml samples of human pregnancy peripheral plasma. It incorporates acid hydrolysis, chemical purification, methylation, chromatography on alumina columns, formation of a derivative and quantitative determination by gas chromatography. A radioactive internal standard was added to correct for procedural losses. Plasma oestriol determinations in five normal patients throughout pregnancy and delivery are reported.

Determination of Phenothiazine and Several of its Derivatives by Gas-Liquid Chromatography

1966 ◽  
Vol 49 (4) ◽  
pp. 857-859
Author(s):  
C L Bramlett
Keyword(s):  
Liquid Chromatography ◽  
Internal Standard ◽  
Flame Ionization Detector ◽  
Gas Liquid Chromatography ◽  
Chromatographic Technique ◽  
Ionization Detector ◽  
Flame Ionization ◽  
Hydrogen Flame

Abstract Phenothiazine, promethazine.HCl, chlorpromazine. HCl, promazine.HCl, and levomepromazine. HCl were chromatographed satisfactorily on a column containing 5% Apiezon L coated on Anakrom ABS, 100/110 mesh, using a hydrogen-flame ionization detector. This gas chromatographic technique is rapid and more specific than existing official methods. The use of an internal standard to improve precision will be investigated.

Gas-Liquid Chromatographic Determination of Pyridazinones in Technical Products and Formulations

1978 ◽  
Vol 61 (1) ◽  
pp. 161-163
Author(s):  
Giuseppe Cellerino ◽  
Mariarosa Re
Keyword(s):  
Internal Standard ◽  
Standard Technique ◽  
Chromatographic Determination ◽  
Gas Liquid Chromatography ◽  
Flame Ionization ◽  
Selective Detector ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Technical Products

Abstract Simultaneous determination of the active ingredient and of by-products in technical and formulated pyridazinones was rapidly performed by gas-liquid chromatography with complete resolution of all compounds. Quantitative determination by the internal standard technique is accurate and precise. The lower limit of detectability is 8 × 10–12 g/sec with a flame ionization detector and 1 × 10–12 g/sec with a nitrogen-phosphorus selective detector operating in the nitrogen mode.

Gas-Liquid Chromatographic Determination of Volatile Organic Acids as Benzyl Esters with Applications to Tuna, Shrimp, and Eggs

1978 ◽  
Vol 61 (4) ◽  
pp. 973-981
Author(s):  
Walter F Staruszkiewicz ◽  
Enrique Fernandez-Flores ◽  
John F Bond
Keyword(s):  
Processing System ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Gas Liquid Chromatography ◽  
Rapid Preparation ◽  
Canned Tuna ◽  
Liquid Phases ◽  
Benzyl Esters ◽  
Liquid Chromatographic

Abstract Volatile acids are recognized as useful indicators of decomposition in a variety of foods. A method has been developed for the rapid preparation of benzyl esters of formic, acetic, propionic, isobutyric, and butyric acids and for their quantitative determination by gas-liquid chromatography. Esters were formed by reaction with BCl3-benzyl alcohol, followed by washing with aqueous ammonia before storage. They were chromatographed, using tetradecane as an internal standard, and were separated at 140°C on columns having DC-200 and SP-1000 as liquid phases. The method offers significant advantages, especially for the determination of formic acid, over the present official AOAC method, 17.042-17.046. Recoveries of volatile acids added to steam distillates of tuna extracts were ≥ 91% with mean recoveries for the 5 volatile acids of 96—104%. Applications to the analysis of canned tuna, frozen headless shrimp, and frozen whole egg resulted in recoveries of ≥ 8 2% with mean recoveries for the 5 acids of 91—101%. The method was compatible with an automated gas chromatograph-data processing system.

Gas-Liquid Chromatographic Determination of Oxydemeton-Methyl in Commercial Formulations

1978 ◽  
Vol 61 (3) ◽  
pp. 500-503
Author(s):  
Leonard R Schronk ◽  
Billy M Colvin ◽  
Alan R Hanks
Keyword(s):  
Rapid Determination ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Peak Height ◽  
Detector Response ◽  
Gel Chromatography ◽  
Gas Liquid Chromatography ◽  
Flame Ionization ◽  
Silica Gel Chromatography

Abstract Flame ionization gas-liquid chromatography (GLC) with a 10% DC-200 on 80-100 mesh Gas-Chrom Q column is used for the rapid determination of oxydemeton-methyl in commercial formulations. The detector response is linear for 1.0–10.0 μg oxydemeton-methyl, with a sensitivity of 4 ng. The column was stabilized before analysis by injection of a lecithin solution. Samples were diluted with chloroform and injected; peak height ratios were used for quantitation with fluoranthrene as the internal standard. Carbaryl was removed from mixed formulations by silica gel chromatography, oxydemeton- methyl was eluted with methanolchloroform (2+98), and the eluate was collected for infrared (IR) and GLC analyses. Methoxychlor and Karathane were removed by chromatography on Florisil before IR analysis. GLC results compare favorably with those for IR, with recoveries ranging from 98.44 to 102.88% for spiked formulations.

Gas-Liquid Chromatographic Determination of β-Asarone in Wines and Flavors

1976 ◽  
Vol 59 (3) ◽  
pp. 675-677
Author(s):  
Randolph H Dyer ◽  
Glenn E Martin ◽  
Peter C Buscemi
Keyword(s):  
Liquid Chromatography ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Gas Liquid Chromatography ◽  
Ethyl Palmitate ◽  
Ultraviolet Spectra ◽  
Liquid Chromatographic Determination ◽  
Mass Spectrometery ◽  
Liquid Chromatographic

Abstract Wine samples containing β-asarone (cis-2,4,5-trimethoxy-1-propenylbenzene) are distilled; β-asarone is extracted by hexane and then quantitatively determined by gas-liquid chromatography (GLC), using ethyl palmitate as the internal standard. The GLC procedure is rapid and yields precise and accurate results. Mass spectrometery confirmed the identity of the GLC peak as β-asarone. The ultraviolet spectra of β-asarone and its isomer were also determined.

Separation of Vitamins D2 and D3 as Isotachysterols D2 and D3 by Gas-Liquid Chromatography

1968 ◽  
Vol 51 (4) ◽  
pp. 834-838
Author(s):  
A J Sheppard ◽  
Denis E Lacroix ◽  
A R Prosser
Keyword(s):  
Liquid Chromatography ◽  
Quantitative Determination ◽  
Infrared Absorption ◽  
Quantitative Measurement ◽  
Acetyl Chloride ◽  
Internal Standard ◽  
The Other ◽  
Gas Liquid Chromatography ◽  
Absorption Data

Abstract A method for the quantitative determination of 0.5—20 μg vitamins D2 and D3 by gas-liquid chromatography is described. Vitamins D2 and D3 are completely isomerized to their respective isotachysterol isomers by acetyl chloride as demonstrated by ultraviolet and infrared absorption data. Dihydrotachysterol D2, isotachysterol D2, and isotachysterol D3 are completely resolved with a 3% JXR on 100-120 mesh Gas Chrom Q column packing. Calibration studies show that each compound exhibited a characteristic dose-response plot. Therefore, one isomer cannot be used as a direct internal standard for the quantitative measurement of the other isomer.

Eco-Friendly Green Liquid Chromatographic Determination of Azelastine in the Presence of its Degradation Products: Applications to Degradation Kinetics

2019 ◽  
Vol 102 (1) ◽  
pp. 81-90 ◽  
Author(s):  
Amal A El-Masry ◽  
Mohammed E A Hammouda ◽  
Dalia R El-Wasseef ◽  
Saadia M El-Ashry
Keyword(s):  
Degradation Products ◽  
Degradation Kinetics ◽  
Sodium Dodecyl ◽  
Internal Standard ◽  
Eye Drops ◽  
Control Analysis ◽  
Stability Indicating ◽  
Highly Sensitive ◽  
Antihistaminic Drug

Abstract Background: Green solvents such as microemulsion were used in the proposed method because they play a vital role in the analytical method’s influence on the environment. Objective: A highly sensitive, specific, and validated stability-indicating eco-friendly green microemulsion liquid chromatography (MELC) method was developed for separation of the antihistaminic drug Azelastine HCl (AZL) from its degradation products with application to degradation kinetics. Methods: Chromatographic separation was operated on a C18 column with a microemulsion mobile phase, which consists of 0.1 M sodium dodecyl sulphate, 10% n-propanol, 1% n-octanol, and 0.3% triethylamine, by using 0.02 M phosphoric acid at pH 3.5 and irbesartan as internal standard. The eluted compounds were monitored at 210 nm with flow rate 1 mL/min at ambient temperature. Results: A linear dependence of the peak area on drug concentration over the concentration range of 0.1 to 25 μg/mL was achieved with an LOD of 0.04 μg/mL and an LOQ of 0.10 μg/mL. Moreover, the proposed method was successfully applied for determination of AZL in eye drops and metered dose nasal inhaler as well as to study the kinetics of alkaline, acidic, neutral, oxidative, and photolytic degradation processes of AZL according to the International Council for Harmonization guidelines. Conclusions: The proposed method could be used as a harmless alternative for quality control analysis of the mentioned drug, without interference from dosage form additives or decomposition products. Highlights: A highly sensitive stability-indicating eco-friendly green MELC method was developed for the separation of the antihistaminic drug AZL from its degradation products.

Gas-Liquid Chromatographic Determination of p-Chloroacetanilide in Acetaminophen

1978 ◽  
Vol 61 (1) ◽  
pp. 68-71
Author(s):  
Dorothy K Wyatt ◽  
Lee T Grady
Keyword(s):  
Liquid Chromatography ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Gas Liquid Chromatography ◽  
Flame Ionization ◽  
Glass Column ◽  
Retention Characteristics ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract Gas-liquid chromatography (GLC) coupled with column chromatography was used to accurately determine as little as 25 ppm p-chloroacetanilide in acetaminophen. p-Chloroacetanilide was eluted from a pH 8 phosphate-buffered diatomite partition column by using purified tetrachloroethylene (acetaminophen was retained). This solution was concentrated, internal standard (docosane) was added, and p-chloroacetanilide was determined by using a 0.9 m × 2 mm glass column packed with 3% Poly A 103 on Supelcoport and a flame ionization detector with electronic integration. Standard curves were linear for 10–100 ppm p-chloroacetanilide. Various chromatographic materials were investigated for optimal retention characteristics. High pressure liquid chromatography (HPLC) was also evaluated as an alternative; however, lack of reproducibility of the HPLC column favored the GLC procedure.

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