An Improved Microprocedure for the Determination of Heparin

The microelectrophoresis method described by Jaques et al. (Can. J. Physiol. Pharmacol. 46, 351–360 (1968)) for identification and quantitation of microquantities of heparin was improved by using the differential effects of inorganic electrolytes on the solubility of quaternary ammonium – mucopolysaccharide complex. Samples were applied to agarose gel coated microscope slides for electrophoresis. The slides were then immersed in 0.1% cetylpyridinium chloride (CPC) in M NaCl at 35 °C with constant agitation for 5 h, washed thoroughly with 0.1% CPC, then stained with toluidine blue. As a result of this treatment, only heparin in concentrations of 0.25–2.0 μg produced optically dense spots on the slides for measurement. Heparin was identified by the combined information from electrophoretic migration, salt fractionation, and metachromatic activity.

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Heparin and sulfated mucopolysaccharides—a micro system for quantitative differentiation and determination

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y77-161 ◽

1977 ◽

Vol 55 (5) ◽

pp. 1179-1189 ◽

Cited By ~ 6

Author(s):

Louis B. Jaques ◽

Tak K. Sue ◽

Norman M. McDuffie ◽

Sandra M. Wice

Keyword(s):

Aqueous Solution ◽

Hyaluronic Acid ◽

Optical Density ◽

Toluidine Blue ◽

Linear Relation ◽

Cetylpyridinium Chloride ◽

Agarose Gel ◽

Azure A ◽

Tissue Extracts ◽

The Individual

Heparin (Hep), hyaluronic acid, chondroitins (sulfate) A, B, and C, and heparitins (sulfate) A, B, C, and D were subjected to microelectrophoresis in barbital–agarose gel, fixed with cetylpyridinium chloride and stained with toluidine blue. The optical densities of the resulting bands were compared with optical densities obtained upon reaction with azure A in aqueous solution and with the carbazole reagent. A linear relation was obtained between optical density and concentration of purified sulfated mucopolysaccharide (SMP). Less than 1 μg of Hep and 2 μg of other SMPs are required for measurement by electrophoresis, while about 30 μg of each is required with the carbazole reagent. The optical density of a mixture of SMPs was equal to the sum of the densities for the individual SMPs upon microelectrophoresis. It was demonstrated that the individual SMPs in mixtures were distinguished by reaction with specific enzymes and by changes in migration in agarose with barbital, phthalate, ethylenediamine, or propane-diamine buffers, permitting ready demonstration and quantitation of various SMP species. Examples are shown of the application of the procedure to measure the total SMPs and individual SMPs in tissue extracts. The method is sensitive, reproducible, flexible, and measures quantities [Formula: see text] of those measured colorimetrically, yet is relatively unaffected by protein, carbohydrate, or inorganic electrolytes.

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Determination of quaternary ammonium compounds in food products by the method of ultra-performance liquid chromatography/high resolution mass-spectrometry

Industrial laboratory Diagnostics of materials ◽

10.26896/1028-6861-2020-86-8-23-31 ◽

2020 ◽

Vol 86 (8) ◽

pp. 23-31

Author(s):

V. G. Amelin ◽

D. S. Bolshakov

Keyword(s):

Mass Spectrometry ◽

High Resolution ◽

Quaternary Ammonium ◽

High Resolution Mass Spectrometry ◽

Food Products ◽

Quaternary Ammonium Compounds ◽

High Resolution Mass ◽

Ammonium Compounds ◽

Resolution Mass

The goal of the study is developing a methodology for determination of the residual amounts of quaternary ammonium compounds (QAC) in food products by UHPLC/high-resolution mass spectrometry after water-acetonitrile extraction of the determined components from the analyzed samples. The identification and determination of QAC was carried out on an «UltiMate 3000» ultra-high-performance liquid chromatograph (Thermo Scientific, USA) equipped with a «maXis 4G» high-resolution quadrupole-time-of-flight mass spectrometric detector and an ion spray «ionBooster» source (Bruker Daltonics, Germany). Samples of milk, cheese (upper cortical layer), dumplings, pork, chicken skin and ground beef were used as working samples. Optimal conditions are specified for chromatographic separation of the mixture of five QAC, two of them being a mixture of homologues with a linear structure (including isomeric forms). The identification of QAC is carried out by the retention time, exact mass of the ions, and coincidence of the mSigma isotopic distribution. The limits for QAC detection are 0.1 – 0.5 ng/ml, the determination limits are 1 ng/ml for aqueous standard solutions. The determinable content of QAC in food products ranges within 1 – 100 ng/g. The results of analysis revealed the residual amount of QAC present in all samples, which confirms data of numerous sources of information about active use of QAC-based disinfectants in the meat and dairy industry. The correctness of the obtained results is verified by introduction of the additives in food products at a level of 10 ng/g for each QAC. The relative standard deviation of the analysis results does not exceed 0.18. The duration of the analysis is 30 – 40 min.

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Separation and size determination of human serum lipoproteins by agarose gel filtration

The Journal of Lipid Research ◽

10.1016/s0022-2275(20)38908-2 ◽

1967 ◽

Vol 8 (5) ◽

pp. 501-507

Author(s):

Simeon Margolis

Keyword(s):

Human Serum ◽

Gel Filtration ◽

Agarose Gel ◽

Size Determination ◽

Serum Lipoproteins

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Concurrent chromatographic determination of pseudoephedrine and loratadine from combination syrups and tablets

Future Journal of Pharmaceutical Sciences ◽

10.1186/s43094-021-00287-3 ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Imad Osman Abu Reid

Keyword(s):

Ammonium Acetate ◽

Chemical Properties ◽

Chromatographic Determination ◽

Analytical Challenge ◽

Intermediate Precision ◽

Box Behnken Design ◽

Complex Samples ◽

System Suitability ◽

Nonpolar Compounds

Abstract Background Chromatographic separation of polar and nonpolar compounds when presented in combined dosage forms has always been considered as great analytical challenge. Separation and retention of both polar and nonpolar compounds by the same stationary phase can be a useful approach for analyses of complex samples with such a difference in chemical properties. Loratadine (nonpolar) and pseudoephedrine (polar) are typical examples of this situation. Results The Box–Behnken design was used to optimize the separation process, an efficient separation of loratadine and pseudoephedrine was achieved within 6 min; employing a mixture of 16.0 mM ammonium acetate buffer (pH 4.5) and acetonitrile (23:77, v/v) as isocratic mobile phase, pumped at 1.0 mL/min through a Zorbax cyanopropyl column (250 mm × 4.6 mm, 5 μm), the analytes were detected at 250 nm. Under the same conditions, separation of sodium benzoate preservative co-formulated with the two analytes in syrup formulation was also achieved. The calibration curve demonstrated excellent linearity in the range of 24.6–123.2 μg/mL and 594.8–2974.0 μg/mL for loratadine and pseudoephedrine, respectively with determination coefficient (r2) > 0.999. Conclusion The method’s accuracy bias < 2.0%, repeatability and intermediate precision (%RSD < 2.0%) were verified. In addition, system suitability parameters were found within the acceptable limits. Satisfactory results were obtained upon the application of the validated method to the analysis of commercial tablet and syrup formulations.

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