Indirect UV detection of carbohydrates in capillary zone electrophoresis

Vorndran, A. E.; Oefner, Peter J.; Scherz, H.; Bonn, Günther K.

doi:10.1007/bf02275899

Cited by 125 publications

(47 citation statements)

References 17 publications

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“…Lactulose content was me asured with the modified method of Vorndran et al [19], which is a ultraviolet inverse detection at Then 0.5 mL of 0.2 mol.L-1 EDTA solution at pH 6 and 2 mL of Clarifying Reagenr" were added; the solution was shaken vigorously and the tubes placed at 37 "C for 3 to 5 min. Absorbance (As) of the transparent-rnodified mixture was read at 412 nm (within 20 min) against a blank tube containing ail reagents except milk.…”

Section: Capillary Electrophoresis Methodsmentioning

confidence: 99%

Screening procedure for evaluating heat load in commercial milks

Guingamp

Humbert

Midon

et al. 1999

Lait

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-The evaluation of heat damages in commercial milk samples has been studied by an ana" lytical procedure which uses two different and complementary methods. The first is the rapid total sulphydryl (SH) group measurement which evaluates whey protein denaturation. The second involves the measurement of absorbance at 340 nm (A 340 ) of milks modified with the Clarifying Reagent'", At .this wavelength sorne coloured compounds resulting from the non-enzymic browning still absorb. There is a satisfying correlation between A 340 and lactulose content (r = 0.98) measured in commercial milk samples by using capillary electrophoresis or high performance liquid chromatography (HPLC). Our analytical procedure using SH and A 340 measurements has been applied to 130 raw and commercial milk samples. Analysis by Student's r-test shows that the values of the two parameters obtained for raw and heat-treated milk samples were significantly different (P < 0.01). This study demonstrates that this simple protocol makes possible rapid evaluation of heat damages in commercial milk sampies as il could be done with official but more sophisticated methods. © Inra/Elsevier, Paris.heat damage / commercial milk / sulphydryl group / absorbance A 340 / transparent-modified miIk / analytical procedure Résumé -Protocole rapide d'évaluation des traitements thermiques dans les laits de consommation. L'évaluation des dénaturations induites par les traitements thermiques appliqués au lait a été étudiée à l'aide d'un protocole utilisant deux méthodes rapides, différentes mais complémentaires. La première évalue la dénaturation des protéines Iactosériques en mesurant les groupements sulfhydryles totaux. La seconde consiste à mesurer l'absorbance à 340 nm (A 340 ) des laits rendus transparents par l'ajout du réactif de transparisation. A 340 est due aux composés issus des réactions de

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Section: Capillary Electrophoresis Methodsmentioning

confidence: 99%

Screening procedure for evaluating heat load in commercial milks

Guingamp

Humbert

Midon

et al. 1999

Lait

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“…By reducing the low-frequency noise and the baseline disturbances, the pH of the BGE can be increased to 13 without major loss of sensitivity. The detection limits obtained with the optimized system are approximately 25 times lower at pH 12.3 when using a riboflavin-NaOH BGE and one order of magnitude lower at higher pH (12.6-13) when using a riboflavin-LiOH BGE, compared to results cited in the literature [18].…”

Section: Discussionmentioning

confidence: 53%

“…Since most sugars have a pK a value between 12 and 13, a high pH of the electrolyte is required for their separation [15][16][17][18]. The conductivity of the medium increases with the pH and the resulting high electrophoretic currents are accompanied with baseline instabilities and low signal-to-noise ratios with indirect UV detection.…”

Section: Noise Reduction By Instrumental Optimizationmentioning

confidence: 99%

“…Generally, the resolution of sugars is improved at a higher pH. With indirect UV detection, the highest utilizable pH was reported to be pH 12.1 and the detection limit was relatively high (0.5 mmol 1-1) [18]. By increasing the pH, the sensitivity decreased rapidly, due to increasing competition of hydroxide ions in the displacement of the chromophore.…”

Section: Introductionmentioning

confidence: 99%

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Sensitive determination of sugars by capillary zone electrophoresis with indirect UV detection under highly alkaline conditions

Kok

Poppe

1995

Journal of Chromatography A

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Sensitive determination of sugars by CZE with indirect UV detection under highly alkaline conditions Xu, X.; Kok, W.T.; Poppe, H. Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. The separation with capillary zone electrophoresis and indirect UV detection of underivatized sugars was studied. It was found that the high pH of the background electrolyte which was required for the separation resulted in a strong increase of the low-frequency noise and baseline instability with indirect detection. It was shown that the baseline instability is related to the Joule heat production and insufficient thermostatting of the capillary. Detection could be strongly improved by using narrow (25/zm) capillaries and low voltages, and by instrumental measures to promote a uniform heat dissipation along the capillary. The low-frequency noise and baseline disturbances were found also to depend on the type of monitoring and counterions in the background electrolyte. By optimization of the experimental conditions the workable pH range for the separation could be extended to 13. After optimization, limits of detection of approximately 0.05 mmol 1 -~ were obtained. Calibration plots were linear up to concentrations of 5 mmol 1 -t. The reproducibility of migration times was within 0.4%; peak areas were reproducible within 4%. The method developed was applied to the analysis of culture medium samples.

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“…Such analyses have included the separation of 16 monosaccharides labeled with PMP 153 and 2-aminoacridone (AMAC) labeled glycans. 154 Acidic oligosaccharides derived from heparins, 155 chondroitin sulfates, 156 and hyaluronic acid 157 can also be separated by this method. Differences in the hydrophobicities of saccharides are quite small, and therefore separation using MEKC is attained using a low pH buffer, such as a phosphate buffer (pH 7) or a phosphate/borate buffer to reduce the EOF velocity.…”

Section: ·4 Micellary Electrokinetic Chromatography (Mekc)mentioning

confidence: 99%

Recent Developments in Liquid Chromatography and Capillary Electrophoresis for the Analysis of Glycoprotein Glycans

Suzuki

2013

ANAL. SCI.

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Indirect UV detection of carbohydrates in capillary zone electrophoresis

Cited by 125 publications

References 17 publications

Screening procedure for evaluating heat load in commercial milks

Screening procedure for evaluating heat load in commercial milks

Sensitive determination of sugars by capillary zone electrophoresis with indirect UV detection under highly alkaline conditions

Recent Developments in Liquid Chromatography and Capillary Electrophoresis for the Analysis of Glycoprotein Glycans

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