The Gran plot analysis of an acid mixture: An undergraduate experiment to highlight this alternate method

Boiani, James A.

doi:10.1021/ed063p724

Cited by 25 publications

(25 citation statements)

References 5 publications

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“…Aqueous glucuronic acid (5 ml at I M) was titrated with 1 M-NaOH standard in a Multi-Dosimat E415 titrator of 20 'C. The 79 data points obtained were analysed by the method of Gran (Gran, 1950;Boiani, 1986) to obtain the pKa.…”

Section: Methodsmentioning

confidence: 99%

Determination of the pKa of glucuronic acid and the carboxy groups of heparin by 13C-nuclear-magnetic-resonance spectroscopy

Wang

Loganathan

Linhardt

1991

Biochemical Journal

138

100

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As part of our continuing studies on heparin, the present paper uses 13C-n.m.r. spectroscopy to examine the acidity of heparin's uronic acid carboxylate groups. Heparin contains three different uronic acids. In porcine mucosal heparin these account for approx. 91, 7 and 2 mol% of the total uronic acid residues. These are alpha-L-idopyranosyluronic acid 2-sulphate, beta-D-glucopyranosyluronic acid and alpha-L-idopyranosyluronic acid. The pKa values of their carboxylate groups were determined as 3.13 (using heparin), 2.79 (using heparin) and 3.0 (predicted by using model compounds) respectively. 18C-n.m.r. spectroscopy, performed at various pH values, provided a convenient method of simultaneously determining the pKa of multiple carboxylate groups, of similar acidity, within heparin D-Glucopyranosyluronic acid and heparin-derived di-, tetra- and hexa-saccharides were used as model compounds to determine pKa values of the different carboxy groups. The results suggested that molecular size had an effect on pKa. Unambiguous assignment of carboxy carbon resonances were accomplished through the use of two-dimensional n.m.r. spectroscopy. Finally, application of this method to the simplest model compound, D-glucopyranosyluronic acid, permitted the determination of the pKa of both its alpha- and beta-anomers.

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Section: Methodsmentioning

confidence: 99%

Determination of the pKa of glucuronic acid and the carboxy groups of heparin by 13C-nuclear-magnetic-resonance spectroscopy

Wang

Loganathan

Linhardt

1991

Biochemical Journal

138

100

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“…This was done using the Gran Plot analysis of simple pH back titrations, i.e., a linearization of the pH data affording the start-and end-point of the back titration, allowing the intended quantification. 36 Interestingly, despite the diversity of precursors and synthetic conditions, CDs displayed a number of acid/base sites in the order of 9,000 mmol/g in the interval from pH 12 to 3. CDs-5 had the smallest number of acid/base sites.…”

Section: Preliminary Studiesmentioning

confidence: 99%

Mapping the Surface Groups of Amine-Rich Carbon Dots Enables Covalent Catalysis in Aqueous Media

Filippini

Amato

Rosso

et al. 2020

Chem

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“…If the titration is monitored potentiometrically, one can compare this endpoint with that determined from the indicator color change. In addition, students can use the potentiometric data to construct first-derivative (∆E/∆V vs. average volume of titrant), second-derivative (∆ 2 E/∆V 2 vs. volume of titrant), and Gran (∆V/∆E vs. average volume of titrant) plots to help locate the endpoint (14)(15)(16)(17).…”

Section: Discussionmentioning

confidence: 99%

A Student-Designed Potentiometric Titration: Quantitative Determination of Iron(II) by Caro's Acid Titration

Powell¹,

Tucker²,

Acree³

et al. 1996

J. Chem. Educ.

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A laboratory experiment involving the feasibility of using Caro's acid, H2SO5, as a titrant in the potentiometric determination of iron (II) is presented. Specific items considered in the experiment include (i) method of endpoint detection; (ii) shelf-life stability of titrant; (iii) accuracy, relative precision and experimental uncertainty; and (iv) which common cations and/or anions (if any) interfere with the titration. Typical student results gave iron (II) concentrations within 1-2 % of the "true" values. Of the 14 cation/anion pairs suggested in the paper, only time(II) was found to interfere with the quantitative determination of iron (II) using Caro's acid titrant.

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The Gran plot analysis of an acid mixture: An undergraduate experiment to highlight this alternate method

Cited by 25 publications

References 5 publications

Determination of the pKa of glucuronic acid and the carboxy groups of heparin by 13C-nuclear-magnetic-resonance spectroscopy

Determination of the pKa of glucuronic acid and the carboxy groups of heparin by 13C-nuclear-magnetic-resonance spectroscopy

Mapping the Surface Groups of Amine-Rich Carbon Dots Enables Covalent Catalysis in Aqueous Media

A Student-Designed Potentiometric Titration: Quantitative Determination of Iron(II) by Caro's Acid Titration

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