Effect of surfactants on the dissociation constants of ascorbic and maleic acids

Jaiswal, Priya V; Ijeri, Vijaykumar S.; Srivastava, Anirudh

doi:10.1016/j.colsurfb.2005.09.001

Cited by 40 publications

(29 citation statements)

References 25 publications

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“…It can be first accepted that DAMR exhibits the character of cationic surfactant (pK a for rutin as 7.1; pK b for second dodecylamine less than 3.7) in the neutral subphase when it is partially dissolved into the bulk phase, corresponding to work by Mounanga et al [23,24] who synthesized the ascorbate salts containing alkylamino groups when considering that the prevailing pH in neutral solution is determined by 3-OH groups (pK a as 4.2). Nevertheless, the ionization of DAMR should be still considered at high temperatures and various subphase pH.…”

Section: Monolayers Of Damr At the Air/water Interfacementioning

confidence: 97%

Monolayers of mixture of alkylaminomethyl rutin and lecithin at the air/water interface

2010

Journal of Colloid and Interface Science

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Section: Monolayers Of Damr At the Air/water Interfacementioning

confidence: 97%

Monolayers of mixture of alkylaminomethyl rutin and lecithin at the air/water interface

2010

Journal of Colloid and Interface Science

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“…It is well known that AA (pK a1 = 4.10) [27] coexists with DA in vivo and that its concentration is much higher than that of DA, causing AA to be the major cause of interference in DA detection. The interference by AA was investigated with both GC/PMeT and GC/Nafion/PMeT electrodes [8,9].…”

Section: Separating the Dpv Peaks Of Da And Aamentioning

confidence: 99%

Polymethylthiophene/Nafion-modified glassy carbon electrode for selective detection of dopamine in the presence of ascorbic acid

et al. 2009

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The possible use of an electrode modified with electroactive conductive poly(3-methylthiophene) (PMeT)/ Nafion as a chemical sensor was investigated for the voltammetric analysis of Dopamine (DA). The electrochemical behavior of dopamine was examined by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. By using a PMeT-modified glassy carbon (GC/PMeT) electrode, DA and Ascorbic Acid (AA) signals could be separated but the AA at high concentrations still caused significant interference by overlapping the DA peak. In comparison to the GC/PMeT electrode, the glassy carbon (GC/Nafion/PMeT) electrode modified with hybrid film Nafion/PMeT was found to permit a superior separation by shifting the oxidation of AA peak toward the less positive potential. The DPV curves for a mixture of DA and AA at an GC/Nafion/PMeT electrode in a 0.1 M H 2 SO 4 solution showed peaks of DA and AA, at 0.45 and 0.21 V, respectively, indicating that the difference in the oxidation potential was 240 mV. In the 0.1 M H 2 SO 4 solution, the oxidation peak current on the differential pulse voltammograms for the GC/PMeT electrode increased linearly with the concentration of DA in the range 1 9 10 -6 to 1 9 10 -3 M, and the oxidation peak current on the differential pulse voltammograms for the GC/Nafion/PMeT electrode in the range 5 9 10 -7 to 2 9 10 -4 M. The DA detection sensitivity of the GC/Nafion/PMeT electrode (26.7 lA lM -1 cm -2 ) was 22 times higher than that of the GC/PMeT electrode (1.21 lA lM -1 cm -2 ).

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“…Since ascorbic acid (pK a = 4.10) [31] as well as catechin and epicatechin (pK a1 = 8.16, pK a2 = 9.20) [15] should form anions in alkaline media, a weak basic buffer system was preferred. The most familiar alkaline buffers like Briton -Robinson, borate and phosphate buffers were tested and the most promising results were obtained in borate buffer.…”

Section: Type and Concentration Of Running Buffermentioning

confidence: 99%

Selective determination of catechin, epicatechin and ascorbic acid in human urine using chiral capillary electrophoresis

El‐Hady¹,

Gotti

El‐Maali

2008

J of Separation Science

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Chiral CE was successfully applied to the separation and quantification of catechin, epicatechin and ascorbic acid in some commercial drinks and human urine. Analysis involved the separation of analytes in less than 5.0 min at 240 nm with an untreated fused-silica capillary under hydrodynamic injection mode. The running buffer consisted of 50 mM borate buffer with 3 mM beta-CD at pH 8.35. Detection limits for catechin, epicatechin and ascorbic acid were 0.028, 0.011 and 0.004 microg/mL, respectively. Linearity was investigated by selecting the ranges of calibration according to the amount of analytes in urine giving correlation coefficient percent (% r(2)) ranging between 99.4 and 99.6 at 99% confidence level. The maximum urinary excretion of catechin and epicatechin were noted at 2.0 and 4.0 h of the administrated dose. Unchanged catechin, epicatechin and ascorbic acid amounted to about 1.500, 8.696 and 0.003% of the administered dose in the 48.0 h urine collection. The proposed method achieved 99.2% completeness (n = 20) in urine media.

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Effect of surfactants on the dissociation constants of ascorbic and maleic acids

Cited by 40 publications

References 25 publications

Monolayers of mixture of alkylaminomethyl rutin and lecithin at the air/water interface

Monolayers of mixture of alkylaminomethyl rutin and lecithin at the air/water interface

Polymethylthiophene/Nafion-modified glassy carbon electrode for selective detection of dopamine in the presence of ascorbic acid

Selective determination of catechin, epicatechin and ascorbic acid in human urine using chiral capillary electrophoresis

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