Spectrophotometric Analysis of the Relationship between Dissociation and Coloration, and of the Structural Formulas of Phenolphthalein in Aqueous Solution

Tamura, Zenzo; Abe, Seiji; Ito, Katsutoshi; Maeda, Masako

doi:10.2116/analsci.12.927

Cited by 57 publications

(51 citation statements)

References 3 publications

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“…2b,c). The increase is caused by shift of the pH from 13 to 11.5, where the absorption is maximal 19. Then the absorption decreased to zero, reflecting a reduction in pH to below 8.2.…”

Section: Resultsmentioning

confidence: 97%

Super liquid-repellent gas membranes for carbon dioxide capture and heart–lung machines

et al. 2013

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In a gas membrane, gas is transferred between a liquid and a gas through a microporous membrane. The main challenge is to achieve a high gas transfer while preventing wetting and clogging. With respect to the oxygenation of blood, haemocompatibility is also required. Here we coat macroporous meshes with a superamphiphobic—or liquid repellent—layer to meet this challenge. The superamphiphobic layer consists of a fractal-like network of fluorinated silicon oxide nanospheres; gas trapped between the nanospheres keeps the liquid from contacting the wall of the membrane. We demonstrate the capabilities of the membrane by capturing carbon dioxide gas into a basic aqueous solution and in addition use it to oxygenate blood. Usually, blood tends to clog membranes because of the abundance of blood cells, platelets, proteins and lipids. We show that human blood stored in a superamphiphobic well for 24 h can be poured off without leaving cells or adsorbed protein behind.

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“…2b,c). The increase is caused by shift of the pH from 13 to 11.5, where the absorption is maximal 19. Then the absorption decreased to zero, reflecting a reduction in pH to below 8.2.…”

Section: Resultsmentioning

confidence: 97%

Super liquid-repellent gas membranes for carbon dioxide capture and heart–lung machines

et al. 2013

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“…pK a1 is usually smaller than pK a2 for successive acid-dissociation processes, because removal of the second proton from the monoanion form is harder than that of the first proton from the neutral form, as exemplified by succinic acid (pK a1 = 4.21 < pK a2 = 5.64), adipic acid (pK a1 = 4.42 < pK a2 = 5.41), and phthalic acid (pK a1 =2.95 < pK a2 = 5.41). 36 Such a reversal of pK a values has not been observed in previous research on fluorescein derivatives, 2,6,22,23,[25][26][27][28][29][30] or even phenolphthalein derivatives 34,37 , with only a few exceptions 38,39 . In principle, the closer the two dissociation constants are, the sharper the pH response is; in other words, this reversal of pK a values accounts for the sharpness of the pH response of 2-COOH TM.…”

Section: Elucidation Of Chemical Equilibrium Of 2-cooh Tmmentioning

confidence: 90%

“…38,39 Similarly, the two pK a values of phenolphthalein are very close each other under aqueous conditions (pK a1 = 9.1 and pK a2 = 9.5), though pK a2 is slightly larger than pK a1 . 34,37 Phenolphthalein tends to form a colorless spirolactone ring in the neutral and monoanion forms, and shows tautomerization of the monoanion form, like 2-COOH TM ( Figure S10). Moreover, the dramatic pH-dependent fluorescence increase of 2-COOH TM due to the pK a inversion suggests that 2-COOH TM might be useful as a pH indicator, like pH-sensors based on pH sensitive polymer 44 or pH-induced micellization 45 .…”

Section: Elucidation Of Chemical Equilibrium Of 2-cooh Tmmentioning

confidence: 99%

Analysis of Chemical Equilibrium of Silicon-Substituted Fluorescein and Its Application to Develop a Scaffold for Red Fluorescent Probes

Hirabayashi¹,

Hanaoka²,

Takayanagi

et al. 2015

Anal. Chem.

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Fluorescein is a representative green fluorophore that has been widely used as a scaffold of practically useful green fluorescent probes. Here, we report synthesis and characterization of a silicon-substituted fluorescein, i.e., 2-COOH TokyoMagenta (2-COOH TM), which is a fluorescein analogue in which the O atom at the 10' position of the xanthene moiety of fluorescein is replaced with a Si atom. This fluorescein analogue forms a spirolactone ring via intramolecular nucleophilic attack of the carboxylic group in a pH-dependent manner. Consequently, 2-COOH TM exhibits characteristic large pH-dependent absorption and fluorescence spectral changes: (1) 2-COOH TM is colorless at acidic pH, whereas fluorescein retains observable absorption and fluorescence even at acidic pH, and the absorption maximum is also shifted; (2) the absorption spectral change occurs above pH 7.0 for 2-COOH TM and below pH 7.0 for fluorescein; (3) 2-COOH TM shows a much sharper pH response than fluorescein because of its pKa inversion, i.e., pKa1 > pKa2. These features are also different from those of a compound without the carboxylic group, 2-Me TokyoMagenta (2-Me TM). Analysis of the chemical equilibrium between pH 3.0 and 11.0 disclosed that 2-COOH TM favors the colorless and nonfluorescent lactone form, compared with fluorescein. Substitution of Cl atoms at the 4' and 5' positions of the xanthene moiety of 2-COOH TM to obtain 2-COOH DCTM shifted the equilibrium so that the new derivative exists predominantly in the strongly fluorescent open form at physiological pH (pH 7.4). To demonstrate the practical utility of 2-COOH DCTM as a novel scaffold for red fluorescent probes, we employed it to develop a probe for β-galactosidase.

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“…At higher pH values (>9), the dianionic form (1 H2À ) predominates (cf. Scheme 1) [7,13,14]. Scheme 1 Figure 1 shows the cyclic voltammograms of phenolphthalein at different concentrations at the HMDE.…”

Section: Resultsmentioning

confidence: 99%

The Adsorption Behavior of Phenolphthalein at a Mercury Electrode in Water-Ethanol Solutions

Abdel-Hamid

1998

Monatshefte fuer Chemie

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A complete characterization of the adsorption of phenolphthalein at the hanging mercury drop electrode in aqueous buffer solutions containing 10% (v/v) ethanol was obtained employing cyclic voltammetry and double potential step chronocoulometry. At pH 3.4, a sharp symmetric cyclic voltammetric wave due to an irreversible weak adsorption of the monoanionic form is obtained at a concentration of 5.1 mmol Á dm À3 . Under these conditions, phenolphthalein adsorbs in a compact layer in which the triphenylmethan moiety is arranged perpendicular to the electrode surface. Upon increasing the concentration, the symmetry of the wave decreases; it can now be attributed to a mixed diffusion-adsorption process. In acidic solutions (pH<3.4) the observed electroactivity is ascribed to the adsorption of the neutral lactone form. In solutions of pH 10.58, no adsorption was detected.

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Spectrophotometric Analysis of the Relationship between Dissociation and Coloration, and of the Structural Formulas of Phenolphthalein in Aqueous Solution

Cited by 57 publications

References 3 publications

Super liquid-repellent gas membranes for carbon dioxide capture and heart–lung machines

Super liquid-repellent gas membranes for carbon dioxide capture and heart–lung machines

Analysis of Chemical Equilibrium of Silicon-Substituted Fluorescein and Its Application to Develop a Scaffold for Red Fluorescent Probes

The Adsorption Behavior of Phenolphthalein at a Mercury Electrode in Water-Ethanol Solutions

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