Thin‐layer chromatographic plates with monolithic layer of silica: Production, physical–chemical characteristics, separation capabilities

Frolova, A. M.; Konovalova, O. Yu.; Loginova, Lidia P.; Bulgakova, A. V.; Boichenko, Alexander P.

doi:10.1002/jssc.201100178

Cited by 17 publications

(8 citation statements)

References 44 publications

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“…At high and medium pH in aqueous media, this cationic indicator slowly converts into the colorless carbinol (R + ROH + H + ). 43,44 The equilibrium pK a w value equals to 6.92-7.10, [44][45][46][47][48] while the non-equilibrium color transition corresponds to pH 11.5-14.0. 49 Indeed, we determined the 'observed' value pK a w = 11.94 ± 0.11 in aqueous diluted NaOH solutions by registering the absorbance within 1 min after mixing.…”

Section: Apparent Ionization Constants Of Indicators In Two-phase Sysmentioning

confidence: 99%

Protolytic properties of dyes embedded in gelatin films

Никитина¹,

Reshetnyak²,

Svetlova³

et al. 2011

J. Braz. Chem. Soc.

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O filme de gelatina endurecida fixo em uma base transparente de triacetilcelulose pode ser utilizado como um suporte conveniente para indicadores ácido-base. Azul de bromofenol, verde de bromocresol, eosina, etil-eosina, n-decil-eosina, n-decil-fluoresceína, vermelho neutro e verde de malaquita foram incorporados nos filmes de gelatina por extração em meio aquoso sob condições apropriadas. A absorção de luz dos filmes dopados com corante exibe uma resposta ao pH de soluções tampão aquosas nas quais foram imersos. Valores reprodutíveis das constantes aparentes de dissociação dos indicadores, pK a app , foram calculados pelo tratamento convencional dos valores de pH do tampão aquoso e também para a água absorvida nos filmes de gelatina. Os experimentos com pH abaixo e acima do ponto isoelétrico da gelatina (em torno de pH 5) resultaram em valores de pK a app semelhantes àqueles em meios micelares de tensoativos catiônicos e aniônicos, respectivamente. Os filmes de gelatina modificados por corantes podem ser recomendados para uso em sensores óticos e dispositivos similares.The hardened gelatin film fixed on the transparent triacetylcellulose support can be utilized as a convenient carrier for acid-base indicator dyes. Bromophenol blue, bromocresol green, eosin, ethyleosin, n-decyleosin, n-decylfluorescein, neutral red, and malachite green were embedded into the gelatin films by extracting from aqueous media under appropriate conditions. The light absorption of dye-doped films exhibits a response to the pH values of aqueous buffer solutions, where they were soaked in. The well-reproducible indices of the apparent ionization constants, pK a app , of the indicators were calculated by conventional equating the pH values of the bulk aqueous buffer and those of the 'internal' water into the gelatin films. The experiments with pH below and above the isoelectric point of gelatin (around pH 5) result in pK a app values, which resemble those in micellar media of cationic and anionic surfactants, respectively. The dye-modified gelatin films can be recommended for use in optical sensors and related devices. Keywords: dye-modified gelatin film, indicators, apparent ionization constants, medium effects IntroductionThis paper is devoted to the influence of hardened gelatin media on the spectral and acid-base properties of immobilized xanthene, sulfonephthalein, and some other dyes.The immobilization of reagents in solid matrix (cellulose, ion-exchangers, polymers, silica, xerogels, etc.) 1-7 or using organized solutions, e.g., surfactant-based ones, [8][9][10][11][12] modifies the properties of guest molecules owing to the change of the microenvironment.Such modifications, or medium effects, are most studied and well documented for acid-base indicators. 8,9 In this case, the influence of the microenvironment results in the shift of the indicator equilibrium as compared to that in aqueous media. The main reasons are the local polarity and the local electrical charge. The latter often (but not always) manifests itself in the decre...

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Section: Apparent Ionization Constants Of Indicators In Two-phase Sysmentioning

confidence: 99%

Protolytic properties of dyes embedded in gelatin films

Никитина¹,

Reshetnyak²,

Svetlova³

et al. 2011

J. Braz. Chem. Soc.

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“…Besides in miniaturized formats, monoliths are routinely prepared also on analytical scale e.g. high throughput screening (HTS) in the format of in 96‐well plates or tips , in sheet format of several centimeters size but thickness of only several 10 μm used for planar chromatography , in format of conventional analytical columns or short analytical columns in disk format , as well as in large volume formats intended for purification .…”

Section: Introductionmentioning

confidence: 99%

Application of monoliths for bioparticle isolation

Podgornik

Krajnc

2012

J of Separation Science

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Monoliths are today probably the most studied chromatographic supports. There are plethora of publications dealing with different aspects of their preparation, characterization, and applications. The reason for this interest is their inherent properties related to their particular structure, like ease of preparation in various volumes, fast analytics at low pressure and room temperature, and high productivity as a consequence of flow-unaffected properties, especially important for isolation of large biological molecules. Because of that, structure of several monoliths was optimized for analytics and purification of biologic nanoparticles like viruses, virus-like particles (VLPs), cells structures, or even intact cells. In this review, some recent applications of monoliths in the field of bioparticle isolation are described and results are discussed in terms of particular monolith properties.

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“…Though the very first monolithic sorbents were prepared from organic polymers, the first monolithic thin layer plates were made of silica . This type of material is formed by hydrolysis and condensation of alkylsiloxanes together with the mixture of porogens on a glass, metal, or silicon plate . The mechanically stable layers are about 10 μm thick with mesopores of 3–4 nm to optimize retention (specific surface area is about 350 m 2 /g) and flow through macropores of 1–2 μm to minimize flow resistance.…”

Section: Preparation Of Monolithic Layersmentioning

confidence: 99%

Recent advances in the preparation of adsorbent layers for thin‐layer chromatography combined with matrix‐assisted laser desorption/ionization mass‐spectrometric detection

Kucherenko

Kanat’eva

Пирогов

et al. 2018

J of Separation Science

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This review is focused on planar chromatography hyphenated with mass-spectrometric detection for analysis of low-molecular-mass solutes. Various kinds of hyphenations are discussed with attention paid to the preparation of thin layer plates suited both for the mass-spectrometric detection of the resolved solutes direct from thin-layer plates and for indirect mass-spectrometric detection of the resolved solutes, performed by scraping, extracting, purifying, and concentrating the analyte from the thin-layer chromatography plate. Plates with monolithic layers are relatively new for thin-layer chromatography but they can successfully be combined with mass-spectrometric technique in a pursuit of comprehensive local sample composition information. Preparation of monolithic layers of different porosity and structure based on organic, inorganic, and composite materials is illustrated together with examples of successful separation and detection of low-molecular-mass solutes by means of matrix-assisted and surface-assisted laser desorption mass spectrometry.

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Thin‐layer chromatographic plates with monolithic layer of silica: Production, physical–chemical characteristics, separation capabilities

Cited by 17 publications

References 44 publications

Protolytic properties of dyes embedded in gelatin films

Protolytic properties of dyes embedded in gelatin films

Application of monoliths for bioparticle isolation

Recent advances in the preparation of adsorbent layers for thin‐layer chromatography combined with matrix‐assisted laser desorption/ionization mass‐spectrometric detection

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