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Capillary monolithic columns based on copolymer of styrene, divinylbenzene and methacrylic acid and their application for separations of small molecules.
Musilová, Adéla
This work is focused on the preparation and characterization of capillary monolithic columns based on a copolymer of styrene, divinylbenzene and methacrylic acid for the chromatographic separation of small molecules. The capillary monolithic columns were prepared in the quartz capillaries by one-step radical copolymerization reaction of monomers of styrene, divinylbenzene and methacrylic acid in the presence of toluene and isooctane as porogenic solvents and azobisisobutyronitrile as an initiator. The effect of incorporation of methacrylic acid into the polymerization mixture on the separation behavior and efficiency in reversed phase capillary liquid chromatography (CLC) and capillary liquid electrochromatography (CEC) was studied using a test mixture of compounds containing thiourea, phenol, aniline, benzene, toluene, ethylbenzene, propylbenzene and butylbenzene. The Walters test for reversed stationary phases was employed to evaluate the hydrophobicity of the prepared columns. Based on the calculated value of hydrophobicity index of 10.76, the prepared monolithic columns can be classified as very hydrophobic. Excellent repeatability of measurements in CLC mode and very good repeatability of the monolithic column preparation were achieved. The effect of polymerization time on the chromatographic...
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Capillary monolithic columns based on copolymer of styrene, divinylbenzene and methacrylic acid and their application for separations of small molecules.
Musilová, Adéla ; Coufal, Pavel (advisor) ; Čabala, Radomír (referee) ; Sýkora, David (referee)
This work is focused on the preparation and characterization of capillary monolithic columns based on a copolymer of styrene, divinylbenzene and methacrylic acid for the chromatographic separation of small molecules. The capillary monolithic columns were prepared in the quartz capillaries by one-step radical copolymerization reaction of monomers of styrene, divinylbenzene and methacrylic acid in the presence of toluene and isooctane as porogenic solvents and azobisisobutyronitrile as an initiator. The effect of incorporation of methacrylic acid into the polymerization mixture on the separation behavior and efficiency in reversed phase capillary liquid chromatography (CLC) and capillary liquid electrochromatography (CEC) was studied using a test mixture of compounds containing thiourea, phenol, aniline, benzene, toluene, ethylbenzene, propylbenzene and butylbenzene. The Walters test for reversed stationary phases was employed to evaluate the hydrophobicity of the prepared columns. Based on the calculated value of hydrophobicity index of 10.76, the prepared monolithic columns can be classified as very hydrophobic. Excellent repeatability of measurements in CLC mode and very good repeatability of the monolithic column preparation were achieved. The effect of polymerization time on the chromatographic...
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Chromatographic characterization of polyaniline-coated stationary phases
Taraba, Lukáš
(EN) This dissertation thesis is focused on physicochemical and chromatographic characterization of polyaniline-coated stationary phases. In the first part, surfaces of bare silica and octadecyl silica sorbents were modified by in-situ chemical polymerization of aniline hydrochloride and their subsequent systematic characterization was performed by using the linear solvation energy relationship approach in the HILIC mode of capillary LC. In addition, several common physicochemical techniques were used to characterize properties of these altered materials. The modified sorbents were then packed into capillary columns. The retention interactions taking place between solute and the separation system were evaluated on the basis of retention data of a number of various solutes. The results showed that polyaniline coating had a significant effect on the retention promoting interactions of both polyaniline-coated stationary phases. The assumed mixed-mode retention mechanism was proven for both the stationary phases. The second part dealt with investigation of the separation potential of polyaniline- coated silica stationary phase in different chromatographic modes. The retention factor curves of structurally similar solutes were constructed as a function of organic modifier portion in the mobile phase....
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Chromatographic characterization of polyaniline-coated stationary phases
Taraba, Lukáš
(EN) This dissertation thesis is focused on physicochemical and chromatographic characterization of polyaniline-coated stationary phases. In the first part, surfaces of bare silica and octadecyl silica sorbents were modified by in-situ chemical polymerization of aniline hydrochloride and their subsequent systematic characterization was performed by using the linear solvation energy relationship approach in the HILIC mode of capillary LC. In addition, several common physicochemical techniques were used to characterize properties of these altered materials. The modified sorbents were then packed into capillary columns. The retention interactions taking place between solute and the separation system were evaluated on the basis of retention data of a number of various solutes. The results showed that polyaniline coating had a significant effect on the retention promoting interactions of both polyaniline-coated stationary phases. The assumed mixed-mode retention mechanism was proven for both the stationary phases. The second part dealt with investigation of the separation potential of polyaniline- coated silica stationary phase in different chromatographic modes. The retention factor curves of structurally similar solutes were constructed as a function of organic modifier portion in the mobile phase....
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Chromatographic characterization of polyaniline-coated stationary phases
Taraba, Lukáš ; Křížek, Tomáš (advisor) ; Pacáková, Věra (referee) ; Srbek, Jan (referee)
(EN) This dissertation thesis is focused on physicochemical and chromatographic characterization of polyaniline-coated stationary phases. In the first part, surfaces of bare silica and octadecyl silica sorbents were modified by in-situ chemical polymerization of aniline hydrochloride and their subsequent systematic characterization was performed by using the linear solvation energy relationship approach in the HILIC mode of capillary LC. In addition, several common physicochemical techniques were used to characterize properties of these altered materials. The modified sorbents were then packed into capillary columns. The retention interactions taking place between solute and the separation system were evaluated on the basis of retention data of a number of various solutes. The results showed that polyaniline coating had a significant effect on the retention promoting interactions of both polyaniline-coated stationary phases. The assumed mixed-mode retention mechanism was proven for both the stationary phases. The second part dealt with investigation of the separation potential of polyaniline- coated silica stationary phase in different chromatographic modes. The retention factor curves of structurally similar solutes were constructed as a function of organic modifier portion in the mobile phase....
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