Abstract Solid-phase extraction and high performance liquid chromatography (HPLC) were used to in... more Abstract Solid-phase extraction and high performance liquid chromatography (HPLC) were used to indirectly (via products of acid hydrolysis) confirm the presence of benzodiazepine metabolites in the urine of patients who had received overdoses of these compounds. The use of solid-phase extraction method for quantitation of benzodiazepine hydrolysis products in urine offers numerous advantages in comparison to extraction with chloroform. The chromatograms of urine extracts were free of interferences. The recoveries of the benzodiazepine hydrolysis products and the internal standard were greater than 96%, which makes this method highly reliable for quantitative analytical purposes.
Three silica hydride based novel chromatographic phases chemically-bonded with allyloxy-DL-alpha-... more Three silica hydride based novel chromatographic phases chemically-bonded with allyloxy-DL-alpha-tocopherol, allylpentafluorophenyl, and 1-eicosene moieties were evaluated as separation media for selected phytocannabinoids and other substances of abuse. In order to assess column selectivity, a series of reference standards was analyzed and detected by using liquid chromatography with mass spectrometry. Fur- ther, quantitative detections of cannabidiol and tetrahydrocannabinol were attempted for the extracts of cannabis plants and cannabidiol gummy formulation. For potential bioanalytical applications, the columns were evaluated for substance screening in a human urine matrix. In summary, the newly developed columns are functional and effective for the analysis of phytocannabinoids and various psychoactive drugs with or without the presence of biological matrices.
ABSTRACT The silanization/hydrosilation bonding method is tested on both a laboratory synthesized... more ABSTRACT The silanization/hydrosilation bonding method is tested on both a laboratory synthesized and commercial titania. The laboratory titania made by the sol-gel process shows evidence of residual organic material that is removed by an initial acid hydolysis followed by bonding of the hydride (triethoxysilane) under acidic conditions. DRIFT and solid state CP-MAS NMR studies are used to confirm the formation of the hydride layer on the titania and the success of the hydrosilation process for attaching an organic moiety (1-octadecene) to the surface. Chromatographic testing, primarily on the commercial titania based C-18 phase, indicates good reverse phase properties and few residual OH groups, either Ti−OH or Si−OH, as determined by the symmetrical peak shapes obtained for anilines and alkylphenylamines using mobile phases with no buffers or masking agents in the aqueous component.
Abstract The chromatographic characterization of two diol stationary phases for HPLC prepared via... more Abstract The chromatographic characterization of two diol stationary phases for HPLC prepared via a hydride intermediate followed by hydrosilation is described. The bonded materials are the result of the reaction of 7-octene-1, 2-diol or allyl glycidyl ether with silica ...
Abstract Solid-phase extraction and high performance liquid chromatography (HPLC) were used to in... more Abstract Solid-phase extraction and high performance liquid chromatography (HPLC) were used to indirectly (via products of acid hydrolysis) confirm the presence of benzodiazepine metabolites in the urine of patients who had received overdoses of these compounds. The use of solid-phase extraction method for quantitation of benzodiazepine hydrolysis products in urine offers numerous advantages in comparison to extraction with chloroform. The chromatograms of urine extracts were free of interferences. The recoveries of the benzodiazepine hydrolysis products and the internal standard were greater than 96%, which makes this method highly reliable for quantitative analytical purposes.
Three silica hydride based novel chromatographic phases chemically-bonded with allyloxy-DL-alpha-... more Three silica hydride based novel chromatographic phases chemically-bonded with allyloxy-DL-alpha-tocopherol, allylpentafluorophenyl, and 1-eicosene moieties were evaluated as separation media for selected phytocannabinoids and other substances of abuse. In order to assess column selectivity, a series of reference standards was analyzed and detected by using liquid chromatography with mass spectrometry. Fur- ther, quantitative detections of cannabidiol and tetrahydrocannabinol were attempted for the extracts of cannabis plants and cannabidiol gummy formulation. For potential bioanalytical applications, the columns were evaluated for substance screening in a human urine matrix. In summary, the newly developed columns are functional and effective for the analysis of phytocannabinoids and various psychoactive drugs with or without the presence of biological matrices.
ABSTRACT The silanization/hydrosilation bonding method is tested on both a laboratory synthesized... more ABSTRACT The silanization/hydrosilation bonding method is tested on both a laboratory synthesized and commercial titania. The laboratory titania made by the sol-gel process shows evidence of residual organic material that is removed by an initial acid hydolysis followed by bonding of the hydride (triethoxysilane) under acidic conditions. DRIFT and solid state CP-MAS NMR studies are used to confirm the formation of the hydride layer on the titania and the success of the hydrosilation process for attaching an organic moiety (1-octadecene) to the surface. Chromatographic testing, primarily on the commercial titania based C-18 phase, indicates good reverse phase properties and few residual OH groups, either Ti−OH or Si−OH, as determined by the symmetrical peak shapes obtained for anilines and alkylphenylamines using mobile phases with no buffers or masking agents in the aqueous component.
Abstract The chromatographic characterization of two diol stationary phases for HPLC prepared via... more Abstract The chromatographic characterization of two diol stationary phases for HPLC prepared via a hydride intermediate followed by hydrosilation is described. The bonded materials are the result of the reaction of 7-octene-1, 2-diol or allyl glycidyl ether with silica ...
Uploads