Supplemental material, sj-pdf-1-ems-10.1177_14690667211002777 for Development of surface ionizati... more Supplemental material, sj-pdf-1-ems-10.1177_14690667211002777 for Development of surface ionization mass spectrometry for detection of stimulants in human urine by Shovkatjon Akhunov, Khatam Ashurov, Sherzod Axmedov, Beknazar Kasimov, Vladimir Rotshteyn, Azim Radjabov and Dilshadbek Usmanov in European Journal of Mass Spectrometry
This paper demonstrates direct detection of stimulants such as amphetamine, methamphetamine and c... more This paper demonstrates direct detection of stimulants such as amphetamine, methamphetamine and cocaine spiked with untreated urine and a real world sample using surface ionization mass spectrometry. Spiked samples were analyzed without preliminary chromatographic separation and extraction procedure using the developed method. Moreover, in order to check the analytical capabilities of the method non-extracted real world sample was analyzed. After liquid–liquid extraction, the same sample was analyzed using the method for comparative study. Limit of detection of spiked samples was in the range of 10 pg (10 ng/ml) to 100 pg (100 ng/ml). Linear ranges of samples were two orders of magnitude or more than two orders of magnitude. It was revealed these spiked samples and real world sample can be analyzed without preliminary chromatographic separation and preliminary extraction procedure due to high selectivity of the method and the presence of the indicator lines of studied analytes in th...
Rapid communications in mass spectrometry : RCM, Jan 15, 2018
Probe electrospray ionization (PESI) is only applicable to liquid or wet samples. In this study, ... more Probe electrospray ionization (PESI) is only applicable to liquid or wet samples. In this study, a sheath-flow PESI method for remote sampling mass spectrometry that can be applied to dry samples was developed. An acupuncture needle (0.12 mm outer diameter, 700 nm tip diameter) was inserted into a gel-loading tip with a 0.1 mm protrusion out of the tip. Analytes were extracted by filling the latter tip with solvent and softly touching the sample surface for a short time (<1 s). A high voltage was applied to the acupuncture needle, and mass spectra of analytes were obtained by self-aspirating electrospray. Dry samples, such as lines of ballpoint pen ink on paper, pharmaceutical tablets, instant coffee, brown rice, and narcotics, gave strong ion signals. The sample carryover was negligible. The sequential electrospray was observed to be similar to conventional PESI. The limits of detection (LODs) for morphine and rhodamine B were found to be of the order of picograms. Because of it...
NATO Science for Peace and Security Series B: Physics and Biophysics, 2013
ABSTRACT A model of the heterogeneous semiconductor medium consisting of multiphase granules, whi... more ABSTRACT A model of the heterogeneous semiconductor medium consisting of multiphase granules, which are the crystal semiconductor grains covered by the oxide film has been proposed. The effective medium model (EMM) of the set of contacting granules has been constructed. Each granule phase is characterised by its own conductivity σ i , heat conductivity χ i , Seebeck factor α i , characteristic size d i and, accordingly, efficiency of thermoelectric transformation Z i . Expressions for the estimation of σ eff , χ eff , α eff and Z eff are constructed, and their values depending on asymmetry degree of characteristics of the granule components are analysed. The complicated ternary thermoelectric media is considered. The possibilities of acquisition of the optimal medium characteristics under various technological conditions and the action of ionizing radiation have been studied.
Supplemental material, sj-pdf-1-ems-10.1177_14690667211002777 for Development of surface ionizati... more Supplemental material, sj-pdf-1-ems-10.1177_14690667211002777 for Development of surface ionization mass spectrometry for detection of stimulants in human urine by Shovkatjon Akhunov, Khatam Ashurov, Sherzod Axmedov, Beknazar Kasimov, Vladimir Rotshteyn, Azim Radjabov and Dilshadbek Usmanov in European Journal of Mass Spectrometry
This paper demonstrates direct detection of stimulants such as amphetamine, methamphetamine and c... more This paper demonstrates direct detection of stimulants such as amphetamine, methamphetamine and cocaine spiked with untreated urine and a real world sample using surface ionization mass spectrometry. Spiked samples were analyzed without preliminary chromatographic separation and extraction procedure using the developed method. Moreover, in order to check the analytical capabilities of the method non-extracted real world sample was analyzed. After liquid–liquid extraction, the same sample was analyzed using the method for comparative study. Limit of detection of spiked samples was in the range of 10 pg (10 ng/ml) to 100 pg (100 ng/ml). Linear ranges of samples were two orders of magnitude or more than two orders of magnitude. It was revealed these spiked samples and real world sample can be analyzed without preliminary chromatographic separation and preliminary extraction procedure due to high selectivity of the method and the presence of the indicator lines of studied analytes in th...
Rapid communications in mass spectrometry : RCM, Jan 15, 2018
Probe electrospray ionization (PESI) is only applicable to liquid or wet samples. In this study, ... more Probe electrospray ionization (PESI) is only applicable to liquid or wet samples. In this study, a sheath-flow PESI method for remote sampling mass spectrometry that can be applied to dry samples was developed. An acupuncture needle (0.12 mm outer diameter, 700 nm tip diameter) was inserted into a gel-loading tip with a 0.1 mm protrusion out of the tip. Analytes were extracted by filling the latter tip with solvent and softly touching the sample surface for a short time (<1 s). A high voltage was applied to the acupuncture needle, and mass spectra of analytes were obtained by self-aspirating electrospray. Dry samples, such as lines of ballpoint pen ink on paper, pharmaceutical tablets, instant coffee, brown rice, and narcotics, gave strong ion signals. The sample carryover was negligible. The sequential electrospray was observed to be similar to conventional PESI. The limits of detection (LODs) for morphine and rhodamine B were found to be of the order of picograms. Because of it...
NATO Science for Peace and Security Series B: Physics and Biophysics, 2013
ABSTRACT A model of the heterogeneous semiconductor medium consisting of multiphase granules, whi... more ABSTRACT A model of the heterogeneous semiconductor medium consisting of multiphase granules, which are the crystal semiconductor grains covered by the oxide film has been proposed. The effective medium model (EMM) of the set of contacting granules has been constructed. Each granule phase is characterised by its own conductivity σ i , heat conductivity χ i , Seebeck factor α i , characteristic size d i and, accordingly, efficiency of thermoelectric transformation Z i . Expressions for the estimation of σ eff , χ eff , α eff and Z eff are constructed, and their values depending on asymmetry degree of characteristics of the granule components are analysed. The complicated ternary thermoelectric media is considered. The possibilities of acquisition of the optimal medium characteristics under various technological conditions and the action of ionizing radiation have been studied.
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