Abstract: A method of producing sulfur-free nanoparticles involves growing yeast in a growth medium containing a source of an element in a bio-reducible oxidation state (e.g. Se(Vl), and, precipitating nanoparticles containing the element in a lower oxidation state (e.g. Se(O)) than the oxidation state of the element in the source. The method advantageously can provide substantially spherical nanoparticles at high production efficiencies.

Abstract: A comprehensive approach for interpretation of the multiple spiking isotope dilution results is described herein. It has now been found that a method of multiple spiking isotope dilution analysis for mass spectrometry is possible using an approach that permits precise and simultaneous characterization of m substances from a sample even if species inter-conversion (degradation and formation) has occurred prior to separation. Advantageously, initial and final amounts of involved analytes, conversion extent, conversion degree and rate constants from the results of a single quantitation experiment may be obtained with the present method. In a particularly advantageous embodiment, uncertainty in the characterization of the substances may be estimated more accurately by also estimating increase in the uncertainty due to inter-conversion of the analytes.

Abstract: A comprehensive approach for interpretation of the multiple spiking isotope dilution results is described herein. It has now been found that a method of multiple spiking isotope dilution analysis for mass spectrometry is possible using an approach that permits precise and simultaneous characterization of m substances from a sample even if species inter-conversion (degradation and formation) has occurred prior to separation. Advantageously, initial and final amounts of involved analytes, conversion extent, conversion degree and rate constants from the results of a single quantitation experiment may be obtained with the present method. In a particularly advantageous embodiment, uncertainty in the characterization of the substances may be estimated more accurately by also estimating increase in the uncertainty due to interconversion of the analytes.

Abstract: A plasma-based dielectric barrier discharge (DBD) ion source is configured for flowing afterglow sampling and ionization of analytes. A method of direct sampling for mass spectrometric analysis includes providing an afterglow from a dielectric barrier discharge (DBD) plasma device, directing the afterglow with a flow of heated plasma support gas to a sample positioned externally to the DBD device, ionizing at least a portion of the sample with the afterglow and heated gas, and, analyzing ionized species from the sample in a mass spectrometer. A system for mass spectrometric analysis of a sample includes a mass spectrometer having an entrance aperture, and, a dielectric barrier discharge (DBD) ion source having a heated plasma support gas for directing DBD afterglow to a sample positioned between the DBD ion source and the entrance aperture of the mass spectrometer.

Abstract: A method of producing sulfur-free nanoparticles involves growing yeast in a growth medium containing a source of an element in a bio-reducible oxidation state (e.g. Se(V1), and, precipitating nanoparticles containing the element in a lower oxidation state (e.g. Se(O)) than the oxidation state of the element in the source. The method advantageously can provide substantially spherical nanoparticles at high production efficiencies.

Abstract: An analyte for atomic spectrometry detection is prepared by introducing an aerosol of the analyte into a chamber, and irradiating the aerosol with ultraviolet light in the presence of a low molecular weight organic acid or other suitable photoactivatable ligand donor species to create vapor containing the analyte. The vapor containing the analyte is extracted from the chamber and used for atomic spectrometry detection.

Abstract: A method of obtaining pure component mass spectra or pure peak elution profiles from mass spectra of a mixture of components involves estimating number of components in the mixture, filtering noise, and extracting individual component mass spectra or pure peak elution profiles using blind entropy minimization with direct optimization (e.g. downhill simplex minimization). The method may be applied to deconvolution of pure GC/MS spectra of overlapping or partially overlapping isotopologues or other compounds, separation of overlapping or partially overlapping compounds in proteomics or metabolomics mass spectrometry applications, peptide sequencing using high voltage fragmentation followed by deconvolution of the obtained mixture mass spectra, deconvolution of MALDI mass spectra in the separation of multiple components present in a single solution, and specific compound monitoring in security and/or environmentally sensitive areas.

Abstract: An analyte for atomic spectrometry detection is prepared by introducing an aerosol of the analyte into a chamber, and irradiating the aerosol with ultraviolet light in the presence of a low molecular weight organic acid or other suitable photoactivatable ligand donor species to create vapor containing the analyte. The vapor containing the analyte is extracted from the chamber and used for atomic spectrometry detection.

Abstract: A method of obtaining pure component mass spectra or pure peak elution profiles from mass spectra of a mixture of components involves estimating number of components in the mixture, filtering noise, and extracting individual component mass spectra or pure peak elution profiles using blind entropy minimization with direct optimization (e.g. downhill simplex minimization). The method may be applied to deconvolution of pure GC/MS spectra of overlapping or partially overlapping isotopologues or other compounds, separation of overlapping or partially overlapping compounds in proteomics or metabolomics mass spectrometry applications, peptide sequencing using high voltage fragmentation followed by deconvolution of the obtained mixture mass spectra, deconvolution of MALDI mass spectra in the separation of multiple components present in a single solution, and specific compound monitoring in security and/or environmentally sensitive areas.

Abstract: The invention comprises a method of photochemical transformation of metallic and non-metallic ions in an aqueous environment. The method comprises exposing the ions to UV irradiation in the presence of an organic acid. The aqueous ions are reduced by the method and may form hydrides, alkyl or carbonyl compounds.

Abstract: The invention comprises a method of photochemical transformation of metallic and non-metallic ions in an aqueous environment. The method comprises exposing the ions to UV irradiation in the presence of an organic acid. The aqueous ions are reduced by the method and may form hydrides, alkyl or carbonyl compounds.

Abstract: The invention comprises a method of photochemical transformation of metallic and non-metallic ions in an aqueous environment. The method comprises exposing the ions to UV irradiation in the presence of an organic acid. The aqueous ions are reduced by the method and may form hydrides, alkyl or carbonyl compounds.

Abstract: The present invention relates to a simple thermal desorption gas introduction interface for sample introduction of volatile analytes into an atomic spectroscopic detector. An injector is connected to the atomic spectroscopic detector via a first port. The injector further comprises a sealed second port for inserting the volatile analyte bound to an extraction phase. A heating block surrounding the injector heats the injector to a predetermined temperature and keeps it substantially at the predetermined temperature. A carrier gas flow of inert gas is provided into the injector through a third port of the injector located in proximity to the second port. An auxiliary gas flow of inert gas is provided via forth port located between the third port and the atomic spectroscopic detector. The volatile analyte bound to an extraction phase is inserted into the injector, wherein the extraction phase is inserted through the seal of the second port for sealed exposure within the injector.