Abstract: A method of separating free target analyte from protein-bound target analyte is described. Such can include obtaining an aqueous sample containing a target analyte in a free form (free target analyte) and the target analyte in a protein-bound form (protein-bound target analyte), passing the aqueous sample through a size exclusion chromatography matrix with a molecular weight cut off sufficient to allow the free target analyte to permeate into pores of the size exclusion chromatography matrix and exclude the protein-bound target analyte, whereupon the free target analyte adheres to and is immobilized by the size exclusion chromatography matrix and the protein-bound target analyte does not adhere to by the size exclusion chromatography matrix, separating the free target analyte from the protein-bound analyte by removing the protein-bound target analyte from the size exclusion chromatography matrix, and eluting the free target analyte from the size exclusion chromatography matrix with an organic solvent.

Abstract: A method of separating free target analyte from protein-bound target analyte is described. Such can include obtaining an aqueous sample containing a target analyte in a free form (free target analyte) and the target analyte in a protein-bound form (protein-bound target analyte), passing the aqueous sample through a size exclusion chromatography matrix with a molecular weight cut off sufficient to allow the free target analyte to permeate into pores of the size exclusion chromatography matrix and exclude the protein-bound target analyte, whereupon the free target analyte adheres to and is immobilized by the size exclusion chromatography matrix and the protein-bound target analyte does not adhere to by the size exclusion chromatography matrix, separating the free target analyte from the protein-bound analyte by removing the protein-bound target analyte from the size exclusion chromatography matrix, and eluting the free target analyte from the size exclusion chromatography matrix with an organic solvent.

Abstract: A method of separating free target analyte from protein-bound target analyte is described. Such can include obtaining an aqueous sample containing a target analyte in a free form (free target analyte) and the target analyte in a protein-bound form (protein-bound target analyte), passing the aqueous sample through a size exclusion chromatography matrix with a molecular weight cut off sufficient to allow the free target analyte to permeate into pores of the size exclusion chromatography matrix and exclude the protein-bound target analyte, whereupon the free target analyte adheres to and is immobilized by the size exclusion chromatography matrix and the protein-bound target analyte does not adhere to by the size exclusion chromatography matrix, separating the free target analyte from the protein-bound analyte by removing the protein-bound target analyte from the size exclusion chromatography matrix, and eluting the free target analyte from the size exclusion chromatography matrix with an organic solvent.

Abstract: The present invention provides methods, compositions, and kits associated with analyzing, enriching, and/or isolating a biomarker or analyte in a biological sample. In one aspect, for example, a method for determining a concentration of a biomarker in a biological sample can include binding any unbound biomarker with an antibody specific for the biomarker to form antibody-bound biomarker, enriching the antibody-bound biomarker and any endogenous autoantibody-bound biomarker to form an enriched fraction, identifying the biomarker in the enriched fraction, and determining the concentration of the biomarker in the biological sample. In one aspect, the concentration of the biomarker is derived from initially unbound biomarker and autoantibody-bound biomarker in the biological sample.

Abstract: Methods for measuring and analyzing parathyroid hormone-related peptide (PTHrP) using LC-MS/MS, including applications of the methods thereof, are disclosed and discussed. Such methods can include, along with the use of an isotope-labeled internal standard, purifying PTHrP from a biological sample, proteolytically digesting the PTHrP, and measuring specific digestion products using the using LC-MS/MS.

Abstract: A method of separating free target analyte from protein-bound target analyte is described. Such can include obtaining an aqueous sample containing a target analyte in a free form (free target analyte) and the target analyte in a protein-bound form (protein-bound target analyte), passing the aqueous sample through a size exclusion chromatography matrix with a molecular weight cut off sufficient to allow the free target analyte to permeate into pores of the size exclusion chromatography matrix and exclude the protein-bound target analyte, whereupon the free target analyte adheres to and is immobilized by the size exclusion chromatography matrix and the protein-bound target analyte does not adhere to by the size exclusion chromatography matrix, separating the free target analyte from the protein-bound analyte by removing the protein-bound target analyte from the size exclusion chromatography matrix, and eluting the free target analyte from the size exclusion chromatography matrix with an organic solvent.

Abstract: Methods for measuring and analyzing parathyroid hormone-related peptide (PTHrP) using LC-MS/MS, including applications of the methods thereof, are disclosed and discussed. Such methods can include, along with the use of an isotope-labeled internal standard, purifying PTHrP from a biological sample, proteolytically digesting the PTHrP, and measuring specific digestion products using the using LC-MS/MS.

Abstract: Processes and methods for modeling non-linear calibration behavior resulting from isotopic interference between a target analyte and an internal standard during a mass spectrometry operation are disclosed and described. In some embodiments, a correction to instrument data obtained during the mass spectrometry operation can be made. Such a correction may entail determining, in some cases experimentally determining, one or two constants, and a single adjustable parameter for each analyte/internal standard pair.

Abstract: The present disclosure provides methods and composition involving increased sensitivity of compounds using mass spectrometry. In one embodiment, a method of increasing the sensitivity for detection of a carbonyl group-containing compound by mass spectrometry can comprise derivatizing the carbonyl group-containing compound with an O-substituted hydroxylamine thereby producing an oxime, resulting in enhanced sensitivity of detection by mass spectrometry, as compared to the underivatized carbonyl group-containing compound. Additionally, a method for assaying a carbonyl group-containing compound can comprise reacting the carbonyl group-containing compound in a sample with an O-substituted hydroxylamine to produce an oxime and performing analysis with mass spectrometric detection of the oxime by a mass spectrometry instrument.

Abstract: Methods for measuring and analyzing parathyroid hormone-related peptide (PTHrP) using LC-MS/MS, including applications of the methods thereof, are disclosed and discussed. Such methods can include, along with the use of an isotope-labeled internal standard, purifying PTHrP from a biological sample, proteolytically digesting the PTHrP, and measuring specific digestion products using the using LC-MS/MS.

Abstract: The present invention provides methods, compositions, and kits associated with analyzing, enriching, and/or isolating a biomarker or analyte in a biological sample. In one aspect, for example, a method for determining a concentration of a biomarker in a biological sample can include binding any unbound biomarker with an antibody specific for the biomarker to form antibody-bound biomarker, enriching the antibody-bound biomarker and any endogenous autoantibody-bound biomarker to form an enriched fraction, identifying the biomarker in the enriched fraction, and determining the concentration of the biomarker in the biological sample. In one aspect, the concentration of the biomarker is derived from initially unbound biomarker and autoantibody-bound biomarker in the biological sample.

Abstract: The present invention provides methods, compositions, and kits associated with analyzing, enriching, and/or isolating a biomarker or analyte in a biological sample. In one aspect, for example, a method for determining a concentration of a biomarker in a biological sample can include binding any unbound biomarker with an antibody specific for the biomarker to form antibody-bound biomarker, enriching the antibody-bound biomarker and any endogenous autoantibody-bound biomarker to form an enriched fraction, identifying the biomarker in the enriched fraction, and determining the concentration of the biomarker in the biological sample. In one aspect, the concentration of the biomarker is derived from initially unbound biomarker and autoantibody-bound biomarker in the biological sample.

Abstract: The present disclosure provides methods and composition involving increased sensitivity of compounds using mass spectrometry. In one embodiment, a method of increasing the sensitivity for detection of a carbonyl group-containing compound by mass spectrometry can comprise derivatizing the carbonyl group-containing compound with an O-substituted hydroxylamine thereby producing an oxime, resulting in enhanced sensitivity of detection by mass spectrometry, as compared to the underivatized carbonyl group-containing compound. Additionally, a method for assaying a carbonyl group-containing compound can comprise reacting the carbonyl group-containing compound in a sample with an O-substituted hydroxylamine to produce an oxime and performing analysis with mass spectrometric detection of the oxime by a mass spectrometry instrument.

Abstract: A virtual ion trap that uses electric focusing fields instead of machined metal electrodes that normally surround the trapping volume, wherein two opposing surfaces include a plurality of uniquely designed and coated electrodes, and wherein the electrodes can be disposed on the two opposing surfaces using plating techniques that enable much higher tolerances to be met than existing machining techniques.

Abstract: A virtual ion trap that uses electric focusing fields instead of machined metal electrodes that normally surround the trapping volume, wherein two opposing surfaces include a plurality of uniquely designed and coated electrodes, and wherein the electrodes can be disposed on the two opposing surfaces using plating techniques that enable much higher tolerances to be met than existing machining techniques.

Abstract: A cross-flow ion mobility analyzer (CIMA) that includes a component of gas flow that opposes an electric field that is established within a channel, wherein ions are carried through the channel, wherein ions of a specific mobility are trapped by the opposing electric field and flow field within the channel and are detected when the ions reach the end of the channel, wherein a detector at the end of the channel sees a continuous stream of mobility-selected ions, and wherein different ions are selected by modifying the electric field and/or the velocity of the flow field.

Abstract: The present invention provides methods for high throughput analysis of analytes in complex mixtures for unresolved chromatographic peaks including specific embodiment for summing intensities for each mass transition of interest over a selected chromatographic peak (50) to generate a signal corresponding to total intensity for each transition (55, 60). The intensities are deconvoluted into intensities of individual analytes (65, 70), based on branching ratios acquired from authentic standards, and a comparison to calibration curve is performed to obtain a quantitative concentration measurement of a particular analyte in a sample.

Abstract: A single set of electrodes, wherein different electrical potentials are applied to the single set of electrodes at different times in order to perform both ion mobility-based spectrometry and mass spectrometry (MS) on a sample of ions, wherein the ions are processed by performing ion mobility-based spectrometry and mass spectrometry in any sequence, any number of times, and as isolated or superposed procedures in order to trap, separate, fragment, and/or analyze charged particles and charged particles derived from atoms, molecules, particles, sub-atomic particles and ions.

Abstract: A radio-frequency quadrupole ion guide having a symmetrical magnetic field disposed along an axis of the ion guide, wherein the system provides prolonged interaction between electrons and uncharged compounds within an ionization volume of the ion guide, resulting in enhanced ion creation.

Abstract: A method and apparatus for focusing ions for delivery to an ion detection device using an aerodynamic ion focusing system that uses a high-velocity converging gas flow at an entrance aperture to focus an ion plume by reducing spreading and increasing desolvation of ions, and wherein a voltage is applied to at least a portion of the aerodynamic ion focusing system to assist in the focusing and delivery of ions to the ion detection device.