Spectrophotometry, AtomicTrace ElementsMass SpectrometryMetals, HeavySpectrum AnalysisMetalsSpectrometry, X-Ray EmissionCopperSpectrometry, Mass, Electrospray IonizationTandem Mass SpectrometryGas Chromatography-Mass SpectrometrySpectrometry, Mass, Matrix-Assisted Laser Desorption-IonizationPositron-Emission TomographyChromatography, LiquidOtoacoustic Emissions, SpontaneousTomography, Emission-ComputedChromatography, High Pressure LiquidSpectrometry, Mass, Secondary IonVehicle EmissionsFluorodeoxyglucose F18RadiopharmaceuticalsProteomicsSpectrometry, Mass, Fast Atom BombardmentTomography, Emission-Computed, Single-PhotonSpectrometry, FluorescenceMolecular Sequence DataProteomeReproducibility of ResultsAmino Acid SequenceSensitivity and SpecificityGreenhouse EffectFluorine RadioisotopesVolatilizationCalibrationIsotope LabelingElectrophoresis, Gel, Two-DimensionalVolatile Organic CompoundsMolecular StructureAir PollutantsCarbon FootprintReference StandardsGasesEnvironmental MonitoringPeptidesMethaneCarbon RadioisotopesDeuterium Exchange MeasurementMagnetic Resonance SpectroscopySubstance Abuse DetectionPentanesBrain