The present disclosure relates to novel and improved methods of analyzing proteins, peptides and polypeptides by mass spectrometry using ion-ion reactions. More specifically the disclosure relates to improved methods for implementing the m/z selective arresting of ion-ion reactions within the ion-ion reaction cell of a mass spectrometer system during a period where ion-ion reactions are performed.

A biomarker diagnostic system includes a sensor to collect a sweat sample from a biological subject; a processor operatively connected to the sensor, wherein the processor is configured to perform metabolic and proteomic profiling of biomarkers in the sweat sample. The metabolic and proteomic profile is compared to a predetermined profile of the biomarkers and to determine a physiological status of the biomarkers. The system further includes a feedback unit operatively coupled to the sensor and the processor and configured to output physiological performance data based on the physiological status.

In a general aspect, microorganisms [e.g., bacteria, etc.) are identified and detected. In some examples, a liquid solvent is supplied through a first channel of a sampling probe to an internal reservoir of the sampling probe; a fixed volume of the liquid solvent in the internal reservoir is held in direct contact with a sample surface for a period of time to form a liquid analyte; gas is supplied to the internal reservoir through a second channel of the sampling probe; the liquid analyte is extracted from the internal reservoir through a third channel of the sampling probe; the liquid analyte is transferred to a mass spectrometer; the mass spectrometer processes the liquid analyte to produce mass spectrometry data; and the mass spectrometry data are analyzed to detect and identify a microorganism [e.g., acteria, fungi, or another type of microorganism) present at the sample surface.

In a general aspect, chemical compounds (e.g., drugs, agrochemicals, and explosives) are detected. In some examples, a chemical detection system includes a container, an ionization system, a mass spectrometer, one or more computer systems, a sampling probe, and a control system. The sampling probe is configured to receive a liquid solvent from the container; to hold a fixed volume of the liquid solvent in direct contact with a sample surface for a period of time to form an analyte in the sampling probe; and to deliver the analyte to the ionization system. The ionization system is configured to ionize the analyte. The mass spectrometer is configured to produce mass spectrometry data by processing the ionized analyte provided by the ionization system. The one or more computer systems are configured to analyze the mass spectrometry data to detect a chemical compound present on the sample surface.

A method for analyzing aromatic compounds, and a reagent kit for LC-MS analysis of aromatic compounds. The method includes preparing a diazonium reagent, contacting aromatic compounds in a sample with the diazonium reagent to form an analyte; and measuring an amount or ratio of the analyte. The reagent kit includes a diazonium reagent, wherein the diazonium reagent includes (i) a diazonium salt that contains a diazonium ion; (ii) an amine and nitrous acid; and/or (iii) a nitrite and an acid.

Assays and methods for verifying the validity of a urine sample submitted for Drugs of Abuse (DOA) testing. Embodiments include a SUD Diagnostic Panel that includes six assays: specific gravity index assay, long-duration counterfeit urine assay, short-duration counterfeit urine assay, oxidant history assay, pH assay, and creatinine assay. The SUD Diagnostic Panel detects twelve principle classes of adulteration. Detection of adulteration of one or more urine samples from a patient indicates an attempt to subvert test results and provides an objective indication in one instance and an object diagnosis in another instance of SUD.

Methods are disclosed to detect, characterize, measure, and quantify human and humanized antibodies, and their conjugates, that may be present in pre-clinical animal biological samples, or human biological samples, including plasma/serum and tissue samples.

A method for rapid, high throughput screening of the activities of enzymes, especially ligninases and its enzyme cocktails, using nanostructure initiator mass spectrometry (NIMS) surfaces, substrates and methodology.

Methods for determining the presence or amount of oxopiperidine in a biological sample using mass spectrometry. These methods may be used to efficiently and non-invasively diagnose pyridoxine dependent epilepsy (PDE) due to deficient a-aminoadipic-δ-semialdehyde (α-AASA) dehydrogenase activity due to mutations in ALDH7A1, resulting in the accumulation of Δ.sup.1-P6C, P6CH, and 6-Oxo-PIP in biological samples.

The teachings herein provide for a method of analyzing testosterone using mass spectrometry. The method entails combining in a vial or well, a tagging reagent that is reactive with testosterone, an aqueous precipitation agent that precipitate proteins from solution, and an internal standard solution, the internal standard solution containing a known concentration of an isotopically enriched testosterone and then adding to the vial or well, a sample containing or suspected to contain testosterone. The vial can then be mixed to cause simultaneous precipitation of proteins and reaction of any testosterone present with the tagging reagent to form a mixture of a precipitate and a liquid solution. The liquid solution can then be separated from any precipitate and then analyzed for testosterone using liquid chromatography tandem mass spectrometry.