Certain configurations described herein are directed to mass spectrometer systems that can use a gas mixture to select and/or detect ions. In some instances, the gas mixture can be used in both a collision mode and in a reaction mode to provide improved detection limits using the same gas mixture.

The present disclosure provides methods and systems for improved detection and/or quantification of selenium (Se) and/or silicon (Si) in samples. In certain embodiment, the methods and systems feature the use of carbon dioxide (CO.sub.2) as a reaction gas in a reaction cell chamber, such as a dynamic reaction cell (DRC), of an inductively coupled plasma mass spectrometer (ICP-MS). It is found that the use of CO.sub.2 as a reaction gas effectively eliminates (or substantially reduces) interfering ionic species for the analytes Se and Si, particularly in samples with complex matrices, and/or in samples with low levels of analyte, thereby enabling more accurate detection of analyte at lower detection limits and in samples having complex matrices.

Disclosed herein are embodiments of a system for selectively ionizing samples that may comprise a plurality of different analytes that are not normally detectable using the same ionization technique. The disclosed system comprises a unique split flow tube that can be coupled with a plurality of ionization sources to facilitate using different ionization techniques for the same sample. Also disclosed herein are embodiments of a method for determining the presence of analytes in a sample, wherein the number and type of detectable analytes that can be identified is increased and sensitivity and selectivity are not sacrificed.

Provided is a mass spectrometer including: a reaction chamber (132) into which a precursor ion is introduced; a radical generation part (54) configured to generate a known radical; a radical supply part (5) configured to react the precursor ion with the radical to generate fragment ions and an adduct ion; a measurement control part (63) configured to measure ions including the precursor ion, the fragment ions, and the adduct ion to obtain a mass spectrum; and an accurate mass estimation part (64) configured to specify a peak of the adduct ion by searching a predetermined mass range centered on a mass value obtained by adding a mass of an atom or molecule derived from the radical to a mass obtained from a peak of the precursor ion, and estimate an accurate mass of the precursor ion by subtracting an accurate mass of the atom or molecule from an accurate mass of the peak.

An ion analyzer includes a reaction chamber into which precursor ions derived from a sample component are introduced, a radical irradiation unit that generates and emits a predetermined type of radicals, a standard substance supply unit that individually supplies kinds of standard substances to the reaction chamber, where activation energy of radical addition reaction is known for each of the kinds of standard substances, and the activation energies are different in magnitude, an ion measurement unit that measures an amount of predetermined product ions generated from precursor ions derived from the standard substance by irradiation with the radicals, and a radical temperature calculation unit that obtains an amount of radicals that caused the radical addition reaction from the amount of the predetermined product ions and obtains a radical temperature based on a relationship between the amount of the radicals obtained for each kind of standard substance and activation energy.

An ion source ionizes a compound, producing precursor ions with different m/z values. A reagent source supplies charge reducing reagent. An ion guide is positioned between a mass filter and both the ion source and the reagent source. The ion guide applies an AC voltage and DC voltage to its electrodes that creates a pseudopotential to trap the precursor ions in the ion guide below a threshold m/z. This AC voltage, in turn, causes the trapped precursor ions to be charge reduced by the reagent so that m/z values of the trapped precursor ions increase to a single m/z value above the threshold m/z. The ion guide applies the DC voltage to its electrodes relative to a DC voltage applied to electrodes of the mass filter that causes the precursor ions with m/z values increased to the single m/z value to be continuously transmitted to the mass filter.

A mass spectrometry device comprises a reaction gas introduction device and a gas phase molecule-ion reaction mass spectrometry analysis device, wherein the reaction gas introduction device is connected to the gas phase molecule-ion reaction mass spectrometry analysis device; the reaction gas introduction device is configured to introduce reaction gas into the gas phase molecule-ion reaction mass spectrometry analysis device; and the gas phase molecule-ion reaction mass spectrometry analysis device is configured to enable molecules or ions to be subjected to a reaction and carry out mass spectrometry analysis on a reaction result. The reaction gas introduction device comprises a reaction gas container, the reaction gas container being configured to contain gas or volatile liquid or solid and generate gas molecules needed by a reaction; and a reaction gas quantitation device, configured to carry out flow control on the gas molecules.

A mass analyzer includes two chambers for ionizing gas to form ions and/or introducing reaction gases to aid in ionization. A first chamber includes an electron to allow electron bombardment of a first gas. A second chamber receives a second gas and ions from the first chamber to allow interaction between the second gas, and the ions from the first chamber. The first and/or second gas may include analyte.

The present invention relates to the field of biomarkers. More specifically, the present invention relates to biomarkers useful in diagnosing brain injury or neurodegeneration. In one embodiment, a method for diagnosing brain injury in a patient comprises the steps of (a) obtaining a sample from the patient; (b) determining the ratio of citrullinated to unmodified arginine residues at one or more arginine residues of one or more brain injury biomarker proteins; and (c) correlating the ratio to a patient having brain injury or to a patient not having brain injury, thereby providing the diagnosis.

To reduce contamination of the apparatus with an additive and to quickly switch spraying and stopping of the additive, provided is an ion analyzer including: an ion source for ionizing a measurement target substance, a spray unit for atomizing and spraying toward the measurement target substance a liquid containing an additive that reacts with the measurement target substance; a separation analysis unit for separately analyzing an ion generated by a reaction between the measurement target substance and the additive; a detector for detecting the ion that has been separately analyzed by the separation analysis unit; and a control unit for lowering a flow rate of the additive supplied to the spray unit during a time when the additive is not necessary.