A method that includes introducing at least one analyte into a gas plasma; generating neutral species from atoms of the analyte in the gas plasma; preferentially transporting the neutral species downstream of the gas plasma relative to any ions produced in the gas plasma; and reacting the neutral species of the analyte with at least one reagent ion downstream of the plasma resulting in ion species of the analyte, wherein the at least one reagent ion is supplied by an independent ion source.

Apparatus include an atmospheric pressure glow discharge (APGD) analyte electrode defining an analyte discharge axis into an APGD volume, and a plurality of APGD counter electrodes having respective electrical discharge ends directed to the APGD volume, wherein the APGD analyte electrode and the APGD counter electrodes are configured to produce an APGD plasma in the APGD volume with a voltage difference between the APGD analyte electrode and one or more of the AGPD counter electrodes. An electrode can be integrated into an ion inlet. Apparatus can be configured to perform auto-ignition and/or provide multi-modal operation through selectively powering electrodes. Electrode holder devices are disclosed. Related methods are disclosed.

A solution-cathode glow discharge mass spectrometry (SCGD-MS) apparatus comprises a SCGD source and a mass spectrometer. The SCGD source may comprise conductive rods, a power source, and a capillary. A method for ionizing an analyte comprises flowing an electrically conductive liquid onto a conductive rod, applying an electric potential to a second conductive rod such that a plasma discharge forms between the first conductive rod and the electrically conductive liquid to produce ions, and separating the ions in a mass spectrometer. The analyte may be a polypeptide that may be contacted with trypsin. The analyte may be a solid, liquid, gas, chemical complex, or ion in solution. The method may comprise sequencing the polypeptide.

An ionizer includes an ionization probe (21) provided with a capillary (211), a metallic slender tube (212), and a nebulizing gas pipe (213). The ionization probe (21) is equipped to perform ESI-based ionization of components in a liquid sample. An electroconductive capillary (22) is disposed at a position forward in a flow direction of a nebulized flow of the liquid sample from the ionization probe (21). A high voltage from a high voltage power supply (23) is applied to the electroconductive capillary (22) to induce corona discharge so that the components in the liquid sample are ionized by the APCI as well. At the time of tuning the ionizer, a standard sample solution is provided through the electroconductive capillary (22), and a high voltage from the high voltage power supply (23) is applied to the electroconductive capillary (22) so that components in the standard sample solution are ionized by the ESI or due to an ion molecular reaction with solvent molecular ions produced in the ionization probe (21). Thus, components in a standard sample can be ionized and subjected to mass spectrometry without pipe rearranging operations or without switch to and from different flow paths using a valve.

A solution-cathode glow discharge mass spectrometry (SCGD-MS) apparatus comprises a SCGD source and a mass spectrometer. The SCGD source may comprise conductive rods, a power source, and a capillary. A method for ionizing an analyte comprises flowing an electrically conductive liquid onto a conductive rod, applying an electric potential to a second conductive rod such that a plasma discharge forms between the first conductive rod and the electrically conductive liquid to produce ions, and separating the ions in a mass spectrometer. The analyte may be a polypeptide that may be contacted with trypsin. The analyte may be a solid, liquid, gas, chemical complex, or ion in solution. The method may comprise sequencing the polypeptide.

Apparatus include an atmospheric pressure glow discharge (APGD) analyte electrode defining an analyte discharge axis into an APGD volume, and a plurality of APGD counter electrodes having respective electrical discharge ends directed to the APGD volume, wherein the APGD analyte electrode and the APGD counter electrodes are configured to produce an APGD plasma in the APGD volume with a voltage difference between the APGD analyte electrode and one or more of the AGPD counter electrodes. An electrode can be integrated into an ion inlet. Apparatus can be configured to perform auto-ignition and/or provide multi-modal operation through selectively powering electrodes. Electrode holder devices are disclosed. Related methods are disclosed.

A solution-cathode glow discharge (SCGD) spectrometry apparatus may comprise an SCGD source and a mass or ion mobility spectrometer. A method for ionizing a molecular analyte may comprise contacting the molecular analyte with a plasma discharge to form ions and separating the ions in a mass spectrometer or ion mobility spectrometer. The contacting step may occur under atmospheric pressure and/or ambient conditions. The molecular analyte may be fragmented by the plasma discharge.

An ionizer includes an ionization probe (21) provided with a capillary (211), a metallic slender tube (212), and a nebulizing gas pipe (213). The ionization probe (21) is equipped to perform ESI-based ionization of components in a liquid sample. An electroconductive capillary (22) is disposed at a position forward in a flow direction of a nebulized flow of the liquid sample from the ionization probe (21). A high voltage from a high voltage power supply (23) is applied to the electroconductive capillary (22) to induce corona discharge so that the components in the liquid sample are ionized by the APCI as well. At the time of tuning the ionizer, a standard sample solution is provided through the electroconductive capillary (22), and a high voltage from the high voltage power supply (23) is applied to the electroconductive capillary (22) so that components in the standard sample solution are ionized by the ESI or due to an ion molecular reaction with solvent molecular ions produced in the ionization probe (21). Thus, components in a standard sample can be ionized and subjected to mass spectrometry without pipe rearranging operations or without switch to and from different flow paths using a valve.

A solution-cathode glow discharge (SCGD) spectrometry apparatus may comprise an SCGD source and a mass or ion mobility spectrometer. A method for ionizing a molecular analyte may comprise contacting the molecular analyte with a plasma discharge to form ions and separating the ions in a mass spectrometer or ion mobility spectrometer. The contacting step may occur under atmospheric pressure and/or ambient conditions. The molecular analyte may be fragmented by the plasma discharge.

A method that includes introducing at least one analyte into a gas plasma; generating neutral species from atoms of the analyte in the gas plasma; preferentially transporting the neutral species downstream of the gas plasma relative to any ions produced in the gas plasma; and reacting the neutral species of the analyte with at least one reagent ion downstream of the plasma resulting in ion species of the analyte, wherein the at least one reagent ion is supplied by an independent ion source.