In an embodiment of the present ambient ionization experiment, the abundance of background chemicals relative to ions of interest is decreased by pulsing the carrier gas used to generate the excited species directed at the sample. The excited species are stepwise directed at the sample reducing the overall abundance of background chemicals introduced into the ionizing region. In an embodiment of the present ambient ionization experiment, the combination of stepping the sample in front of the excited species and pulsing the carrier gas used to generate the excited species increases the sensitivity of detection.

The invention relates to the detection of non-metabolized vitamin D. In a particular aspect, the invention relates to methods for detecting underivatized non-metabolized vitamin D by mass spectrometry.

A method of ionizing a sample is disclosed that comprises heating a sample so that analyte is released from the sample, producing charged particles such as charged droplets downstream of the sample, and using the charged particles to ionize at least some of the analyte released from the sample so as to produce analyte ions.

The present invention relates to an apparatus and a method for IMR-MS and/or PTR-MS, comprising a sample gas inlet (202, 206), a first ion source (209), a reaction chamber (203), a mass analyzer (204), wherein the reaction chamber (203) and the mass analyzer (204) are arranged along a central axis (A), characterized by a second ion source (209), wherein the sample gas inlet (202, 206) is arranged to introduce gas essentially along the central axis (A) and is connected to the reaction chamber (203); wherein the first ion source (209) and the second ion source (209) are arranged so as to emit reagent ions essentially perpendicularly to the central axis (A); said apparatus further comprising at least one electrode (302, 303, 304, 305), such that the reagent ions emitted from the first or second ion source (209) can be deflected into the reaction chamber (203) essentially in the downstream direction of the central axis (A).

A system for the mass spectrometry analysis of an analyte includes a droplet ejection device, a spray head comprising a spray tip for ejecting the solvent as a spray, and a solvent delivery conduit for delivering solvent to the spray tip. The spray head includes a droplet inlet opening communicating with the surrounding atmosphere for receiving liquid droplets comprising the analyte. The droplet ejection device selectively ejects a liquid analyte droplet comprising the analyte through a surrounding atmosphere and the droplet inlet opening into a solvent flowing through the solvent delivery conduit. A method for the mass spectrometry analysis of an analyte is also disclosed.

Certain configurations of plasma discharge chambers and plasma ionization sources comprising a plasma discharge chamber are described. In some examples, the discharge chamber comprises a conductive area and is configured to sustain a plasma discharge within the discharge chamber. In other examples, the discharge chamber comprises at least one inlet configured to receive a plasma gas and at least one outlet configured to provide ionized analyte from the discharge chamber. Systems and methods using the discharge chambers are also described.

Described herein are monitoring systems and methods, including for airborne molecular contamination (AMC), that combine a sampler, such as an impinger or sorbent tube with a real time analyzer, such as an ion mobility spectrometer (IMS) or optical particle counter. The system may allow for selective sampling in which the sampler is only exposed to the target fluid during periods in which the real time analyzer detects analytes, such as molecular contamination or particles, meeting particular criteria such the composition and/or concentration of analytes. The invention also includes impinger systems having a sampler reservoir comprising an anion leaching resistant material characterized by low anion leach rates in the presence of deionized water.

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.

A method and apparatus that ionize vapors for their chemical analysis is described. The new ionizer improves the ionization efficiency by reducing dilution of sample molecules and improving transmission of ions to the analyzer. This is accomplished by a new flow configuration, in which a stream of clean gas focuses the ions towards the analyzer. A deflector prevents the formation of turbulent perturbation, and the ionization maintains a laminar regime without the need for additional separating walls or electrodes. The flow within the ionizer is configured so that contaminants released by the inner walls of the ionizer do not reach the ionization region. The resulting ionizer improves the ionization efficiency, and the background levels for low volatility species. This makes it ideal for the analysis of low volatility species in the gas phase. One application of this ionizer is the analysis of human breath in real time.

Laser ablation devices and methods including laser ablation are provided. The ablation devices can include a deep UV laser. Dual-laser ablation devices are also provided. Biomolecules can be ablated using a combination of deep UV laser and nanoelectrospray, resulting in protonated sample molecules.