187 results about "Photo ionization" patented technology

An improved ion source for collecting and focusing dispersed gas-phase ions from a reagent source at atmospheric or intermediate pressure, having a remote source of reagent ions separated from a low-field sample ionization region by a stratified array of elements, each element populated with a plurality of openings, wherein DC potentials are applied to each element necessary for transferring reagent ions from the remote source into the low-field sample ionization region where the reagent ions react with neutral and / or ionic sample forming ionic species. The resulting ionic species are then introduced into the vacuum system of a mass spectrometer or ion mobility spectrometer. Embodiments of this invention are methods and devices for improving sensitivity of mass spectrometry when gas and liquid chromatographic separation techniques are coupled to atmospheric and intermediate pressure photo-ionization, chemical ionization, and thermospray ionization sources.

An improved ion source and means for collecting and focusing dispersed gas-phase ions from a remote reagent chemical ionization source (R2CIS) at atmospheric or intermediate pressure is described. The R2CIS is under electronic control and can produce positive, negative, or positive and negative reagent ions simultaneously. This remote source of reagent ions is separated from a low-field sample ionization region by a stratified array of elements, each element populated with a plurality of openings, wherein DC potentials are applied to each element necessary for transferring reagent ions from the R2CIS into the low-field sample ionization region where the reagent ions react with neutral and / or ionic sample forming sample ionic species. The resulting sample ionic species are then introduced into a mass spectrometer, ion mobility spectrometer or other sensor capable of detecting the sample ions. Embodiments of this invention are methods and devices for improving sensitivity of mass spectrometry when gas and liquid chromatographic separation techniques are coupled to atmospheric and intermediate pressure photo-ionization, chemical ionization, and thermospray ionization sources; and improving the sensitivity of chemical detectors or probes.

A method and apparatus are provided for identifying analytes at low concentrations in a liquid sample. The liquid sample is introduced through a continuous flow membrane inlet system. The analytes that permeate the membrane are analyzed by photoionization-time-of-flight mass spectrometry. The analytes remaining in the liquid sample that do not permeate the membrane are conducted to a capillary tube inlet that introduces the liquid sample and other analytes as droplets into the photoionization zone. Any analytes remaining absorbed or adsorbed on the membrane are driven through the membrane by application of heat. Analytes may be analyzed by either resonance enhanced multiphoton ionization (REMPI) or single photon ionization (SPI), both of which are provided in the apparatus and can be selected as alternative sources.

An apparatus and method for regenerating ion samples for a mass spectrometer are provided. Source samples are loaded on a support which is heated by a laser beam, desorbing the sample without ionization. The desorbed sample is carried by a carrier gas flow through a transfer tube, at the output of which it is ionized by corona discharge or photo-ionization. The obtained ionized sample may be analyzed in a mass spectrometer or used to serve any other appropriate purpose.

An RF-driven plasma source, including a pair of spaced-apart plasma electrodes, wherein the electrodes act as plates of a capacitor, the gas electrically discharges and creates a plasma of both positive and negative ions, in a clean process that enables efficient sample analysis, with preferred isolated sample photo-ionization, reduced-power operation and also including signal detection with modulated drive electronics.

The invention provides improved apparatus for, and methods of, ionizing analyte molecules in a flow of gas, typically at or around atmospheric pressure. The invention may be used to facilitate mass spectrometric analysis of analytes comprised in the effluent form a gas chromatograph. Ionization may be effected by atmospheric pressure chemical ionization or by atmospheric pressure photo ionization.

Methods and systems are provided for the soft desorption of analyte from a sample, in which an optical beam absorbed within an irradiate zone of the sample causes vibrational excitations of a component within the sample. The optical beam, providing sufficient energy to superheat the component, is provided for a time interval that is less than the time duration required for the loss of energy out of the irradiated zone due to thermal diffusion and acoustic expansion. The superheated component thus drives ablation within the irradiated zone, resulting in the soft desorption of analyte without ionization and fragmentation. The ejected ablation plume may be directed towards the inlet of a mass analysis device for detection of the desorbed analyte, which is preferably ionized by a linear resonant photo-ionization step.

A vapor trap for detecting VOCs includes a housing, having a first end portion, a second end portion and at least one opening for receiving gas vapor. The housing is at least partially buried in ground with a vapor containment mechanism detachably connected to the first end portion of the housing. The vapor containment mechanism can be removed and replaced with a vapor sampling mechanism. An organic vapor analyzer can be connected in fluid relationship to the vapor sampling mechanism to measure VOCs. Optionally, a vacuum pump can be utilized to draw vapor into the vapor trap and then subsequently into the organic vapor analyzer. There can be a first selector valve located between the vapor sampling mechanism and the vacuum pump and a second selector valve located between the vapor sampling mechanism and the organic vapor analyzer. A preferred organic vapor analyzer is a photo-ionization detector.

An auto-cleaning and auto-zeroing system (1) comprises a first conduit for flow of ambient gas (16) and a 2nd conduit (22) for flow of ambient air (18). A cleaning chamber (12) removes impurities from ambient air (18). The 1st conduit (20) and 2nd conduit (22) are connected to a valve, operated by the continuous motor, which continuously draws ambient gas (16) or cleaned and filtered ambient air (18) through the system. Cleaned and filtered ambient air (18) enters the ionization chamber (10) to carry out a cleaning (flushing) and a cleaning (ionization) cycle. In this manner, contaminants and pollutants left in the ionization chamber (10) from the measurement of ambient gas (16) are flushed out and removed.