141 results about "Chemical ionization" patented technology

An improved ion source and portable analyzer for collecting and focusing dispersed gas-phase ions from a reagent source at atmospheric or intermediate pressure, having a remote source of reagent ions generated by direct or alternating currents, 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 or probes containing samples are coupled to atmospheric and intermediate pressure photo-ionization, chemical ionization, and thermospray ionization sources.

An improved ion source for collecting and focusing dispersed gas-phase ions from a reagent source at sub-atmospheric or intermediate pressure, having a remote source of reagent ions separated from a low-field sample ionization region by a barrier, comprised of alternating laminates of metal and insulator, populated with a plurality of openings, wherein DC potentials are applied to each metal laminate 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 sub-atmospheric and intermediate pressure photo-ionization, chemical ionization, and thermal-pneumatic ionization sources.

Improvements have been made for collecting, focusing, and directing of ions and/or charged particles generated at atmospheric or near atmospheric pressure sources, such as but not limited to, electrospray; atmospheric pressure discharge ionization, chemical ionization, photoionization, and matrix assisted laser desorption ionization; and inductively coupled plasma ionization. A multiple-aperture laminated structure is place at the interface of two pressure regions. Electric fields geometries and strengths across the laminated structure and diameters of the apertures; all of which act to optimize the transfer of the ions from the higher pressure region into the lower pressure region while reducing the gas-load on the lower pressure region. Embodiments of this invention are methods and devices for improving sensitivity of mass spectrometry when coupled to atmospheric, near atmospheric, or higher pressure ionization sources by reducing the gas-load on the vacuum system.

A new ionization source named Surface Activated Chemical Ionization (SACI) has been discovered and used to improve the sensitivity of the mass spectrometer. According to this invention the ionization chamber of a mass spectrometer is heated and contains a physical new surface to improve the ionization process. The analyte neutral molecules that are present in gas phase are ionized on this surface. The surface can be made of various materials and may also chemically modified so to bind different molecules. This new ionization source is able to generate ions with high molecular weight and low charge, an essential new key feature of the invention so to improve sensitivity and reduce noise. The new device can be especially used for the analysis of proteins, peptides and other macromolecules. The new invention overcomes some of the well known and critical limitations of the Electrospray (ESI) and Matrix Assisted Laser Desorption Ionization (MALDI) mass spectrometric techniques.

The invention discloses a detection method of a phthalate plasticizer, comprising the following steps: 1. pretreatment: putting a sample to be detected into an organic solvent, and then dissolving and treating to obtain the solution to be detected in which the plasticizer is dissolved; and 2. content determination of the plasticizer: utilizing a gas chromatogram method and a chemical ionization mass spectrometry method to detect the type and the content of the plasticizer in the detected solution, wherein, the chemical ionization reagent used in the chemical ionization mass spectrometry method is composed of isobutane, methane or ammonia. The detection method of the phthalate plasticizer provided by the invention has high qualitative and quantitative accuracy and high quantitative detection sensitivity.

A system and methods are described for generating reagent ions and product ions for use in a mass spectrometry system. Applications for the system and method are also disclosed for detecting volatile organic compounds in trace concentrations. A microwave or high-frequency RF energy source ionizes particles of a reagent vapor to form reagent ions. The reagent ions enter a chamber, such as a drift chamber, to interact with a fluid sample. An electric field directs the reagent ions and facilitates an interaction with the fluid sample to form product ions. The reagent ions and product ions then exit the chamber under the influence of an electric field for detection by a mass spectrometer module. The system includes various control modules for setting values of system parameters and analysis modules for detection of mass and peak intensity values for ion species during spectrometry and faults within the system.

This invention relates to chemical ionization base on medium resisting discharging and mass spectrum ion source, it belongs to chemical engineering technique field. It especially relates to active base group ionization to organic matter molecular based on medium resisting discharging technique and mass spectrum ion source used for organic matter detecting. The features are that the medium resisting discharging device is used to ionize the reaction gas that can be used to chemical ionization, the reaction gas is ionized to generate ion and the reaction ion is ion-molecular react with the measuring organic matter to make the organic matter ionization, so mass spectrum can be used t realize detecting. The discharging voltage is 220V-10000V, frequency is 50 Hz to 50MHz, and reaction gas flow velocity is 10ml/min-1000ml/min. The corresponding mass spectrum is also provided. The measuring organic matter can be ionized in this invention, and it can be realized in atmospheric pressure environment, the device volume is small, energy consumption is low.

A method and system for desorbing and ionizing molecules from a sample for mass spectrometry using a microplasma device is disclosed. The system and method relies upon a microplasma device, or array of such devices, to partially ionize a gas to form a microplasma. The ionized gas can be a mixture of a noble gas, such as neon or argon, and hydrogen (H₂). The ionized gas can form a effluent stream directed onto the surface of a sample to desorb molecules from the remainder of the sample. The desorbed molecules can be ionized by the effluent stream as they leave the surface of the sample. The ionization process can include: photoionization, penning ionization, chemical ionization (proton transfer), and electron impact ionization. The ionized particles from the sample can be directed to a mass spectrometer for analysis. This can produce spatially-resolved mass spectral data, and can be conducted concurrently with another imaging system, such as a microscope.

Plasma-assisted reaction chemical ionization (PARCI) provides highly sensitive elemental analysis by producing positively and negatively charged ions. The PARCI apparatuses, kits, and methods described in this application relate to systems that comprise a chemical reaction interface (CRI) containing reactant gas plasma and an ionization chamber that is downstream from the CRI. The ionization chamber facilitates formation of ions from element-specific products of the CRI by an electron source or an ionization gas. In particular, PARCI provides a method for conducting highly sensitive mass spectrometric elemental analysis of analyte compounds with high ionization potential elements; for example, fluorine, chlorine, and bromine.

The invention belongs to the field of analytical chemistry, and specifically relates to a method for determining short-chain chlorinated paraffins in plastics, rubber, and textile materials. (2) purification by sulfonation with concentrated sulfuric acid; and (3) detection step (2) using gas chromatography-electron capture detector or gas chromatography-negative chemical ionization (NCI) mass spectrometry detector The content of short-chain chlorinated paraffins in the obtained purified samples. Beneficial effects of the present invention: Utilize concentrated sulfuric acid sulfonation purification method, can effectively remove interference, use gas chromatography-electron capture detector and NCI mass spectrometry detector to detect medium and short-chain chlorinated paraffins in plastics, rubber, textile materials, can realize Accurate quantification; according to the specific mass spectrum of short-chain chlorinated paraffins, the interference of medium and long-chain chlorinated paraffins can be effectively eliminated, making the qualitative more accurate, the selectivity stronger, and the sensitivity higher.

The invention aims at providing a method for online-analyzing organic monomer chlorine or bromine isotope, which adopts a direct negative chemical ionization to replace an original complex organic monomer conversion process. The method is characterized by including the steps: A. gathering chlorine or bromine substitute; B. separating gas chromatography: placing the gathered chlorine or bromine substitute into the gas chromatography to be separated; C. conducting negative chemical ionization: components analyzed through chromatography directly flow into a negative chemical ion source through acapillary column, the negative chemical ion source replaces an original electron bombardment source configured on an isotope ratio mass spectrum to conduct the negative chemical ionization; D. mass spectrometric detecting: on a gas isotope ratio mass spectrum, selecting a faraday receiving cup corresponding to mass number of chlorine or bromine substitute directly, and receiving electronegative isotope fragment ions generated by the negative chemical ionization. The process is conducted under high vacuum state, and degree of vacuum is higher than 1.0*10<-3> Pa. The method greatly simplifies aprocess of online-analyzing organic monomer chlorine or bromine isotope and can form various special devices for detecting organic monomer isotope ratio.

Methods and apparatus for obtaining a mass spectrum of a sample and determining a concentration of a component of the sample by utilizing a model of chemical and electron ionization and the obtained mass spectrum.

The invention relates to an ionization source, in particular to a composite ionization source which comprises a VUV single-photon ionization source based on radio-frequency voltage discharge and a chemical ionization source obtained by utilizing photoelectron ionization reagent gas in the photoelectric effect. The composite ionization source comprises a radio-frequency VUV source, an ion transmission optical system and an ion source cavity. An ion repulsing electrode, an ion focusing electrode and a difference interface electrode plate are sequentially arranged in the VUV source emergent direction of radio-frequency discharge, the three electrodes are all round sheet electrodes with round holes in the centers, and the three electrodes are spaced through insulation pads and are coaxially arranged in parallel. The VUV light beam of the radio-frequency voltage discharge and coaxial light beams of all the round sheet electrodes penetrate through the center holes of all the electrodes in the axis direction, and finally the beams are irradiated on the surface of the difference interface electrode plate. Chemical ionization is acted on the photoelectrons after reagent gas is added. Soft ionization of sample molecules with ionization energy higher than the photon energy is achieved, the range of analyzable samples is enlarged, and the detection sensitivity of instruments is improved.

The invention relates to a mass spectrum analysis instrument, in particular to a vacuum ultraviolet photoionization and chemical ionization compound ionization source based on radio frequency electric field enhancement of quadrupole rods. The vacuum ultraviolet photoionization and chemical ionization compound ionization source based on radio frequency electric field enhancement of the quadrupole rod comprises a vacuum ultraviolet light source and an ionization chamber cavity; a plurality of transmission electrodes, the quadrupole rods and vacuum differential hole electrodes are coaxially arranged in an ionization chamber in a spaced mode; a metal grid mesh is attached to the transmission electrode far away from an ultraviolet light inlet, ultraviolet light emitted by the vacuum ultraviolet light source is irradiated to the metal grid mesh and phoelectrons are generated; direct-current voltage and radio frequency voltage are applied to the quadrupole rods. On the basis of vacuum ultraviolet photoionization, the compound ionization source ionizes reagent gas through the phoelectrons generated through the photoelectric effect, and therefore chemical ionization happens to samples through reagent ions; through the radio frequency electric field of the quadrupole rods, ionization efficiency of chemical ionization caused by the phoelectrons can be improved; besides, chemical compounds with ionization higher than vacuum ultraviolet light photon energy can be ionized through chemical ionization, and the range of the chemical compounds capable of being ionized is widened.

A variable duty cycle ion source assembly is coupled to a continuous beam mass spectrometer. The duty cycle can be adjusted based on previous scan data or real time sampling of ion intensities during mass analysis. This provides the ability to control the total number of ions formed, mass analyzed and detected for each ion mass of interest. The frequency of the ion source can be sufficiently high (kHz range) so as to maintain accurate peak centroiding. The ion source assembly can be used for both electron ionization (EI) or chemical ionization (CI) modes of operation.

The invention discloses a method for detection of electronegative element containing pesticides by a negative chemical ionization mass spectrum database. The method includes the steps of: establishment of the negative chemical ionization mass spectrum database and detection of pesticide residue in unknown sample. And establishment of the negative chemical ionization mass spectrum database consists of mass spectrum acquisition and mass spectral library establishment. The database involved in the invention includes full scan mass spectrum data of over 300 common electronegative element containing pesticides in a Thermofisher gas chromatography negative chemical ionization mass spectrum, after installation and operation on a Thermofisher gas chromatograph-mass spectrometer, spectrum library search comparison with an unknown sample can be carried out, or according to the ion information provided by the spectrum library, a selected ion monitoring (SIM) scan mode can be set directly to perform qualitative and quantitative detection on designated pesticides. The negative chemical ionization mass spectrum database is convenient to use, the impurity interference is small, the selectivity is high and the comparison result is accurate.