15 results about "ESI mass spectrometry" patented technology

The invention discloses a plasma electrospray fusion ionization source and mass spectrum combined system and a detection method. The plasma electrospray fusion ionization source and mass spectrum combined system comprises a coaxially nested electrospray needle, a sample injector, an ultrahigh voltage generator, a grounded metal grid mesh, a mass spectrometer and a detector thereof. A grounded metal grid is installed between a spray needle and a mass spectrum inlet, voltage is applied to the spray needle, carrier gas is excited to generate plasmas, the macroscopic plasmas at the front end of the spray needle are fused with electrospray, and the plasmas and micro-droplets at the tip of the spray needle are fused. According to the unique ionization source constructed by the plasma-micro-droplet fusion system, on one hand, the ionization efficiency is improved, mass spectrum signals are enhanced, the application range of analytes is widened, excellent sensitivity to high-polarity compounds is kept, and effective ionization and detection of low-polarity compounds are achieved; on the other hand, higher energy and active species are provided for the micro-droplet reaction, the energy barrier required by traditional synthesis is broken, and efficient spontaneous product generation of the micro-droplet chemical reaction is achieved.

This invention relates to the field of compound analysis and detection, and more specifically to a method for detecting NMP in soil. The method includes sample pretreatment, extraction, purification, concentration, and LC-MS / MS detection: soil samples are purified, coarsely separated using a quartering method, freeze-dried for dehydration, ground, sieved, and homogenized; extracted with deionized water, the supernatant is collected by low-speed shaking and high-speed centrifugation; purified using an HLB solid-phase extraction column activated with methanol and water, concentrated and diluted to volume with nitrogen blowing before detection. Chromatography uses a C18 column with a trapping column, eluted with formic acid-water and formic acid-acetonitrile gradients; mass spectrometry uses electrospray ionization in positive ion mode with multiple reaction monitoring, using a precursor ion of 100, a quantitative product ion of 58.1, and a qualitative product ion of 69.1 for qualitative and quantitative analysis. This method avoids target analyte loss, reduces matrix interference and background contamination, has high sensitivity, accurate qualitative analysis, and stable recovery rate (98.9% spiked recovery), filling the gap in domestic methods for the dedicated detection of NMP in soil, and is suitable for site investigations and environmental monitoring.

An ionizer disposed in an ionization chamber separated from an analysis chamber by a partition provided with an ion introduction port, the ionizer including: an electrospray ionization probe 111 configured to charge and nebulize a liquid sample as charged droplets, the electrospray ionization probe being disposed such that a nebulization axis is orthogonal to a central axis of the ion introduction port; and a heated gas supply mechanism configured to blow a heated gas to a position between a tip of the electrospray ionization probe and an intersection point X of the nebulization axis and the central axis, where the position is separated from the tip by a predetermined distance or more.

The application relates to a capillary electrophoresis system and method combined with a non-continuous sample injection mass spectrum, wherein the system comprises: an electrophoretic separation-electrospray ionization module for separating components in a target analyte according to different electrophoretic mobilities; a real-time adjustable high-voltage power supply device for providing a voltage required by capillary electrophoresis according to the requirements of an electroosmotic flow and an electrophoretic speed in a capillary; a target component signal feedback module for detecting a target analyte or a real-time electroosmotic flow speed; an electrophoretic current measurement and migration time correction module; a real-time feedback signal processing and control module; and a non-continuous sample injection mass spectrum system. Thus, the problems in the prior art that, when a continuous capillary electrophoresis technology is combined with a non-continuous sample injection small mass spectrum system, the accuracy is reduced, the analysis quality is poor, the sampling frequency is greatly limited, it is difficult to ensure that mass spectrum data at the highest point of a chromatographic peak can be collected, and the sensitivity of detection and the accuracy of quantitative analysis are affected are solved.

This invention belongs to the technical field of bactericide residue analysis and determination in plant-derived foods, specifically relating to a method for detecting isobutylethoxyquinoline and its metabolites in plant-derived foods. The method includes extraction with acetonitrile under citrate conditions, followed by purification with C18 (25 mg), PAX (25 mg), and XFM64 (nitrogen-doped multi-walled carbon nanotubes, 10 mg) adsorbents. Chromatographic separation is performed using a C18 column with methanol-2 mmol / L ammonium acetate (containing 0.1% formic acid) as the mobile phase, isocratic elution at a flow rate of 0.40 mL / min, electrospray ionization (ESI+), and detection in multiple reaction monitoring (MRM) mode. This invention is simple to operate, has high pretreatment efficiency, and its precision and recovery rate meet the regulatory residue limit monitoring requirements. It is suitable for the simultaneous determination of isobutylethoxyquinoline and its metabolites in plant-derived foods.

This invention discloses a method for the quantitative analysis and detection of 19 branched-chain fatty acid ester isomers of four classes of hydroxy fatty acids in the field of biomedical quantitative detection technology. The method involves preparing single-standard stock solutions of 19 hydroxy fatty acid branched-chain fatty acid ester reference standards, mixing the stock solutions and diluting them stepwise to prepare mixed reference standard solutions with ≥5 concentration levels. Then, using ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS / MS), the hydroxy fatty acid branched-chain fatty acid esters in the mixed reference standard solutions are separated by reversed-phase chromatography. Mass spectrometry employs electrospray ionization mode and multiple reaction monitoring (MRM) to monitor the characteristic ion pairs of each hydroxy fatty acid branched-chain fatty acid ester. A standard curve is plotted using peak area versus concentration, and the content is calculated. This method achieves, for the first time, simultaneous, highly specific, and highly sensitive quantitative analysis of 19 isomers of four classes of FAHFAs, providing a tool for exploring the biological functions of FAHFAs and related biomarkers.

The application provides an electrospray needle, an ionization device and an analysis method, the electrospray needle is made of an organic polymer material, and the polymer material contains at least one of a hydroxyl group, a carboxyl group, a sulfonic acid group, an amino group and a halogen polar functional group. The electrospray ionization device comprises the electrospray needle, a three-way connector, an electrode, a sample tube, a gas tube and a sleeve; the three-way connector comprises a first interface, a second interface and a third interface, the electrode is connected to the first interface, the sample tube is connected to the second interface, and the tail end of the electrospray needle is connected to the third interface; sample solution in the electrospray needle forms an electrospray under the action of the electrode, the electrospray can be ionized to enter the inlet of a mass spectrometer; one end of the sleeve is provided with an end cover, the end cover is provided with a mounting hole coaxial with the sleeve, the electrospray needle is arranged in the mounting hole and the sleeve, and the inner diameter of the sleeve is greater than the maximum diameter of the electrospray needle; the end cover is provided with an air inlet, and the air inlet is connected to the gas tube.

This application relates to the field of analytical chemistry technology and provides a method for detecting perfluorinated and polyfluoroalkane (PFAS) compounds in petroleum-contaminated soil. The method includes: freeze-drying, pulverizing, and sieving the petroleum-contaminated soil; mixing the sieved soil with diatomaceous earth, placing it in an extraction cell for extraction, and collecting the extract; drying the extract, redissolving it with methanol, filtering, and diluting to obtain the sample to be tested; detecting the sample using high-performance liquid chromatography-high-resolution mass spectrometry (HPLC-MS / MS) in negative ion electrospray ionization mode; and identifying compounds based on molecular ion mass, retention time, and peak shape. This application provides a standardized detection method adapted to petroleum-based soil matrices, integrating targeted precise qualitative analysis and non-targeted broad-spectrum screening of PFAS based on rapid solvent extraction and HPLC-MS / MS, solving the problems of low extraction efficiency, poor purification effect, and inaccurate qualitative analysis of PFAS trace detection under strong interference from petroleum hydrocarbons.

This invention belongs to the field of pharmaceutical analytical chemistry technology, and provides a method for detecting meropenem concentration in human serum based on UPLC-MS / MS. This method uses acetonitrile protein precipitation for serum sample pretreatment, with C... 18 Separation was performed using a reversed-phase column with gradient elution of water-methanol as the mobile phase, and the total run time was 3 min. Mass spectrometry was performed in positive ion electrospray ionization mode and multiple reaction monitoring mode. Method validation results showed that meropenem was effective in the range of 1.563–100 μg / mL. ‑1 The linear relationship was good within the range, and the lower limit of quantitation was 1.563 μg·mL. ‑1 The intra-day and inter-day precision RSD were <5.69%, and the accuracy RE was within ±14.20%. Matrix effect, recovery, and stability all met the requirements for biological sample analysis. This method was used to determine the concentration of meropenem in human serum, providing technical support for therapeutic drug monitoring (TDM).

An integrated system for liquid separation and electrospray ionization includes an emitter-enabled capillary column including an emitter portion and a column portion; and a retractable protective sleeve for covering and / or supporting the emitter portion along at least a portion of its axis. The protective sleeve is mounted around the emitter-enabled capillary column. The retractable protective sleeve is moveable to an extended position wherein a tip of the emitter portion is covered by the protective sleeve. A resilient member is provided to bias the protective sleeve towards the extended position. The protective sleeve is enclosed and moveable within an outer electrically conductive sheath adapted for insertion within a holder having a high-voltage contact point. The sheath is adapted to contact the high-voltage contact point and provide an electrical connection to enable the emitter-enabled capillary column to receive a high voltage. The sheath has a recess to receive the high-voltage contact point.

The application discloses a method for detecting the oxygen content of trimethylaluminum, comprising: adding anhydrous solvent to the trimethylaluminum to be detected to dilute the trimethylaluminum to be detected and obtain a to-be-detected system; adding octamethyltrisiloxane to the to-be-detected system to react, pulling the oxygen aluminum to dissociate and generate specific anions through the coordination capture effect of the octamethyltrisiloxane; performing electrospray ionization-time of flight mass spectrometry on the to-be-detected system, detecting characteristic peaks of the specific anions; and quantitatively detecting the content of oxygen aluminum species based on the characteristic peak area of the specific anions. + The application utilizes the principle that the octamethyltrisiloxane captures the dissociated cation Me2Al + in the coordination system, pulls the oxygen aluminum to continuously dissociate to generate specific anions, realizes quantitative detection of the oxygen aluminum through the electrospray ionization-time of flight mass spectrometry, eliminates the TMA body interference, and effectively improves the detection precision.

This invention belongs to the field of analytical chemistry and biomedical detection, and discloses a method for detecting nucleotides in biological samples based on liquid chromatography-mass spectrometry (LC-MS). The method includes: pretreatment of the biological sample by homogenization with a weakly basic ammonium acetate buffer, protein precipitation with organic solvent, vacuum concentration, and reconstitution; separation using an alkali-resistant C18 column and a weakly basic mobile phase with gradient elution; and detection by multiple reaction monitoring (MRM) in negative ion mode using an electrospray ionization source. This invention can simultaneously detect more than 40 target substances, covering bases, nucleosides, deoxynucleosides, and their phosphorylated forms and modified metabolites, with a limit of quantitation at the ng / pg / mL level. It exhibits strong resistance to matrix interference and excellent chromatographic separation. This method is rapid, highly sensitive, and stable, suitable for high-throughput and precise detection of nucleotides in biological samples, providing a powerful tool for disease biomarker screening and related basic research.