112 results about "Laser desorption ionization mass spectrometry" patented technology

Zwitterionic polymers bearing positive and negative charges are readily prepared from easily accessible precursors. The polymers show enhanced binding affinities for analytes under high salt conditions, compared to similar polymers bearing a charge of a single polarity. The polymers can also include an energy absorbing moiety for use in matrix assisted laser desorption/ionization mass spectrometry. The polymer can also include a photo-curable group, which can be used to form cross-links within the bulk polymer or between the polymer and a surface functionalized with a polymerizable moiety. The polymers are incorporated into devices of use for the analysis, capture, separation, or purification of an analyte. In an exemplary embodiment, the invention provides a substrate coated with a polymer of the invention, the substrate being adapted for use as a probe for a mass spectrometer.

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.

Analytical methods and devices are disclosed for separating low abundance analytes by electrophoretically driving the analytes through a sieving matrix to first remove high molecular weight species. Subsequently the remaining low abundance analytes are electrophoretically focused onto a capture membrane where the analytes become bound within a small capture site. After this step the capture membrane may be allowed to dry and then attached to a conductive MALDI sample plate.

A novel Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry (MALDI-MS) sample support plate is described. The plate comprises a top sample presentation surface and a lower surface, wherein the top sample presentation surface comprises at least one aperture for receiving a sample. The aperture extends through and between the top sample presentation surface and the bottom surface, and contains a porous material that retains and concentrates at the target spot analyte and matrix molecules contained in the sample on the surface of the aperture. Methods for making and using the sample support plate in conventional and automated MALDI-MS are also described.

Embodiments of the present invention relate to the identification of proteins using laser desorption ionization mass spectrometry, the identification of source organisms comprising the identified proteins and a computer readable storage medium storing instructions that, when executed by a computer cause the computer to perform a method for the identification of proteins using mass spectra generated through the application of laser desorption ionization mass spectrometry of the proteins.

The present invention relates to small sample spots for MALDI targets and methods for producing the same. The sample spots are composed of a layer of matrix material and a layer of analyte. In some instances, the samples spots have diameters of no more than 50 micrometers or even smaller. The sample spots are deposited onto a MALDI target substrate using ultrasonic deposition from a nozzle.

Arginine-containing cysteine-modifying compounds useful for MALDI-MS analysis of proteins are provided. These compounds termed isotope-coded ionization enhancement reagents (ICIER) can provide ionization enhancement in MALDI-MS, relative quantitation, and additional database searching constraints at the same time without any extra sample manipulation. More specifically, ICIER increase the ionization efficiency of cysteine-containing peptides by attachment of a guanidino functional group. ICIER also increase the overall hydrophilicity of these peptides due to the hydrophilic nature of ICIER and thus increase the percentage of recovery of these peptides during sample handling and processing such as in-gel digestion or liquid chromatography. Finally, a combination of both light and heavy ICIER provides an accurate way to obtain relative quantitation of proteins by MALDI-MS and additional database searching constraints (number of cysteine residues in every single peptide peak) to increase the confidence of protein identification by peptide mass mapping.

A self-assembled engineered lattice of nanometer-scale silica particles, or other suitable particles generally resembling regularly-sized spheres, is configured in a separation bed for electrophoresis, isoelectric focusing, chromatography, or other voltage-induced separation of analytes. After separation, the analytes are immobilized on the separation bed and then ionized using matrix-assisted laser desorption/ionization (MALDI) for use with a mass spectrometer. The nanoparticles can be coated with polymers that activate to immobilize the analytes or assist with MALDI. The separation can occur in two dimensions.

A method of analyzing a polynucleotide using matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS) is described. The method includes obtaining the polynucleotide bound to a substrate via a linker moiety having a triaryl methyl linker group. The polynucleotide bound to the substrate is then contacted with a matrix material and analyzed by MALDI-MS. During the MALDI-MS analysis, laser radiation is directed at the matrix material, thereby exciting the matrix material and causing cleavage of the linker moiety. Ions generated as a result of this excitation and cleavage process are then analyzed to provide information about the polynucleotide.

A plate for laser desorption ionization mass spectrometry comprising an electrically conductive substrate (1) covered with an array of spots of sintered nanoparticles (2) acting as a highly efficient sorbing phase, a very sensitive photo-reactive phase and an ionization device when covered by an organic matrix or by a hole conductor or electron donor instead of an organic matrix.

The invention discloses application of naphthylethylenediamine inorganic acid salt or naphthylethylenediamine organic acid salt as a matrix in MALDI MS (matrix-assisted laser desorption/ionization mass spectrometry). In the application, the MALDI MS is MALDI-TOF MS (matrix-assisted laser desorption/ionization - time-of-flight mass spectrometry); the naphthylethylenediamine inorganic acid salt is naphthylethylenediamine hydrochloride, naphthylethylenediamine nitrate, naphthylethylenediamine phosphate or naphthylethylenediamine sulfate; and the naphthylethylenediamine organic acid salt is naphthylethylenediamine trifluoroacetate, naphthylethylenediamine acetate, naphthylethylenediamine formate, naphthylethylenediamine citrate or naphthylethylenediamine oxalate. The invention technically overcomes the defect that small-molecule samples cannot be effectively analyzed because serious matrix background interference is apt to be caused in a low molecular weight zone when organic small-molecule matrices are commonly used. The matrix used by the invention is not required to be added with ionizing reagent and the requirements on sample treatment are reduced; and since background interference hardly exists within a testing range (m/z: 0-1000), kinds of complex mixed systems can also be analyzed by using the matrix.

A plate for matrix-assisted laser desorption ionization (MALDI) mass spectrometry comprising an electrically conductive substrate (1) covered with a light sensitive matrix (2), the matrix (2) comprising a light absorber, a charge carrier, a probe molecule and a photo-sensitizer (3) arranged to oxidise the probe molecule when irradiated with light (4).

The invention discloses an application of tungsten disulfide in laser desorption ionization mass spectrometric detection. According to the invention, the tungsten disulfide is taken as a surface material for surface-assisted laser desorption ionization for mass spectrometric detection on small organic molecules. A tungsten disulfide suspension liquid is prepared firstly, and then subjected to ultrasonic oscillation for 5 minutes; 1 muL of the tungsten disulfide suspension liquid is dripped on sample target points; 1 muL of the small organic molecule solution to be detected is dropwisely adding on the films formed by the dried the tungsten disulfide suspension liquid; mass spectrometry is conducted after the small organic molecule solution is dried. The application has the advantages as follows: the mass spectrometric detection method is convenient in operation and low in cost; the degree of dispersion of the tungsten disulfide in the solvent is good; the sample target points are uniform in distribution; the reproducibility and the universality are high; the ionization efficiency of the organic molecules is high; the tungsten disulfide can effectively inhibit reduction reactions of riboflavin during the laser desorption ionization process and has important significance for researching the metabolic process of riboflavin in human bodies.

The invention discloses application of naphthylhydrazine inorganic acid salt or naphthylhydrazine organic acid salt as a matrix in MALDI MS (matrix-assisted laser desorption/ionization mass spectrometry). The MALDI MS is MALDI-TOF MS (matrix-assisted laser desorption/ionization - time-of-flight mass spectrometry); the naphthylhydrazine inorganic acid salt is naphthylhydrazine hydrochloride, naphthylhydrazine nitrate, naphthylhydrazine phosphate or naphthylhydrazine sulfate; and the naphthylhydrazine organic acid salt is naphthylhydrazine trifluoroacetate, naphthylhydrazine acetate, naphthylhydrazine formate, naphthylhydrazine citrate or naphthylhydrazine oxalate; and hydrazine radicals on the naphthylhydrazine inorganic acid salt or naphthylhydrazine organic acid salt are all 1-substituted or 2-substituted. The application technically overcomes the defect that small-molecule samples cannot be effectively analyzed because serious matrix background interference is apt to be caused in a low molecular weight zone when organic small-molecule matrices are commonly used. The matrix used by the invention is not required to be added with ionizing reagent and the requirements on sample treatment are reduced; and since background interference hardly exists when m/z is smaller than 500, various complex mixed systems can also be analyzed by using the matrix.

The invention provides a simple, rapid and cost-effective metal oxide-assisted laser desorption/ionization mass spectrometry (MOALDI MS) without the addition of light-absorbing organic-matrix, comprising the use of (a) an inorganic metal oxide with light absorbing capability as an assisting material to render desorption/ionization of samples in laser desorption/ionization mass spectrometry and (b) a citric acid buffer as the proton source for enhancing the iorization efficiency for analytes. Metal oxide assisting materials is not only restricted to the uses of films. Metal oxide nanoparticles are also suitable to be used as the assisting materials. Low matrix background, stable surface feature, homogeneous sample deposition, and wide detectable mass range are the merits of MOALDI MS.

The invention discloses a surface assistant laser desorption ionization mass spectrometry analysis method for improving desorption ionization efficiency of analyte by enriching the analyte to a metal nanocone array tip, and belongs to the technical field of detection. A metal membrane is applied to the surface of a silicon nanocone array in an evaporation manner, then surface plasma element conduction is carried out, photon energy is accumulated in tip positions, and thus a photon library is formed. As the surface is modified with fluoro-substitution alkyl sulfhydryl, a substrate has a large contact angle and a small rolling angle, then the friction of water droplets on the substrate is very small, analyte molecules of a solution are preferentially concentrated at the tips, and the utilization rate of laser energy can be further increased. Therefore, when the silicon nanocone array covered by the metal membrane modified with the fluoro-substitution alkyl sulfhydryl is used as substrate detection analyte molecules, the laser energy can be sufficiently absorbed and effectively utilized, furthermore the desorption ionization efficiency of the analyte molecules can be improved, and the method is applicable to various types of molecules.

The invention relates to a method for separating, enriching and identifying macromolecular weight protein, belonging to the field of biochemical analysis. In the invention, a mixed gel of low-melting point agarose and polyacrylamide is used as an electrophoresis supporting medium, and an analysis path of gel slab electrophoresis combined with efficient liquid-phase chromatography - electrical spraying mass spectrum identification and another analysis path of solid-phase gradient pH dry adhesive tape isoelectro-focusing combined with gel slab electrophoresis separation - matrix auxiliary laser desorption ionization mass spectrum identification are collectively used to separate and identify the macromolecular weight protein. The gel provided by the invention has the advantages of big aperture, high mechanical strength, high resolution ratio, good repeatability and good mass spectrum compatibility; the macromolecular weight separation scope can be adjusted based on different component proportions; and protein with the molecular weight interval above 100kDa can be selectively separated with repeatability RSD up to 7.6%, thereby obviously improving the identification ratio. The method is an effective tool for separating the macromolecular weight protein, which can be applied to proteomics study field.

An object of the present invention is to provide a sample substrate for laser desorption ionization mass spectrometry for LDI-MS which substrate enables mass spectrometric analysis of a sample correctly at high sensitivity without generating interference peaks upon irradiation of the sample to laser light and uniform application of the sample onto a base. Another object of the invention is to provide a mass spectrometer (device) employing the sample substrate.

In the sample substrate for laser desorption ionization mass spectrometry, the sample substrate is formed of a base and carbon nanowalls having wall surfaces onto which a sample to undergo mass spectrometry is applied, wherein the carbon nanowalls are formed on the base so as to stand on the base. The surfaces of carbon nanowalls serve as an ionization medium and hydrophilized. By use of the sample substrate, mass spectrometry of a sample having a wide range (high to low) molecular weight can be reliably performed at high precision and sensitivity.

A mass spectrometric imaging method includes the steps of: forcing sequentially generated charge-laden liquid drops to move towards a receiving unit of a mass spectrometer along a traveling path; scanning a sample with a laser beam which has an irradiation energy sufficient to cause analytes contained in the sample to be desorbed to fly along a plurality of flying paths respectively; and positioning the sample relative to the laser beam to render the plurality of flying paths intersecting the traveling path so as to permit a plurality of the analytes respectively along the plurality of flying paths to be occluded in a plurality of the charge-laden liquid drops respectively to thereby form a plurality of corresponding ionized analytes.

The invention provides methods of monitoring the production of a target polypeptide by generating surface enhanced laser desorption/ionization mass spectral profiles of samples taken from multiple cell culture batches or of samples taken at different times from a given batch. The invention additionally provides methods for monitoring the purification of a target polypeptide from a mixture by generating surface enhanced laser desorption/ionization mass spectral profiles of samples taken at various times during a purification process. In addition, the invention relates to methods of identifying conditions that can be used in increasing the scale of a given purification process.