580 results about "Liquid chromatography mass spectroscopy" patented technology

The invention relates to the fields of analytical chemistry and food safety, in particular to a method for detecting the residual quantity of multiple alkaline drugs in animal derived food. Based on the vortex mixed extracting of acetonitrile, isopropanol and citric acid buffer solutions, the purification of a hydrophilic polystyrene-divinylbenzene solid phase extraction column and a cation exchange solid phase extraction column and the liquid phase chromatography-mass spectra determination, the method can detect the residual quantity of multiple alkaline drugs in pork, pork liver, eggs, shrimps and milk, such as beta-receptor agonists,sulfonamides, benzodiazepines, nitroimidazoles, benzimidazoles and triphenylmethanes. The method has the advantages of simple operation, fast and accurate detection and high efficiency.

The present invention is directed to a novel method of analysis of high molecular weight proteins. More specifically, it is directed to a novel reversed-phase LC/MS method of analysis of high molecular weight proteins including antibodies.

The invention discloses a method for simultaneous extraction and analysis of a metabolite group and a lipid group in microtissue. The method comprises the following steps: freeze drying to-be-analyzed microtissue, accurately weighing 1 to 25 mg of the freeze-dried microtissue and adding solvents like methanol (MeOH), methyl tert butyl ether (MTBE) and water in certain proportion for extraction; allowing a solution obtained after completion of extraction to be divided into two layers, wherein an upper layer mainly contains nonpolar metabolites and lipids, and the lower layer mainly comprises polar and medium-polar metabolites; and subjecting the upper-layer solution and the lower-layer solution to mixing in proportion and freeze-drying, then carrying out redissolving and then metabonomical analysis based on liquid chromatography-mass spectrometry, subjecting the upper-layer solution to freeze-drying and then to redissolving and carrying out lipidomical analysis based on liquid chromatography-mass spectrometry. The method has the following advantages: metabolites and lipids are extracted as many as possible through one extraction of a small amount of tissue, and through metabonomical and lipidomical analysis, the amount of a tissue sample is saved, which benefits other biochemical analysis of the tissue sample.

The invention relates to a quantitative detection method for thermal-denaturation and non-denaturation bovine alpha-lactalbumin in milk and milk products by applying an enzymolysis-liquid chromatography and mass spectrometry combination technology. The quantitative detection method comprises the steps as follows: taking a certain amount of milk or milk samples, dissolving and diluting the milk or milk samples in water to obtain solution with total protein content being about 1mg/mL; after volume metering, correctly sucking 500 mu L, adding an internal standard substance, reacting disulfide bond with dithiothreitol (DTT), alkylating to protect sulfydryl produced in reaction by iodoacetamide (IAA), and then conducting constant-temperature and constant-time enzymolysis with trypsin; and separating enzymolysis products by reversed phase liquid chromatography, conducting detection with a mass spectrum multiple reaction monitoring (MRM) manner, and calculating the result by an internal standard method. The quantitation limit of the method is 0.001g/100g; when adding amount is 0.2, 1.7 and 5.0g/100g, the recovery rate is 98.9-110.8% (n is equal to 6) and repeatability: RSD (Relative Standard Deviation) is smaller than 7.6%; and the quantitative detection method can be applicable to the quantitative detection of samples with different contents of bovine alpha-lactalbumin.

LC/MS data generated by an LC/MS system is analyzed to determine groupings of ions associated with originating molecules. Ions arc grouped initially according to retention time, for example, using retention time or chromatographic peaks in mass chromatograms. After initial groupings are determined based on retention time, ion peak shapes are compared to determine whether ions should be excluded. Ions having peak shapes not matching other ions, or alternatively a reference peak shape, are excluded from the group.

The invention discloses an LC/MS (liquid chromatography-mass spectrometer) metabonomics analysis method based on serum of a GDM (gestational diabetes mellitus) patient. The method comprises the steps as follows: serum samples of a normal pregnant woman and a pregnant woman with GDM are collected, processed and separated by a chromatographic column, and mass spectrometric detection analysis is adopted; original data of an instrument is extracted and aligned after LC/MS detection analysis, and data free of noise disturbance and capable of being used for statistical analysis is obtained; and a multi-dimensional statistical model is established and visually displays metabolic profiling difference between the two groups, so that differential metabolites of the two groups are obtained, and the substances are subjected to preliminary evaluation. With the adoption of the method, the variation condition of the metabolites of the GDM patient can be presented comprehensively and synthetically, and the method can be used for providing powerful technical support for early diagnosis and prognosis of GDM.

[The invention teaches the uses of a plurality of electric fields and of orthogonal spray configurations of vaporized analyte which combine so as to operate to enhance the efficiency of analyte detection and mass analysis with a mass spectrometer by reducing vapor in the vacuum system and concomitant noise. Several embodiments of the invention are described for purposes of illustration.] The invention relates to a method and apparatus for improving signal relative to noise without loss of ion collection efficiency in electrospray mass spectrometry, including liquid chromatography/mass spectrometry.

The invention relates to a liquid chromatography for detecting anabolic hormone drug residue in animal-derived food, which is characterized by first sampling: animal musculature is taken off the fat and connective tissue, then minced and evenly ground, and the sample is weighed; extracting: anabolic hormone extract is extracted from the weighed sample by methanol ultrasonic extraction, the extract is evaporated to dryness in water bath through a rotary evaporator, and the residue is dissolved by methanol aqueous solution; purifying: C18 Solidoid extraction column on the extract is carried out solid phase extraction; and testing by devices: the filtrate is tested by opposite phase high efficiency liquid chromatography, quantified by external reference method-peak area, and then carried out with binary gradient elution. In the invention, the detected sample is complex biological sample; the established method can complete one detection in about one hour and is simple and fast, with reliable sensitivity and low cost; the method can analyze more veterinary hormone drug species than the synchronous usage of the existing GC or HPLC methods with easier operation, and has lower cost than the existing GC/MS and LC/MS or LC/MS/MS methods with low solvent toxicity.

An interface for mass spectrometers. The interface uses non coaxial sampling pathways of the analyte ion beam prior to entering the entrance of a mass spectrometer for decreasing chemical background, and can be done in such a way as to permit multiple sprayers, increasing sample throughput and sensitivity for LC/MS (liquid chromatography/MS). The interface includes an ion source having an exit from which a beam of analyte ions are emitted, a curtain plate and an aperture in the curtain plate member, an orifice plate having an orifice therein. The orifice plate is being spaced from the curtain plate member defining a flow passageway therebetween, and the aperture in the orifice plate is aligned with a sample entrance to a first vacuum stage of a mass spectrometer maintained substantially lower than atmospheric pressure. The aperture in the curtain plate member is non coaxially aligned with the orifice in the orifice plate and the interface includes a gas flow mechanism for directing a counter flow gas into the flow passageway.

Disclosed are a device and method for improved interfacing of differential mobility spectrometry (DMS) or field asymmetric waveform ion mobility spectrometry (FAIMS) analyzers of substantially planar geometry to subsequent or preceding instrument stages. Interfacing is achieved using curved DMS elements, where a thick ion beam emitted by planar DMS analyzers or injected into them for ion filtering is compressed to the gap median by DMS ion focusing effect in a spatially inhomogeneous electric field. Resulting thinner beams are more effectively transmitted through necessarily constrained conductance limit apertures to subsequent instrument stages operated at a pressure lower than DMS, and/or more effectively injected into planar DMS analyzers. The technology is synergetic with slit apertures, slit aperture/ion funnels, and high-pressure ion funnel interfaces known in the art which allow for increasing cross-sectional area of MS inlets. The invention may be used in integrated analytical platforms, including, e.g., DMS/MS, LC/DMS/MS, and DMS/IMS/MS that could replace and/or enhance current LC/MS methods, e.g., for proteomics research.

The present invention relates to bioactivity-guided isolation and identification of bioactive compounds from oregano and mint plants, in particular, rosmarinic acid, oleanolic acid and ursolic acid, and use of these compounds or combinations thereof as anti-inflammatory agents for the treatment of conditions related to pain and inflammation and/or as ingredients of dietary supplements. The invention also relates to optimization of the methods for qualitative and quantitative analysis of the bioactive compounds in oregano and mint plants. In particular, this invention introduces an LC/MS (SIM mode) method to achieve co-quantitation of the three organic acids using a unique tandem column system. In addition, the invention also relates to the methods for recovering various water-soluble polyphenols and triterpenes from aromatic plants.

The present invention relates to liquid phase chromatography-tandem mass spectrometry process for detecting specific tobacco fume nitrosamine content. The detection process includes: trapping tobacco fume with filtering sheet, adding internal standard substances, vibration extracting the filtering sheet with citric acid-phosphate buffering solution and cyclohexane, concentrating the organic phase extracted liquid in N2 protection, acidifying with hydrochloric acid, phase separating, neutralizing water phase with alkali solution, transferring the water phase solution into reverse chemical bonded solid phase extracting column, leaching with polar organic solvent aqua, eluting with polar organic solvent aqua, concentrating elutent, and analyzing in LC/MS/MS instrument quantitatively based on the area ratio between the component peak and the internal standard substance peak. The present invention has high repeatability, high recovering rate and low detection limit.

The invention relates to a method for detecting antibiotic residues in milk, and an application thereof, and belongs to the field of food safety. The invention discloses an online solid phase extraction-high performance liquid chromatography-mass spectrometry detection method in order to solve the detection problem of antibiotic residues in milk. The method allows five types of 33 veterinary drug residues comprising sulfanilamides, quinolones, beta-lactams, tetracyclines and chloramphenicols in the milk to be simultaneously detected. Influences of various factors on the reservation and selectivity of various antibiotics are optimized, so the method has the characteristics of high sensitivity, high recovery rate, high stability and high precision. The detected antibiotics can be qualitatively and quantitatively determined according to the reservation time and accurate mass numbers. The amounts of samples and reagents required and used in the method are small, the detection speed is fast, all operation processes are completed within 15.5min, and cost reduction and operating risk mitigation of dairy product processing enterprises are guaranteed.

The invention discloses a liquid chromatography-mass spectrometry screening method of unknown toxic substances in blood. The liquid chromatography-mass spectrometry screening method comprises the following steps: taking a blood sample to be detected, adding acetonitrile precipitated protein, oscillating, centrifuging, taking a supernatant, filtering by using a 0.22-micron microporous organic filter membrane, then performing LC-MS/MS analysis, and judging whether the blood sample to be detected contains toxic substance components or not according to an analysis result; the used instrument is an ultraLC 100-XL-4000Q TRAP liquid chromatograph/mass spectrometer or an Agilent 1100 liquid chromatography-AB 3200 QTRAP triple serial quadrupole mass spectrometer from an AB company. By the liquid chromatography-mass spectrometry screening method, detection methods of different types of toxic substances are established, detection is fast and accurate, the detection limits of common toxic substances are given, high-sensitivity and effective detection of all target objects are guaranteed, a scientific data support is provided for a negative detection result, and thus a strong scientific basis is provided for relevant clinical diagnosis and rescue as well as criminal investigation and litigation.

The invention discloses a rapid screening method for comprehensively evaluating the in-vitro inhibitory effect of nine human liver CYP450 metabolic enzymes by utilizing 14 probe substrates and 16 probe reaction. The invention mainly relates to a method for monitoring metabolic activity variation of 9 human liver CYP450 enzymes and rapidly and comprehensively evaluating an inhibitory effect of a tested compound on the metabolic enzyme by adopting an in-vitro mixed probe incubation method and LC/MS/MS. According to the method, the exclusiveness and diversity of the probe substrate, interaction of the probe substrates, influence of different inoculation conditions (by charging organic solvent, buffer solution and BSA) in a warm inoculation system and the enzyme kinetics characteristics of 16 probe reactions under the selected inoculation condition are comprehensively considered, a brand new in-vitro system is established by integrating high-sensitive and high-selective LC-MS/MS technology, so that the inhibitory effect of the tested compounds on the nine human liver main metabolic enzymes can be more accurately and comprehensively predicted in the high-throughput screening of the novel drug development, and the predictability on the interaction of the later metabolism can be improved.

A determination method quantifies a specific protein or peptide contained in a trace amount with high accuracy and in a simple manner without the need of using any expensive reagent. A protein or peptide of interest can be quantified by LC/MS/MS by using, as an internal standard, a protein or peptide including an amino acid sequence having the reshuffling the binding order of amino acid residues in the amino acid sequence for the protein or peptide of interest.