2996 results about "Internal standard" patented technology

The present invention pertains to methods of quantifying the levels of at least one analyte in a sample or extract comprising adding a known quantity of at least one internal standard to the sample or extract. The present invention also relates to internal standards used in mass spectrometry, as well as compositions thereof. Internal standards for mass spectrometry according to the invention can be used, for example, to assist aligning mass spectra obtained from two different samples, each of which comprises the internal standard. In one aspect of the invention, the internal standard is a dendrimer. A labile internal standard may be used in conjunction with the dendrimer.

The invention provides reagents, kits and methods for detecting and/or quantifying proteins in complex mixtures, such as a cell lysate. The methods can be used in high throughput assays to profile cellular proteomes. In one aspect, the invention provides a peptide internal standard labeled with a stable isotope and corresponding in amino acid sequence to the amino acid sequence of a subsequence of a target polypeptide. In another aspect, the peptide internal standard is labeled at a modified amino acid residue and is used to determine the presence of, and/or quantitate the amount of a particular modified form of a protein.

The invention provides a method detecting and quantifying proteins by mass spectrophotometric analysis using peptide internal standards and provides a highly sensitive way of detecting protein modifications. In one aspect, the invention provides a method for determining a site of ubiquitination in a polypeptide and for evaluating ubiquitination targets in a population of polypeptides. In this way, a proteome ubiquitination map can be obtained which comprises information relating to the ubiquitination states of a plurality of cellular polypeptides. Maps can be obtained for a variety of different types of cells and cell states. For example, ubiquitination targets in normal and diseased cells can be evaluated. Preferably, the map is stored as data files in a database. Individual ubiquitinated polypeptides identified can be used to generate molecular probes diagnostic of a cell state and/or can serve as targets for agents that modulate one or more cellular processes.

The present invention is a flow cytometry-based hematology system useful in the analysis of biological samples, particularly whole blood or blood-derived samples. The system is capable of determining at least a complete blood count (CBC), a five-part white blood cell differential, and a reticulocyte count from a whole blood sample. The system preferably uses a laser diode that emits a thin beam to illuminate cells in a flow cell and a lensless optical detection system to measure one or more of axial light loss, low-angle forward scattered light, high-angle forward scattered light, right angle scattered light, and time-of-flight measurements produced by the cells. The lensless optical detection system contains no optical components, other than photoreactive elements, and does not include any moving parts. Finally, the system uses a unique system of consumable reagent tubes that act as reaction chambers, mixing chambers, and waste chambers for the blood sample analyses. The consumable tubes incorporate reference particles, which act as internal standards to ensure that the dilutions made during processing of the samples have been carried out correctly, and to ensure that the instrument is working properly. The present invention also relates to methods for using the system.

The present invention provides materials, devices, and methods related to determination of an analyte. In some embodiments, an analyte may be determined by monitoring, for example, a change in an optical signal of a luminescent material (e.g., particle) upon exposure to an analyte. The present invention may be particularly advantageous in that some embodiments may comprise an emissive species useful as an internal reference standard. Methods of the invention may also be useful in the quantitative determination of an analyte. In some cases, the present invention may allow for selective determination of an analyte.

The present invention relates to a method and apparatus for ionizing a neutral MALDI desorption plume, and in particular, for efficiently measuring the ionized MALDI desorption plume when post-ionization techniques are combined with a medium pressure MALDI-IM-oTOFMS instrument. Additionally, the present disclosure provides a method and apparatus that simultaneously separates tissue-sample MALDI ions by IM-oTOFMS according to their chemical family. After separation, the MALDI ions are directly compared to the ions created by post-ionizing the co-desorbed neutral molecules with a second laser wherein the second laser is delayed by a few hundred microseconds. The present disclosure further provides novel approaches that enhance the analysis of ions, including the use of giant fullerene internal standards to enhance mass accuracy, and ultraviolet (UV) declustering lasers to generate intact peptides and proteins, either of which may be followed by VUV post-ionization which generates identifiable structural fragments.

The present invention concerns a method for the quantification of a target nucleic acid in a sample comprising the following steps: (i) determination of the amplification efficiency of the target nucleic acid under defined amplification conditions, (ii) amplification of the target nucleic acid contained in the sample under the same defined reaction conditions, (iii) measuring the amplification in real-time, (iv) quantification of the original amount of target nucleic acid in the sample by correction of the original amount derived from step (iii) with the aid of the determined amplification efficiency. The efficiency correction of PCR reactions according to the invention for the quantification of nucleic acids can be used for absolute quantification with the aid of an external or internal standard as well as for relative quantification compared to the expression of housekeeping genes.

The invention discloses a measurement method of a volatile organic compound in tobacco lining paper with high determination accuracy and good repeatability, which is suitable for simultaneously determining dozens of volatile organic compounds. The measurement method is as follows: taking fluorobenzene as an internal standard substance; using headspace gas chromatography for measuring the content of the volatile organic compound in the tobacco lining paper; wherein a detector in the headspace gas chromatography is a mass spectrometry detector. The measurement method takes the fluorobenzene as the internal standard substance, uses the headspace gas chromatography/mass spectrometry for measuring the content of the volatile organic compound in the tobacco lining paper, and has the following advantages that the fluorobenzene has stable chemical property and are very similar to determinand in every performance, and the peak time appears in the middle of 19 target VOCs to be detected; therefore, the fluorobenzene is the very suitable internal standard substance, can eliminate the influence of ground substance in the tobacco lining paper on the measurement, causes materials which can not or are difficult to peak to be measured, and has high measurement accuracy and few interference factors.

The invention relates to a method for measuring tobacco-specific nitrosamines (TSNAs for short) by using a super efficient liquid chromatogram-tandem mass spectrum combined method, and belongs to a method for detecting TSNAs. The method comprises the following steps of: adding internal standard-containing aqueous solution of ammonium acetate into a filter sheet after trapping smoke and cigarette filters smoked completely under standard conditions or tobacco shreds, performing ultrasonic extraction, transferring 1 to 2mL of extract into a small solid-phase extraction column taking N-vinyl pyrrolidone-benzene sulfonic acid copolymer as filler, flushing the small column by using aqueous solution of methanoic acid and methanol, finally eluting the small column by using solution of aqueous ammonia and methanol solution, analyzing the eluant by using an ultra performance liquid chromatography-mass spectrometer/mass spectrometer (UPLC-MS/MS), and quantifying according to the area ratio of a component peak to an isotope internal standard peak. The detecting method can be used for detecting the TSNAs in cured and hybrid cigarette mainstream smoke, cigarette side-stream smoke, filter tip intercepting smoke and tobacco shreds, and has the advantages of simple pretreatment, accurate quantification, high instrument analysis speed, low detection limit, high sample treatment flux and the like.

A method for preparing oligonucleotide chip for transgene product detection and use are disclosed. It includes: designing specific oligonucleotide probe and related primer by heterogeneric inserting gene, species internal standard gene, specific boundary sequence in transgene product gene set, fixing probe on glass slide to form transgene product detecting chip, amplifying DNA of plant to be tested by related primmer, marking by fluorescence, and hybridizing with chip. It can be use to acquire variable information.

A multi-dimensional separation system having parallel traps for effluent from prior separation dimension and parallel latter separation columns, the latter columns being coupled to the traps. At least one trap enriches components of effluent while at least one other trap is releasing trapped components to a detector, which may be a mass spectrometer. Internal standards may be provided, as in a release solvent, for the calibration of one of the chromatographic columns and the detection system. The system may comprise a multiple channel selector for multiple streams, wherein all of the streams flow at the same time.

The invention provides a method for detecting volatile organic compound in a cigarette filter, which comprises the following steps: a) preparing a sample; b) preparing a matrix correcting agent; c) preparing an interior label solution; d) preparing a standard sample; e) preparing a standard working solution; f) performing detection by using headspace-gas chromatography/ mass-spectrography; and g) calculating a detection result of the volatile organic compound in the sample. The invention establishes the method for detecting the volatile organic compound residue in the cigarette filter for the first time. By using the saturation sodium chloride aqueous solution as the matrix correcting agent and the fluorobenzene as the interior label, the matrix effect of a solid absorption matrix (namely the cigarette filter) is efficiently reduced and the error caused by the poor repeatability of the pre-treatment and the low precision of instrument is reduced. In the whole process, no organic solvent is used. The method has the advantages of environmental friendliness, energy-saving and low consumption. The detecting method has few interference factors and good repeatability, is accurate in measuring result, is simple to operate, and can be used for obviously increasing the sensitivity of headspace analysis.

The invention discloses an analysis method for simultaneously measuring residues of 12 sulfonamide medicaments, 19 quinolone medicaments and 8 benzimidazole medicaments and metabolites thereof in chicken liver by quick, easy, cheap, effective, rugged and safe (QuEChERS) extraction and purification-ultrahigh performance liquid chromatography-tandem mass spectrometry (QuEChERS-UPLC-MS/MS). The method comprises the following steps of: extracting a sample by using 1 percent acetic acid-acetonitrile solution, purifying the sample by using NH2 adsorbent, and degreasing the sample by using n-hexane;and then performing separation by using a Kromasil Eternity C18 chromatographic column (100mm*2.1mm, 2.5mum), performing gradient elution by using 0.1 percent formic acid and methanol as mobile phases, performing ionization in an electron spray positive ion (ESI<+>) mode, performing detection in a multi-reaction monitoring (MRM) mode, and performing quantification by an internal standard method. The 39 medicaments have good linearity (r is more than 0.98) in a blank adding concentration range of 5 to 100mug/kg, the average recovery rate of the medicaments in the adding level range of 10 to 50mug/kg, the relative standard deviation (RSD) is 1.5 to 23.4 percent, the limit of detection (LOD) of the 39 medicaments is 5mug/kg, and the low limit of quantification (LOQ) is 10mug/kg. The method is simple, convenient, quick, sensitive, accurate and rugged, and is suitable for confirmation and quantitative determination of the residues of the residues of the sulfonamide, quinolone and benzimidazole medicaments in the chicken liver.

The invention discloses a method for simultaneously measuring multiple residues of organic chloride and pyrethroid pesticides. The method comprises the following working procedures: crushing a tobacco sample until grain diameters are less than 450 mu m; adding 10 to 20ml of extracting solution and internal standard solution into every program of tobacco sample; extracting the mixed solution by using ultrasonic wave; filtering the mixed solution by using a funnel filled with anhydrous sodium sulfate to obtain the extracting solution; adding the extracting solution into a Florisil solid extraction column for extracting and eluting; collecting an eluent; analyzing the eluent by using a gas chromatograph, wherein the analysis comprises the following conditions: adopting an Elite 5MS capillary column, high-purity N2 as a carrier gas, a constant flow mode in which the flow rate is 0.5 to 1.5 ml/min, a sample inlet temperature of between 280 and 320 DEG C, a detector temperature of between 330 and 370 DEG C, splitless sampling in which the sampling volume is between 1 and 2 mu L, and an initial temperature of 100 DEG C which rises from 100 to 180 DEG C at a speed of 8 DEG C/min, is kept for 4 minutes, rises from 180 to 270 DEG C at the speed of 5 DEG C/min and is kept for 15 minutes until all sample flows out completely; and determining the nature of the sample by using the retaining time of a standard sample and quantifying by using an internal standard method. In the method, ultrasonic wave is adopted for extracting and a solid extraction column is adopted for purifying, so that the method has the advantages of operating step simplification, high work efficiency, good purification effect, capability of simultaneously measuring multiple residues of 25 kinds of pesticides including 17 organic chloride pesticides of hexachlorocyclohexane, DDT and the like, seven pyrethroid pesticides such as fenpropathrin and the like, and one plant growth regulator.

The method for analyzing diesel hydrocarbon composition by using solid phase extraction and mass spectrography includes the following steps: using solid phase extraction process to separate saturated hydrocarbon and aromatic hydrocarbon in diesel sample, collecting all the saturated hydrocarbon solution and aromatic hydrocarbon solution, respectively adding equivalent internal standard material, then respectively sampling and making gas chromatography and mass spectrography; utilizing gas chromatomap of aromatic hydrocarbon and saturated hydrocarbon to calculate relative content of both them, and utilizing mass spectrogram to obtain hydrocarbon composition of aromatic hydrocarbon and saturated hydrocarbon; according to the relative content of saturated hydrocarbon and aromatic hydrocarbon using normalization-calculation method to obtain the hydrocarbon composition of diesel.

The invention relates to a quantitative measuring method of a lithium ion battery electrolyte solvent, which relates to a quantitative measuring method of a battery electrolyte solvent, and solves the problems of the existing lithium ion battery electrolyte solvent and the additive quantitative analysis method that the requirement on detection equipment is high, the price is high, the detection process is complicated, the quantitative detection accuracy is low and the detection is easily subjected to the interference of impurities. The measuring method comprises the following steps: I, preparing an inner standard solution identical in internal standard substance concentration; II, drawing an internal standard working curve; III, preparing a detection solution; and IV, calculating the concentration of a component in the detection solution according to a specific value Y of the chromatographic peak area to the internal standard substance chromatographic peak area. The method is suitable for detecting a great number of analysis samples and has advantages of high detection speed, little time, high efficiency and the like.