15 results about "Isotope dilution" patented technology

This invention relates to the field of analytical chemistry, and discloses an isotope dilution-bismuth reagent-LA-ICP-MS method for the determination of noble metals. The method involves adding geochemical samples to bismuth reagent kits... 194 Pt isotope diluent was mixed with a silver carrier, and then melted and blown to obtain silver alloy particles. The silver alloy particles were annealed and pressed into silver sheets. The content of Pt in the silver sheets was determined by LA-ICP-MS. 105 Pd, 195 Pt and 197 The mass spectrometry intensity of Au was determined by adding platinum isotope diluent. 194 Pt was used as an internal standard for signal correction; the contents of gold, platinum, and palladium in the sample were calculated based on the measurement results. This invention utilizes solid-state injection of prepared Ag sheets and multi-point ablation by LA-ICP-MS, improving the analysis speed and avoiding interference from polyatomic ions and dilution effects in the solution; the added platinum isotope diluent... 194 Pt, as an internal standard, is consistent with the distribution trend of the element to be measured, thus solving the problem of uneven element distribution in Ag tablets. Ag tablets prepared with standard substances serve as a standard series with consistent matrix. The standard curve is plotted using the empirical coefficient method, showing good linearity.

The invention provides a method for simultaneously detecting dichloroacetic acid and trichloroacetic acid in urine, and belongs to the technical field of analysis detection and occupational health / environmental health. According to the method disclosed by the invention, a synergistic pretreatment strategy of acidic sample loading, WAX / reversed-phase mixed mode solid-phase extraction, water / low-proportion organic phase step-by-step leaching and ammonia-water-containing organic phase elution is adopted; a technical route of protein precipitation, acidification pH regulation, purification and enrichment by adopting WAX / reversed-phase mixed mode solid-phase extraction on a 96-well plate and stable isotope internal standard isotope dilution LC-MS / MS quantification is adopted, the method can effectively reduce the matrix effect and realize high-throughput analysis in a high-salinity urine matrix, the quantitation limits of DCEA and TCAA are not higher than 0.30 g / L and 0.20 g / L respectively, and the method has the advantages that the method is simple and convenient to operate, and the method is suitable for large-scale popularization and application. The method is suitable for biological monitoring and risk assessment of occupational and environmental low-level exposure crowds.

The invention relates to a human urine creatinine detection standard substance as well as preparation and valuing thereof. The preparation method comprises the following steps: processing and preparing the standard substance; checking the uniformity of the urine creatinine standard substance; testing the stability of the urine creatinine standard substance; determining a standard value of the urine creatinine standard substance by a high performance liquid chromatography-isotope dilution mass spectrometry method; and performing statistical calculation on the affirmed value of the urine creatinine standard substance and performing uncertainty evaluation on the affirmed value result. The invention provides a preparation and valuing method of a urine creatinine standard substance aiming at the problem that the urine creatinine detection result is inaccurate and incomparable because no human urine creatinine standard substance exists at present, so that the preparation and valuing method of the urine creatinine standard substance is used for developing a urine creatinine detection reagent, verifying the performance of the method and tracing the quantity value of the urine creatinine detection result. The accuracy and comparability of clinical urine creatinine detection results are ensured, and clinical examination of diseases such as chronic kidney diseases is facilitated.

This invention relates to the field of analytical chemistry, and more particularly to an analytical method for determining the hafnium content in nuclear-grade zirconium alloys. The analytical method includes the following steps: Step S2: Dissolving a metallic or oxide hafnium isotope in concentrated hydrochloric acid and concentrated hydrofluoric acid to prepare an isotope diluent stock solution; Step S2: Adding a corresponding hafnium single-element standard solution to the isotope diluent stock solution, determining the isotope ratio R value, and calibrating the concentration of the diluent solution; Adding the calibrated isotope diluent solution to the zirconium alloy, dissolving the zirconium alloy sample in concentrated hydrochloric acid and concentrated hydrofluoric acid to obtain a sample solution to be separated; Performing extraction chromatography on the sample solution to obtain a hafnium-containing test solution; Determining the hafnium content in the hafnium-containing test solution using inductively coupled plasma mass spectrometry. This invention can accurately determine the hafnium content in nuclear-grade zirconium alloys, improving the stability and accuracy of the analytical results.

The invention belongs to the technical field of biosynthesis, and particularly relates to a method for biosynthesizing a < 15 > N-labeled amino acid isotope standard substance by using yeast and application of the < 15 > N-labeled amino acid isotope standard substance. The full-spectrum 15N labeled amino acid can be efficiently and economically produced. The obtained labeled amino acid extract is used as a mixed internal standard, and high-precision and high-accuracy absolute quantification of multiple amino acids in a biological sample can be realized by combining an isotope dilution mass spectrometry. The method is simple in preparation process, low in cost, high in labeling efficiency and good in product biocompatibility, perfectly solves the problems that chemical synthesis isotope internal labels are high in price and limited in variety and possibly have biological interference, and provides a powerful tool for metabonomics research, disease marker discovery and clinical diagnosis.

The invention discloses a method for rapidly separating Rb and high-purity Sr from a geological sample with high Rb and low Sr.The method comprises the steps that after the sample is digested through HF-HNO3, secondary digestion is conducted through 6 mol / L HCl, then extraction is conducted through 5 mol / L HCl-15 mol / L HNO3 mixed acid according to the volume ratio of 1: 1, a Sr special-effect resin column is arranged, HCl can dissolve fluoride precipitates generated by HF sample dissolution, Sr is prevented from being co-precipitated through SrF3, and the Sr extraction rate is increased to 95% or above; and eluting Rb and matrix elements by using 7mol / L HNO3 to improve the separation effect of Rb and Sr and improve the recovery rate of Sr and the bearing capacity of the column. The high-precision Rb-Sr dating method for the sample with the high Rb / Sr ratio is established in combination with an isotope dilution mass spectrometry technology, the analysis success rate and dating accuracy are improved, and technical support is provided for research of rare metal minerals.

The application discloses a preparation method of a human insulin purity standard substance, which comprises the following steps of raw material selection, qualitative identification, standard substance uniformity, stability test, value determination and uncertainty evaluation. The application uses commercially available high-purity human insulin as a raw material, and after purity analysis, qualitative identification, uniformity test and stability test, isotope-labeled Val, Leu and Phe are used as internal standards, and liquid chromatography-isotope dilution mass spectrometry is used for value determination, so that the interference and influence of possible isoleucine substitution leucine impurities, isomer impurities or other molecular weight protein impurities on the value determination result can be effectively excluded, and the value determination result is more accurate and reliable. The purity standard substance prepared by the application can be used for serum insulin standard substance quality value tracing, quality control of insulin measurement results in in-vitro diagnosis, related method confirmation and evaluation, and evaluation of repeatability, linearity and cross contamination rate of a closed light-emitting immune analyzer.

This application discloses a method for determining the standard value of neuron-specific enolase (NSE) solution, belonging to the field of biotechnology. The determination method provided in this application includes characterizing the physicochemical properties of the NSE standard candidate solution, such as purity, molecular weight, secondary structure, and bioactivity; diluting and dispensing the NSE standard candidate solution; accurately determining the content of the NSE standard candidate solution and verifying its homogeneity and stability using isotope dilution mass spectrometry based on amino acid analysis and characteristic peptide analysis; and evaluating the uncertainty of the NSE solution standard value determination results. The determination method provided in this application has good reliability and accuracy, and the determination results are traceable to SI units (mol).

The application belongs to the technical field of protein standard substance value determination, and particularly relates to a TNF-alpha value determination method based on a peptide segment isotope dilution mass spectrometry. The application discloses a TNF-alpha value determination method based on a peptide segment isotope dilution mass spectrometry, which comprises characteristic peptide segment selection (determining ANALLANGVELR and VNLLSAIK as the characteristic peptide segments for quantification according to the amino acid sequence of TNF-alpha), characteristic peptide segment purity determination, characteristic peptide segment mass spectrometry parameter optimization, characteristic peptide segment linear range determination, TNF-alpha protein sample pretreatment, sample enzyme cutting solution mass spectrometry analysis, and characteristic peptide segment content calculation. Finally, the concentration of the target protein in the solution is calculated according to the molecular weights of TNF-alpha and the characteristic peptide segments, and is taken as the quantification result. The TNF-alpha specificity determined by the method is high, and the peptide segments can be traced to the national amino acid standard substance, and finally traced to the SI unit system, so that the accuracy and reliability of the quantification result are ensured.

DNA logic circuits have a huge success in the past due to their unique performance in terms of scalability and computational correctness. However, DNA logic circuit-based computations still have two challenges that are often considered. Firstly, for complex multi-task analysis and output, a mainstream optical probe is often influenced by spectrum overlapping interference. Secondly, the absolute quantification result capable of being traced back to the main international unit system is impossible, especially for laboratory-to-laboratory comparison and quality assurance. In this case, a DNA logic circuit encoded by lanthanide isotope and decoded by element mass spectrometry is constructed. The 155Gd-enriched isotope and the 145Nd-enriched isotope are incorporated into a DNA logic circuit for the absolute quantification of the isotope dilution-based miRNA. The diversity and calculation precision of the isotope DNA logic circuit are greatly improved, and huge potential is provided for related diagnosis of cancer biomarkers.

The present application relates to oxalic acid detection technical field, specifically to a kind of method for detecting the oxalic acid content in human blood and urine by isotope dilution high performance liquid chromatography tandem mass spectrometry, the present application is with 4-methoxy o-phenylenediamine dihydrochloride as derivatization reagent, and oxalic acid is reacted to generate 2,3-dihydroxy-6-methoxy quinoline, it is well retained on ordinary reversed-phase chromatographic column, and isotope dilution high performance liquid chromatography tandem mass spectrometry is used to detect.The method provided in the present application, sample need not be pretreated, derivatization reaction process is simple to operate, condition is mild and well retained on ordinary reversed-phase chromatographic column, peak type is good, repeatability is good, anti-interference ability is strong, flux is high, suitable for the detection of large quantities of samples in clinic.

The invention relates to a human urine uric acid detection standard substance as well as preparation and valuing thereof. The method comprises the following steps: processing and preparing the standard substance; checking the uniformity of the urine uric acid standard substance; testing the stability of the urine uric acid standard substance; determining a standard value of the urine uric acid standard substance by a high performance liquid chromatography-isotope dilution mass spectrometry method; and carrying out statistical calculation on the determination value of the urine uric acid standard substance and carrying out uncertainty evaluation on the determination result. Aiming at the problem that the urine uric acid detection result is inaccurate and uncomparable because no human urine uric acid standard substance exists at present, the invention provides the preparation and valuing method of the urine uric acid standard substance, so that the method is used for developing a urine uric acid detection reagent and verifying the performance of the method, and is used for tracing the quantity value of the urine uric acid detection result. The accuracy and comparability of clinical urine uric acid detection results are ensured, and clinical examination of diseases such as chronic kidney diseases is facilitated.

The invention provides an isotope dilution mass spectrometry valuing method for a plasma gastrin-releasing peptide precursor. According to the method, two plasma pretreatment strategies of immunoaffinity capture and protein precipitation are adopted, and an isotope dilution mass spectrometry technology is combined, so that high-accuracy quantification of the ProGRP in the plasma is realized. Target protein is efficiently enriched through two complementary pretreatment methods respectively, after trypsin digestion, isotope-labeled characteristic peptide fragments are introduced to serve as internal labels, absolute quantification is conducted on ProGRP through isotope dilution mass spectrometry, and the measurement result is traceable to the international unit (SI). The method effectively overcomes measurement deviation caused by cross reaction in a traditional immunoassay method, has high recovery rate, high specificity and high sensitivity, is suitable for reliable and accurate value determination of ProGRP in plasma, and can be used as a candidate scheme of a protein reference measurement procedure.

The present application relates to the technical field of biometrics and in vitro diagnosis standardization, and particularly relates to a preparation and value determination method of alpha-synuclein solution standard substance, comprising the following steps: cloning a gene coding alpha-synuclein into a prokaryotic expression vector for recombinant expression, purifying the protein raw material with purity greater than or equal to 99% through affinity chromatography and ion exchange chromatography; diluting and sub-packaging the protein raw material for storage to obtain the solution standard substance; determining the value of the standard substance by using an isotope dilution mass spectrometry method based on amino acid analysis, calculating the mass concentration value by measuring the peak area ratio of stable amino acids and isotope-labeled amino acids after hydrolysis, and tracing the value to the international unit system through the amino acid primary standard substance; and performing uniformity testing and stability investigation on the standard substance, solving the problem of lack of standard substance with metrological traceability in the alpha-synuclein detection field, and obtaining the standard substance which can be used for value transmission and detection result standardization among different in vitro diagnosis platforms.

The invention relates to a human urine glucose detection standard substance as well as preparation and valuing thereof. The method comprises the following steps: processing and preparing the standard substance; performing uniformity test on the urine glucose standard substance; testing the stability of the urine glucose standard substance; determining a standard value of the urine glucose standard substance by a high performance liquid chromatography-isotope dilution mass spectrometry method; and carrying out statistical calculation on the determination value of the urine glucose standard substance and carrying out uncertainty evaluation on the determination result. The invention provides a method for preparing and valuing a urine glucose standard substance, aiming at the problem that the urine glucose detection result is inaccurate and incomparable because no human urine glucose standard substance exists at present, so that the method is used for developing a urine glucose detection reagent and verifying the performance of the method. And the kit can be used for measuring value traceability of urine glucose detection results, so that accuracy and comparability of clinical urine glucose detection results are guaranteed, and clinical examination of diseases such as chronic kidney diseases is facilitated.