10 results about "Stable isotope ratio" patented technology

The invention provides a method for analyzing the oxygen stable isotope ratio of water in a highly alcoholic beverage, and relates to the technical field of oxygen isotope analysis. The analysis method comprises the following steps: selecting at least two water samples with known oxygen isotope ratios and different values as additive water; diluting the same high-alcohol beverage to be detected by adding water to obtain a diluted sample; measuring an oxygen isotope ratio; and according to the oxygen isotope ratio of the added water and the oxygen isotope ratio of the diluted sample, calculating the oxygen isotope ratio of the water in the highly alcoholic beverage to be measured. According to the analysis method, the concentration of ethanol is reduced through dilution, so that interference of isobaric elements is avoided; and physical separation is replaced by mass conservation equation calculation, and a complex distillation device is not needed. According to the method, pretreatment is remarkably simplified, cost and errors are reduced, and rapid and accurate analysis of the water oxygen isotope in the highly alcoholic beverage is achieved.

This invention discloses a method for determining the origin of tea based on the stable isotope ratio of EGCG monomers, belonging to the field of tea origin identification technology. It aims to solve the technical problem of insufficient accuracy in existing tea origin identification methods. The method involves measuring the overall stable isotope ratio δ in the tea sample. 13 C 茶叶 δ 15 N 茶叶 δ 2 H 茶叶 δ 18 O 茶叶 and the δ¹² value of stable isotope ratios of EGCG monomers 13 C EGCG δ 2 H EGCG and δ 18 O EGCG The preparation method of EGCG monomer involves making tea powder from tea samples, extracting and purifying epigallocatechin gallate (EGCG) monomer from the tea powder, and then determining the stable isotope ratio of the EGCG monomer. Based on the above stable isotope ratio, the origin of the tea sample is identified. This invention is mainly used for the accurate identification of tea origin, providing technical support for tea traceability and quality control.

The invention discloses a method for identifying the producing area of saffron crocus by extracting saffron crocus aldehyde and measuring the stable isotope ratio of the saffron crocus aldehyde. The invention discloses a method for extracting crocetin from saffron crocus and measuring the stable isotope ratio of carbon to hydrogen to oxygen. The method comprises the following steps: S1, determining the stable isotope ratio of carbon to hydrogen to oxygen of a crocetin standard substance by using an elemental analysis-stable isotope mass spectrometer; s2, extracting crocus sativus aldehyde from the crocus sativus sample to obtain a crocus sativus aldehyde extracting solution; s3, determining the carbon, hydrogen and oxygen stable isotope ratio of crocetin in the crocetin extracting solution by using a gas chromatography-stable isotope mass spectrometer; and S4, calibrating the carbon, hydrogen and oxygen stable isotope ratio of crocetin in the crocetin extracting solution by adopting the carbon, hydrogen and oxygen stable isotope ratio of the crocetin standard substance. The standard substance is used for calibrating the stable isotope ratio of carbon, hydrogen and oxygen of the single compound crocetin, and the method can be used for identifying the producing area of crocetin.

The invention discloses a reaction furnace capable of observing the change of a reaction column for element isotope analysis, which is mainly used for visualization and quantification of an oxidation-reduction process in an element-stable isotope ratio mass spectrometer and comprises a reaction furnace body, a reaction tube and an observation strip, the reaction tube is arranged in the reaction furnace body, an opening is formed in the surface of the reaction tube, a through hole is formed in the surface of the reaction furnace body, the observation strip is arranged between the through hole and the opening, the observation strip covers the through hole and the opening in a sealing manner, and the observation strip is made of a transparent material. By adopting the arrangement, the oxidation reduction process can be observed and quantified at any time during use, and the visualization and quantification of the ash content volume and the reduced copper residual degree are realized.

The invention provides a method for determining the oxygen isotope ratio of water in high-alcohol-content Baijiu, and relates to the field of stable isotope ratio mass spectrometry detection. The determination method comprises the following steps: diluting to-be-determined high-degree white spirit by using water with a known oxygen isotope ratio to obtain a diluted target spirit sample; performing equilibrium exchange reaction on 16O of water in the target wine sample and 18O of the carbon dioxide standard gas to obtain a reaction wine sample; measuring the oxygen isotope ratio of water in the reaction wine sample; and performing conversion to obtain the oxygen isotope ratio. According to the method, the high-degree white spirit is diluted with water with the known oxygen isotope ratio, the ethanol concentration is reduced to avoid interference of isotopic, and the original value is inversely calculated by combining the mass conservation principle. According to the method, tedious off-line physical separation is not needed, automatic analysis can be carried out by directly utilizing the on-line mass spectrometer, the operation process is greatly simplified, and the detection efficiency is remarkably improved while it is guaranteed that the result is accurate and reliable.

The application belongs to the field of analysis and detection, and particularly relates to a method for detecting the content of directly absorbed exogenous glycine of microorganisms in soil, which comprises the following steps: firstly, mixing a double-labeled glycine solution with soil, adding sodium laureth sulfate and chloroform for fumigation, then extracting, deriving by hydrocarbonation reaction of ethyl bromoformate, and completing the extraction of glycine in microorganisms after stable layering by using sodium bicarbonate solution; and after the extraction is cracked by a stable isotope ratio mass spectrometer, exogenous glycine and original glycine in microorganisms are distinguished by characteristic ions to be determined. The method can effectively detect the content of directly absorbed exogenous glycine of microorganisms, is simple in operation, strong in specificity, has a good linear relationship, high sensitivity and accuracy, and effectively solves the problem that the content of directly absorbed exogenous glycine of microorganisms cannot be directly quantified. Thus, the direct utilization pathway of soil microorganisms to exogenous amino acid substances is quantitatively judged.

The application belongs to the field of analysis and detection, and particularly relates to a method for detecting the content of directly absorbed exogenous glycine of microorganisms in soil, which comprises the following steps: firstly, mixing a double-labeled glycine solution with soil, adding sodium laureth sulfate and chloroform for fumigation, then extracting, deriving by hydrocarbonation reaction of ethyl bromoformate, and completing the extraction of glycine in microorganisms after stable layering by using sodium bicarbonate solution; and after the extraction is cracked by a stable isotope ratio mass spectrometer, exogenous glycine and original glycine in microorganisms are distinguished by characteristic ions to be determined. The method can effectively detect the content of directly absorbed exogenous glycine of microorganisms, is simple in operation, strong in specificity, has a good linear relationship, high sensitivity and accuracy, and effectively solves the problem that the content of directly absorbed exogenous glycine of microorganisms cannot be directly quantified. Thus, the direct utilization pathway of soil microorganisms to exogenous amino acid substances is quantitatively judged.

The invention provides a method for continuously testing three stable carbon isotopes in soil, and belongs to the technical field of soil detection. The pretreatment process of stable carbon isotope testing of three carbon forms (carbonate inorganic carbon, soluble organic carbon and non-soluble organic carbon) of soil is simplified and integrated, then the same stable isotope ratio mass spectrometer is externally connected with a multipurpose online gas preparation and introduction device and an element analyzer, and the external connection sequence is controlled; and efficient and continuous testing of three carbon isotopes is realized. Compared with a traditional method in which single carbon forms are respectively treated and independently detected, the method has the advantages that the time cost of sample pretreatment and instrument analysis is reduced, error accumulation caused by sample transfer and multiple pretreatment is avoided, and the detection result is more accurate.

The invention belongs to the technical field of stable isotope analysis, and discloses a method for determining the stable isotope ratio of caffeine hydrogen in tea leaves. According to the method, caffeine in the tea leaves is extracted through the processes of water extraction, liquid-liquid extraction and the like, a large number of impurity components are effectively removed, the GC-IRMS with an online high-temperature cracking reaction device is used for carrying out caffeine separation and hydrogen stable isotope ratio determination on the caffeine extract, and the method has the advantages of being easy and convenient to operate, high in efficiency and good in repeatability; technical support and scientific basis are provided for tea producing area traceability by using a monomer isotope technology.