108 results about "Mass spectrum" patented technology

The invention relates to a method for analysing mass spectral data obtained from a sample in GC×GC (2-dimensional) mass spectrometry, comprising: (a) comparing mass spectral data of an analyte with mass spectral data of candidate compounds of known structure in a data library; (b) identifying a plurality of candidate compounds from the library based on similarities of mass spectral data; (c) predicting, for each candidate compound, a value of at least one analytical property using a quantitative model based on a plurality of molecular descriptors; and (d) calculating a match score for each candidate compound based on the value predicted in step (c) and a measured value of the analytical property for the analyte.

The invention discloses a detection method for single-cis and double-cis lutein isomers. The method adopts a diode array detector and a YMC carotenoid C30 chromatographic column, and takes methyl alcohol, acetonitrile and dichlormethane as mobile phases, wherein the ratio of methyl alcohol to acetonitrile to dichlormethane is 50 to 30 to 20; according to the method, the time is 13 minutes, the flow velocity is 1.0mL / minute, the column temperature is 25 DEG C, the sample injection amount is 20 microliters, the scanning wavelength is 300-500nm, and the detection wavelength is 450nm; after the method is adopted, the single-cis and double-cis lutein isomers can be well separated; furthermore, an atmospheric pressure chemical ionization (APCI) positive ion mass spectrum is utilized, the flow velocity of chromatographic column outflow components entering a mass spectrometer is 10 microliters per minute, the scanning range m / z=80-900, the vaporization temperature is 350 DEG C, the flow velocity of dry gas is 5L / minute, the corona current is 4 microamperes, the crushing voltage is 150 V, and the capillary voltage is 2,500V. According to the mass spectrum and optical spectrum information, the single-cis and double-cis lutein isomers are respectively determined to be 13, 15-double-cis form, 9, 15-double-cis form, 15-cis form, 13-cis form, 13'-cis form, 9, 9'-double-cis form, 9-cis form and 9'-cis form lutein. The method has the advantages of being rapid, effective, good in reproducibility, high in recycling rate and the like, and can be used for carrying out qualitative and quantitative analysis on the single-cis and double-cis lutein isomers.

The invention discloses a phosphorylated and / or glycosylated protein or peptide one-step enrichment modification determination method. The method includes the following steps: 1) modification on end alkynyl or triazon of protein or peptide; 2) resin capturing of protein or peptide with modified end alkynyl; 3) cutting of the peptide / protein with modified alkynyl on resin. The protein or peptide enrichment modification determination method provided by the invention not only can enrich and purify the modified protein or peptide after translation but also can add one molecule segment on the protein or peptide, and the molecule segment has the functions of mass spectrum label and mass spectrum signal gain. The method has wide application prospect in the science analysis field.

The present invention provides a method of determining the absolute amount of a target polypeptide in a sample, said method comprising the following steps: (a) adding (aa) a fusion polypeptide to said sample, said fusion polypeptide comprising (i) at least one tag sequence and (ii) a subsequence of the target polypeptide; and (ab) a known absolute amount of a tag polypeptide comprising or consisting of said tag sequence according to (aa) to said sample, wherein said fusion polypeptide on the one hand is mass-altered as compared to said target polypeptide and said tag polypeptide on the other hand, for example, said fusion polypeptide on the one hand and said target polypeptide and said tag polypeptide on the other hand are differently isotope labeled; (b) performing proteolytic digestion of the mixture obtained in step (a); (c) subjecting the result of proteolytic digestion of step (b), optionally after chromatography, to mass spectrometric analysis; and (d) determining the absolute amount of said target polypeptide from (i) the peak intensities in the mass spectrum acquired in step (c) of said fusion polypeptide, said tag polypeptide and said target polypeptide and (ii) said known absolute amount of said tag polypeptide.Furthermore provided is a fusion polypeptide for the quantification of a target polypeptide by mass spectroscopy, wherein: said fusion polypeptide consists of 35 to 455 amino acid residues and comprises (i) a target region, which is a fragment of the target polypeptide, and (ii) a tag region, which is not a fragment of the target polypeptide, said target region consists of 15 to 205 amino acid residues and comprises at least two signature regions; said tag region consists of 20 to 250 amino acid residues and comprises at least two signature regions; and each signature region has the structure Y-Z-X4-28-Y-Z, wherein all Y:s are selected from one of (i)-(iv), wherein (i) is R or K, (ii) is Y, F, W or L, (iii) is E and (iv) is D and each X and each Z are independently any amino acid residue, provided that the Z:s are not P if the Y:s are selected from (i)-(iii); and each signature region comprises at least one amino acid residue comprising a heavy isotope.

The invention relates to microbial-source pesticide, in particular to a Destruxin depsipeptide derivative and a preparation method and application thereof. The Destruxin depsipeptide derivative is as shown in formula (I) and formula (II). The Destruxin depsipeptide derivative is prepared by the strain BeauveriafelinaAS-70 through fermentation, culture, extraction and separation. By authentication using technologies such as nuclear magnetic resonance and mass spectrum, the chemical structure of the Destruxin depsipeptide derivative is good in pesticide activity.

The invention provides a synthetic method and a synthetic product of symmetric eight methyl cucurbit[6]uril, which are a synthetic method of organic chemistry macrocyclic supramolecular compounds symmetric eight methyl cucurbit[6]uril and a synthetic symmetric eight methyl cucurbit[6]uril. The symmetric eight methyl cucurbit[6]uril is formed by taking dimethyl replacing glycosides urea dimer, general glycoluril and paraformaldehyde as raw materials, replacing glycosides urea dimer with dimethyl through formaldehyde, and carrying out condensating selective formation between dimethyl and general glycoluril, so as to form the symmetric eight methyl cucurbit[6]uril. The invention discloses the synthetic method and a specific technology condition, and conducts sufficient structural characterization by analyzing measures such as nuclear magnetic resonance, single-crystal X-ray diffraction, mass spectrum, IR, and DSC-TG.

The invention provides a method for quickly screening and authenticating edible oil through surface assisted laser desorption ionization mass spectrometry. In the method, a magnetic metal organic framework nanomaterial is used as matrix, the magnetic metal organic framework nanomaterial matrix is mixed with the edible oil and dropped on a target plate, and the target plate is dried at room temperature; then, mass spectrometric detection is executed, and a result is analyzed. The method overcomes a lot of problems, such as serious background interference of the conventional organic matrix at alow molecular weight region (m / z is less than 1000 Da), and can be directly used for quick screening and authentication of the edible oil. The method has the advantages of consuming less samples, being simple in sample preparation and fast in analysis, having high signal-to-noise ratio and excellent signal repeatability, and so on, and has better use value and potential application foreground in the food safety field.