A process for decreasing contamination of a commercial refining process by vanadyl porphyrins and/or nickel porphyrins by allowing rapid screening of porphyrins directly from asphaltenes isolated from crude oil without enrichment by use of positive-ion electrospray ionization mass spectrometry (ESI MS). Sodium formate is utilized as a ESI spray modifier. The vanadyl porphyrins are detected predominantly as sodiated species, while nickel porphyrins are observed as both sodiated species and molecular ions. Crude oil feedstocks exceeding a defined threshold concentration of vanadyl porphyrins and/or nickel porphyrins are rejected or diluted prior to utilization as refinery feedstock. Certain embodiments additionally quantitate both deoxophylloerythroetioporphyrins and etioporphyrin content (and their ratio) to predict crude oil thermal maturity.

In a method for estimating a noise level representing the magnitude of a noise component from measurement data, first waveform data composed of high frequency noise components extracted from assumed noise data are divided into segments so that each section where positive values successively occur or each section where negative values successively occur in the first waveform data is defined as one segment. A segment-width threshold is determined based on the distribution of the widths of the segments. Second waveform data composed of high frequency noise components extracted from measurement data are divided into segments in the same manner. Each segment having a width larger than the threshold is excluded from the segments in the second waveform data, to create a first segment group. The noise level is determined based on the heights or areas of the plurality of segments included in the first segment group.

A method for identifying and analyzing dissolved organic nitrogen of different sources in wastewater includes extracting DON in wastewater to obtain a DON extract, detecting mass spectrum peaks in the DON extract, pre-processing the spectral data of the wastewater sample; constructing a network relationship of the substance reaction in the wastewater sample; screening the substance reaction relationship of DON; and determining different sources of DON.

A fingerprint detection method for a pharmaceutical preparation. The detection method uses an HPLC-DAD wavelength switching method to simultaneously determine a plurality of active ingredients such as mulberroside A, hydroxysafflor yellow pigment A, paeoniflorin, ferulic acid, calycosin-7-O-β-D-glucoside, rosmarinic acid, salvianolic acid B, formononetin, etc. in the pharmaceutical preparation. The sensitivity and accuracy of the detection method are greatly enhanced so as to ensure the comprehensive evaluation of the quality of the pharmaceutical preparation.

The present invention discloses a method for product quality control and fingerprint detection of an epimedium brevicornu complex. The method uses high performance liquid chromatography, and can effectively realize the quality control of products containing traditional Chinese medicine components, and especially stable control of the quality of products containing a large quantity of non-traditional Chinese medicine components in formulas. Through step-by-step quality control, product quality fluctuation is reduced and stable quality is ensured. Meanwhile, the method is simple and convenient, does not need additional instruments and standards, saves the cost and is more conducive to actual production.

A method for synchronizing data for gas samples with volatile organic compounds. The data includes chromatographic data indicative of molecule retention times. The method includes identifying or selecting marker molecules and clustering the plurality of gas samples into a plurality of clusters according to a clustering criterion. Next, a first correction of retention time deviations is performed on the data for the gas samples between clusters by using the marker molecules as anchor points to provide a coarse reduction of retention time deviations between the data. Finally, a second correction of retention time deviations is performed on the data, so as to further reduce retention time deviations between the data. The method reduces significant retention time deviations to allow, e.g., breath sample fingerprints obtained by different equipment at different times to be compared in one database for use on a digital platform.

Disclosed are methods of identifying pathogens and determining their antimicrobial susceptibility. The methods comprise detecting biomarkers in a test sample, locating the sample in a phylogenetic tree based on biomarker information, obtaining drug susceptibility prediction rules based on the phylogenetic tree positioning of the sample, and determining the drug susceptibility of a pathogen according to the prediction rules. Further disclosed are an application of the phylogenetic tree in the preparation of pathogen identification and/or drug susceptibility diagnostic product, and a pathogen identification and drug susceptibility diagnostic kit.

A method for analysing a crude oil to determine the amount of organic acid compounds contained in the crude oil includes extracting the organic acid compounds from a sample of crude oil to form an extract and determining the amount of the extracted organic acids In addition, the method includes dissolving the extract in a polar solvent to form a solution of the extracted organic acid compounds Further, the method includes introducing a sample of the solution of the extracted organic acid to an apparatus including a reversed phase liquid chromatography (LC) column and a mass spectrometer (MS) arranged in series. The reversed phase LC column contains a hydrophobic sorbent and the mobile phase for the LC column includes a polar organic solvent. Still further, the method includes separating the organic acid compounds in the LC column of the LC-MS apparatus and continuously passing the separated organic acid compounds from the LC column to the MS of the LC-MS apparatus to ionize the organic acid compounds and to obtain a chromatogram with mass spectral data over time for the ionized organic acid compounds. Moreover, the method includes determining the area(s) under the peak(s) in an extracted ion chromatogram derived from the mass spectral data assigned to one or more organic acid compounds. The method also includes determining the amount of the organic acid compound(s) in the sample by comparing the area under the peak(s) assigned to the organic acid compound(s) with the area under a peak in an extracted ion chromatogram assigned to a specific amount of a standard organic acid compound. In addition, the method includes extrapolating from the amount of the organic acid compound(s) in the sample to provide the total amount of the organic acid compound(s) in the extract.

A method for the identification of unknown compounds based on a novel Retention Index System having a TAGs homologous series, wherein such identification is performed by means of liquid chromatography (LC), or liquid chromatography coupled with mass spectrometry (LC-MS) is disclosed.

The present invention belongs to the technical field of metabolomics, and relates to a metabolomics relative quantitative analysis method based on UPLC/HRMS. Specifically, the present method mainly comprises the steps of formulating an isotope internal standard mixed solution, a standard curve correction solution, and a metabolomics sample solution; acquiring raw mass spectrum data of the standard curve correction solution and the metabolomics sample solution; transposing and deconvolving the raw data; identifying and selecting the optimal isotope internal standard; fitting a linear equation and calculating the relative quantitative results of metabolites in the metabolomics sample solution; and completing the structural identification of metabolites and differential metabolites in the metabolomics sample solution. The method can meet both qualitative and quantitative requirements using only a high-resolution mass spectrometry platform; the quantitative results are accurate, and the accuracy of the qualitative results are higher, having low costs, simple operation, and wide applicability.