A method for analyzing the structure of an insoluble pigment compound is disclosed. In some embodiments, a method comprise determining a molecular weight of the pigment compound, the insoluble pigment compound by ultrasonic treatment in a solvent to form partial structural compounds, analyzing the elemental composition and the structure of partial structural compounds by liquid chromatography/mass spectrometry and nuclear magnetic resonance, respectively and determining the structure of the insoluble pigment compound from the analysis of the partial structural compounds and the molecular weight of the insoluble pigment compound. In some embodiments, a method comprises determining molecular weight of the pigment compound using matrix assisted laser desorption ionization-time of flight mass spectrometry, selecting a parent mass, fragmenting the parent mass and determining the molecular weight of each fragment, and determining the structure of the insoluble pigment compound from the molecular weight of the insoluble pigment compound and that of the fragments.

A method of controlling the operation of an ion mobility separation device is disclosed. The method comprises displaying to a user via a user interface a pool of modes of operation of the ion mobility separation device, wherein each one of the modes is selectable by the user for inclusion in an experiment, and the modes are displayed in a first area 202 of the user interface. The method comprises receiving, via the user interface, an indication from the user of a selection of one or more instance of each one of a plurality of the modes from the pool to be included in an experiment, and an indication from the user of a set of one or more parameters for controlling the ion mobility separation device in respect of one or more selected instances of a mode. The selected instances of modes are displayed in a sequence in a second area 204 of the user interface. The operation of the ion mobility separation device is controlled in accordance with the received indications.

A system capable of performing both single and multidimensional liquid chromatography includes a solvent delivery system, a sample injection system, a first dimension column path configured to perform a separation process in a first dimension, a second dimension column path configured to perform a separation process in a second dimension that is different than the first dimension, a valve system; and a sample injection system fluidically connected to the valve system. The valve system is configured to direct flow from a sample injection system to a first dimension column path when the valve system is in a first position, and to direct flow from the sample injection system to the second dimension column path without the flow path flowing through the first dimension column path in the chromatography system when the valve system is in a second position.

The invention provides methods for rapid and quantitative extraction and detection of coenzyme Q10 in a sample readily adaptable to high throughput screening methods. The invention further provides reagents and kits for practicing the methods of the invention.

Before repeating the processing that an LC/MS analysis is performed after diluting a large number of pretreated media samples (S16 to S19), an LC-MS stabilization processing (S11) of supplying a mobile phase to the LC-MS and performing an analysis without a sample according to the same gradient profile as that in a culture medium sample analysis and a standard sample analysis (S13) of supplying a standard sample to the LC-MS and obtaining data for generating a calibration curve are performed. Before the LC-MS stabilization processing and before the standard sample analysis, respectively, a standby time corresponding to a required time of a sample dilution is provided (Steps S10 and S12). With this, the time of the cycle including the LC-MS stabilization processing and the time of the cycle including the standard sample analysis are made to be the same as the time of the cycle of a dilution and an analysis to a culture medium sample. As a result, the stoppage time of the mobile phase before the mobile phase is fed according to the gradient profile becomes the same in every cycle, and the staying time of the mobile phase in the degassing device becomes uniform, so that it is possible to avoid changes in the compositions of the mobile phases in the column and to achieve higher quantitativity.

The present invention relates to a mass spectrometric method for determining (predicting) the presence or absence of a chemical element in an analyte which provides valuable information towards reduction of complexity for annotating a chemical formula to the analyte. The method is based on representing a measured isotopic pattern of an analyte as a feature vector and assigning the feature vector to the presence/absence class using a machine learning algorithm, like a support vector machine (SVM) or an artificial neural network (NN).

Real-time search (RTS) for mass spectrometry is described. In one aspect, a mass spectrometer can identify a candidate peptide for a product ion spectrum by searching a mass spectral database. While executing the search of the mass spectral database, a candidate peptide score representing a confidence of a match between the product ion spectrum and a theoretical mass spectrum stored in the mass spectral database is generated. A failing score can be promoted to a passing result based on attributes of the candidate peptide.

A method for testing for the presence and quantification of A1-type beta-casein variants or A2-type beta-caseins, in milk and milk derived dairy products, using chymotrypsin digestion followed by LC-MS analysis to determining the concentrations of beta-casein digestion peptides and using the concentrations to calculate the amounts of A1-type beta-casein variants or A2-type beta-casein variants present.

The present disclosure provides a method for accurately measuring post-translational modifications in proteins such as antibodies. In particular, the method pertains to the use of heavy isotopic standards to generate a calibration curve to allow for accurate quantitation of a modified peptide. The method may be used to accurately quantify C-terminal truncation in antibodies using mass spectrometry.

The present invention discloses a method for predicting the postoperative risk of brain-injured patients and a use of steroids/proteins for predicting the postoperative risk of brain-injured patients, mainly for testing the concentration of steroids/protein in patient samples. Acquire one-day in-vitro waste cerebrospinal fluid samples from brain-injured patients after surgery and conduct specific steroid and protein concentration tests. By confirming the concentration of specific steroid in the waste cerebrospinal fluid samples or the type and concentration of proteins detected therein, the postoperative risks of brain-injured patients can be predicted.