A method for relative quantitative analysis of a polymer using MALDI mass spectrometry, the method comprising the steps of preparing a plurality of polymer specimens having a thickness variation of 30% or less by electrospraying a solution including a polymer sample, a monomeric internal standard material, and a matrix through a mask for each different concentration of the polymer sample; obtaining MALDI mass spectra by irradiating laser beams to each of the plurality of polymer specimens, and calculating a signal intensity ratio of the polymer sample to the small molecule internal standard from peak results of the spectra; and depicting the calculated signal intensity ratio according to the concentration of the polymer sample to prepare a quantitative calibration curve, and the method capable of providing MALDI mass spectra with reduced overlapping peaks and thereby providing the relative quantitative analysis of a polymer with improved accuracy.

The present invention comprises novel methods of continuously monitoring the performance of an atmospheric pressure ionization (API) system. The methods of the invention allow for improved quality monitoring of the processes that leads to the formation of ions at atmospheric pressure. The methods of the invention further allow for continuously monitoring for the quality of the ion formation process in API without the addition of extraneous material (such as labelled compounds or control known compounds) to the system being monitored.

A CDMS may include an ELIT having a charge detection cylinder (CD), a charge generator for generating a high frequency charge (HFC), a charge sensitive preamplifier (CP) having an input coupled to the CD and an output configured to produce a charge detection signal (CHD) in response to a charge induced on the CD, and a processor configured to (a) control the charge generator to induce an HFC on the CD, (b) control operation of the ELIT to cause a trapped ion to oscillate back and forth through the CD each time inducing a charge thereon, and (c) process CHD to (i) determine a gain factor as a function of the HFC induced on the CD, and (ii) modify a magnitude of the portion of CHD resulting from the charge induced on the CD by the trapped ion passing therethrough as a function of the gain factor.

An analytical system including a mass spectrometer (MS) coupled to liquid chromatography (LC) via an ionization source (IS), and an automated method of maintaining the analytical system in a QC-compliant status are described. The method comprises determining a deviation of the analytical system from a QC-compliant status by determining a deviation of one or more predetermined parameters in an m/z spectrum above one or more predetermined thresholds, triggering an IS and/or MS maintenance procedure upon determining a deviation from the QC-compliant status, determining a return or a failed return to the QC-compliant status during and/or after the IS and/or MS maintenance procedure by determining a return or a failed return respectively of the one or more predetermined parameters in an m/z spectrum below the one or more predetermined thresholds, triggering another IS and/or MS maintenance procedure upon determining a failed return to the QC-compliant status.

The present invention provides reagents for instrumentation quality control and methods of use thereof. In particular, sets of peptides or other molecules are provided for evaluating the performance of instruments with mass spectrometry (MS) and/or liquid chromatography (LC) functionalities.

A method and an apparatus for determining a concentration of a target analyte in a sample of bodily fluid are disclosed. The method involves providing a sample of bodily fluid including the target analyte, providing an internal standard solution including a mixture of components having a plurality of isotopes of the target analyte, wherein a concentration of each isotope is unknown, adding the internal standard solution to the sample, analyzing the sample including the internal standard solution using a mass spectrometer, creating a sample function curve based on signal intensities, wherein the signal intensities define arbitrary units, transferring an analyte signal into a corresponding arbitrary analyte unit by means of the sample function curve, and transferring the arbitrary analyte unit into the concentration of a target analyte by means of a standardization function representing a curve of concentrations depending on the arbitrary units.

Systems and methods are disclosed for determining if the dynamic range of quantitation in mass spectrometry can be extended. A DIA method is performed on a sample for a compound of interest at each acquisition time of a plurality of acquisition times. A plurality of product ion spectra are produced for each window of two or more precursor ion mass selection windows. A known product ion of the compound of interest is selected. Two or more XICs are calculated from two or more different precursor ion windows for the known product ion. A ratio of one XIC of the two or more XICs to at least one other XIC of the two or more XICs is calculated. If the ratio is above a threshold, the XIC is used in the quantitation. If not, two or more XICs can be combined into a single XIC that is used for the quantitation.

A method for determining in a sample, by mass spectrometry, the amount of one or more analytes selected from the group consisting of 12,13-DiHOME, 3-hydroxybutyrate (BHBA), 3-hydroxyoctanoate, 3-methylglutarylcarnitine, 3-ureidopropionate, 7-alpha-hydroxy-4-cholesten-3-one (7-Hoca), citrate, fucose, fumarate, gamma-tocopherol, glutamate, glutarate, glycerol, glycochenodeoxycholate, glycocholate, hypoxanthine, maleate, malonate, mannose, orotate, 2,3-pyrdinedicarboxylate, ribose, serine, taurine, taurochenodeoxycholate, taurocholate, palmitoleate, linolenate, xanthine, xylitol, and combinations thereof is described. The method comprises subjecting the sample to an ionization source under conditions suitable to produce one or more ions detectable by mass spectrometry from each of the one or more analytes; measuring, by mass spectrometry, the amount of the one or more ions from each of the one or more analytes; and using the measured amount to determine the amount of each of the one or more analytes in the sample.

A mass spectrometry method includes: preparing calibration data for performing calibration on a basis of first data obtained by detecting a chlorobiphenyl in first mass spectrometry of a reference sample of the chlorobiphenyl; acquiring second data obtained by detecting, in second mass spectrometry of a sample, at least one chlorobiphenyl that has a same chlorine number as and is different in kind from the chlorobiphenyl detected in the first mass spectrometry; and calculating a quantitative value for the chlorobiphenyl contained in the sample on a basis of the calibration data and the second data.

The present invention provides a method for analyzing a sample containing metal fine particles with an inductive coupling plasma mass spectrometer. The method enables analysis of the sample without the need of standard metal fine particles. Specifically, the present invention relates to a method for analyzing metal fine particles in liquid by use of an inductive coupling plasma mass spectrometer. In the method, the analysis apparatus is provided with a standard solution introduction apparatus including a standard solution storage unit for storing a standard solution containing a specific element in a known concentration, a syringe pump for suctioning and discharging the standard solution, and a solution introduction unit having a standard solution nebulizer and a standard solution spray chamber that are supplied with the standard solution, the standard solution is directly supplied to the standard solution nebulizer at a flow rate of 3 μL/min or less.