Patent ID: 11933770
Assignee: THERMO FINNIGAN LLC
Field: Measurement (Instruments)
Classification: CPC G  H | IPC G  H

Claim 20:
21. A Liquid Chromatography Mass Spectrometry (LCMS) system comprising:
a chromatograph configured to receive a continuous stream of a sample;
a mass spectrometer configured to receive separated fractions of the sample from the chromatograph and to ionize said separated fractions, whereby the ionization generates a plurality of precursor ion species; and
a programmable processor comprising computer-readable instructions that are operable to:
repeatedly:
cause the mass spectrometer to perform a data-independent analysis of a subset of the precursor ion species using a mass analyzer of the mass spectrometer, whereby mass spectra of a plurality of product-ion species generated by fragmentation of the precursor ion species are acquired; and
calculate a rate of change of a mass spectrometric signal that relates to a rate of change of a detected number of ions of an internal standard; and

if a magnitude of the calculated rate of change is less than a threshold value, cause the mass spectrometer to:
perform a quantitative tandem mass spectrometric analysis of the internal standard and a quantitative tandem mass spectrometric analysis of the analyte; and
calculate a quantity of the analyte in the sample by comparison between an intensity of a mass spectral signal generated by the quantitative tandem mass spectrometric analyses of the analyte and an intensity of a mass spectral signals generated by the quantitative tandem mass spectrometric analyses of the internal standard.