Abstract: A method for fractionating a sample solution includes the steps of setting a first mass spectrometry condition and mass range information; setting a second mass spectrometry condition and mass range information; executing a mass scan by the mass spectrum acquisition portion under the first mass spectrometry condition and obtaining first mass spectrum data; extracting first chromatogram data from the first mass spectrum data based on the first mass range information; executing a mass scan by the mass spectrum acquisition portion under the second mass spectrometry condition to obtain second mass spectrum data; extracting second chromatogram data from the second mass spectrum data based on the second mass range information; switching the first and second spectrometry conditions and repeating the mass scan cyclically; adding the first and second chromatograph data to obtain a chromatogram data; and operating the fraction collector based on the chromatogram data.

Abstract: Disclosed is a Fourier transform infrared spectrophotometer, which comprises: a main interferometer section including a beam splitter, a fixed mirror, a movable mirror, and a phase plate disposed between the beam splitter and the fixed mirror; a control interferometer section having a quadrature control system for calculating a position of the movable mirror; a center-burst-position detection section operable, based on an input of interference signals and interferograms, to subject respective intensities of the interferograms to an addition processing while correcting a positional deviation of the movable mirror, so as to obtain a cumulative interferogram, and detecting a center burst position having a maximum intensity value in the cumulative interferogram; a center-burst-position storage section operable to store the detected center burst position; and a measurement-start-position determination section operable, based on the stored center burst position, to determine a measurement start position of the mova

Abstract: An exact centroid spectrum with a mass number corrected is determined from a profile spectrum adjacent to a plurality of peaks. Regarding a profile spectrum determined by a mass spectrometer, overlapping with adjacent peaks occurs, and compounds having a plurality of peaks with different overlapping degrees is measured, a correction function is created from a relationship between an overlapping degrees with respect to the plurality of peaks and a shift of the mass number, and a centroid peak is corrected by the correction function when the profile spectrum is converted into the centroid spectrum.

Abstract: In a liquid chromatograph mass spectrometer, chromatogram data is obtained by carrying out alternately a mass scan in a molecular ion detection mode and a mass scan in a fragment ion detection mode, obtaining the chromatogram data by adding spectrum intensities in the mass spectrum data obtained at the respective mass scans, and further adding sums of the spectrum intensities. Since the chromatograms in both modes are averaged, even if there is a difference in baseline levels therebetween, a chromatogram in a normal form can be obtained.

Abstract: In a liquid chromatograph mass spectrometer, chromatogram data is obtained by carrying out alternately a mass scanning in a positive ion detection mode and a mass scanning in a negative ion detection mode, obtaining the chromatogram data in every positive and negative polarities through summing up the mass spectrum data obtained at the respective mass scannings, and adding the data of both polarities. Since the chromatograms in both polarities are averaged, even if there is a level difference therebetween, a chromatogram in a normal form can be obtained.

Abstract: A mass spectrometer for a liquid chromatograph includes an atomization chamber into which a liquid sample from the liquid chromatograph is sprayed to be converted into ions, an intermediate chamber at a reduced inner pressure and a detection chamber containing a mass analyzer. A solvent-removing tube is between the atomization chamber and the intermediate chamber for causing liquid droplets containing these ions to pass through. A deflector with at least one pair of planar electrodes is disposed inside the intermediate chamber and opposite each other sandwiching in between the travel path of the ions. Voltage sources apply a variable DC voltage to the solvent-removing tube and different variable DC voltages to each of the electrodes. Data on voltages to be applied to the solvent-removing tube and to the electrodes for optimizing efficiency with which ions with different mass numbers are received by the mass analyzer are preliminarily obtained by using standard samples and stored in a memory device.