Chromatogram data processing system

A chromatogram data processing system, comprising:

• a) a three-dimensional data storage section for storing three-dimensional chromatogram data with time, wavelength and absorbance as dimensions;
• b) a wavelength chromatogram creator for extracting, from the three-dimensional chromatogram data, a set of data obtained at a specific wavelength which is an absorption wavelength of a target component and for creating a wavelength chromatogram showing a relationship between the time and the absorbance at the specific wavelength;
• c) a peak detector for detecting a peak of the created wavelength chromatogram;
• d) a processor configured to create graphs showing a presence or absence of at least one impurity in the detected peak by performing two or more detection methods on the three-dimensional chromatogram data sequentially in one analyzing process, wherein the two or more detection methods are designed to enable to detect different impurity, respectively, and are applied to a same peak of the three-dimensional chromatogram data;
• and
• e) a display unit for displaying the graphs that are different from each other obtained by the two or more detection methods in a superposed form on the wavelength chromatogram to determine a presence or absence of the at least one impurity in the detected peak,
• wherein the two or more methods are selected from a group consisting of a degree-of-matching determination method in which a degree of matching between an absorbance spectrum at time T0 corresponding to a peak top of a target peak on the wavelength chromatogram and an absorbance spectrum at an arbitrary time T before or after T0 is calculated, a differential spectrum method in which a differential coefficient of an absorbance spectrum with respect to wavelength at a local maximum or local minimum absorption wavelength of the target component is determined, and if a peak is located in a waveform of a differential chromatogram which shows a temporal change of the differential coefficient, it is determined that an impurity is contained, and a purity determination method in which the presence or absence of an impurity is determined by comparing a degree of similarity between a spectrum on a target peak and a reference spectrum, with a degree of similarity of these two spectra which is determined taking into account an influence of noise components.