Chromatogram data processing device and processing method

A system, comprising:

• a chromatograph including a column that separates components of a target sample and a detector that detects the separated components;
• a chromatogram data processing device configured to process three-dimensional chromatogram data collected on the detected separated components of the target sample in which dimensions are made up of time, wavelength, and absorbance, and generate an absorbance spectrum representing a relation of the wavelength and the absorbance;
• a display configured to display a window of the absorbance spectrum;
• an operating unit configured to receive a wavelength designated on the absorbance spectrum displayed by an operator,
• wherein the chromatogram data processing device is configured to act as:
• a computing unit configured to calculate a specific wavelength closest to the wavelength designated by the operator, the specific wavelength being either one of a local maximum absorption wavelength and a local minimum absorption wavelength of the target sample at which a differential coefficient reaches zero on the absorbance spectrum;
• a differential chromatogram generating unit configured to calculate a differential coefficient at the specific wavelength of the absorbance spectrum obtained at each time and configured to generate a differential spectrum at each time that represents a change in the differential coefficient at the specific wavelength;
• and
• a determination unit configured to determine whether or not one or plural other components are included a peak of a target component, based on the change in the differential coefficient at each time, and whether or not the target sample includes impurities.