Fractional Determination of Co-eluted Compounds Using a New Data Processing Method for Photodiode Array Detector

The i-PDeA derivative spectrum chromatogram method was developed as a new data processing technique for photodiode array detectors for HPLC. A derivative spectrum is created by performing differential processing on the UV-Vis absorption spectrum at each measurement time. Plotting the derivative spectrum values at the specified wavelength against retention time creates a derivative spectrum chromatogram that is able to separate co-eluted peaks. The high selectivity of the derivative spectrum chromatogram can detect unexpected impurities and quantitate the target component only, without effects from interfering components that elute simultaneously. This paper formulates the theory of the derivative spectrum chromatogram method into mathematical expressions and reports details of verification of the basic performance using standard samples.