Distinguishing and dating carbonless copy papers by ultra-high-performance liquid chromatography and mass spectrometry

摘要

A method to differentiate between carbonless copy papers and to date the ink entries on those papers has been developed based on ultra-high-performance liquid chromatography and mass spectrometric methods. A total of 52 paper samples were distinguished and classified according to compositional differences reflected by their chromatograms, with a discrimination power as high as 99.3%. The degradation kinetics of a common dye, crystal violet lactone, was investigated, and a quantitative determination method for the dye and its decomposition products was established. The results showed that relative peak area for both the dye and its degradation products versus aging time exhibits satisfactory linearity, which was utilized to date the ink entries on the samples. Overall, this work details an approach that can discriminate between different samples on the basis of compositional differences and describes the degradation rate of the dye, which can be used to age and authenticate ink entries.