Application of Principal Component Analysis to DART-TOFMS Determination of Writing Age of Gel Ink Pen

DART-TOFMS was used to analyze 48 handwriting samples made with the same type of ink at 6 different periods of time.The MS finger-print spectra were established and the projected data were further analyzed by principal component analysis methodology.It was found that the 48 samples could be categorized into 6 different types,which were consistent with the sample categories known to be classified by writing age.The established principal component projection was used to identify 6 unknown samples and a satisfactory result had been attained.