Dating the writing age of black roller and gel inks by gas chromatography and UV–vis spectrophotometer

The relative and absolute age of roller and gel ink entries determined by gas chromatography (GC) and UV–vis methods are presented in this paper. The relative age of ink entries is concluded by the comparison of solvent amount between questioned and known dated entries. Absolute age of ink entries is estimated through the changing ratio of solvent components between heated and unheated samples without known samples for comparison. The methods are accurate and reliable.