Determination of glycol-based solvents in different colours (blue, black, green and red) of gel pen inks by gas chromatography-mass spectrometry (GC-MS)

Forensic science is a multidisciplinary field that includes the processes of collecting, analyzing and interpreting evidence using scientific methods in criminal investigations and trials. Forensic document analysis is an important branch of forensic sciences; because document forgery is one of the most common types of crimes. In this context, document forgery; It is an important issue that affects legal procedures and judicial processes. Document forgery is the deliberate alteration, imitation or manipulation of letters, numbers or signatures on a document. In cases where document forgery is the subject of a lawsuit, prosecutors and judges demand answers from experts to the questions of who owns the writing or signature on the suspicious document and when the document was created. While the identity of the writing and signature is determined by optical examinations, the time of creation of the document is based on the detection of the time-dependent change of the ink in the suspicious document using analytical methods. These changes are the degradation of dyestuffs in the structure of the ink, the evaporation of solvents and the polymerization of resins. Many methods have been developed to detect these changes. Most of these methods are aimed at detecting the evaporation of solvents present in the structure of the ink. In this thesis, it is aimed to develop a method that allows the analysis of glycol-based solvents in the structure of gel pen inks of different colors (blue, black, green, red) with GC MS and to draw the age curve by evaluating the data obtained from the archive results analyzed with the developed method. The method developed as a result of this thesis study is aimed to serve justice.