Analysis of ink extracted from a charred document using thin layer chromatography

Arson is intentional setting of fire to a property or document. A charred document is a type of document which is burnt either fully or partially. In questioned documents, the examination of ink plays a pivotal role in differentiation of two documents. Differentiations of two inks from one another are carried out either using a destructive technique (TLC and UV-Visible spectroscopy) or a non-destructive technique (Video spectral comparator). The present study includes the use of destructive and nondestructive techniques for ink examination. Ink extracted from a normal document was compared against ink extracted from a charred document using Thin Layer chromatography (TLC), to draw inferences from both. Subsequently, ash analysis was done to ascertain the effect of heat on paper subjected to controlled and uncontrolled combustion.

Ash analysis showed minor variations in samples obtained after uncontrolled combustion. The chromatographic analysis did not exhibit any band formation in charred document samples visualized under Video Spectral comparator (VSC). A different combination of solvent phase might aid in the band formation in TLC as it might ensure better extraction of sample.

A clear distinction between ink extracted from charred documents and a normal document could not be established using the protocols followed in the research. Formation of soot due to uncontrolled combustion, application of primitive extraction procedure of the samples and the physical and chemical changes occurring as a result of combustion could be the contributing factors of the obtained result in the research.