(Received 18 September 1980; accepted 9 October 1980)
Published Online: April
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Evidence in the form of paper documents can be highly valuable in crimes of fraud. Available methods of examination do not provide absolute certainty that two samples have the same origin. A new technique for testing paper, known as inverse paper chromatography, is based on using the paper as a chromatographic sorbent medium on which a known mixture of dyestuffs is separated under standard conditions. The resulting chromatogram will uniquely designate the paper grade and composition. This principle has been validated in a standard test with more than 30 types of paper. The experimental technique is simple, inexpensive, and largely nondestructive. Only a small specimen is required, and it provides a permanent exhibit for evidence. While printing on the paper or wetting it does not alter its chromatographic behavior, artificial aging by heat or exposure to sunlight does. The individualization of paper specimens for unambiguous identification requires further research.
Visiting scientist, Research … Development Division and Analytical Laboratory of Criminal Identification Branch, Israel Police Headquarters,
Stock #: JFS11373J