A team at University College, London, has developed a test which can measure degradation of old books as well as precious historical documents on the basis of their aroma. According to them, the non-destructive “sniff” test could help libraries and museums preserve a range of prized paper-based objects, some of which are degrading rapidly due to advancing age.

Lead scientist Matija Strlic said that the well-known musty smell of an old book, as readers leaf through the pages, is the result of hundreds of volatile organic compounds (VOCs) released into the air from the paper. “The aroma of an old book is familiar to every user of a traditional library. A combination of grassy notes with a tang of acids and a hint of vanilla over an underlying mustiness, this unmistakable smell is as much a part of the book as its contents.” said Strlic

Original composition

“It is the result of the several hundred VOCs off-gassing from paper and the object in general. The particular blend of compounds is a result of a network of degradation pathways and is dependent on the original composition of the object including paper substrate, applied media, and binding,” Strlic also said.

Those substances hold clues to the paper’s condition, according to the scientists. The new technique — an approach called “material degradomics” — analyses the gases emitted by old books and documents without altering the documents themselves.

The scientists used it to “sniff” 72 historical papers from the 19th and 20th centuries. Some of the papers contained rosin and wood fibre, which are the most rapidly degrading types of paper found in old books. The scientists identified 15 VOCs that seem good candidates as markers to track the degradation of paper in order to optimise their preservation. The method also could help preserve other historic artifacts, they said. The findings have been published in the ‘Analytical Chemistry’ journal.