Smell the decay


ResearchBlogging.orgBeen to a library lately? Those of you who, like me, get their current literature via the internet, probably thoroughly repressed the memory of literature research without a search mask, but there are things that stay with you. Such as the smell of old books.

Turns out that there is more to this smell that meets the… uh… nose. It is the result of degradation and depends on the age of the book and the type of paper used.

But not just that. The ink plays a role, the glue and of course the cover, in fact the unique biography of a book contributes to its distinctive odour. There recently was a publication in Analytical Chemistry about the chemical compounds that are responsible for minuscule differences in smell that might tell if a historical book is merely old or already on the verge of disintegration.

The volatile organic compounds emitted by decaying books are captured and separated by headspace GC/MS. As one would expect the main contribution comes from the degradation products of rotting cellulose, for example furfural. How fast cellulose disintegrates, however, strongly depends on whatever else is in the paper. Lignin, for example, accelerates cellulose decay, so that papers produced from wood pulp are a lot less durable than papers made out of rags.

The same goes for Paper made hydrophobic by rosin, a mixture of diterpene acids that makes paper hydrophobic and stops ink from spreading in the fibres. Rosin, however, is precipitated by aluminium salts, which make the paper acidic and destroys cellulose. There are a lot of similar things that can be sniffed from the air just above the pages, so you can in principle learn about the composition and state of valuable historical books without taking samples. So it’s a rather clever and useful method.

Nevertheless I think the authors should be severely punished. There are already far too much –omics around to be useful any more, but at least as far as I know, all –omics so far are at least somehow related to cell biology, where they belong. There is really no excuse for calling a bunch of random volatile chemicals “degradomics”. What’s next? What about the “Sidereactomics” of my latest failed synthesis? Come on…

Strlič, M., Thomas, J., Trafela, T., Cséfalvayová, L., Kralj Cigić, I., Kolar, J., & Cassar, M. (2009). Material Degradomics: On the Smell of Old Books Analytical Chemistry, 81 (20), 8617-8622 DOI: 10.1021/ac9016049

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