resumo
The identification of paper composition, pH, early signs of paper degradation, and emitting volatile organic compounds (VOCs) are mandatory for effective preventive conservation of paper/books. Sampling restrictions in the analysis of cultural heritage materials limit the choice of appropriate analytical methods. Solvent-free analytical techniques with nondestructive sampling are needed. Addressing this challenge, an electronic nose based on six-coated piezoelectric quartz crystals was assembled and used to analyze VOCs emitted from books. Careful selection of sensor coatings and cluster analysis allowed us to achieve a clear distinction between cotton/linen rag and wood pulp paper, and among the letter group, the discrimination between papers manufactured from alkaline and acidic stocks. This six-element sensor array was therefore able to replace destructive tests as the ones ordinarily used for paper pH measurements. The same electronic nose was able to separate aged pale-yellow paper, a visible initial sign of paper degradation, from well-preserved still white papers, even when made from the same raw material. One of the used sensors detected furfural, often seen as a marker of cellulose degradation, at lower levels than the detection limit found in the literature with gas chromatography-mass spectrometry, a much more complex bulky and expensive instrument.
palavras-chave
VOLATILE ORGANIC-COMPOUNDS; ELECTRONIC NOSE; PAPER; CHEMISTRY; IDENTIFICATION
categoria
Chemistry; Science & Technology - Other Topics
autores
Verissimo, MIS; Oliveira, JABP; Evtuguin, DV; Gomes, MTSR
nossos autores
Dmitry Evtyugin
Professor Associado com Agregação
Marta Veríssimo
Bolseiro de pós-Doutoramentoagradecimentos
Thanks are due to FCT/MCTES for the financial support to CESAM (UID/AMB/50017/2019) and to CICECO-Aveiro Institute of Materials (UID/CTM/S0011/2019), through national funds. M.I.S.V. would like to acknowledge the Portuguese Foundation for Science and Technology (FCT), for the post-doctoral grant BPD/394267/2013. Authors would like to acknowledge University of Aveiro Library for the loan of some of the oldest books used and for the interest shown in the device.