Sampling restrictions in analysis of cultural heritage materials narrow the choice of appropriate analytical methods considerably. In this work, near- and mid-FT-IR reflectance data were related to paper properties determined with classical analytical methods using partial least-squares. Nondestructive determination of properties, which are of importance for evaluation of the long-term stability of historical paper, i.e., ash content, lignin content, degree of polymerization of cellulose, pH, and aluminum content, is possible. With the use of a considerable sample set, satisfactory reliability was achieved for all properties but aluminum content. Considering that with age, chemical properties of paper change, dating of historical documents was attempted for the first time, also with success.

An efficient and rapid protocol has been developed for extracting ginkgolides and bilobalide (terpene trilactones) from Ginkgo biloba leaves. The procedure takes advantage of the extraordinary stability of the terpene trilactone structure to a variety of chemical treatments, especially oxidation, despite the presence of multiple oxygen functions. The protocol involves boiling the aqueous extract of leaves with dilute hydrogen peroxide, extraction with ethyl acetate, washing with basic solutions, and charcoal filtration to yield an off-white powder, terpene trilactone content 60-70%. It is likely that the hydrogen peroxide treatment degrades the undesired leaf constituents that lead to intense emulsification during extractions. Further reversed-phase chromatography of the extracts with polymeric resins removes the undesirable ginkgolic acids to amounts less than 10 ppm. The extracts are suited for pure terpene trilactone preparation, enrichment of terpene trilactone content in nutraceuticals, and preparations of low-flavonoid/high-terpene trilactone controls in medicinal studies. The four ginkgolides (ginkgolides A, B, C, J) and bilobalide isolated from the extract were identical in all respects with authentic specimens.

An innovative survey was conducted of the collections of the historical Biblioteca Classense, located in the urban area of Ravenna (Northern Italy). The survey aimed to evaluate the current conservation state of the book collections, where 297 paper-based items, including incunabulae, manuscripts and books, dating from the 14th to the 20th century, were selected for analysis. This innovative survey was carried out non-destructively by assessing degradation visually and by measuring NIR spectral data followed by multivariate data analysis. Chemical and physical paper properties, important for paper characterisation and implementation of conservation strategies were determined, including paper type, pH, degree of polymerisation, tensile strength, lignin, protein, and rosin content. This survey provided a significant quantitative dataset for rag paper covering a 600-year period. The analysis of DP changes over time allowed the first experimental estimation of the rate constant for historical rag paper, i.e., (4.2 ± 0.6)·10−7 year−1, which was validated with predictions based on the Collections Demography dose response function for historic paper taking into account the past climate in Ravenna. Statistical methods were employed to describe the correlations between the measured variables and different features of the books, suggesting that the degree of polymerisation can be used as a general proxy for rag paper mechanical strength.

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