Background: Mass spectrometry (MS) is one of the most powerful analytical methods available for exact structural identification of organic compounds. This includes organic compounds found in documents (such as paper, film or tape) in the form both of original components and of degradation products. The use of MS in preservation science has traditionally required the investment of time (for sample preparation) and solvents (for extraction). New, more efficient methods are now available for evaluation at the Library of Congress, using Direct Analysis in Real Time (DART) mass spectrometry. One of the major benefits of this instrument is the potential for non-invasive testing of materials and current studies are developing the technique for a range of compound analyses.
Contributing Study:
R. B. Cody, J. A. Laramée, H. D. Durst, Versatile new ion source for the analysis of materials in open air under ambient conditions, Analytical Chemistry 77 (2005) 2297-2302.
ASTM Paper Aging Research Program, ASTM Research Report (RR:D06-1004); available as Adjunct to D6789 Standard Test Method for Accelerated Light Aging of Printing and Writing Paper by Xenon-Arc Exposure Apparatus; ASTM International: West Conshohocken, PA; 2002.
Adams, J. "Analysis of Printing and Writing Papers by using Direct Analysis in Real Time Mass Spectrometry." International Journal of Mass Spectrometry 301, no. 1-3 (2011): 109–26.
Project Description: Papers in library and archival collections are highly variable and subject to chemical degradation at variable rates. Effects of environmental conditions and previous treatments impact degradation, and new methods to assess and characterize paper and other materials degradation products are a focus of research studies at the Library. DART provides a rapid, sensitive, and relatively noninvasive analytical method for analyzing low levels of organic degradation products that could serve as early markers of paper degradation in lower-temperature accelerated aging and natural aging studies, and for characterizing the stage of deterioration of collections.
In relation to other paper degradation research, samples of Whatman #1 filter paper and 15 reference papers from the ASTM Paper Aging Research Program (INSERT LINK) were analyzed using positive and negative ion DART-MS.
Outcomes/Findings: Preliminary research and development is underway to evaluate the feasibility of using DART-MS to analyze a variety of library collection materials, including the following:
- The DART-MS technique was fast, simple, and repeatable.
- Undetectable microsamples as small as ~ 10 mg, the approximate size of a printed period, could be tweezed from the paper surface for analyses.
- Unique DART mass spectra were obtained from bleached northern hardwood kraft (BNHWK), bleached northern softwood kraft (BNSWK), hardwood- (HW-) and softwood- (SW-) bleached chemithermomechanical (BCTMP), and stone groundwood (SGW) papers in real time without extractions, derivatizations, chromatographic separations, and time-, chemical-, and sample-consuming preparations.
- Phytosteroids in BNHWK papers differentiate them from BNSWK papers; lignin in BCTMP papers differentiates them from kraft papers; syringyl lignin in HW-BCTMP papers differentiates them from SW-BCTMP papers, which contain guaiacyl and coumaryl lignin; extractives in SGW papers differentiate them from all the other papers; and rosin sizing is immediately discerned and differentiated from alkyl ketene dimer (AKD) sizing.
Support: Library of Congress Preservation Directorate
Left: The JEOL JMS-AccuTOF mass spectrometer with the (blue) DART ion source installed.
Right: a leaf from a book being non-destructively sampled and analyzed in real time for volatile organic acids.
