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Testing the Effectiveness of Protocols for Removal of Common Conservation Treatments for Radiocarbon Dating
| Content Provider | Scilit |
|---|---|
| Author | Brock, Fiona Dee, Michael Hughes, Andrew Snoeck, Christophe Staff, Richard Ramsey, Christopher Bronk |
| Copyright Year | 2017 |
| Description | To achieve a reliable radiocarbon $(^{14}$C) date for an object, any contamination that may be of a different age must be removed prior to dating. Samples that have been conserved with treatments such as adhesives, varnishes or consolidants can pose a particular challenge to$ ^{14}$C dating. At the Oxford Radiocarbon Accelerator Unit (ORAU), common examples of such substances encountered include shellac, the acrylic polymers Paraloid B-67 and B-72, and vinyl acetate-derived polymers (e.g. PVA). Here, a non-carbon-containing absorbent substrate called $Chromosorb^{®}$ was deliberately contaminated with a range of varieties or brands of these conservation treatments, as well as two cellulose nitrate lacquers. A selection of chemical pretreatments was tested for their efficiency at removing them. While the varieties of shellac and Paraloid tested were completely removed with some treatments (water/methanol and acetone/methanol/chloroform sequential washes, respectively), no method was found that was capable of completely removing any of the vinyl acetate-derived materials or the cellulose nitrate lacquers. While Chromosorb is not an exact analog of archaeological wood or bone, for example, this study suggests that it may be possible to remove aged shellac and Paraloid from archaeological specimens with standard organic solvent-acid-base-acid pretreatments, but it may be significantly more difficult to remove vinyl acetate-derived polymers and cellulose nitrate lacquers sufficiently to provide reliable$ ^{14}$C dates. The four categories of conservation treatment studied demonstrate characteristic FTIR spectra, while highlighting subtle chemical and molecular differences between different varieties of shellac, Paraloid and cellulose nitrate lacquers, and significant differences between the vinyl acetate derivatives. |
| Related Links | http://eprints.gla.ac.uk/142551/13/142551.pdf https://www.cambridge.org/core/services/aop-cambridge-core/content/view/453BB5A216E728ED359BAC67CBE00397/S0033822217000686a.pdf/div-class-title-testing-the-effectiveness-of-protocols-for-removal-of-common-conservation-treatments-for-radiocarbon-dating-div.pdf |
| Ending Page | 50 |
| Page Count | 16 |
| Starting Page | 35 |
| ISSN | 00338222 |
| e-ISSN | 19455755 |
| DOI | 10.1017/rdc.2017.68 |
| Journal | Radiocarbon |
| Issue Number | 1 |
| Volume Number | 60 |
| Language | English |
| Publisher | Cambridge University Press (CUP) |
| Publisher Date | 2018-02-01 |
| Access Restriction | Open |
| Subject Keyword | Radiocarbon Chemical Analysis Radiocarbon Ams Dating |
| Content Type | Text |
| Resource Type | Article |
| Subject | Earth and Planetary Sciences Archeology (arts and humanities) |
