41026
Accession Number
38780
Title Of Article Chaper
Chemical removal of conservation substances by ‘Soxhlet’- type extraction
Title Of Journal Book
Radiocarbon
Volume
43
Issue
2A
Pages
229-237
ISSN
0033-8222
Language Of Text
English
Literature Type
Serial
Literature Level
Analytic
Abstract
“At the Leibniz radiocarbon lab, art and archaeological objects, often chemically conserved and thus potentially contaminated with respect to their <sup>14</sup>C content, are treated using a computer-controlled “Soxhletâ€-type series extractor. This device uses a continuous procedure of boiling and condensation of different solvents for extraction and vacuum filtration under constant process conditions. An elutrope sequence of five solvents that dissolve most customary conservation chemicals was selected. A study of these different contaminants applied to reference wood samples with subsequent accelerator mass spectrometry (AMS) measurements demonstrates that their effective removal is dependent on the use of adequate solvents. For many contaminants (e.g. wood glue, methyl cellulose, Klucel®, sugar, and polyethylene glyclol), routine acid-alkali-acid (AAA) treatment already yields satisfactory results, whereas for Caparol® and beeswax a relatively “mild†treatment with acetone, methanol, water, and subsequent standard AAA extraction is sufficient. Complete removal of rubber glue, epoxy resin, and paraffin can only be accomplished with our full set of solvents. The latter procedure is also appropriate when no or only incomplete information about the type of conservation material is available. For epoxy resin the contamination appears to be enriched in the alkali residue, and the easily soluble “humic acid†fraction, even after standard AAA treatment, gives satisfactory results. Two case studies on the application of the extraction procedures are presented.†(from the article)
pub_id
41026