Journal of Archaeological Science: Reports | 2019
FT-IR and GC–MS analyses of Dressel IA amphorae from the Grand Congloué 2 wreck
Abstract
Abstract This research work is focused on the chemical characterization of the substance present in the internal surfaces of Roman amphorae that made them waterproof and on the identification of their content. The samples come from the wreck of the Grand Congloue 2 that was studied in the Bay of Marseille by Commander Cousteau in 1952. The twenty studied amphorae are of type Dressel 1A and were provided by Cosa in Etruria (Tuscany, Italy). The FT-IR analysis indicated different bands concerning organic matter, as the chemical link O–H from carboxylic acid, C–H of the methylene group and C–O of the methyl ester. The study carried out by GC–MS showed nineteen diterpenoids, such as dehydroabietic acid and retene, which are chemical markers of Pinaceae family. Methyl ester by-products were also characterized and they revealed a pitch pyrogenically prepared from resinous wood (Pinus sp.). Principal Component Analysis allowed to group all of the twenty studied amphorae in two lots indicating two types of pitch. Concerning the content of these amphorae, the results from pitch as well as shards allowed to detect the presence of tartaric and syringic acids which are the main markers of the red wine. The comparison study between pitch and shard samples of same amphorae indicates that pitch analyses has permitted to obtain a high qualitative and quantitative proportion of wine markers.