The Vigani Cabinet - Analysis of historical resinous materials by gas chromatography - mass spectrometry and infrared spectroscopy

Abstract

Natural resins have been in use for a long time and for manifold purposes resulting in a long and complex terminological history. The investigation of this history has so far been based on the connection between nomenclature and chemical composition. Because resin chemistry and the botanical classification of source plants are connected as well, the investigation of natural resins can be enhanced by adding taxonomy as an additional dimension, providing a more complex and complete picture of resin chemistry and resin use. The Vigani Cabinet, a collection of 300-year-old pharmaceutical and chemical materials owned by Queens’ College, Cambridge (UK), allows doing just that. A wide range of historical literature provides information about contemporary terminology, botanical and geographical origin, manufacture, trade and properties of resinous materials from the 18th century. This contemporary context is a particular feature of the Cabinet, which allows adding a historical dimension to the correlations between terminology, chemical composition and taxonomy. The dissertation thesis presented here provides an investigation of 17 botanical, 80 reference materials and samples from 24 natural resins from the Vigani Cabinet, studying these complex correlations and changes over time. The analytical method employed in this study was gas chromatography-mass spectrometry (GC-MS) with and without methylation with trimethylsulfoniumhydroxide. This technique provided detailed molecular compositions of the studied materials. Analysed botanical samples are taken from Pinaceae, Cupressaceae and Pistacia resins, commerical references from Araucariaceae, Copaifera, Fabaceae, Myroxylon and Burseraceae. Additionally, the soluble fraction of Baltic amber was analysed. Materials from the Vigani Cabinet analysed in this work were labelled as "turpentines", "pix burgundica", "sandaracha", "copaiba", "balsamum peruvianum and tolutanum", "mastiche", "anime", "copal", "elemi", "tacamahaca" and "succinum". Historical nomenclature of natural resins has not always been unequivocally associated with a botanical origin. The availability of natural resins changed throughout the centuries. Lack of knowledge, in particular about resins from over-seas, or adulterations resulting from changing harvesting methods, led to changes in trade names or variations in the composition of products traded under the same name. Generic names were used for resins with similar properties but different botanical (and geographical) origin. The thesis shows that a chemotaxonomic reference system is suitable for the identification of unknown resinous materials, and a number of new insights into the nomenclature of natural resins from the 17th and 18th century is obtained. The study of historical literature contributed in a significant way to the historico-cultural and archeometric research of the samples from the Vigani Cabinet and of natural resins in general and provided a basis for the interpretation of the chemical data from the Vigani samples.:CONTENTS 1 INTRODUCTION 1 1.1 Natural resins in a historical and modern context 1 1.2 The Vigani Cabinet and its historical background 3 1.3 Aim of the thesis - outline 6 2 LITERATURE REVIEW 8 2.1 Gymnosperm resins – conifer resins and products 9 2.1.1 Pinaceae 9 2.1.2 Cupressaceae 17 2.1.3 Araucariaceae 20 2.2 Angiosperm resins I – Fabales 21 2.3 Angiosperm resins II – Sapindales 30 2.3.1 Anacardiaceae 30 2.3.2 Burseraceae 35 2.3.3 Rutaceae 43 2.4 Fossil resins 45 2.5 Summary and research deficits 49 3 EXPERIMENTAL 53 3.1 Coupled gas chromatography and mass spectrometry 53 3.1.1 Materials 53 3.1.2 Sample preparation 54 3.1.3 Instrumentation 54 3.1.4 Data-Evaluation 58 3.2 Fourier transformation infrared spectroscopy 60 3.2.1 Sample preparation 61 3.2.2 Instrumentation 61 3.2.3 Data evaluation 61 4 RESULTS – REFERENCE MATERIALS 62 4.1 Gymnosperm resins – conifer resins and products 62 4.1.1 Pinaceae – Coniferous turpentines 62 4.1.1.1 Phytochemical markers – detection of adulterations 62 4.1.1.2 Aging by heat and light 73 4.1.2 Cupressaceae – Sandarac 80 4.1.3 Araucariaceae – Coniferous copals 88 4.1.4 Discussion 91 4.2 Angiosperm Resins I - Fabales 94 4.2.1 Copaifera – Copaiba balsam 94 4.2.2 Legume copals 102 4.2.3 Myroxylon – Balsam of Tolu and Peru 108 4.2.4 Discussion 117 4.3 Angiosperm resins II - Sapindales 120 4.3.1 Anacardiaceae – Pistacia resins 120 4.3.2 Burseraceae – Elemi, copal and others 127 4.3.3 Discussion 142 4.4 Fossil resins 144 4.4.1 Baltic amber 144 4.4.2 Discussion 153 4.5 Summary and research deficits 155 5 RESULTS – RESINOUS MATERIALS FROM THE VIGANI CABINET 160 5.1 Gymnosperm resins – conifer resins and products 162 5.1.1 1/8 Terebin. Strasb. 163 5.1.2 1/9 Tereb Com 170 5.1.3 1/10 Venice Turpentine 176 5.1.4 1/11 Venic. Turpent. 183 5.1.5 1/13 Tereb E Chio 188 5.1.6 A/23 Pix Burgundica 194 5.1.7 A/26 Sandaracha 203 5.2 Angiosperm resins I - Fabales 210 5.2.1 1/4 Balsam Cipivi 211 5.2.2 A/5 Gum Animi 218 5.2.3 La2/7 Unknown resin 228 5.2.4 1/31 Bals Peruv 230 5.2.5 2/1 Bals Peru 237 5.2.6 Z/17 Balsam Tolutanum 240 5. 3 Angiosperm resins II – Sapindales 245 5.3.1 A/11 Mastiche 246 5.3.2 1/14 Tereb i E Cypri 252 5.3.3 A/21 Gum Copal 258 5.3.4 A/24 [.] Elemi 268 5.3.5 A/22 Tacamahaca 276 5.3.6 Z/1 Tacamahaca 283 5.4 Fossil Resins 287 5.4.1 E/13 Succinum Citrinum 288 5.4.2 E/14 Succinum flavan 295 5.4.3 E/15 Succinum albam 302 5.4.4 E/16 Succinum nigram 307 5.4.5 F/13 L. Gagatis 313 6 CONCLUSIONS 316 7 REFERENCES 324 APPENDIX 365 Investigated materials from the Vigani Cabinet 366 Annotated list of historical literature 367 List of figures 374 List of tables 379 Compound lists 381 Atlas of mass spectra 422