Abstract：
Cacao seeds, Theobroma cacao, provide the basis for a ceremonially important Mesoamerican food. Past efforts to identify cacao in ceramics focused on highly decorative vessel forms associated with elite ceremonial contexts, creating assumptions as to how cacao was distributed and who could access it. This study examines 54 archaeological ceramic sherds from El Pilar (Belize/Guatemala) of Late Classic (600 to 900 CE) residential and civic contexts representing a cross-section of ancient Maya inhabitants. Identification of cacao in ancient sherds has depended on the general presence of theobromine; we used the discrete presence of theophylline, a unique key biomarker for cacao in the region. Analysis was done by grinding off all outside surfaces to reduce contamination, pulverizing the inner clay matrix, extracting absorbed molecules, and concentrating the extractions. In order to obtain especially high selectivity and low limits of detection, our study utilized the technique of resonance-enhanced multiphoton ionization coupled with laser-desorption jet-cooling mass spectrometry. This technique isolates molecules in the cold gas phase where they can be selectively ionized through a resonant two-photon process. Of the sherds analyzed, 30 samples (56%) were found to contain significant amounts of theophylline and thus test positive for cacao. Importantly, cacao is present in all contexts, common to all Maya residents near and far from centers.
摘要：
可可种子,可可病，为重要的中美洲食品提供基础。过去在陶瓷中识别可可的努力集中在与精英礼仪环境相关的高度装饰性容器形式上，对可可是如何分发的，以及谁可以访问它进行假设。这项研究考察了来自ElPilar（伯利兹/危地马拉）的54个考古陶瓷石板，这些石板来自晚期经典（600至900CE）的住宅和公民环境，代表了古代玛雅居民的横截面。在古代草木中对可可的鉴定取决于可可碱的普遍存在；我们使用了茶碱的离散存在，该地区可可的独特关键生物标志物。通过打磨所有外表面以减少污染来进行分析，粉碎内部粘土基质，提取吸收的分子，浓缩提取物。为了获得特别高的选择性和低的检测限,我们的研究利用了共振增强多光子电离技术与激光解吸射流冷却质谱联用。该技术分离冷气相中的分子,其中它们可以通过共振双光子过程被选择性地电离。在被分析的谢尔德中，发现30个样品（56％）含有大量的茶碱，因此对可可呈阳性。重要的是,可可在所有情况下都存在，常见的所有玛雅居民附近和远离中心。
