DETERMINATION OF THE U-37(K) INDEX IN GEOLOGICAL SAMPLES

The U-37(K) index is a tool for sea surface paleotemperature (SST) rec onstruction and is defined by the relative abundance of three long-cha in alkenones (C-37) commonly found in Quaternary marine sediments. A s imple, fast, and reliable analytical technique is required for the ana lysis of these compounds in deep-sea sediment cores in order to provid e time series of SST and hence contribute to the understanding of past climates. The method described here employs a robotic workstation for sample preparation and gas chromatography (GC) coupled to mass spectr ometry with ammonia chemical ionization (CI-MS) to quantify the target ed analytes. This semiautomated procedure provides enhanced sensitivit y, selectivity, and speed of analysis when compared to conventional, m anual sample preparation and GC name ionization detector analysis.