Inter-comparison of ICP and XRF-scanning results by four different XRF-labs (dried pellets from IODP core MD01-2407)

Four discrete samples were freeze-dried and powdered and pressed into disc-shaped pellets about 2 cm in diameter from nearby Core MD01-2407 on the Oki Ridge (37°04'N, 134°42'E, 932m water depth). The four samples have a similar matrix to the seven sediment sections scanned in this study. The four samples from Core MD01-2407 covered a range of sediment types (calcareous, siliceous, light-, and dark-colored; Kido et al., 2007) that span the dynamic range of at least Fe and Ca element cps scanned for this study. A set of four pellets was sent to four of the seven labs (1 ITRAX and 3 Avaatech) involved in the study to be scanned using the same instrument parameters they used on the sediment sections. Three labs used the same instrument and parameters used for the sediment section, but the fourth lab replaced the X-ray tube in between scanning the pellets and sediment sections. The major and trace element concentrations of the pellets were also analyzed by inductively coupled plasma (ICP)-optical emission spectrometry (OES) and ICP-mass spectrometry (MS) in the Analytical Geochemistry Facilities at Boston University, Boston, MA, USA. The ICP analyses had ~2% precision and a standard reference material analyzed as an unknown alongside the samples was accurate within precision.