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Our newest instrument, installed in April 2001, the Isoprime has a dual-inlet configuration and is coupled to a Eurovector elemental analyzer. The Isoprime is currently dedicated to analysis of H/D ratios in water via a chrome reduction method. Fully automated throughput is typically 60 samples a day, requiring 500 microliters of water, at a routine precision of 0.5%.
Our dual-inlet SIRA has recently been upgraded with Micromass PRISM-Up software and a Multi-Prep peripheral. The primary analytical role of the SIRA is 16O/18O ratios in water, which can be measured on 1 ml of water at 0.05% precision (fully-automated throughput ~60 samples/day). The SIRA also has a hydrogen spur, and thus has the capability of measuring H/D ratios in water if needed. The Multi-Prep peripheral can also be used to measure 160/180 and 12C/13C ratios in carbonates, by injecting phosphoric acid onto each sample individually (precisions for carbonate .18
O and .13
C are 0.05% and 0.1 %, respectively).
The dual-inlet PRISM is our primary machine for automated carbonate analysis, via a 30-place carousel and common acid bath. The PRISM has an extended-geometry flight tube, and has a long-term precision of 0.03% for .18
O and 0.05% for .13
C in carbonates. Both marine carbonates (foraminifers, bivalves, bulk carbonates, corals) and freshwater carbonates (marl, bivalves, ostracodes) are routinely analyzed. The excellent sensitivity and linearity of the PRISM allows small sample sizes (~20 mg carbonate), such that individual foraminifera tests can be analyzed.
Our Carlo-Erba elemental analyzer (EA; Model 1500) allows analysis of bulk organic material for .13C and .15N ratios. Traditionally, we have coupled the Carlo-Erba to the SIRA for such analyses, and obtained precisions of 0.10%. We now have the option of coupling the Carlo-Erba to either the SIRA or PRISM for carbon and nitrogen analyses, and are working on methods for .34
S analysis as well.
Sample and Field Preparation
Our wet lab includes a Millipore Elix 10/Gradient ultra-pure water system for preparation of bottles/vials for fieldwork and analysis, reagents, and sample cleaning. We also have equipment for micropaleontology work (Wild microscopes, Mettler microbalance), micro-milling of bivalve shells, drying ovens, and mills for homogenization of organic material.