SIREAL is capable of analysis of carbon and oxygen from the carbonate component of bioapatites. These analyses are done with a ThermoElectron Gasbench II coupled to a ThermoElectron Deltaplus XP IRMS in continuous-flow mode. From this, we are able to measure δ13C and δ18O simultaneously.

GasBench
The Gasbench itself is the box with the gauges in the back. The big black box on stilts is the heating block in which we place samples of bioapatite and carbonate for analysis.

Our methods

Two milligrams of powdered and pretreated bioapatite is placed into a 4mL vial, capped with a pierceable septum.

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Vials for bioapatite analysis

Vials are flushed with helium to remove any room air. Then 103% phosphoric acid is injected through the septum. The resultant reaction releases carbon dioxide into the vial. A sample needle draws this carbon dioxide out and into the ion source of the mass spectrometer.

A single analysis is the result of ten pulses of gas from the vial into the ion source. The delta values for these ten peaks are then averaged to provide the reported value and the standard deviation of the values of the ten peaks provides analytical error.

Rates

Rates are $20 per sample. There is no additional charge for replicates or standards. We only charge for successful analyses.

Packaging your samples

Samples for bioapatite analysis may be send in any form, though there will be an extra $5 per sample charge if we receive solid bones and teeth and have to powder them ourselves. Pretreated or unpretreated powdered samples are best sent in carefully labeled 1.5-1.7 mL microcentrifuge vials. Make sure the tops and sides of the vials are labeled.

Our analyses require two milligrams of pure bioapatite. We understand that this may be near the limit of what may be collected, especially for serial analysis of single teeth. We’ll do our best. Sending us 5-10 mg of powder is ideal.

Questions

If you have questions or concerns, please contact Penny Higgins at pennilyn [dot] higgins [at] rochester [dot] edu.