In museum collections bivalve shells are typically dry stored, whereas gentle tissues are preserved in 70% ethanol, at times following fixation with ten% formalin. Nevertheless, typically the total animal is preserved in ethanol and shells are not stored individually. For the application of these preserved specimens in the investigation of previous d N values it is crucial to know if liquid preservation strategies have an effect on the d N values of bivalve shells and if this result is predictable. The results of liquid preservation on the d N values of biological tissues have been examined in a assortment of For testing the in uence of CaCO 3 content on d N measurements, different mixtures of acetanilide with inorganic pure CaCO 3 had been manufactured, containing in between and ten.

4 excess weight % N. Powder calcite samples have been loaded into 4 _ 6 mm tin cups and Purely natural products weighed. d N values have been measured utilizing an elemental analyzer coupled by way of a CONFLO III to a ThermoFinnigan Delta V t isotope ratio mass spectrometer. An inline soda lime CO trap was used to scrub CO 2 from the gasoline stream getting into the gasoline chromatography column of the custom peptide price . IAEA N1 was used as a standard, with an accepted value of . 4 _ . 2% Long term. standard reproducibility is greater than . 1% for samples nature, even samples between 5 and mg N offered realistic information. There is also an upper limit to the amount of shell material that can be loaded into the EA, but this was not evaluated here.

This approach is robust due to the fact calcium carbonate com pletely decomposes close to 8258C and the ash combustion in the EA was about 10208C, therefore, all N should be released from the matrix and carried to the IRMS. In addition, previous studies have utilized an EA IRMS program to combust Fig. 2 that the narrow and near symmetrical peak shapes are comparable for both shell carbonate and synthetic mixtures, which suggests that the two matrices are reacting similarly in the EA IRMS. We consequently argue that it is achievable to measure carbonates for d C examination. It is clear from the traces in more substantial than 30 mg N. d N values are expressed in % vs. atmospheric nitrogen. Pure synthetic CaCO 3 had peaks similar to empty tin cups, empty tin cup 1/4 . 49 Vs) and for that reason did not contribute much to the calculated delta values. The acetanilide normal had a d N value of 2.

12 _ . 13% when it was run without synthetic CaCO 3 and was _2. 02 _ . 11% when it was run with 98. 4 to 66. 8% CaCO 3. These values are not substantially various. In addition, for the duration of a preliminary trial, we ran . 4 mg of the IAEA N1 AG 879 ammonium sulfate SO 4) normal in. 72 mg CaCO 3 and identified no offset from N1 standards run with out Torin 2 .