How well do non-traditional stable isotope results compare between different laboratories: results from the interlaboratory comparison of boron isotope measurements

In order to address the correct reporting and therefore comparison of isotopic measurements across different instrument types and instrumental techniques a prepared set of synthetic standards was sent to 28 laboratories for boron (B) isotopic analyses. Standards were prepared from enriched and purified isotopic salts to avoid any sample preparation fractionation. The range in uncertainties of the analyses between different instrumental analytical techniques is as large as the differences within an instrumental analytical technique obscuring any systematic offset. We conclude that uncertainties in the measurement of delta B-11 values were often underestimated and a procedure is suggested to allow a better comparison of the different techniques. Two new standards (JABA and JABB) have been quantified and these are available to all laboratories for testing their analyses. The delta B-11 values of these new standards are 10.0 parts per thousand and -23.7 parts per thousand. The results from this exercise impact on the way all isotope measurements are performed and reported. Guidelines are defined to aid the comparison of measurements between different laboratories.