We present data on the concentration, the isotope composition and the
homogeneity of boron in NIST silicate glass reference materials SRM 610
and SRM 612, and in powders and glasses of geological reference
materials JB-2 (basalt) and JR-2 (rhyolite). Our data are intended to
serve as references for both microanalytical and wet-chemical
techniques. The delta(11)B compositions determined by N-TIMS and P-TIMS
agree within 0.5%(0) and compare with SIMS data within 2.5%(0). SIMS
profiles demonstrate boron isotope homogeneity to better than delta(11)B
= 2%(0) for both NIST glasses, however a slight boron depletion was
detected towards the outermost 200 mum of the rim of each sample wafer.
The boron isotope compositions of SRM 610 and SRM 612 were
indistinguishable. Glasses produced in this study by fusing JB-2 and
JR-2 powder also showed good boron isotope homogeneity both within and
between different glass fragments. Their major element abundance as well
as boron isotope compositions and concentrations were identical to those
of the starting composition. Hence, reference materials (glasses) for
the in situ measurement of boron isotopes can be produced from already
well-studied volcanic samples without significant isotope fractionation.
Oxygen isotope ratios, both within and between wafers, of NIST reference
glasses SRM 610 and SRM 612 are uniform. In contrast to boron,
significant differences in oxygen isotope compositions were found
between the two glasses, which may be due to the different amounts of
trace element oxides added at ten-fold different concentration levels to
the silicate matrix.