Tyler B. Coplen
James A. Jordan
Haiping Qi
2016
<p id="sp0070">Comparative measurements of stable hydrogen and oxygen isotopes in wood are hampered by the lack of proper reference materials (RMs). The U.S. Geological Survey (USGS) has prepared three powdered, whole-wood RMs, USGS54 (<i>Pinus contorta</i>, Canadian lodgepole pine), USGS55 (<i>Cordia</i> cf. <i>dodecandra</i>, Mexican ziricote), and USGS56 (<i>Berchemia</i> cf. <i>zeyheri</i>, South African red ivorywood). The stable isotopes of hydrogen, oxygen, carbon, and nitrogen in these RMs span ranges as <i>δ</i><sup>2</sup>H<sub>VSMOW</sub> from –150.4 to –28.2 mUr or ‰, as <i>δ</i><sup>18</sup>O<sub>VSMOW</sub> from + 17.79 to + 27.23 mUr, as <i>δ</i><sup>13</sup>C<sub>VPDB</sub> from –27.13 to –24.34 mUr, and as <i>δ</i><sup>15</sup>N <sub>AIR-N2</sub> from –2.42 to + 1.8 mUr. These RMs will enable users to normalize measurements of wood samples to isotope–delta scales, and they are intended primarily for the normalization of <i>δ</i><sup>2</sup>H and <i>δ</i><sup>18</sup>O measurements of unknown wood samples. However, they also are suitable for normalization of stable isotope measurements of carbon and nitrogen in wood samples. In addition, these RMs are suitable for inter-laboratory calibration for the dual-water suilibration procedure for the measurements of <i>δ</i><sup>2</sup>H<sub>VSMOW</sub> values of non-exchangeable hydrogen. The isotopic compositions with 1-σ uncertainties, mass fractions of each element, and fractions of exchangeable hydrogen of these materials are:</p><p id="sp0075">USGS54 (<i>Pinus contorta</i>, Canadian Lodgepole pine)</p><p id="sp0080"><i>δ</i><sup>2</sup>H<sub>VSMOW</sub> = –150.4 ± 1.1 mUr (n = 29), hydrogen mass fraction = 6.00 ± 0.04 % (n = 10)</p><p id="sp0085">Fraction of exchangeable hydrogen = 5.4 ± 0.6 % (n = 29)</p><p id="sp0090"><i>δ</i><sup>18</sup>O<sub>VSMOW</sub> = + 17.79 ± 0.15 mUr (n = 18), oxygen mass fraction = 40.4 ± 0.2 % (n = 6)</p><p id="sp0095"><i>δ</i><sup>13</sup>C<sub>VPDB</sub> = –24.43 ± 0.02 mUr (n = 18), carbon mass fraction = 48.3 ± 0.4 % (n = 12)</p><p id="sp0100"><i>δ</i><sup>15</sup>N<sub>AIR-</sub><sub>N2</sub> = –2.42 ± 0.32 mUr (n = 17), nitrogen mass fraction = 0.05 % (n = 4)</p><p id="sp0105">USGS55 (<i>Cordia</i> cf. <i>dodecandra</i>, Mexican ziricote)</p><p id="sp0110"><i>δ</i><sup>2</sup>H<sub>VSMOW</sub> = –28.2 ± 1.7 mUr (n = 30), hydrogen mass fraction = 5.65 ± 0.06 % (n = 10)</p><p id="sp0115">Fraction of exchangeable hydrogen = 4.1 ± 0.5 % (n = 30)</p><p id="sp0120"><i>δ</i><sup>18</sup>O<sub>VSMOW</sub> = + 19.12 ± 0.07 mUr (n = 18), oxygen mass fraction = 35.3 ± 0.2 % (n = 6)</p><p id="sp0125"><i>δ</i><sup>13</sup>C<sub>VPDB</sub> = –27.13 ± 0.02 mUr (n = 18), carbon mass fraction = 53.3 ± 0.6 % (n = 12)</p><p id="sp0130"><i>δ</i><sup>15</sup>N<sub>AIR-N2</sub> = –0.3 ± 0.4 mUr (n = 16), nitrogen mass fraction = 0.25 % (n = 4)</p><p id="sp0135">USGS56 (<i>Berchemia</i> cf. <i>zeyheri</i>, South African red ivorywood)</p><p id="sp0140"><i>δ</i><sup>2</sup>H<sub>VSMOW</sub> = –44.0 ± 1.8 mUr (n = 30), hydrogen mass fraction = 5.65 ± 0.05 % (n = 10)</p><p id="sp0145">Fraction of exchangeable hydrogen = 6.6 ± 0.3 % (n = 30)</p><p id="sp0150"><i>δ</i><sup>18</sup>O<sub>VSMOW</sub> = + 27.23 ± 0.03 mUr (n = 12), oxygen mass fraction = 41.1 ± 0.2 % (n = 6)</p><p id="sp0155"><i>δ</i><sup>13</sup>C<sub>VPDB</sub> = –24.34 ± 0.01 mUr (n = 12), carbon mass fraction = 47.3 ± 0.2 % (n = 12)</p><p id="sp0160"><i>δ</i><sup>15</sup>N<sub>AIR-N2</sub> = + 1.8 ± 0.4 mUr (n = 15), nitrogen mass fraction = 0.27 % (n = 4)</p>
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10.1016/j.chemgeo.2016.07.017
en
Elsevier
Three whole-wood isotopic reference materials, USGS54, USGS55, and USGS56, for δ2H, δ13C, δ15N, and δ18O measurements
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