<?xml version='1.0' encoding='utf-8'?>
<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:contributor>Tyler B. Coplen</dc:contributor>
  <dc:contributor>Gerard Olack</dc:contributor>
  <dc:contributor>Torsten W. Vennemann</dc:contributor>
  <dc:creator>Haiping Qi</dc:creator>
  <dc:date>2014</dc:date>
  <dc:description>&lt;p&gt;RATIONALE&lt;/p&gt;&lt;p&gt;The supply of NBS 30 biotite is nearly exhausted. During measurements of NBS 30 and potential replacements, reproducible &lt;i&gt;δ&lt;/i&gt;&lt;sup&gt;2&lt;/sup&gt;H&lt;sub&gt;VSMOW-SLAP&lt;/sub&gt; values could not be obtained by three laboratories using high-temperature conversion (HTC) systems. The cause of this issue has been investigated using the silver-tube technique for hydrogen-isotope measurements of water.&lt;/p&gt;&lt;p&gt;METHODS&lt;/p&gt;&lt;p&gt;The &lt;i&gt;δ&lt;/i&gt;&lt;sup&gt;2&lt;/sup&gt;H&lt;sub&gt;VSMOW-SLAP&lt;/sub&gt; values of NBS 30 biotite, other biotites, muscovites, and kaolinite with different particle sizes, along with IAEA-CH-7 polyethylene, and reference waters and NBS 22 oil that were sealed in silver-tube segments, were measured. The effect of absorbed water on mineral surfaces was investigated with waters both enriched and depleted in &lt;sup&gt;2&lt;/sup&gt;H. The quantitative conversion of hydrogen from biotite into gaseous hydrogen as a function of mass and particle size was also investigated.&lt;/p&gt;&lt;p&gt;RESULTS&lt;/p&gt;&lt;p&gt;The &lt;i&gt;δ&lt;/i&gt;&lt;sup&gt;2&lt;/sup&gt;H&lt;sub&gt;VSMOW-SLAP&lt;/sub&gt; values of NBS 30 obtained by three laboratories were as much as 21 ‰ too high compared with the accepted value of −65.7 ‰, determined by conventional off-line measurements. The experiments showed a strong correlation between grain size and the &lt;i&gt;δ&lt;/i&gt;&lt;sup&gt;2&lt;/sup&gt;H&lt;sub&gt;VSMOW-SLAP&lt;/sub&gt; value of NBS 30 biotite, but not of biotites with lower iron content. The &lt;i&gt;δ&lt;/i&gt;&lt;sup&gt;2&lt;/sup&gt;H&lt;sub&gt;VSMOW-SLAP&lt;/sub&gt; values of NBS 30 as a function of particle size show a clear trend toward −65.7 ‰ with finer grain size.&lt;/p&gt;&lt;p&gt;CONCLUSIONS&lt;/p&gt;&lt;p&gt;Determination of the &lt;i&gt;δ&lt;/i&gt;&lt;sup&gt;2&lt;/sup&gt;H&lt;sub&gt;VSMOW-SLAP&lt;/sub&gt; values of hydrous minerals and of NBS 30 biotite by on-line HTC systems coupled to isotope-ratio mass spectrometers may be unreliable because hydrogen in this biotite may not be converted quantitatively into molecular hydrogen. Extreme caution in the use and interpretation of &lt;i&gt;δ&lt;/i&gt;&lt;sup&gt;2&lt;/sup&gt;H&lt;sub&gt;VSMOW-SLAP&lt;/sub&gt; on-line measurements of hydrous minerals is recommended.&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1002/rcm.6983</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>Wiley</dc:publisher>
  <dc:title>Caution on the use of NBS 30 biotite for hydrogen-isotope measurements with on-line high-temperature conversion systems</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>