RATIONALE Rapid, reliable isolation of pyrogenic carbon (PyC; also known as char, soot, black carbon, or biochar) for the determination of stable carbon isotope (δ13 C) composition and radiocarbon (14 C) dating is needed across multiple fields of research in geoscience, environmental science and archaeology. Many current techniques do not provide reliable isolation from contaminating organics and/or are relatively time-consuming. Hydrogen pyrolysis (HyPy) does provide reliable isolation of PyC, but the current methodology is time consuming. METHODS We explored the potential for subjecting multiple samples to HyPy analysis by placing up to nine individual samples in custom-designed borosilicate sample vessels in a single reactor run. We tested for cross-contamination between samples in the same run using materials with highly divergent radiocarbon activities (~0.04-116.3 pMC), δ13 C values (-11.9 to -26.5‰) and labile carbon content. We determined 14 C/13 C using accelerator mass spectrometry and δ13 C values using an elemental analyser coupled to a continuous flow isotope ratio mass spectrometer. RESULTS Very small but measurable transfer between samples of highly divergent isotope composition was detectable. For samples having a similar composition, this cross-contamination is considered negligible with respect to measurement uncertainty. For samples having divergent composition, we found that placing a sample vessel loaded with silica mesh adsorbent between samples eliminated measurable cross-contamination in all cases for both 14 C/13 C and δ13 C values. CONCLUSIONS It is possible to subject up to seven samples to HyPy in the same reactor run for the determination of radiocarbon content and δ13 C value without diminishing the precision or accuracy of the results. This approach enables an increase in sample throughput of 300-600%. HyPy process background values are consistently lower than the nominal laboratory process background for quartz tube combustion in the NERC Radiocarbon Laboratory, indicating that HyPy may also be advantageous as a relatively 'clean' radiocarbon pre-treatment method.

中文翻译：

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一种通过氢气热解分离热解碳的快速通量技术，用于稳定同位素和放射性碳分析。

理由要在多个研究领域中快速，可靠地分离热解碳（PyC；也称为炭，烟灰，黑碳或生物炭），以确定稳定的碳同位素（δ13C）组成和放射性碳（14 ​​C）定年地球科学，环境科学和考古学。许多当前的技术不能提供对污染有机物的可靠隔离和/或相对耗时。氢热解（HyPy）确实提供了PyC的可靠分离，但当前的方法耗时。方法我们探索了通过在单个反应器运行中将多达9个单独的样品放置在定制设计的硼硅酸盐样品容器中来对多个样品进行HyPy分析的潜力。我们使用放射性碳活度（〜0.04-116.3 pMC），δ13C值（-11.9至-26.5‰）和不稳定的碳含量高度发散的材料，对同一样品中的交叉污染进行了测试。我们使用加速器质谱法确定了14 C / 13 C，使用与连续流同位素比质谱仪耦合的元素分析仪确定了δ13C值。结果可以检测到极小但可测量的高发散同位素组成样品之间的转移。对于具有相似组成的样品，就测量不确定度而言，这种交叉污染可以忽略不计。对于具有不同成分的样品，我们发现，在所有情况下，对于14 C / 13 C和δ13C值，在样品之间放置装有硅胶网状吸附剂的样品容器都可以消除可测量的交叉污染。结论在相同的反应器运行中，最多可以对七个样品进行HyPy测定，以测定放射性碳含量和δ13C值，而不会降低结果的准确性或准确性。这种方法可使样品通量提高300-600％。HyPy的过程背景值始终低于NERC放射性碳实验室中石英管燃烧的标称实验室过程背景，这表明HyPy作为相对“清洁”的放射性碳预处理方法也可能是有利的。