Pyrogenic carbon (charcoal, black carbon, elemental carbon) is one of the most common materials used for radiocarbon dating of terrestrial samples. However, exogenous carbon contamination can compromise the accuracy of radiocarbon ages. This study presents the results of two chemical pretreatments prior to hydrogen pyrolysis (hypy) as improved protocols for the isolation and decontamination of pyrogenic carbon, i) a simple acid-oxidation step (A-Ox/hypy) and ii) acid-base-acid (ABA/hypy). The A-Ox/hypy protocol uses HNO₃ and H₂O₂, while ABA/hypy uses HCl and NaOH. Both pretreatments remove labile and inorganic carbon before hypy, decreasing the potential for in situ production of pyrogenic carbon during the hypy reaction. The effectiveness of each protocol was directly measured on charcoal artificially produced at 350 °C, 450 °C and 550 °C from radiocarbon-free wood, and exposed to environmental contamination for 1–3 yrs. The results show a >94% reduction in carbon contamination for the 450 °C and 550 °C charcoal samples occurred using A-Ox/hypy, but this treatment was less effective for the 350 °C charcoal. A >99% reduction in carbon contamination in all charcoal samples examined occurred using ABA/hypy. The A-Ox/hypy protocol was further tested on cave guano sediments, which had previously reported erroneous dates following simple organic solvent extraction followed by ABA pretreatment. Effective decontamination was achieved using A-Ox/hypy on the guano, which corrected a radiocarbon age reversal. Overall, ABA/hypy effectively decontaminated the charcoals and was a more efficient pretreatment for charcoal than A-Ox/hypy, however resulting in larger sample mass loss. Therefore, ABA/hypy is the recommended protocol for older (>30,000 ¹⁴C yr BP) charcoal or sediment samples, or where date accuracy is imperative, while A-Ox/hypy represents an improved protocol for the quick and cost-effective measurement of younger samples (<30,000 ¹⁴C yr BP) when sample size is of concern.

热解碳（木炭，黑碳，元素碳）是用于陆地样品放射性碳测年的最常见材料之一。但是，外源碳污染会损害放射性碳年龄的准确性。这项研究提出了氢热解（hypy）之前进行两种化学预处理的结果，作为分离和净化热原碳的改进方案，i）简单的酸氧化步骤（A-Ox / hypy）和ii）酸碱-酸（ABA / hypy）。A-Ox / hypy协议使用HNO ₃和H ₂ O ₂，而ABA / hypy协议使用HCl和NaOH。两种预处理都可以在热解之前除去不稳定的碳和无机碳，从而降低原位的可能性在hypy反应期间产生热解碳。每种协议的有效性都直接在无辐射碳木材中分别在350°C，450°C和550°C人工生产的木炭上测量，并暴露于环境污染中1-3年。结果表明，使用A-Ox / hypy可以在450°C和550°C的木炭样品中减少94％以上的碳污染，但这种处理对350°C的木炭效果不佳。使用ABA / hypy，所有检测到的木炭样品中的碳污染降低了> 99％。A-Ox / hypy实验方案在洞穴鸟粪沉积物上进行了进一步测试，该洞穴鸟粪沉积物以前曾报道过简单的有机溶剂萃取和ABA预处理后的错误日期。使用鸟粪上的A-Ox / hypy可实现有效的去污，从而纠正了放射性碳年龄的逆转。总体而言，ABA / hypy有效地净化了木炭，并且比A-Ox / hypy更有效地预处理了木炭，但导致样品质量损失更大。因此，对于年长者（> 30,000，建议使用ABA / hypy¹⁴ C yr BP）木炭或沉积物样品，或必须保证日期精度的情况，而当样本量为时，A-Ox / hypy代表了一种改进的方案，可快速，经济高效地测量较年轻的样品（<30,000 ¹⁴ C yr BP）值得关注。