Yip Christopher, Weyman Philip D, Wemmer Kimberly A, Yang Yun-Ya, Chowdhury Anupam, Traag Bjorn A, Timmermann Tania, Fuenzalida-Meriz Gonzalo
Andes Ag, Inc., Alameda, California, United States America.
PLoS One. 2025 May 5;20(5):e0320778. doi: 10.1371/journal.pone.0320778. eCollection 2025.
Carbon dioxide is the primary greenhouse gas emitted through human activities, and these emissions impact the carbon cycle for hundreds to thousands of years. As carbon dioxide removal strategies to address this challenge continue to be explored and scaled, faster methodologies with high accuracy and precision are required to support the carbon measurements on which these strategies hinge. Of the many available methods to measure soil inorganic carbon, only a select few satisfy all the following criteria: measure inorganic carbon directly, use standardized equipment, perform the measurement automatically, and operate at high throughput. In this work we present a robust protocol for the sensitive and specific quantification of inorganic carbon from soils using gas chromatography to quantify carbon dioxide evolved from carbonates in soil with sulfamic acid. We demonstrate the precision of this method with purified carbonates, carbonate minerals, biogenic carbonates, and agricultural soil samples. We also demonstrate the accuracy of this method by adding known amounts of calcium carbonate to a variety of soil matrices. We find that sulfamic acid is well suited for carbonate dissolution and is compatible with gas chromatography applications, and we note that the method generates results that are equivalent to the typical methods used in this field. This method is compatible with automation and operation at a greater scale and enables the creation of higher resolution soil inorganic carbon datasets.
二氧化碳是人类活动排放的主要温室气体，这些排放会在数百年至数千年的时间里影响碳循环。随着为应对这一挑战而探索和扩大规模的二氧化碳去除策略不断推进，需要更快且具有高精度和高准确度的方法来支持这些策略所依赖的碳测量。在众多可用于测量土壤无机碳的方法中，只有少数几种满足以下所有标准：直接测量无机碳、使用标准化设备、自动进行测量以及实现高通量操作。在这项工作中，我们提出了一种稳健的方案，用于使用气相色谱法灵敏且特异地定量土壤中的无机碳，该方法通过用氨基磺酸定量土壤中碳酸盐释放出的二氧化碳来实现。我们用纯化的碳酸盐、碳酸盐矿物、生物源碳酸盐和农业土壤样品证明了该方法的精密度。我们还通过向多种土壤基质中添加已知量的碳酸钙来证明该方法的准确度。我们发现氨基磺酸非常适合碳酸盐溶解，并且与气相色谱应用兼容，我们注意到该方法产生的结果与该领域常用的典型方法相当。此方法与自动化和更大规模的操作兼容，能够创建更高分辨率的土壤无机碳数据集。
