海水中的颗粒有机碳(POC)是联系海洋生命与非生命过程最重要的参数之一, 其在全球碳循环的作用异常重要, 准确获取海水中颗粒有机碳的含量是揭示其重要作用的前提.目前, 元素分析仪测定POC是其准确测定最常用的方法, 但元素分析仪分析海水中颗粒有机碳过滤的膜样时, 存在包样困难、滤膜对反应管损坏严重、灰分难以清理等问题, 严重影响仪器的正常使用.本文采用总有机碳分析仪固体进样装置建立了海水中颗粒有机碳的分析方法, 优化了样品前处理过程, 对玻璃纤维膜进行了空白校正, 考察了酸化方式和时间对测定结果的影响, 方法检出限为 CL(C)=0.019%.对青岛近海三个不同采样站位海水样品 POC 的测定结果相对标准偏差(RSD)为0.95%~2.66%(n=12), 结果重复性好,精密度高, 经国家标准样品水系沉积物 GDS-9验证, 结果与标准值符合, 表明方法准确可靠, 能满足海水中的颗粒有机碳(POC)的准确测定要求.所建立的方法完全克服了常规元素分析仪测定POC的弊端, 同时降低了仪器的维护成本.%Particulate organic carbon in seawater (POC) is one of the most important parameters in both living and non-living marine processes. As a critical factor in the global carbon cycle, obtaining accurate POC contents is a fundamental requirement for assessing its important role. The elemental analyzer is the most commonly used method for accurately determining POC, but it has a number of limitations, such as difficulty with sample packag-ing, damage to the reaction tube by the membrane, and difficulty in cleaning up the ash, all of which seriously affect routine use of the instrument. In this paper, we propose a novel analytical method for determining POC using the solid sampling device of the total organic carbon analyzer, which optimizes the sample pretreatment process and corrects the glass fiber membrane blank. We investigated the effects of acidification mode and time on the POC determination results and found the detection limit of this method to be CL(C) = 0.019%. The relative standard de-viations (RSDs) of three POC samples taken from different sampling stations in Qingdao coastal seawater ranged between 0.95–2.66% (n = 12). Along with its good repeatability and high precision, the POC results accord with the standard values of the GDS-9 validation of the national standard sample stream sediments. Our proposed method completely overcomes the disadvantages of the conventional elemental analyzer for POC determination and reduces instrument maintenance costs.
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