选用碳元素常见的有机形态(C6H7O2)和碳酸盐形态(CaCO3)样品为实验对象, 配置一系列不同含碳量的样品进行激光诱导击穿光谱实验, 实验分析了不同形态碳元素样品在空气气氛条件下的激发特性.研究结果表明, 碳酸盐形态中可探测到明显的碳元素的原子谱线, 且与碳元素含量有良好的线性关系, 但较难探测到碳元素的分子光谱; 对于有机形态, 不仅能探测到碳的原子谱线, 还能探测到碳的CN分子谱线和C2分子谱线, 且分子光谱与碳元素含量具有较好的相关性, 说明碳元素分子光谱的形成与有机形态有关.将两种形态混合后, 发现CN分子光谱与有机形态中的碳元素含量具有较好的相关性, 说明利用探测到的CN分子光谱可以实现有机形态的鉴别.同时利用CN分子光谱的形成机制, 在两种形态混合后的样品中添加一定量的氮元素, 在氩气条件下, CN分子光谱与样品中有机碳元素含量存在较好的线性关系.进一步说明来源于空气中N和样品中N所形成的CN, 均可用于有机形态碳元素的鉴别.

Organic carbon (C6H7O2) and carbonate carbon (CaCO3) with different carbon concentration were selected as the model samples to perform laser induced breakdown spectroscopy experiments. The excitation characteristics of carbon with different forms were analyzed in air atmosphere. The results showed that carbon atomic emissions could be detected from carbonate carbon, which had a good linear relationship with the carbon content. But it is difficult to detect the molecular carbon. For organic samples, not only the atomic carbon could be detected, but also can detect the molecular carbon (CN and C2), and the molecular emissions had a good correlation with carbon content. The results indicated that the formation of molecular carbon is related with the organic form. After mixing the two forms of samples, it is found that there is a good correlation between the molecular CN and the organic carbon content, which indicated that the molecular CN could be used to realize the identification of organic carbon form. On the other hand, according to the formation route of molecular CN, a certain amount of nitrogen was added to the mixed samples with two forms of carbon, performed under the Ar atmosphere, it was also found that there exist the good linear relationship between the molecular CN and the organic carbon content. All the measurements showed that either the nitrogen from the air or from the sample itself could be both used for the identification of carbon from the organic forms.