波谱吸收特征一般和物质成分具有密切联系, 其中描述波谱吸收特征的参数——波谱吸收深度可以作为一种定量评估样品化学组成的参数。 波谱吸收特征及化学特征之间的相关性研究已经在土壤学、 矿物学及植被科学等领域得到了证实, 但是针对稀土元素及其化学特征之间的相关性研究目前还未开展相关工作。 为开展此方面的研究, 针对赣南稀土矿区采集的10个不同浓度的稀土溶液样品, 运用便携式地物波谱仪和等离子质谱仪分别获取了其波谱特征和稀土总浓度, 研究结果表明稀土溶液呈现出水体和稀土氧化物的混合波谱特性, 在可见光-近红外波段有6个明显的稀土特征吸收谷。 针对这6个特征吸收谷, 运用原始波谱与纯水波谱比值的方法计算得出的波谱吸收深度和稀土总浓度进行线性回归分析, 表明两者高度线性相关, 由此建立了稀土浓度定量评估模型。 这一研究提供了一种间接评估溶液中稀土浓度的新方法, 并且为稀土元素高光谱信息提取研究提供了理论基础。

In the present paper, ten aqueous samples which contain different concentrations of REE were collected in south Jiangxi province, and the reflectance spectra and the concentrations of REE were measured by analytical spectral devices (ASD) FieldSpec-3 reflectance spectroscopy and inductively coupled plasma mass spectrometry (ICP-MS), respectively. The results show that the spectra presented mix characteristics of pure water and rare earth oxide. In addition, six diagnostic absorption features caused by REE in visible and near-infrared wavelengths were detected. Then, relative absorption depths of the six absorption wavelength were calculated by the ratio spectra of sample spectra and pure water spectra. Finally, concentrations of total REE of ten samples and relative absorption depths of the six absorption wavelength were selected as two factors, and their relationship was perfectly described using linear regression analysis in which correlation coefficient was up to 96%-97%. The study provides a new method for quantitative estimation of different concentrations of dissolved REE in aqueous media, and strengthens theoretical basis for hyperspectral information extraction of REE.