共沉淀富集法测定海水中稀土元素含量方法研究

稀土元素已越来越多地应用于示踪各类地球化学体系的物质来源与岩石矿物形成等演化过程。但在进行海水样品的稀土元素检测时，由于样品的高盐特征和稀土元素的痕量特征又使得分析具有相当的挑战性。本研究旨在从高盐的海水基质中有效分离并富集痕量的稀土元素，同时结合电感耦合等离子体质谱（Inductively Coupled Plasma Mass Spectrometry, ICP-MS）技术对海水中的稀土进行定量分析。通过对海水样品稀土元素的定量限分析、加标回收实验和梯度加标回收实验，验证了方法的准确性，评估方法的分离富集效率。通过共沉淀过程中的pH比较、氢氧化钠与氨水作为共沉淀剂的比较，确定了富集过程中共沉淀剂用量、种类等影响因素。通过稀土元素配分曲线的绘制与类似样品结果进行比对，以及标准海水的检测结果，验证了方法在实际样品中的可行性。本研究探索了共沉淀富集法在分离富集海水中稀土元素的实验条件，实现高盐背景下痕量稀土的准确定量，并将其用于近岸海水与孔隙水的实际检测。

Experimental conditions for determination of rare earth elements in seawater by coprecipitation enrichment method

Rare earth elements (REEs) have been increasingly used to trace the material sources and the formation of rocks and minerals in various geochemical systems. However, in the detection of REEs in seawater samples, the high salinity and low concentration of REEs make the analysis quite challenging. The aim of this study is to effectively separate and enrich REEs from the background of high saline seawater and to quantitatively analyze REEs with ICP-MS. By the analyses of quantitation limit of REEs in seawater samples, the standard addition recovery experiments and the gradient standard addition recovery experiments, we evaluated the accuracy and enrichment efficiency of the method. By using different pH value in the process of co-precipitation and comparing sodium hydroxide and ammonia water as co-precipitators, we determined the influencing factors such as the dosage and types of co-precipitators in the process of enrichment. The feasibility of this method in practical samples is verified by comparing the results of REE partition curves with those of similar samples and the results of standard seawater detection. In summary, we have explored the experimental conditions of coprecipitation and enrichment for REEs in seawater samples, and this method can be applied to the actual detection of coastal seawater and pore seawater.