Mattei Giorgia, Sette Clara, Lucentini Luca, Veschetti Enrico
National Centre for Water Safety, Italian National Institute of Health, Rome, Italy.
J Sep Sci. 2025 Jul;48(7):e70228. doi: 10.1002/jssc.70228.
The accurate determination of trace elements in seawater is essential for environmental monitoring and the study of oceanic biogeochemical processes. However, traditional analytical techniques often face limitations due to the ultra-trace concentrations of metals and the high salinity of seawater, which introduces significant matrix effects. In this study, a novel flow injection-inductively coupled plasma mass spectrometry (FI-ICP-MS) method coupled with an ultrasonic nebulizer was developed and optimized for the direct quantification of cadmium, cobalt, lead, manganese, molybdenum, tin, uranium, and vanadium in seawater samples. The method was optimized by evaluating the effects of eluent concentration (0.05-0.20% HNO3, with 0.05% selected as the minimum effective value to ensure analyte stability, prevent precipitation, and minimize salt-related stress on the FI system), flow rate (0.4-1.0 mL/min), and sodium chloride matrix composition, ensuring minimal spectral interferences while maintaining high sensitivity. The selected operating conditions (0.05% HNO3 eluent at 0.70 mL/min with 103Rhodium and 193Iridium as internal standards) provided a robust analytical performance with low procedural limits of detection and quantification (ranging from 0.003 to 0.2 µg/L for LoDs and from 0.01 to 0.7 µg/L for LoQs) and excellent instrumental repeatability (1.2%-6.6%). The overall method was validated using the IAEA-443 seawater certified reference material, yielding recoveries between 104%-118% and procedural reproducibility ranging from 3.8% to 15%. The optimized FI-ICP-MS method was applied to real seawater samples collected from two distinct Mediterranean transects: offshore Livorno, a site influenced by intense maritime and industrial activities, and Montecristo Island, a protected marine reserve with minimal anthropogenic impact. Results indicated no significant differences in trace metal concentrations between the two areas, suggesting that natural geochemical processes predominantly regulate elemental distributions. Most elements followed a conservative vertical distribution, with localized anomalies observed for manganese and cadmium. Furthermore, all measured cadmium and lead concentrations were well below the regulatory thresholds set by Directive 2013/39/EU, confirming compliance with environmental quality standards.
准确测定海水中的微量元素对于环境监测和海洋生物地球化学过程的研究至关重要。然而，由于海水中金属的超痕量浓度以及高盐度，传统分析技术常常面临局限性，这会引入显著的基体效应。在本研究中，开发并优化了一种结合超声雾化器的新型流动注射-电感耦合等离子体质谱法（FI-ICP-MS），用于直接定量分析海水样品中的镉、钴、铅、锰、钼、锡、铀和钒。通过评估洗脱液浓度（0.05 - 0.20% HNO₃，选择0.05%作为确保分析物稳定性、防止沉淀并使FI系统上与盐相关压力最小化所需的最小有效值）、流速（0.4 - 1.0 mL/min）和氯化钠基体组成的影响来优化该方法，确保在保持高灵敏度的同时将光谱干扰降至最低。选定的操作条件（0.05% HNO₃洗脱液，流速0.70 mL/min，以¹⁰³铑和¹⁹³铱作为内标）提供了稳健的分析性能以及较低的方法检测限和定量限（检测限范围为0.003至0.2 μg/L，定量限范围为0.01至0.7 μg/L）和出色的仪器重复性（1.2% - 6.6%）。使用国际原子能机构（IAEA）-443海水标准物质对整个方法进行了验证，回收率在104% - 118%之间，方法重现性范围为3.8%至15%。将优化后的FI-ICP-MS方法应用于从地中海两个不同断面采集的实际海水样品：利沃诺近海，该区域受强烈的海上和工业活动影响；蒙特克里斯托岛，一个受人为影响极小的受保护海洋保护区。结果表明两个区域之间痕量金属浓度没有显著差异，这表明自然地球化学过程主要控制着元素分布。大多数元素呈现保守的垂直分布，锰和镉出现局部异常。此外，所有测得的镉和铅浓度均远低于2013/39/EU指令设定的监管阈值，证实符合环境质量标准。
