地衣是应用广泛的大气污染生物监测器。 电感耦合等离子体发射光谱法/质谱法(ICP-MS/AES)是植物元素定性定量分析的重要和高效的方法。 但受严重大气污染影响, 我国部分地区的地衣元素水平远高于其他植物, 且在空间、 时间、 物种和元素类别方面存在巨大差异。 虽然地衣在大气污染监测方面具有良好的应用前景, 但我国地衣元素分析测试方面尚缺乏专门的方法学研究, 这限制了大气质量的地衣生物监测在我国的开展。 因此, 有必要对地衣样品元素含量的ICP-MS/AES法进行优化。 以国家一级标准物质GBW10014(圆白菜)、 GBW10015(菠菜)、 GBW10052(绿茶)和地衣标准物质(IAEA-336)为材料, 探讨了地衣样品的不同消解方法、 取样量、 分析谱线、 同位素、 内标元素及仪器参数对ICP-MS和ICP-AES结果的影响。 确定了适用于大批量地衣元素测试的干法灰化-碱熔ICP-AES和微波消解ICP-MS的优化条件, 该优化条件具有线性关系好(r>0.999 0)、 检出限低、 准确度高和精密度好的特点。 以优化后的测试方法测定采自我国太行山区和南极阿德利岛的地衣样品, 结果表明太行山地衣体内元素含量远高于南极阿德利岛, 大气沉降对太行山地衣元素组成的相对贡献也较大。 验证了优化方法的适用性, 为京津冀环境治理提供科学数据和技术支持。

Lichens are one of the best materials for air quality biomonitoring, and they have been widely used in atmospheric element deposition monitoring in many regions. Inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma atomic emission spectrometry (ICP-AES) are two efficient techniques widely used in quantifying and quantifying plant elements. However, elemental levels in lichens from some regions in China are much higher than in other plants, and their variation is highly dependent on space, time, species and elements. Although atmospheric pollution monitoring is urgently needed in China in recent decades, little studies have been performed on biomonitoring in the country. Therefore, the methodological studies on the determination of lichen elements in China are needed to accelerate future biomonitoring studies with lichens. Two techniques such as ICP-MS and ICP-AES were used to determine elements in four reference materials, as GBW10014 (cabbage), GBW10015 (spinach), GBW10052 (green tea) and IAEA-336 (lichen), with an attempt to reveal the effects of different digestions, sampling size, spectral lines, isotopes and internal standard elements on measured results. ICP-AES after dry ashing-alkali fusion digestion and ICP-MS after microwave digestion were optimized for lichen element determination. In the optimized techniques, good linear relationship (r>0.999 0), low detection limit, high analytic accuracy and precision were obtained. The optimized techniques were applied to lichen samples collected from Taihang Mountains of China and Ardley Island of Antarctica. The results show that all lichen samples from Taihang Mountains were much higher in elemental concentration with the contribution of atmospheric deposition higher than those from Antarctica. These results suggest the applicability of the techniques in determining lichen elements, and provide evidences and technique supports for air pollution biomonitoring in China.