Institute for Ecopreneurship, University of Applied Sciences and Arts Northwestern Switzerland (FHNW), School of Life Sciences, Gründenstrasse 40, 4132 Muttenz, Switzerland.
Environ Sci Technol. 2012 Nov 6;46(21):11988-94. doi: 10.1021/es302550b. Epub 2012 Oct 19.
Selenium (Se) is of key importance to human health with a very narrow concentration range of optimal dietary intake. Due to the inherent analytical challenge linked with the low natural abundance, information on precise and accurate Se speciation in deficient environments is hardly existent. This study presents a novel approach to determine Se species-specifically at ultratraces, by online coupling of a preconcentration (trap) column to an ion chromatography inductively coupled plasma mass spectrometry (IC-ICP-MS) system. It is demonstrated that with this robust and work/time efficient method, the predominant selenium oxyanions, selenite (Se(IV)) and selenate (Se(VI)), can be quantified down to 7.3 and 8.3 picogram total Se, respectively, in an overall analytical time of 420 s, only. The applicability for environmental samples was proven on pristine volcanic ashes collected from seven different volcanoes. The high sensitivity of the novel approach allowed to determine speciation in samples that were strongly depleted in total selenium (<0.05 mg kg(-1) Se) with only minor fractions of Se mobilized (i.e., less than 10% of the total selenium was leached in 10 out of 12 samples). The studied samples showed considerate differences in selenium speciation, with selenite and selenate co-occurring in most samples. The fact that the studied sample leachates had a wide range of pH (3.78-9.55) and major anion/cation composition underlines the versatility and wide potential application range of the method presented.
硒（Se）对人类健康至关重要，其最佳膳食摄入量的浓度范围非常狭窄。由于与低天然丰度相关的固有分析挑战，关于缺硒环境中硒形态的确切和准确信息几乎不存在。本研究提出了一种新颖的方法，通过将预浓缩（捕集）柱与离子色谱-电感耦合等离子体质谱（IC-ICP-MS）系统在线耦合，实现了对硒形态的超痕量特异性分析。研究表明，采用这种强大且高效的方法，可以定量检测到主要的硒含氧阴离子亚硒酸盐（Se(IV)）和硒酸盐（Se(VI)），其检测下限分别低至 7.3 和 8.3 皮克总硒，总分析时间仅为 420 秒。该方法在从七个不同火山采集的原始火山灰环境样品中的应用得到了验证。该新方法的高灵敏度允许在总硒严重缺乏（<0.05 毫克/千克硒）的样品中进行形态分析，只有少量的硒被迁移（即在 12 个样品中的 10 个样品中，仅有不到 10%的总硒被浸出）。所研究的样品在硒形态上表现出明显的差异，亚硒酸盐和硒酸盐在大多数样品中同时存在。研究样品的浸出液具有广泛的 pH 值（3.78-9.55）和主要阴离子/阳离子组成，这突出了所提出方法的多功能性和广泛的潜在应用范围。
