Ludwig Christian, Wochele Jörg, Jörimann Urs
Paul Scherrer Institut (ENE-LEM), CH-5232 Villigen PSI, Switzerland.
Anal Chem. 2007 Apr 1;79(7):2992-6. doi: 10.1021/ac0622173. Epub 2007 Mar 1.
A thermogravimeter (TGA, Mettler-Toledo TGA/SDTA851e) was connected to an inductively coupled plasma optical emission spectrometer (ICP-OES, Varian Liberty 110) using a condensation interface (CI), which transforms gaseous high-boiling-temperature substances into solid (or liquid) aerosols. Argon was used as the carrier gas to transfer the aerosols into the ICP-OES for on-line elemental analysis. This new analytical TGA-CI-ICP-OES device, called TGA-ICP, is the first of its kind and allows one to study the thermochemically induced evaporation behavior of high-boiling-temperature substances, such as heavy metal compounds, under different thermochemical conditions. It allows the investigation of the behavior of large solid or liquid samples (100-500 mg), which is important for applying the results to industrial processes. So far, the CI principle has allowed only semiquantitative elemental analyses of hot gases when connected to an ICP-OES. In this work, we show that a direct calibration of the CI-ICP-OES device is possible in combination with a TGA. The intensities determined by ICP-OES could be directly related to gravimetrically determined evaporation rates of volatile model compounds. The results show model evaporation experiments with native CdCl2 and CdCl2 resulting from the reaction of CaCl2 with CdO. Cadmium was studied because it is a volatile toxic heavy metal and its thermal behavior is relevant in various waste-treatment and recycling processes.
使用冷凝接口（CI）将热重分析仪（TGA，梅特勒-托利多TGA/SDTA851e）与电感耦合等离子体发射光谱仪（ICP-OES，瓦里安Liberty 110）相连，该冷凝接口可将气态高沸点物质转化为固体（或液体）气溶胶。使用氩气作为载气，将气溶胶传输至ICP-OES进行在线元素分析。这种新型分析设备TGA-CI-ICP-OES，简称为TGA-ICP，尚属首例，它能让人们研究高沸点物质（如重金属化合物）在不同热化学条件下的热化学诱导蒸发行为。它能够对大尺寸固体或液体样品（100 - 500毫克）的行为进行研究，这对于将研究结果应用于工业过程非常重要。到目前为止，CI原理在与ICP-OES相连时，仅能对热气体进行半定量元素分析。在本研究中，我们证明了结合TGA对CI-ICP-OES设备进行直接校准是可行的。由ICP-OES测定的强度可以直接与通过重量法测定的挥发性模型化合物的蒸发速率相关联。结果展示了天然CdCl₂以及由CaCl₂与CdO反应生成的CdCl₂的模型蒸发实验。选择镉进行研究是因为它是一种挥发性有毒重金属，其热行为在各种废物处理和回收过程中都具有相关性。
