Advanced Techniques for Organic Analysis

研究的重点将是推进高效、多维分离，包括综合二维气相色谱（GCxGC）和液相色谱（LCxLC）。该研究的目标包括通过非常规方法提高分离的速度和效率。空气中挥发性有机化合物的被动采样将进一步发展，特别侧重于土壤气体分析。*我们开发了一种新型的GCxGC热调制器，不需要冷冻剂或移动部件。它是基于一段失活不锈钢管，涂有一种专有的涂层，该涂层由通过热处理聚二甲基硅氧烷（PDMS）获得的二氧化硅纳米颗粒组成。我们将尝试通过加入具有大表面积和高吸附能力的碳基纳米材料来显着增加涂层的容量。这些将包括纳米金刚石，它具有极高的机械和热稳定性，并且在所有材料中具有最高的导热性，以及石墨烯/氧化石墨烯，以非常高的吸附能力和高热稳定性而闻名。我们还计划探索溶胶-凝胶化学，以加入纳米材料，并增加调制器内活性相的数量。*高效液相色谱中的现代小颗粒柱提供非常有效的分离，但需要非常高的压力来驱动流动相。我们将探索由滑铁卢大学的Eric Prouzet博士开发的一类新的固定相颗粒，它将亚微米大小与非常高的中间孔隙度结合在一起，使它们具有很强的渗透性。我们期望填充这些颗粒的柱在相对适度的背压下提供卓越的效率。将探讨这些列在环境分析中的应用。* lclc仍然是一种正在开发中的技术，特别是在其在线版本中。我们将利用我们在GCxGC领域获得的经验来推进这项技术。特别是，我们将重点关注通过使用非常短的（但高效的）填充了上述纳米颗粒的柱来提高二维分离的速度。将使用非常快的梯度，在极低体积的专有微制造混合器的帮助下生成。我们还将探讨热调制在lclc中的应用。其他小组报告的方法适用性的初步结果看起来非常有希望，我们在热调制领域的专业知识应该是毋庸置疑的资产。*越来越需要廉价的工具来表征受污染地点的土壤气体。本课程组研制的基于pdm的渗透被动采样器已成功应用于此目的，但由于饥饿效应，其性能在低渗透介质中受到影响。我们计划开发一种基于平衡采样的土壤气体分析新方法。一根涂有相对较厚一层PDMS的玻璃棒将使用一个特殊设计的探针暴露在土壤气体中。经过足够长的时间后，PDMS涂层将与周围的大气达到平衡，涂层中分析物的浓度将与它们在土壤气体中的浓度成正比。该探测器将使采样器与大气分离，以便回收。然后将采样器转移到含有吸附剂的热解吸管中，以便运送到实验室。在运输过程中，任何可能从PDMS中解吸的分析物都将被吸附剂捕获，因此样品的完整性将得到保存。如果成功，这种方法将具有巨大的商业化潜力。

The main thrust of the research will be the advancement of high efficiency and multidimensional separations, including comprehensive two-dimensional gas chromatography (GCxGC) and liquid chromatography (LCxLC). The goals of the research include increasing the speed and efficiency of the separations through unconventional approaches. Passive sampling of volatile organic compounds in air will be further developed with a particular focus on soil gas analysis.*We have developed a novel thermal modulator for GCxGC requiring no cryogens or moving parts. It is based on a segment of deactivated stainless steel tubing coated with a proprietary coating consisting of silica nanoparticles obtained through thermal treatment of polydimethylsiloxane (PDMS). We will attempt to significantly increase the capacity of the coating through incorporation of carbon-based nanomaterials characterized by large surface areas and high sorption capacities. These will include nanodiamonds, which are extremely mechanically and thermally stable and have the highest heat conductivity of all materials, as well as graphene/graphene oxide, known for very high sorption capacity and high thermal stability. We also plan to explore sol-gel chemistry to incorporate the nanomaterials and increase the amount of the active phase inside the modulator. *Modern small particle columns in HPLC provide very efficient separations, but require very high pressures to drive the mobile phase. We will explore a new class of stationary phase particles developed by Dr. Eric Prouzet from the University of Waterloo, which combine sub-micron size with very high intermediate porosity, making them very permeable. We expect columns packed with these particles to offer exceptional efficiency at relatively modest backpressures. Applications of these columns in environmental analysis will be explored. *LCxLC remains a technique under development, especially in its on-line version. We will use our experience gained in the area of GCxGC to advance the technique. In particular, we will focus on increasing the speed of second-dimension separations through the use of very short (but highly efficient) columns packed with the nanoparticles described above. Very fast gradients will be used, generated with the help of proprietary microfabricated mixers of extremely low volume. We will also explore the use of thermal modulation in LCxLC. Preliminary results on the suitability of the approach reported by other groups look very promising, and our expertise in the area of thermal modulation should be an unquestionable asset. *There is a growing need for inexpensive tools for the characterization of soil gas at polluted sites. PDMS-based permeation passive samplers developed by our group have been adopted for this purpose with some success, but their performance suffers in low permeability media because of the starvation effect. We plan to develop a novel approach to soil gas analysis based on equilibrium sampling. A glass rod coated with a relatively thick layer of PDMS will be exposed to the soil gas using a specially designed probe. After a sufficiently long time the PDMS coating will reach equilibrium with the surrounding atmosphere, and the concentration of the analytes in the coating will be proportional to their concentration in the soil gas. The probe will allow isolating the sampler from the atmosphere for retrieval. The sampler will then be transferred to a thermal desorption tube containing a sorbent for transport to the laboratory. Any analyte that could potentially desorb from the PDMS during transport will be trapped by the sorbent, hence integrity of the sample will be preserved. If successful, this method has a tremendous potential for commercialization.