Advanced Separation and Detection Methods for Supercritical Fluid Chromatography

我们的研究旨在用环境更清洁的替代品取代有机溶剂，这是分析化学中日益关注的问题。由于超临界二氧化碳的低成本、相对绿色和卓越的性能，许多分析实验室正在应对堆积如山的危险废物和缓慢的样品处理能力，现在正转向超临界二氧化碳作为流动相。例如，在超临界流体色谱(SFC)中，它提供了比液体色谱更快的分离速度，并允许比气相色谱分析更重的化合物。然而，超临界二氧化碳是非极性的，需要添加一种极性有机改进剂，如甲醇，以使其分离极性分析物。这消除了SFC的绿色优势，并破坏了其使用非常理想的通用火焰电离检测器(FID)的独特能力。这些限制可能会严重限制SFC用户，这些用户通常包括制药、石油和聚合物行业，这些行业在加拿大很普遍。*我们将开发一种新的SFC分离方法，这是我们实验室最近发现的。它的基础是使用水作为一种新的固定相，并且不使用有机改性剂，而只使用纯超临界二氧化碳。该方法还可以很好地分析极性分子，并与FID兼容，使其具有潜在的非常有用的作用。我们的工作将极大地推进这一方法及其能力，并使其能够分析目前有问题的重要分子类别。例如，我们将尝试改变水固定相的组成，使其能够分离手性分子，这对药物发现非常重要。如果可能，它将开辟一条定制药物分离的新途径。通过改变水相的pH值，还将努力分离可电离的分析物。这可以实现对有机酸和碱的大量重要分析，这是制药、石化和其他行业广泛关注的问题。在一种平行的方法中，我们将进行一种非常规的尝试，在分离过程中动态改变水固定相的pH值，以操纵分析物保留。如果它奏效，它可以对分离进行最终控制，在分离过程中，分析物可以按需洗脱。这一进展可能会对分析大型复杂基质中的目标物质的能力产生巨大影响，例如重油中的环烷酸。在其他工作中，我们将检查是否也可以分析硫物种，以及分析的程度。如果是这样的话，我们将把水相与硫磺特定的检测器配对，并创造出现有的最具选择性的硫磺分析方法之一。我们发明的一种强大的新硫探测器也将以相关的方法进行检查。这些努力将极大地简化原油等复杂样品中硫化物的分析，并将为石化用户带来竞争优势。

Our research is aimed at replacing organic solvents with environmentally cleaner alternatives, which is a growing concern in analytical chemistry. Many analytical laboratories coping with mounting hazardous waste and slow sample throughput are now switching to supercritical CO2 as a mobile phase, due to its low cost, relatively green nature, and remarkable properties. For instance, in supercritical fluid chromatography (SFC), it provides faster separations than liquid chromatography and allows heavier compounds to be analyzed than gas chromatography. However, supercritical carbon dioxide is non-polar and requires a polar organic modifier like methanol to be added for it to separate polar analytes. This removes the green benefits of SFC and destroys its otherwise unique ability to use the highly desirable universal flame ionization detector (FID). These limitations can seriously constrain SFC users, who frequently include the pharmaceutical, petroleum, and polymer industries, which are prevalent in Canada.***We will develop a new separation method for SFC that was recently discovered in our laboratory. It is based on using water as a novel stationary phase and does not employ organic modifiers but only pure supercritical carbon dioxide. The method also analyzes polar molecules well and is FID compatible, making it potentially very useful. Our work will critically advance this approach and its capabilities, and allow it to analyze important classes of molecules that are currently problematic. For instance, we will attempt to alter the water stationary phase composition to allow it to separate chiral molecules, which are of tremendous importance to drug discovery. If possible, it will open a new avenue to customizing pharmaceutical separations. Through altering the pH of the water phase, efforts to separate ionizable analytes will also be made. This could allow a host of important analyses of organic acids and bases, which are of broad concern to pharmaceutical, petrochemical, and other industries. In a parallel approach, we will make an unconventional attempt to dynamically alter the water stationary phase pH during separations in order to manipulate analyte retention. If it works, it could allow for the ultimate control in separations, where analytes can be eluted on demand. Such an advance could have huge impact in the ability to analyze for target substances in large complex matrices, such as naphthenic acids in heavy oil. In other work, we will examine if sulfur species can also be analyzed and to what extent. If so, we will pair the water phase with a sulfur specific detector and create one of the most selective approaches to sulfur analysis available. A powerful new sulfur detector that we invented will also be examined in a related approach. These efforts will greatly simplify the analysis of sulfur compounds in complex samples like crude oil and will give a competitive edge to petrochemical users.