Advanced Separation Techniques in the Analysis of Environmental Pollutants

Abstract

Recent developments in chromatographic supports and instrumentation for liquid chromatography are enabling rapid and highly efficient separations. Various analytical strategies have been recently proposed, for example the use of monolithic supports, elevated mobile phase temperatures, columns packed with sub-2 μm fully porous particles for use in ultra-high-pressure liquid chromatography (UHPLC) and superficially porous particles (fused core). All these approaches could be used to enhance the efficiency and shorten the analysis time. In the presented work, a high efficiency HPLC method was proposed based on coupling three columns packed with fully porous sub-2 µm particles and operating them at high temperature to reduce the solvent viscosity, thus reducing the column backpressure. The developed method could increase the number of theoretical plates compared to a single column at 30 ºC. The approach of column coupling was applicable for both isocratic and gradient mode of separation. Also, fast analysis methods were proposed based on using either a column packed with fully porous sub-2 μm particles and operated at high temperature or a column packed with superficially porous particles as a tool to increase the analysis speed. An ultra-fast green method was also proposed by using a short narrow bore column packed with fully porous particles. In addition, the chromatographic performance of columns packed with fused-core particles was investigated and compared to that of fully porous particles (sub-2 µm) at elevated temperature and extended column lengths. The study involved a comparison of chromatographic parameters such as retention, selectivity, resolution, efficiency and pressure drop. This study demonstrated that the fused-core particles can produce key advantages over the sub-2 µm particle columns in terms of separation speed, resolution and efficiency. All the developed methods were validated and applied to the analysis of environmental pollutants in surface water and/or waste water. The fast and efficient methods developed could be used as an alternative to the traditional ones for the environmental analysis of many pollutants.