Superheated Water in Extraction and Chromatographic Methods

Superheated water has been widely utilized in the extraction of organic pollutants, pesticides, natural products as well as inorganic compounds from a variety of sample matrices. The rapid development of superheated water extraction (SWE) has led to the direct combination of this technique with conventional chromatographic methods. However, these coupling methods still required a considerable amount of organic solvent. This book, therefore, introduces a design of an on-line coupled system of SWE method with superheated water chromatography (SWC) by using simple switching valves and a solid-phase trap as the interface between the extractor and the chromatograph. The trap column was used to collect the extracted analytes and pre-concentrate them prior to chromatographic analysis. It could also be used as a clean-up step for the removal of the matrix interferences from the extract. Because superheated water was used as the extractant, as the mobile phase, as well as the washing solvent, the use of organic solvent has been avoided in any stages of this on-line SWE-SWC method, and hence it is compatible with ‘green chemistry’.