Solventless Sample Preparation Method Using Supercritical or Subcritical Water as the Medium

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In the past ten years, supercritical fluid extraction (SFE) is being paid much attention as an analytical sample preparation technique, SFE provides shorter extraction time, which is a great reduction to Soxhlet extraction that may take days to perform, simple preconcentration steps, and most of all, significant reduction in the volumes of toxic and environmentally hazardous organic solvents used. However, in SFE some amounts of organic solvents are used as the collection media for the extracted analytes and as the modifier for the supercritical fluid. On the other hand, recent studies had also shown solid phase microextraction (SPME) to be fast, solvent free and an excellent performance technique. Similarly, SPME coupled to high performance liquid chromatography (HPLC) for non-volatile or thermally unstable compounds such as pesticides analysis also employs a small amount of organic solvent.For these reasons described above, this project has been intended to study the development of a solventless sample preparation method using supercritical or subcritical fluids as the extraction medium where SPME is a major extraction technique. As the results the analysis of pesticides in water has been made effectively by using SPME coupled with SFE with supercritical fluid as the medium and solventless sample preparation process has been realized by this technique. In the further development using supercritical water or subcritical water will improve the method developed in this project and this is the next target of this series of the projects.