Study Of Solid Phase Microextraction With Sol-gel Derived Polyethylene Glycol Fiber

Solid phase microextraction (SPME), based on solid phase extraction, was a new separation technique with function of sampling, extraction, concentration and injection. SPME was compatible with analyte separation and detection by gas chromatography, high performance liquid chromatography, and other instrumental methods. It was effectively used to extract volatile or nonvolatile compounds from different environmental matrix. It could provide many advantages, such as short analytical time, low solvents and samples consumption, better precision, low detection limit, and so on. However, the device of SPME needed to be improved because of limited fiber species, not good selectivity, short use life-span. It was vital to develop novel fibers with good selectivity, stability and high efficiency. In this study, sol-gel method was applied for the preparation of SPME fibers with polyethylene glycol 20000(PEG-20M) coating. SPME devices, assembled with fabricated fibers, were used to analyse and detect different compounds. The surfaces of glass, capillary, fused-silica fiber were coated with sol-gel layer through chemical bond. Chemical reactions in sol-gel process were described. Preparation conditions for sol-gel and processing parameters of sol-gel coating preparation, such as component proportion, operating temperature, base pretreatment, coating, dryness and aging, were put emphasis on. Single factor and orthogonal test methods are applied for prescription selection of different preparation parameters. Many operating paramameters in SPME, such as extraction time, extraction temperature, pH, stirring conditions, desorption temperature and desorption time, were discussed.Hydroquinone in water was detected by SPME with sol-gel-derived PEG-20M fiber in the system of hydroquinone restraining H2O2-Luminol-Co2+ chemical luminescence. A better precision with 3% and the linear range from 10-5 mol·L-1 to 10-7 mol·L-1 are obtained. The limit of detection is 10-7 mol·L-1. Detection of prometryne in acetone and in vegetable with SPME-GC was achieved using sol-gel-derived PEG-20M fiber with a precision better than 2%, the linear concentration range from 10-5 mol·L-1 to 10-7 mol·L-1 and limits of detection at the 10-7 mol·L-1level. The PEG-20M fiber has better thermal stability and solvent stability.