| Summary: | 博士 === 國立中興大學 === 化學系 === 92 === A coupled technique, microwave-assisted headspace solid-phase microextraction (MA-HS-SPME), was investigated for one-step in-situ sample pretreatment for multi-pesticides screening prior to gas chromatographic determination. The pesticides were collected by the proposed method and analyzed by gas chromatography with an electron capture detector (GC-ECD) or flame photometric detector (GC-FPD). To perform the MA-HP-SPME, six types of SPME fibers were examined and compared. The parameters affecting the efficiency in MA-HS-SPME process such as sampling time and temperature, microwave irradiation power, desorption temperature and time were studied to obtain the optimal conditions.
Results showed that the optimum extraction efficiency of OCPs in aqueous matrix was obtained by irradiation of sample solution with irradiation power 244 Watt for 10 min. The detection was linear in the studied concentration range with γ2 > 0.9978. The detection limits varied from 0.002-0.070μg/l. For pyrethroids, irradiation power 157 Watt for 10 min. The detection was linear in the studied concentration range with γ2 >0.9913 except bifethrin. The detection limits varied from 0.0002-0.0026μg/l. For Organophosphate pesticides, OPPs irradiation power 244 Watt for 15 min can get the optimum extraction efficiency. The detection was linear in the studied concentration range with γ2 > 0.9867. The detection limits varied from 0.023-1.432 μg/l. The results indicate that the proposed method provides a very simple, fast, and solvent-free procedure to achieve the sample pretreatment prior to the trace-level screening determination of pesticides by gas chromatography.
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