Studies And Applications On Ultrasound/Microwave Hybrid-assisted Extraction

Ultrasound/microwave hybrid-assisted extraction coupled to headspace solid-phase microextraction(UMHE-HS-SPME)and non-polar solvent ultrasound/microwave hybrid-assisted extraction(NP-UMHE)based on ultrasound/microwave hybrid-assisted extraction(UMHE)were developed.UMHE and UMHE-HS-SPME were used for determination of essential oils in dry traditional Chinese medicine(TCM)by gas chromatography-mass spectrometry(GC-MS),including Linderae Aggregata(SIMS)KOSTERM,the dry roots of Angelica dahurica.A sample preparation technique termed non-polar solvent ultrasound/microwave hybrid-assisted extraction followed to a Chromato-Probe direct sample introduction(DSI)device injecting was also developed in this study,which was used for determination of 23 organochlorine pesticides in soil based on gas chromatography-mass spectrometry(GC-MS).A brief descripton was given as follows:1.A novel method named ultrasound/microwave hybrid-assisted hydro-distillation(UMHD)for the determination of the oil from Linderae Aggregata(SIMS)KOSTERM by gas chromatography-mass spectrometry was proposed.Microwave-assisted hydro-distillation(MHD)and steam distillation(SD)were also studied,the plant in Zhejiang province was studied to optimize microwave power and ultrasound power.Under optimized conditions,the weight of essential oil was the highest with UMHE,there were 70 compounds identified,and 68,65 compounds identified by MHD,SD;What's more,we also studied Linderae Aggregata(SIMS)KOSTERM in different provinces.There were 37,41,61 compounds identified in Shangxi province,Anhui province and Guangxi province.The method has been demonstrated to be rapid for collecting the oil from Linderae Aggregata(SIMS)KOSTERM,and the essential oil in Linderae Aggregata(SIMS)KOSTERM from zhejiang province was the best quality compare to the other three provinces.2.A novel one-step sample preparation technique termed ultrasound/microwave hybrid-assisted extraction coupled to headspace solid-phase microextraction(UMHE-HS-SPME)was developed,which was used for determination of essential oils in Angelica dahurica based on gas chromatography-mass spectrometry(GC-MS).Sample preparations including isolation,extraction and concentration of essential oils were performed in a single step.The effects of various parameters including fiber coating,ultrasound power and irradiation time were investigated and optimized.To further demonstrate the method feasibility,the conventional steam distillation(SD)method was also studied to compare to the proposed method.The results showed that more essential oil compounds were isolated and identified by UMHE-HS-SPME than those by SD.Moreover,UMHE-HS-SPME needed only 10 min to prepare sample,and no organic solvent.In addition,the compounds with higher boiling point and many more oxygenated compounds were extracted from Angelica dahurica by the proposed method.UMHE-HS-SPME is an alternative tool for fast analysis of essential oils in dry TCMs and potentially extended to other target analytes in dry matrix.3.Non-polar solvent ultrasound/microwave hybrid-assisted extraction followed to Chromato-Probe direct sample introduction(NP-UMHE)device was developed,which was used for determination of 23 organochlorine pesticides in soil based on gas chromatography-mass spectrometry(GC-MS).A new self-designed microwave absorption tube was used in the extraction and the non-polar solvent was used as extraction solvent.Direct sample introduction(DSI)for GC injection is one technique that greatly minimizes sample preparation and yet still provides a rugged analytical approach for complex matrices.The effects of experimental parameters were investigated and optimized,including absorbing medium and the quality,the solvent,ultrasound power and irradiation time.Under the optimum conditions the targets recoveries were in the range of 74.8%-104.1%,and the relative standard deviations were lower than 19.24%.The proposed method provides a technical support in environmental monitoring.