【作者】 朱晓楠；

【导师】 宋大千；

【作者基本信息】 吉林大学 ， 分析化学， 2010， 硕士

【摘要】 本文将微波和超声两种技术分别应用于中药肉桂活性成分和水发食品中甲醛含量的检测,建立了中药肉桂有效成分非极性溶剂微波辅助提取法(NPSMAE)和水发食品中甲醛的超声波辅助提取-顶空-单滴微提取(UAE-HS-SDME)技术。1. NPSMAE是在极性溶剂或混合溶剂高压微波提取法的基础上,通过在样品中加入能够吸收微波能的微波吸收介质,迅速加热样品,使中药活性成分快速溶解在周围的非极性溶剂中,达到直接提取干燥植物样品中活性成分的目的。实验将这种新的微波提取模式应用于肉桂挥发油的提取,并用GC-MS测定提取物,将NPSMAE与混合溶剂提取法、超声波辅助提取法、水蒸气蒸馏法的提取效果进行比较。结果显示,NPSMAE同其它方法相比,提取的活性成分基本相同,且提取产率高、节省时间和溶剂,是一种较好的中药提取法。2.将超声波辅助提取与顶空-单滴微提取(UAE-HS-SDME)相结合,测定水发食品中甲醛的含量。实验以含有PFBHA的十二烷溶液为甲醛提取剂,使甲醛的衍生富集在单滴内同时进行,实验首次将动态和静态顶空微提取相结合,提高了甲醛的富集浓度,达到快速提取水发食品中的甲醛的效果,通过采用GC-MS对甲醛衍生物的含量进行检测,从而达到了检测甲醛含量的目的。将UAE-HS-SDME与蒸馏-乙酰丙酮法进行比较,得之,UAE-HS-SDME具有节省提取时间和溶剂,操作简便,提取效果好等优点。更多还原

【Abstract】 Analytical chemistry is the science for people to know the composition, structure and information of materials. Sample preparation in analytical testing occupies the important position, and it plays direct impact on the results of sample analysis. The extraction methods of chemical constituents of the sample have been important part in the study of sample pretreatment methods. Therefore, the improvements of the separation efficiency, the effectiveness in analysis, reducing energy consumption and costs have been the primary task for today’s analytical chemistry.1. NPSMAEIn this work, a new non-polar solvent microwave-assisted extraction (NPSMAE) - gas chromatography mass spectrometry was developed and demonstrated by analysis and determination of the main active ingredient cinnamaldehyde in cinnamon essential oil from cinnamon.In the assay, microwave absorbing materials (carbonyl iron powders, CIP) were added in samples and non-polar solvent was used to extract the volatile oil in dried plant samples. This experiment improved the traditional method which using polar solvent or combination of microwave-assisted solvent for extraction. By using orthogonal method, we studied the influence of NPSMAE extraction solvent, extraction temperature, extraction time and ratio of solid to liquid on the determination. The optimized extraction conditions of NPSMAE were selected as followed, the extraction temperature of 120℃, extraction time of 10 min, extraction solvent of hexane and the ratio of solid to liquid of 1:7.5 (mg/ml). Under these conditions, we used the improved NPSMAE method to extract the essential oil from dried cinnamon and the products of this method was compared with ultrasonic assisted extraction (UAE), steam distillation (HD) and other methods. The quantitative analysis to the main active ingredient cinnamaldehyde in cinnamon essential oil from cinnamon was separately determined by these methods. The reproducibility and recovery were also studied by NPSMAE method and satisfactory results were obtained.The experimental results indicate that both the compound species and the relative content of volatile oil obtained by NPSMAE method and other methods are basically the same. This indicated that CIP only functioned as a heating source and there was no chemical reaction between the volatile oil component and CIP. In CSMAE extraction of essential oil, pigment, carbohydrates and a lot of impurities resulted in poor quality of volatile oil. Compared with NPSMAE, volatile oil obtained with the UAE and the HD got a lower extraction rate and the total content was less than that of NPSMAE. Furthermore, NPSMAE extraction time is only 15-20 min, with a short extraction time and the advantages of a very high extraction yields. Therefore, this method is practical for volatile oil extraction in Chinese medicine plant.2.UAE-HS-SDMEA new headspace single-drop microextraction was developed based on the ultrasound assisted extraction. It was the first time to extract formaldehyde in water-fat foods using ultrasound-assisted extraction - headspace liquid phase microextraction (UAE-HS-SDME) and simultaneously derivative with PFBHA. The influences of experimental parameters on the extraction yield were studied in the extraction process and the extraction conditions were optimized finally with extraction temperature of 40℃, headspace volume of 4 mL, a single drop of 2μL of dodecane with PFBHA that hanging in the sample above for 50 s and then withdrawn micro injector for 10 s, repeated 8 min under the extraction conditions above. In this way, the extraction of formaldehyde in water-fat food was conducted and then directly injected into the GC-MS for detection. The highest extraction yield of formaldehyde was obtained.In the optimal conditions, the formaldehydes in five kinds of water-fat foods were investigated with the UAE-HS-SDME extraction and determined with the GC-MS. Meanwhile, the test results were compared with the traditional distillation - acetyl acetone method which showed that there was no significant difference between the two methods. However, traditional distillation - acetyl acetone method is tedious and time-consuming. UAE-HS-SDME is a simple, rapid and convenient sample technique. More important, it can avoid the complex food matrix interference and improve the sensitivity of the sample test. In addition, from the method verification we can see that UAE-HS-SDME has a good reproducibility, detection limit, recovery and linearity.更多还原