The Extraction And Determination Of Active Components In Traditional Chinese Medicine And Formaldehyde In Food

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.