Studies On The Extraction Method Of Capsaicin And Dihydrocapsaicin

Analytical Chemistry is an important branch of Chemistry. It is the access to learn the composition and structure information of substance, and it is also the basis of scientific research. It has many main tasks, such as determination of the composition and quantity of chemicals, characterization of the chemical structure, morphology and energy state, characterization of the kinetics of composition, content, structure, shape and energy. Generally speaking, in the whole process of extraction and determination, sample extraction was firstly carried out, followed by determination. So selection of an appropriate extraction method is very important in Analytical chemistry.In this paper, different methods of extracting the two main capsaicinoids in hot peppers were studied. The main contents are as follows:1. Extraction and determination of capsaicinoids in hot peppers used matrix solid-phase dispersion and HPLCIn this section, matrix solid-phase dispersion (MSPD) was firstly developed for the rapid and simple extraction of capsaicinoids from hot peppers, followed by determination with high performance liquid chromatography (HPLC). The optimization of MSPD extraction parameters were carried out, such as the type of solid sorbent and elution solvent, the quantity of the solid sorbent and the volume of the elution solvent. Under the optimal extraction conditions, the proposed method was compared with ultrasound assisted extraction. The intra-day and inter-day precision and the mean recoveries of the proposed method were also carried out.The experiment results indicate the optimal extraction parameters of MSPD,0.5 g hot pepper mixed with 0.5 g silica gel, and then 15 mL methanol used as elution solvent. And the relative standard deviations (RSDs) for intra-day and inter-day determination of capsaicin and dihydrocapsaicin were less than 2.46%(n=3) and 3.54%(n=3), respectively. And the mean recovery of the two capsaicinoids was 72.7-92.9% with the RSDs between 2.05% and 4.87%(n=3). By comparing the proposed method with ultrasound-assisted extraction, the proposed method has higher extraction yields and is suitable to extract capsaicinoids in hot peppers.2. In this study, microwave pretreatment was applied to assist the extraction of the main capsaicinoid compounds. And ultrasound was applied in the following step using sodium hydroxide aqueous solution as the extraction solvent. Finally, HPLC was used in the determination of capsaicinoids. Some experimental conditions were studied and optimized, such as type of extraction solvent, microwave power, extraction time for microwave pretreatment; concentration and volume of sodium hydroxide aqueous solution, extraction time for ultrasound-assisted extraction and pH of the sample solution. Under the optimum conditions, the capsaicinoids have been extracted in a short time of 5 min. And the relative standard deviations (RSDs) for determination of capsaicin and dihydrocapsaicin in one day were 1.2% and 2.0%, respectively (n=3). And the relative standard deviations (RSDs) for inter-day determination of capsaicin and dihydrocapsaicin were 1.43% and 1.78%, respectively (n=3). The recoveries are 85.6%-93.2%(RSDs=1.3-6.5%, n=3) for capsaicin, and 87.4%-89.1%(RSDs=2.1-4.5%, n=3) for dihydrocapsaicin. Compared to ultrasound-assisted extraction, the proposed method made extraction time shorten and reduced the consumption of the organic solvent and the pollution of laboratory.