【作者】 刘同举；

【导师】 李淑芬；

【作者基本信息】 天津大学 ， 化学工艺， 2009， 博士

【摘要】 超临界流体萃取(supercritical fluid extraction, SFE)是一种环境友好的新型化工分离技术,近年来在分析领域作为生物样品的痕量药检前处理方法正在逐步代替某些传统方法,展示了诱人的应用前景。同时,SFE被视为先进的关键技术在天然产物和中药有效成分的提取中得到广泛研究与应用。有机锡是人类带入海洋最毒的污染物之一,本文采用分析型超临界萃取等技术对食品安全中亟待解决的有机锡污染物的检测进行了研究;同时也对采用SFE提取中药党参中的有效成分进行了探讨。该研究对提高食品安全检测技术水平以及促进中药生产现代化具有重要意义。本文建立了高效的SFE/HS-SPME/GC-MS测定海产品中有机锡含量的检测技术,即采用分析型SFE结合顶空固相微萃取(HS-SPME)为样品前处理技术,对海产品中六种不同形态有机锡(即:三甲基一氯化锡(TMT)、一丁基三氯化锡(MBT)、二丁基二氯化锡(DBT)、三丁基一氯化锡(TBT)、一苯基三氯化锡(MPT)、三苯基一氯化锡(TPT) )污染物进行提取与净化,而后采用GC-MS进行检测。通过实验研究多种因素对检测效果的影响,得到优化的操作条件为:0.5g蛤肉样品经含5% (mol)甲醇的超临界CO2在温度为45℃、压力为30 MPa条件下萃取15分钟(流速1.2 L·min-1以常压CO2计),然后用0.02 g·mL-1的四乙基硼化钠(NaBEt4)进行衍生化处理,并用聚二甲基硅氧烷/二乙烯基苯(PDMS/DVB)纤维进行固相微萃取富集后,进行GC-MS分析。整个分析过程仅需1小时,消耗有机溶剂还不到10mL。结果表明,该方法对于DBT、MPT、TBT和TPT四种有机锡的回收率在79 % ~ 90 %之间,最低检出限在0.04 ng.g-1(Sn) ~ 0.26 ng.g-1(Sn),满足定量回收的要求。精密度、最低检出限和线性范围也满足海产品中痕量有机锡检测的要求。但该方法用于TMT和MBT检测时的回收率较低(分别为26%和63%),而不适宜作为这两种有机锡的定量检测技术。本文建立了一套动态法测定溶质在超临界流体中溶解度的实验装置。通过测定苯甲酸在超临界CO2中的溶解度对设备的可靠性进行了验证,实测值与文献值偏差在5%以内。利用该设备测定了在温度35.0℃~ 65.0℃、压力15.0 MPa ~ 40.0 MPa的范围内三苯基一氯化锡(TPT)和三苯基一氯甲烷(TPC)两种化合物在超临界CO2中的溶解度。结果表明,TPT的溶解度在4.12×10-4 ~1.10×10-3范围内,TPC的溶解度在3.82×10-4 ~ 2.70×10-3范围内。分别用Gordillo方程、Christil方程和改进的Christil经验方程对TPT和TPC在超临界CO2中的溶解度数据进行了关联,结果良好。对于TPT各方程计算值与实验值的AARD分别为5.0%、8.6%和7.1 %,对于TPC,各方程计算值与实验值的平均相对偏差(AARD)分别为11.4%、6.4%和7.3%。在对常用中药党参进行超临界CO2萃取工艺研究中,首先以收膏率和总皂苷元为目标函数,通过单因素实验研究了超临界CO2萃取党参中脂溶性成分的适宜工艺条件。结果表明,在原料粒度40目~ 60目,萃取压力30MPa,萃取温度65℃的优化条件下得到的收膏率和总皂苷元得率分别为0.0111 g.g-1和2.23 mg.g-1。党参炔苷是党参中的一种重要的有效成分,采用中心实验设计和二次响应曲面法,系统考察温度、压力、夹带剂用量和时间等因素对收膏率和党参炔苷的萃取结果的影响及其相互作用。确定了夹带剂用量是提高党参炔苷生产效率最有效的控制因素,增加夹带剂用量可同时提高收膏率和党参炔苷得率。进一步优化了含动态夹带剂的党参炔苷超临界萃取工艺。实验结果表明,中药党参在动态夹带剂乙醇流速为1 mL·min-1,CO2流速为2 L·min-1,30 MPa,60℃下萃取100 min,党参炔苷得率为0.078 6 mg·g-1,优于超声萃取法。研究结果为建立一种党参炔苷提取的绿色工艺提供了基础数据。更多还原

【Abstract】 Supercritical fluid extraction (SFE) is environmentally friendly and high effective technology. It has been presently considered as analytical extraction method and has been proposed as an alternative approach for analyzing harmful chemical residues in biological samples. It has been also considered as one of the most attractive technology for processing natural product and traditional China medicines (TCM). In this thesis, analytical SFE was used for determination of the harmful organotin compounds (OTCs) in foods, and industrial SFE was used for extraction of active components from codonopsis pilosula. The two kinds of projects are important in the fields of food safety and modernization of TCM.A rapid and green method for the determination of six OTCs, namely trimethyltin chloride (TMT), butyltin trichloride (MBT), dibutyltin dichloride (DBT), tributyltin chloride(TBT), triphenyltin chloride (MPT) and phenyltin trichloride(TPT), in clam samples was established by combining SFE and headspace solid-phase microextraction (HS-SPME) as pretreatment method and then by gas chromatography with mass spectrometry (GC-MS) analysis. Effect of some factors on extraction efficiency was investigated and the optimal operation parameters were obtained as follows. The clam sample was first extracted at 45℃and 30 MPa with supercritical carbon dioxide in presence of 5% (mol) methanol at 1.2 L·min-1 (as carbon dioxide in ambient pressure) for 15 min. The SFE extract was then ethylated with 0.02 g·mL-1 sodium tetraethylborate (NaBEt4) in pH 4 buffer solution and simultaneously adsorbed by HS-SPME with polydimethylsiloxane / divinylbenzene (PDMS/DVB) fiber at 50℃for 30 min. And then GC-MS was performed. The whole process for sampling and analyzing was within 1h, and only less than 10 milliliters of organic solvent was used. Six OTCs in the spiked clam sample were determined with the established method, in which the recoveries of DBT、MPT、TBT and TPT were from 79 % ~ 90 % with LOD ranging from 0.04 to 0.26 ng/g, which indicate that the established procedure in this paper should be reliable and accurate for the determination the four OTCs in biotic sample. However, the established method may not suitable for determination of TMT and MBT as their recoveries were between 26% and 63%.A semiflow-type, dynamic apparatus was established for determinating the solubility of compounds in supercritical fluid. An equipment reliability proof test was made with the benzoic acid-carbon dioxide system. Comparing the measured benzoic acid solubility data with literature data, the average deviation is within 5%. The solubility of TPT and triphenylmethyl chloride (TPC) in supercritical CO2 were measured at a temperature ranging from 308.15 K to 338.15 K and various pressures in the range of 15 MPa to 40 MPa. The mole fraction solubilities ranged from 4.12×10-4 ~1.10×10-3 for TPT, and 3.82×10-4 ~ 2.70×10-3 for TPC. The experimental data of the solubility of TPT and TPC were correlated by Gordillo equation, Chrastil equation and modified Chrastil models separately, and good fit results were obtained. The correlation errors of the three models for TPT are 5.0%, 8.6% and 7.1 % respectively. And the correlation errors of the three models for TPC are 11.4%, 6.4% and 7.3% respectively.Finally, supercritical extraction of active compounds from Codonopsis pilosula with CO2 was studied. The influences of particle size, pressure and temperature on yield together with the yield of total sapogenins were discussed, Based on one-factor-at-a-time experiments. The optimal yield of 0.0111g·g-1 and yield of total sapogenins 2.23 mg·g-1 were obtained, when Codonopsis was extracted at 30 MPa, 65℃and 2 L·min-1 (as CO2 in normal pressure and temperature) for 2 hours with pure supercritical Carbon Dioxide. To develop a green and rapid method for extraction of lobetyolin from Codonopsis pilosula, extraction of lobetyolin from Codonopsis pilosula with supercritical carbon dioxide in the presence of ethanol was studied. The effect of pressure, temperature, volume of cosolvent and extraction time on efficiency and their interactive relationships were discussed, based on central composite design and response surface methodology (RSM). The key factor, volume of cosolvent was found. The extraction yield of lobetyolin was 0.0786 mg·g-1 when Codonopsis pilosula was extracted at 30 MPa, 60℃and 2 L·min-1(as CO2 in normal pressure and temperature) for 100 minutes with supercritical CO2 and 1 mL·min-1 ethanol as dynamic cosolvent. This result is better than that obtained from ultrasonic method. Therefore, the optimized process is a valuable method for extraction of lobetyolin from Codonopsis pilosula.更多还原