Supercritical Fluid Extraction and Chromatography of Lipids in Bilberry

A supercritical fluid extraction (SFE) method has been developed for the extraction of lipids in bilberry. Experimental design was used to optimize pressure, temperature and extraction time using CO₂ as solvent. Best SFE condition for total lipids was 450 bar, 60 °C and 45 min. The SFE method was compared to conventional Bligh & Dyer (B&D) extraction. The amount of fatty acid methyl esters (FAME) was found to be 4.84 ± 0.06 mg and 4.564 ± 0.003 mg per g of the freeze‐dried bilberry sample for the developed SFE and B&D methods, respectively, while the amount of total lipids was found to be 54.40 ± 6.06 mg and 65.70 ± 0.67 mg per g of sample for SFE and B&D, respectively. This discrepancy between FAME and total lipids could be explained by the presence of wax esters, sterol esters, carotenoids and phospholipids, as determined by supercritical fluid chromatography.     

SOM特征提取与ELM在电力负荷预测中的应用

随着电力负荷内涵复杂度和非线性增加,单纯追求电力负荷预测精度将变得困难。研究根据负荷样本分析其趋势、抽取特征来解决预测精度问题,即提出一种基于自组织特征映射网络(SOM)进行特征提取并与极限学习机(ELM)相结合的短期电力负荷预测方法。通过SOM特征提取找出与预测日同类型的历史数据作为训练样本;然后采用ELM进行预测,该方法预测过程简捷,能得到唯一的最优解。实验以某市的电力负荷数据进行仿真和比较。结果表明,基于SOM特征提取的ELM方法不仅精简了训练样本数量,且使训练更具有针对性,提高了预测精度和泛化性能,具有一定的理论意义和较好的应用前景。     

乙醇/磷酸氢二钾双水相体系分离大豆异黄酮

利用乙醇/磷酸氢二钾双水相体系浸提大豆异黄酮固体,并采用四因素四水平正交试验,考察了乙醇质量分数、磷酸氢二钾质量分数、温度、时间对大豆异黄酮的分配系数和萃取收率的影响。结果发现,影响大豆异黄酮萃取收率的因素为:时间磷酸氢二钾质量分数乙醇质量分数温度。最佳提取条件为:25%乙醇/25%磷酸氢二钾双水相体系,室温(20℃)浸提30 min。大豆异黄酮几乎全部分配在上相,其上相收率为97.0%。     

Sol-Gel Glass-Encapsulated Crown Ethers for the Separation and Preconcentration of Strontium from Acidic Media

Extraction chromatography employing an inert polymeric support impregnated with a crown ether (typically, 4,4’,(5’)-di-(tert-butylcyclohexano)-18-crown-6 (DtBuCH18C6)), either neat (i.e., undiluted) or as a solution in 1-octanol, has previously been shown to provide an effective means for the isolation of radiostrontium from a variety of sample types for subsequent determination. In this study, sol-gel chemistry has been employed to prepare sorbents in which DtBuCH18C6 is encapsulated in a silica matrix. The resultant materials have been evaluated for their ability to retain strontium ion and compared to a commercially available extraction chromatographic (EXC) resin. Certain of the new materials are shown to provide uptake efficiencies comparable to those obtained with the commercial resins, although unless a porogen is employed, the kinetics of strontium uptake are significantly slower. In contrast to conventional EXC materials, however, strontium uptake by DtBuCH18C6-loaded glasses does not increase in proportion to the amount of extractant present, indicating that not all of the crown ether present is available for interaction with the metal ion.     

Extraction of Uranyl Ion Using 2-Thenoyltrifluoro Acetone (HTTA) in Room Temperature Ionic Liquids

The extraction of UO₂²⁺ ion was studied using six different solvent systems containing 2-thenoyltrifluoroacetone (HTTA) in room temperature ionic liquids such as [C_nmim][X] (where, n = 4, 6, or 8 and X^? = PF₆^? or NTf₂^?) from low to moderate pH solutions for the first time. The extraction kinetics studies indicated rather slow attainment of equilibrium which in some cases improved if the solutions were pre-equilibrated with the aqueous phase prior to the actual experiments. The D_U values were found to increase with increasing pH and leading to a plateau like profile at higher pH values. The D values were quite high as compared to that obtained with molecular diluents. The nature of the extracted species was ascertained by slope analysis method which suggested species of the type: UO₂(TTA)⁺_IL, UO₂(TTA)_2,IL, and UO₂(TTA)₂(HTTA)_IL in different ionic liquid based solvents. Temperature variation studies on UO₂²⁺ ion extraction were also carried out and the thermodynamic parameters were calculated which indicated high endothermicity of the reactions with large positive entropy values.     

吡啶-2,6-二[N-(1'-羟乙基)酰胺]的合成及其与金属离子的相互作用研究

合成了标题化合物,通过元素分析、1HNMR、13CNMR、IR及UV对其结构进行了表征,利用紫外光谱法考察了标题化合物对14种金属离子的识别性、萃取性和液膜传输性,讨论了它与金属离子之间的相互作用。结果表明,标题化合物对Cr3+、Pb2+离子具有良好的选择性识别作用及优良的萃取性和液膜传输性,它与两种金属离子均形成1∶1型配合物,并可实现水样中Cr3+、Pb2+的含量分析。     

双模板分子印迹聚合物在奶粉检验中的应用研究

采用本体聚合法制备三聚氰胺(MEL)与双氰胺(DCD)双模板分子印迹聚合物(MEL/DCD-MIPs),将其作为固相萃取介质,实现了奶粉中MEL与DCD富集与纯化,建立了奶粉中两种物质同时检测的方法。通过热力学、选择性和动态结合试验表明,与单模板分子印迹聚合物相比,双模板分子印迹聚合物由于双模板-功能单体分子间的多位点协同作用而有更好的印迹效应,对MEL和DCD结合能力高于结构类似物三聚氰酸(CYA)。固相萃取试验显示,MEL/DCD-MIPs可以从市售奶粉中选择性地分离、富集MEL与DCD,对MEL与DCD的加样回收率分别为93.1%~100.1%和75.7%~82.5%,RSD均小于5.2%。所制得的MEL/DCD-MIPs可应用于奶粉等食品中氰胺类物质的检测。     

多效反应精馏过程生产氯化苄的能量集成

以甲苯氯化生产氯化苄为研究对象,对带侧反应器的反应精馏与精制塔串联工艺(CSRRT)进行研究及能量分析,建立了分段反应精馏与精制塔串联生产氯化苄的新工艺。利用精制塔塔顶蒸汽潜热加热第一段反应精馏塔的塔釜,建立了多效反应精馏(MERD);进一步利用侧反应器的甲苯氯化反应热加热第一段反应精馏塔的塔板物料,建立了多效透热反应精馏(MEDRD)。在相同生产要求下,对3种工艺的能耗进行比较。结果表明,MERD和MEDRD过程实现了能量的优化利用,与CSRRT过程相比,塔釜总再沸器热负荷分别降低16.8%和33.7%。     

木瓜蛋白酶在[Cnmim]BF4-NaH2PO4双水相体系中的分配行为

为了研究木瓜蛋白酶在[Cnmim]BF4-NaH2PO4双水相体系中的分配行为,在298.15 K条件下利用浊点法测定了[Cnmim]BF4-NaH2PO4双水相体系的双节线和液液相平衡数据,建立了木瓜蛋白酶在该体系中的三维分配模型。利用Merchuk方程、Othmer-Tobias方程和Bancroft方程分别关联了双节线数据、液液相平衡数据,拟合度分别在0.975、0.994以上,结果满意。木瓜蛋白酶分配系数的对数与该体系上相的离子液体浓度和下相的盐浓度相关度都较高,故通过Matlab建立了三者之间的分配模型,实验值和预测值之间的相对偏差均在5%以内,表明该模型能有效地预测木瓜蛋白酶在[Cnmim]BF4-NaH2PO4双水相体系中的分配行为。