Quality assurance of Chinese herbal medicines: Procedure for single‐herb extraction

A procedure for herbal extraction has been developed for producing a Chinese herbal medicine (CHM) with consistent quality regardless of the source of the herb. The quality assurance (QA) procedure is based on a model which accounts for the physicochemical phenomena governing herbal extraction. With this model and the companion experiments for determining the relevant model parameters, the amount of each herb needed from different herb quality classes to produce a CHM decoction with consistent quality can be determined. The procedure was illustrated by the extraction of Danshen and that of Gegen. For both examples, the experimental chemical marker concentrations fell within ± 10% of the specified concentrations by using the amount of herb from each herb class as predicted. © 2013 American Institute of Chemical Engineers AIChE J, 59: 4241–4254, 2013     

Nuclear Field Shift Effect of Chromium(III) in Repeated Extraction Using a Crown Ether

Abstract

Chromium isotopes were fractionated by continuous extraction using dicyclohexano‐18‐crown‐6 as an extractant. This system was designed for accumulating isotope effect into the aqueous phase. After a long period of operation (～2 weeks), the Cr isotope ratios in the residual aqueous phase were precisely measured by using a multi‐collector thermal ionization mass spectrometer with the total evaporation technique. The analytical results showed a clear mass‐independent isotope fractionation. The mass‐independent property was consistent with that obtained from a batch extraction. The isotopic mass balance was verified to be preserved in the continuous extraction. The Bigeleisen's 1996 theory gave the consistent explanation on the Cr isotope effect, in which the mass‐independent isotope effect was identified to be the nuclear field shift effect.     

超临界CO_2配合萃取巴戟天中的有害元素

以二乙基二硫代氨基甲酸钠(NaDDC)作为配合剂,乙醇为改性剂,采用超临界CO2配合萃取广东道地药材巴戟天中的有害元素Cu,Pb,As。考察了配合萃取方式、时间、压力、温度、配合剂用量等因素对中药材中有害元素萃取的影响。通过正交实验,建立了有害元素萃取工艺为:萃取压力28 MPa,萃取温度60℃,m(药材)∶m(NaDDC)=5∶1,m(药材)∶m(乙醇)=1∶1,静态萃取1 h,动态萃取2 h。在此条件下,巴戟天中Cu,Pb,As的脱除率均达60%以上,萃取后的药材中有害元素质量比达到美国FDA标准,而生理活性成分巴戟天多糖的质量比保持不变,研究成果为中药材中有害元素的脱除开辟了一条新途径。     

心血管中药方剂暖心方微波提取

因煎煮法等传统萃取方法不适用于提取热稳定性低的成分、萃取率不高，且目前研究主要集中于对单一药材的提取，故本研究使用微波提取技术提取中药复方（暖心方）中的有效成分；采用HPLC技术对提取液中有效成分含量进行分析；采用单因素实验法探究微波功率、萃取时间、提取次数三个因素对提取工艺的影响；此外，通过SEM对细胞破壁情况分析，了解其微波提取机理。实验结果显示，微波提取有效成分的最佳提取条件为：微波功率1200 W、萃取时间40 min、提取次数1次。与传统加热萃取法相比，微波辅助萃取技术能明显地缩短萃取时间，实现了节能高效。微波辐射因能深入并作用于中药材内部，使细胞壁破损，更好地将中药材中的有效成分析出。     

基于Pickering乳液介质萃取苯胺的研究

以Pickering乳液为介质,研究了苯胺的静态和动态萃取过程.考察了乳液用量、氧化镁粒子用量和萃取级数对静态萃取效率的影响作用,以及苯胺进水浓度、乳液用量和进水流速对动态萃取过程的影响作用.结果表明,在静态条件下,乳液单级萃取苯胺的效率为70％,三级萃取效率超过98％.随着Pickering乳液的用量和萃取级数的增加,静态萃取效率提高:随着MgO粒子用量的增大,静态萃取效率呈现先提高后减小的变化趋势.苯胺的动态萃取行为与固定床吸附过程类似,随着乳液用量增加、进水流速减小和进水浓度的减小,出水保持较低浓度(萃取效率高于99％)的时间延长,相应的穿透时间也增长.该研究方法为萃取工艺开辟了新的思路,还可用于中草药有效成分提取、污水处理等分离过程.     

Investigation of liquid–liquid phase equilibria for reactive extraction of lactic acid with organophosphorus solvents

BACKGROUND: Lactic acid is a versatile commodity chemical with a variety of applications. Synthesis of lactic acid either through fermentation of carbohydrates or through chemical synthesis is state of the art. Separation from dilute aqueous solution is complex and accounts for the major part of production costs. Reactive extraction based on reversible adduct formation is a promising alternative for the separation of lactic acid. RESULTS: Extraction was carried out with the organophosphorus solvents tri‐n‐butyl phosphate, tri‐n‐octylphosphine oxide and Cyanex 923. Shellsol T was used as diluent. Partition coefficients increase with increasing extractant content and decreasing temperature. Cyanex 923 has several advantages compared with tri‐n‐butyl phosphate and tri‐n‐octylphosphine oxide with respect to lactic acid distribution and hydrodynamic properties. Liquid‐liquid phase equilibria for lactic acid extraction with Cyanex 923 were modeled. Selectivity of lactic acid extraction with respect to glycolic acid and formic acid was discussed. CONCLUSION: The organophosphorus extractant Cyanex 923 was found to be an appropriate solvent for lactic acid extraction from aqueous solutions. Experimental data and model data based on the Law of Mass Action showed good agreement. Lactic acid extraction from multi‐acid solution showed good selectivity compared with glycolic acid. Lactic acid selectivity is low with respect to formic acid. © 2012 Society of Chemical Industry     

AB-8大孔树脂对黄连解毒汤不同药物组合物理化学参数影响的初步研究

探索大孔树脂分离技术对中药复方不同药物组合物理化学参数的影响。以黄连解毒汤为实验体系,测定AB—8大孔树脂分离前后该复方不同药物组合原液及醇洗脱液的pH值、电导率、浊度、粘度等指标。黄连解毒汤不同药物组合在AB—8大孔树脂分离前后的pH值、电导率、浊度、粘度等方面表现出不同的变化。大孔树脂分离技术可改变中药复方不同药物组合的物理化学参数。     

Sensitive Colorimetric Detection of Explosive 2,6‐Bis(picrylamino)pyridine after Preconcentration by Dispersive Liquid‐Liquid Microextraction

An experimental investigation for sensitive spectrophotometric detection of explosive, 2,6‐bis(picrylamino)pyridine (BPAP) using dispersive liquid‐liquid microextraction was carried out. Based on this procedure, which is a dispersive‐solvent‐free technique, the extractant is dispersed in the aqueous sample solution using Aliquat 336 (acted as disperser agent and carrier to extraction solvent) and monitored with microvolume UV/Vis spectrophotometer. The effect of different variables such as pH, concentration of sodium hydroxide, type and volume of extraction solvent, concentration of Aliquat 336 solution and coexisting substances were systematically investigated and optimized. Interference tests showed that the developed method has a good selectivity and could be used conveniently for determination of explosive analyte. The proposed method is capable of determining BPAP over a range of 2.0–150.0 ng mL⁻¹ with a limit of detection 1.0 ng mL⁻¹. Relative standard deviations (RSD) for 20.0 and 80.0 ng mL⁻¹ of BPAP were 3.3 and 1.2 % (n=10), respectively. This colorimetric method was applied to determine BPAP in different water and soil samples.     

EXTRACTION MECHANISM OF PHENOL BY SULFURIC ACID SALTS OF TRIOCTYLAMINE

In the present study, the extraction mechanism of phenol from an aqueous solution by sulfuric acid salts of trioctylamine (TOA salts) was investigated. Based on the experimental evidence that the affinity of sulfuric acid and amine is greater than that of phenol and amine, the procedure of the extraction mechanism is assumed to involve two independent steps, i.e., trioctylamine (TOA) is first reacted with sulfuric acid to form TOA salts and phenol is extracted from the aqueous phase by TOA salts. The Wilson model, which accounts for the reaction of trioctylamine and sulfuric acid to form different kinds of TOA-salts, is employed to predict the extraction of phenol in the present study. The number of water molecules in the neighborhood of the different TOA-salts, which directly reflects the extraction capability of phenol, was determined. This prediction from the Wilson model is fairly consistent with the experimental data.     

MODEL OF CHEMICAL REACTION EQUILIBRIUM OF SULFURIC ACID SALTS OF TRIOCTYLAMINE

The chemical reaction of trioctylamine (TOA) and sulfuric acid in organic solvent/aqueous solution was carried out. TOA salt products of various kinds were obtained based on different conditions of operation and organic solvents. An equilibrium model, based on the chemical reaction of sulfuric acid and trioctylamine, is proposed. The equilibrium constants of various reactions of trioctylamine and sulfuric acid were searched by means of the modified LETAGROP-DISTR computer program, from which the sum of the least-square error of the extraction of sulfuric acid per unit concentration of TOA salts was minimized. The corresponding concentration profiles of the various main products as a function of the activity of sulfuric acid in the aqueous solution were also obtained. The activity coefficient of the sulfuric acid in the aqueous phase and the density of the aqueous solution of sulfuric acid were considered in order to evaluate the activity of the sulfuric acid in the aqueous solution more accurately. The results obtained from the proposed model are consistent with that of Wilson's published model.     

A new bubbling extraction tower: Toward liquid–liquid solvent extraction at large aqueous‐to‐oil phase ratios

Enrichment and recovery of valuable components in industrial waste waters by traditional liquid–liquid solvent extraction is not economic due to extremely low concentrations of those targets. Large‐phase‐ratio extraction exhibits potential advantages for recovery of small quantities of target components from large volume of aqueous solutions. A novel bubbling extraction tower is proposed toward performing solvent extraction at large aqueous‐to‐oil phase ratios in this work. Organic extractants were covered onto surface of gas bubbles to form a layer of organic liquid membrane and the dispersed organic phase in tower could be small enough. The target components are extracted from aqueous feed solution onto the surface of the bubbles, and the enrichment ratios could be extremely high. We develop a feasible methodology to calculate tower height and operation phase ratios of the bubbling extraction tower, which is essential for future industrial scale‐up. Experimental results in pilot test are highly consistent with calculations. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3889–3897, 2015     

Salt Effects on the Recovery of Phenol by Liquid‐Liquid Extraction with Cyanex 923

Abstract

In this work, the effect of salt addition on the recovery of phenol from a 46 g/L aqueous solution simulating a phenolic resin plant effluent by liquid‐liquid extraction at 298 K has been studied by using an organic phase containing 0.6 M Cyanex 923 extractant in ShellSol T. Addition of sodium sulfate, potassium nitrate, and sodium chloride to the aqueous phase was tested and sodium chloride was selected. Based on the obtained results, a study of phenol recovery process was undergone by taking advantage of the salting‐out effect. Equilibrium curves are presented for liquid‐liquid extraction with and without salt addition to the aqueous phase. An integrated process involving salting‐out and liquid‐liquid extraction was proposed. The stripping concentrates can be reused for phenolic resin production.     

Separation of isopropanol from aqueous solution by salting‐out extraction

A novel salting‐out extraction process has been developed to separate isopropanol from aqueous solution. Potassium carbonate was experimentally shown to be effective in modifying the liquid–liquid equilibrium (LLE) of an isopropanol/water/hexane system in favour of the solvent extraction of isopropanol from an aqueous solution with hexane, particularly at suitable salt concentrations. Potassium carbonate enlarged the area of the two‐phase region. This effect essentially increased the distribution coefficient of isopropanol between hexane and water and increased the separation factor for isopropanol vs water, which is an important consideration in designing a solvent extraction process. The effects of potassium carbonate concentration, temperature and pH on the LLE were studied. Finally, a ?30 mm × 1200 mm reciprocating plate column (RPC) was tested to separate isopropanol from an aqueous solution. When isopropanol in an aqueous solution with composition of isopropanol/water = 1:0.95 (wt/wt) was extracted by hexane assisted with 30% (wt%) potassium carbonate aqueous solution, the alcohol–water ratio increased to 11:1 in the extract. © 2001 Society of Chemical Industry     

用均匀设计和回归分析法优化黄连提取工艺

运用均匀设计和回归分析方法优化中草药黄连的提取工艺。以提取物中药根碱、巴马亭和小檗碱的含量为考察指标,对影响黄连提取工艺的因素进行分析。经优化筛选得到最佳提取工艺,其药根碱、巴马亭和小檗碱的收率分别为10.52、23.58、68.17mgg-1药粉,优于文献报道,可以用于黄连的工业提取过程。研究结果表明,均匀设计和回归分析方法尤其适合应用于多因素、多水平地筛选中药提取过程参数。     

COSMO-RS modeling on the extraction of stimulant drugs from urine sample by the double actions of supercritical carbon dioxide and ionic liquid

This work presents the first research linking chemical engineering and sport science as far as we know. The COSMO-RS (conductor-like screening model for real solvents) model was used to make a priori prediction for the extraction of stimulants from aqueous solution by the double action of supercritical carbon dioxide (SC CO₂) and ionic liquid. It was found that the suitable ionic liquids should have small molecular volume, unbranched group and no sterical shielding effect around anion charge center, and thus [C₂MIM]⁺[OAc]^- is the best among all the ionic liquids investigated. The calculated results from the COSMO-RS model were qualitatively consistent with those from experiments. On this basis, partition coefficients of amphetamine (C9N) and nikethamide (C10N) between aqueous phase and supercritical fluid (or MTBE) phase at different temperatures were calculated. It was shown that the separation efficiency of supercritical extraction with ionic liquid is generally higher than that of traditional liquid-liquid extraction. The modeling present can also be extended to the separation of trace amount of organic substances from aqueous solutions for other purposes.     

NaCl溶液静态闪蒸的蒸发特性

对不同初始条件下NaCl溶液静态闪蒸过程中蒸发质量的变化规律进行了实验研究,实验过程中溶液初始质量分数为5%～26%,初温为74～104℃,初始液位高度为0.1～0.3 m,过热度为0.79～42 K。结果表明:在以ΔT_s为过程参量时,溶液闪蒸蒸发质量随NaCl初始质量分数的增加明显下降;以ΔT为过程参量时,相同初始液位高度,不同初始质量分数NaCl溶液闪蒸蒸发质量相差较小;增加初始液位高度虽可增加总蒸发质量,但使单位质量溶液闪蒸蒸发质量下降;闪蒸蒸发质量随过热度增大而呈近似线性增加。综合分析静态闪蒸过程中主要过程参量对蒸发质量的影响,在实验基础上,提出蒸发质量的量纲1关联式。     

Extraction of rice bran oil using aqueous media

Aqueous extraction of oil from rice bran was studied on a laboratory scale and the resulting product was examined. The following process parameters influencing oil extraction were individually investigated: pH of aqueous media, extraction temperature, extraction time, agitation speed and rice bran‐to‐water ratio. Extraction temperature and pH were found to be the main factors influencing oil extraction. The highest oil yield was obtained at pH 12.0, extraction temperature 50 °C, extraction time 30 min, agitation speed 1000 rpm, and rice bran‐to‐water ratio 1.5‐to‐10. The quality of aqueous‐extracted oil in terms of free fatty acid, iodine value and saponification value was similar to a commercial sample of rice bran oil and hexane‐extracted oil, but the peroxide value was higher. Furthermore, the colour of aqueous‐extracted oil was paler than solvent‐extracted oil. © 2000 Society of Chemical Industry     

Antioxidant activities of selected oriental herb extracts

Antioxidant activities of methanol extracts of 180 Oriental herbs were studied by determining the peroxide values of linoleic acid during storage at 50°C. Among the herb extracts tested, 44 species showed strong antioxidant activities on the oxidation of linoleic acid. The antioxidative effects of these 44 selected herb extracts were studied further in a methyl linoleate system during storage for 35 d. Among the 44 species tested, 11 species had particularly high antioxidative effects. The effects of type of extraction solvent (methanol, petroleum ether and ethyl acetate) on the antioxidant activities of the 11 species were studied. Antioxidant activities of most herb extracts were greatly dependent on the extraction solvent used; however, some of the extracts showed strong antioxidant activities regardless of the solvents used for the extraction. Among the 11 herbs selected, based on the antioxidant activity of their methanol extracts, two (i.e.,Psoralea corylifolia L. andSorphora angustifolia Sieb. & Zucc.) were selected for further study in lard held at 75°C for 7 d. The methanol extracts ofP. corylifolia L. andS. angustifolia Sieb. & Zucc. greatly decreased the peroxide formation of lard during storage. Treatment with 0.20% methanolic extract ofP. corylifolia L. exhibited significantly stronger antioxidant effect on the oxidation of lard than treatment with 0.02% butylated hydroxyanisole (P<0.05).     

Fluorenyl‐containing Quaternary Ammonium Poly(arylene ether sulfone)s for Anion Exchange Membrane Applications

A series of anion exchange membranes (AEM) based on block quaternary ammonium poly(arylene ether sulfone) (QA‐bPAES) were successfully synthesized from 9,9′‐bis(4‐hydroxyphenyl) fluorene, 4,4′‐(hexafluoroisopropylidene) diphenol and 4,4′‐difluorodiphenyl sulfone via block polymerization, chloromethylation, quaternization, alkalization and solution casting. Properties of the obtained QA‐bPAES membranes, including ion exchange capacity (IEC), water uptake, swelling ratios, methanol permeability and ion conductivity were investigated. The obtained QA‐bPAES membranes showed low water uptakes, high ion conductivities and good physical and chemical stability. For example, the membrane of QA‐bPAES(20/10)‐1.34 with IEC of 1.34 mmol g⁻¹ exhibited swelling ratios of 5.0% and 5.1% in in‐plane and through‐plane direction, respectively, and ion conductivity of 15.6 mS cm⁻¹ in water at 60 °C with low methanol permeability of 1.06 × 10⁻⁷ cm² s⁻¹ (25 °C). All the results indicated that this type of block membranes had good potentials for alkaline anion exchange membrane fuel cell applications.     

Predicting the Distribution Constants of Butane Extraction of Organic Pollutants from Aqueous Solubility

The n‐butane/water distribution constant is one of the key parameters in determining the extraction efficiency. Experimental results on 34 organic compounds illustrated that a fundamental linear relationship exists between the distribution constant and the aqueous solubility of the solute. The relationship can be broadly applied to many different classes of chemical compounds as well as to many different solvent extraction systems. The linear equation obtained by a regression method allows one to estimate the distribution constant and predict the result of butane extraction if the aqueous solubility of certain solute is available.