Microwave-assisted extraction and fingerprint studies of Schisandra chinensis (Turcz.) by high performance liquid chromatography and gas chromatography

In order to choose an appropriate extraction method, samples of Schisandra chinensis (Turcz.) Baill were extracted by different methods and it was found that microwave-assisted extraction gave the best results. The contents of schisandrin, schisantherin, deoxyschizandrin, and r-schizandrin of 10 samples collected from different regions in China were determined by HPLC. The chromatograms of ten samples were used to establish the fingerprints of Schisandra chinensis (Turcz.) Baill and two methods based on HPLC and GC were applied to them simultaneously. The fingerprints consisted of 18 common peaks obtained by HPLC and 17 common peaks obtained by GC, which showed good stability and repeatability with RSD less than 3% for retention time. The fingerprints are suitable for identifying and differentiating samples by geographical origin and can be used for quality control.     

Development of a quality evaluation method for Fructus schisandrae by pressurized capillary electrochromatography

A pressurized CEC (pCEC) method with postcolumn detection cell had been developed for quantifying the lignans from Fructus schisandrae extracts. The effects of different experimental conditions, such as the ACN content of the mobile phase, the concentration and pH of the buffer, the applied voltage, and the supplementary pressure were studied. Five lignans (schisandrin, gomisin A, schisantherin C, deoxyschizandrin, schisandrin B) were baseline separated using a mobile phase of ACN-phosphate buffer (pH 5.4; 5 mM) (40:60 v/v) under -4 kV applied voltage. The method showed the satisfactory retention time and peak area repeatability. The calibration curves were linear in the range 50.0-1000.0 microg/mL for schisandrin, 20.0-500.0 microg/mL for gomisin A, 10.0-200.0 microg/mL for schisantherin C, 20.0-500.0 microg/mL for deoxyschizandrin, and 20.0-500.0 microg/mL for schisandrin B. The correlation coefficients were between 0.9978 and 0.9989. With this pCEC system, fingerprints of F. schisandrae were preliminarily established to distinguish two members S. chinensis (Turcz.) Baill. and S. sphenanthera Rehd. Et Wils. of F. schisandrae by characteristic peaks, and evaluate the quality of various sources of raw materials by determining the contents of the five lignans.     

Simultaneous and rapid determination of main lignans in different parts of Schisandra sphenanthera by micellar electrokinetic capillary chromatography

Lignans are imporant active ingredients of Schisandra sphenanthera. A micellar electrokinetic chromatography method was developed for the simultaneous determination of eight lignans--schizandrin, schisandrol B, schisantherin A, schisanhenol, anwulignan, deoxyschizandrin, schizandrin B and schizandrin C--in different parts of S. sphenanthera. The key factors for separation and determination were studied and the best analysis conditions were obtained using a background electrolyte of 10 mM phosphate-37.5 mM SDS-35% v/v acetonitrile (pH 8.0) at the separation voltage of 28 kV and detection at 214 nm, whereby the plant samples could be analyzed within 9.0 min. Analysis yielded good reproducibility (RSD between 1.19-2.28%) and good recovery (between 92.2-103.8%). The detection limits (LOD) and limit of quantification (LOQ) were within 0.4-1.2 mg/L and 1.5-4.0 mg/L. This method is promising to improve the quality control of different parts of S. sphenanthera.     

南北五味子荧光光谱差异的原因

建立了用荧光法快速鉴别五味子和部分含五味子制剂中五味子是属于北五味子还是南五味子的方法,探明了南北五味子荧光光谱差异的主要原因。研究了五味子的五种活性成分五味子醇甲、五味子酯甲、五味子甲素、五味子乙素和安五脂素的荧光性质和五味子以及护肝片乙醇提取液的荧光光谱,并用高效液相色谱测定了供试品五种活性成分的含量。研究表明：发光效率按安五脂素、五味子乙素、五味子甲素和五味子醇甲依次减弱,五味子酯甲不具有荧光性;北五味子的主要荧光物质为五味子乙素,而南五味子的主要荧光物质是安五脂素,它们是导致南北五味子荧光光谱差异的主要原因。用荧光法鉴别南北五味子具有简单、快速和灵敏的特点     

二维反相液相色谱制备五味子中的木脂素

应用自主研发的具有分离-富集模式的制备色谱工厂,建立了分离制备五味子木脂素有效部位及其单体化合物的方法。该方法首先以C₁₈（250 mm×4.6 mm,5 μm）为色谱柱,水和甲醇为流动相,分离度和保留时间为考察指标,采集4个不同梯度的色谱信息,通过XTool色谱专家系统软件模拟,确定五味子木脂素第一、二维色谱条件;然后采用线性放大的方法,以C₁₈（250 mm×30 mm,10 μm）为第一、二维分离柱,C₁₈（80 mm×30 mm,10 μm）为富集柱,水为富集稀释液,对五味子木脂素进行二维色谱分离纯化;最后第一维分离得到9个可重复组分,第二维分离得到20个高纯度化合物,其中有6个单体化合物。结果表明该法重现性良好,可以实现五味子木脂素的系统性分离,对五味子化学成分的研究具有重要意义。     

多功能离子液体分散液液微萃取结合高效液相色谱法检测人尿中5种邻苯二甲酸酯代谢物

将多功能离子液体与分散液液微萃取（DLLME）技术相结合，建立了测定尿液中5种邻苯二甲酸酯类（PAEs）物质代谢产物的高灵敏度新方法。对影响DLLME效率的各单因素进行了优化，包括萃取剂的种类及体积、分散剂的种类及体积、萃取温度、超声时间、冷却时间、离心时间和盐效应等条件，经过严格的优化，最佳的萃取条件分别为：萃取剂[C₈MIM]PF₆]35 μL，分散剂[BSO₃HMIm]OTf]30 μL和[C₄MIM]BF₆]120 μL，萃取温度为35℃，超声时间5 min，冷却时间5 min，离心时间5 min，盐析剂NH₄PF₆ 0.1 g。在最佳的萃取条件下，5种PAEs代谢物在0.5~1000 μg/L范围内具有良好的线性关系，决定系数（R²）均大于0.9955，方法检出限为0.16~0.19 μg/L，尿液中添加低中高水平（5、20、100 μg/L）的PAEs代谢物，其回收率为92.9%~105.0%，日内精密度及日间精密度的相对标准偏差（RSD）均小于5.96%，方法学验证各指标及稳定性均符合分析要求。对所采集的10份糖尿病患者的尿液进行检测，并对该人群PAEs代谢物的暴露水平进行评价。结果表明，各PAEs代谢物均有检出，其中邻苯二甲酸单（2-乙基己基）酯（MEHP）的检出率为100%。总之，该方法萃取过程中未添加有毒的有机试剂，均使用多功能离子液体作为萃取剂、分散剂和盐析剂，萃取过程绿色环保，简单高效；方法的灵敏度较高，稳定性较好，适用于人体尿液中痕量PAEs代谢物的检测。     

Determination of lignans in Wuweizi by using magnetic bar microextraction and HPLC

In this paper, a magnetic bar microextraction was developed to extract schisandrin A, schisantherin A, and deoxyschizandrin from Wuweizi. The analytes were determined by HPLC. A stainless‐steel wire was inserted into the hollow of the hollow fiber to make the magnetic bar. The bar can be used to stir the extraction system and extract the analytes, and was isolated from the extract system by magnetic force. Several experimental parameters, including type and volume of extraction solvent, the number of magnetic bars, extraction temperature and time, stirring speed and NaCl concentration were investigated and optimized. The LODs for schisandrin A, schisantherin A, and deoxyschizandrin were 0.14, 0.06, and 0.10 μg/mL, respectively. The recoveries were in the range of 70.90–106.67% and the RSDs were < 8.84%. Compared with ultrasound‐assisted and Soxhlet extraction, when the present method was applied, the extraction time was shorter, the sample amount was smaller, and the consumption of organic solvent was lower.     

基于离子液体的分散液液微萃取-柱前荧光衍生高效液相色谱法测定水样中8种磺胺类药物

建立了一种基于离子液体的分散液液微萃取技术结合柱前荧光衍生高效液相色谱(IL-DLLME-HPLC-FL)对8种磺胺类药物进行检测的方法,并成功应用于实际环境水样的分析。实验考察了萃取参数对磺胺萃取效率的影响及衍生产物的稳定性。最佳实验条件:以40 μL [C₆MIM]PF₆]为萃取剂,0.1 mL丙酮为分散剂,对pH=4且不含NaCl的水溶液进行不超声的分散液液微萃取,并衍生化反应6 h。结果表明:在最佳实验条件下,该法在0.2~10 μg/L和10~500 μg/L两个浓度范围内线性良好,线性相关系数r ≥0.9989;检出限为0.08~0.5 μg/L (S/N=3)。对实验室自来水、湖水、珠江水、池塘水分别加标5、50、200 μg/L的回收率为87.2%~101.4%,相对标准偏差为3.7%~6.2%。该法环保、简便,可用于测定实际水样中磺胺类药物。     

LC Analysis of Lignans from Schisandra sphenanthera Rehd. et Wils.

Schisandra sphenanthera Rehd. et Wils. is widely used in traditional Chinese medicine. A rapid and convenient method to separate and quantify four lignans (schisandrin, schisantherin A, deoxyschizandrin, and γ-schizandrin) was established by reversed-phase liquid chromatographic. On a Shimadzu C₁₈ column (Phenomenex, 150 × 4.6 mm; 5 μm particle size), an isocratic flow elution program and a simplified sample pretreatment approach were used in the experiment. Samples from different parts of S. sphenanthera were extracted by chloroform and then separated with methanol and deionized water (70:30 v/v) at a flow rate of 0.8 mL min^?1. The detection wavelength was set at 280 nm. The content of lignans in fruits is the highest, and the quantities of schisantherin A, deoxyschizandrin, and γ-schizandrin from fruits are 0.56, 0.54 and 0.30%, respectively. Schisandrin is not detected in all the plant extracts. This research forms a basic framework for the better use of S. sphenanthera in medicine.     

LC Analysis of Lignans from Schisandra sphenanthera Rehd. et Wils.

Schisandra sphenanthera Rehd. et Wils. is widely used in traditional Chinese medicine. A rapid and convenient method to separate and quantify four lignans (schisandrin, schisantherin A, deoxyschizandrin, and γ-schizandrin) was established by reversed-phase liquid chromatographic. On a Shimadzu C₁₈ column (Phenomenex, 150 × 4.6 mm; 5 μm particle size), an isocratic flow elution program and a simplified sample pretreatment approach were used in the experiment. Samples from different parts of S. sphenanthera were extracted by chloroform and then separated with methanol and deionized water (70:30 v/v) at a flow rate of 0.8 mL min⁻¹. The detection wavelength was set at 280 nm. The content of lignans in fruits is the highest, and the quantities of schisantherin A, deoxyschizandrin, and γ-schizandrin from fruits are 0.56, 0.54 and 0.30%, respectively. Schisandrin is not detected in all the plant extracts. This research forms a basic framework for the better use of S. sphenanthera in medicine.

     

Electrical impedance spectroscopy characterisation of supported ionic liquid membranes

Supported liquid membranes (SLMs), prepared by immobilising the room temperature ionic liquids (RTILs) [C_nMIM]PF₆ (n = 4 and 8) and [C₁₀MIM]BF₄ in a polyvinylidene (PVDF) supporting membrane, were prepared and characterised by electrochemical impedance spectroscopy (IS). This non-invasive technique allows the determination of the electrical properties of a given sample, such as the electrical resistance and capacitance under working conditions, i.e., in contact with saline solutions.

Bearing in mind that the water content of the ionic liquids can drastically affect their physicochemical properties, impedance measurements of the SLMs, placed between two aqueous solutions, were carried out at regular time intervals, in order to assess the impact of the presence of water inside the RTILs on the electrical properties of supported ionic liquid membranes. The electrical resistance of the SLMs and its variation during long-term operation was also used as a physical parameter to identify the presence/loss of ionic liquid from the pores of the support. Additionally, the comparison of the IS results obtained for the SLMs with those obtained for the supporting membrane was carried out, in order to gather information about electrical changes associated with the presence of ionic liquid in the pores.     

Variation of the Lignan Content of Schisandra chinensis (Turcz.) Baill. and Schisandra sphenanthera Rehd. et Wils.

A rapid and convenient extraction technique followed by HPLC analysis has been developed for determination of lignans in Schisandra chinensis (Turcz.) Baill. and Schisandra sphenanthera Rehd. et Wils. Under the optimized conditions the lignans schisandrin, schisantherin, deoxyschisandrin, and γ-schisandrin were extracted from ten samples collected from different regions in China and then quantified by HPLC. The lignan content of the ten samples is different. S. sphenanthera Rehd. et Wils. is richer in deoxyschisandrin but there is less schisandrin and γ-schisandrin is not found. S. chinensis (Turcz.) Baill. is usually richer in γ-schisandrin, the maximum amount being 4.263 mg g⁻¹, although one sample contained none. This method is simple, rapid, sensitive, and repeatable, and is suitable for identification and differentiation of samples from different regions of China.     

Combination of ionic liquid dispersive liquid-phase microextraction and high performance liquid chromatography for the determination of triazine herbicides in water samples

A temperature-controlled ionic liquid dispersive liquid-phase microextraction in combination with high performance liquid chromatography was developed for the enrichment and determination of triazine herbicides such as cyanazine,simazine,and atrazine in water samples.1-Octyl-3-methylimidazolium hexafluorophosphate([C8MIM][PF6]) was selected as the extraction solvent.Several experimental parameters were optimized.Under the optimal conditions,the linear range for cyanazine was in the concentration range of 0.5–80 mg/L and the linear range for simazine and atrazine was in the range of1.0–100 mg/L.The limit of detection(LOD,S/N = 3) was in the ranges of 0.05–0.06 mg/L,and the intra day and inter day precision(RSDs,n = 6) was in the ranges of 3.2%–6.6% and 4.8%–8.9%,respectively.Four real water samples were analyzed with the developed method,and the experimental results showed that the spiked recoveries were satisfactory.All these exhibited that the developed method was a valuable tool for monitoring such pollutants.     

超分子有序聚集凝固液相微萃取及其对五味子中木脂素类化合物的测定及质量评价

通过分析比较漂浮有机液滴凝固液相微萃取(SFODLPME)对木脂素类化合物萃取前后紫外光谱的变化, 提出了超分子有序聚集凝固液相微萃取(SSMOALPME)机理; 建立了简单、 快速、 灵敏的SSMOALPME高效液相色谱法(HPLC)同时测定中药五味子中5种低丰度木脂素类化合物含量的方法, 并对不同产地五味子的质量进行比较和评价. 在最佳的SSMOALPME条件下, 测得五味子醇甲, 五味子酯甲, 五味子甲素, 五味子乙素和五味子丙素的线性范围分别为2.48×10^-3~6.21, 2.27×10^-3~28.5, 2.31×10^-3~28.8, 2.27×10^-3~5.69和1.05×10^-3~5.25 μg/mL; 检出限分别为0.4, 0.4, 0.4, 0.08和0.08 ng/mL; 日内及日间精密度RSD<9.7%; 药材中分析物的回收率为91.9% ~104.7%; SSMOALPME对5种分析物的富集倍数分别在39 ~529倍之间. 本法测定结果与药典法测定结果相比无显著差异(P=95%). SSMOALPME方法的提出为液相微萃取的理论研究奠定了基础, 为反映中药多成分、 多靶点及协同作用的特性, 建立科学的质量控制方法提供了理论依据和实验基础.     

Ionic Liquid-based Microwave-assisted Liquid-liquid Microextraction and High Performance Liquid Chromatography Determination of Sulfonamides from Animal Oils

The authors performed ionic liquid-based microwave-assisted liquid-liquid microextraction(IL-based MALLME) coupled with high performance liquid chromatographic separation for the determination of 6 sulfonamides (SAs) from animal oils. The target analytes were extracted from animal oil samples with sodium hydroxide solution containing 1-butyl-3-methylimidazolium tetrafluoroborateand as the extraction solvent under microwave irradiation. The experimental parameters of the IL-based MALLME, including types of ILs, volume of IL, amount of ion-pairing agent(NH₄PF₆), pH value of sample solution, and extraction temperature and time were evaluated. The limits of detection and quantification obtained were in a range of 0.4―0.5 μg/kg and a range of 1.2―1.8 μg/kg, respectively. The accuracy of the method was evaluated by analyzing five spiked animal oil samples at two fortified levels(5 and 50 μg/kg), and the recoveries of SAs varied from 81.4% to 114.5% with relative standard deviations ranging from 0.8% to 9.0%.     

Homogeneous ionic liquid microextraction of the active constituents from fruits of Schisandra chinensis and Schisandra sphenanthera

Homogeneous ionic liquid microextraction (HILME) was developed for the extraction of schizandrin, schisantherin A and deoxyschizandrin from Schisandra chinensis and Schisandra sphenanthera. 1-Butyl-3-methylimidazolium tetrafluoroborate ([C₄MIM][BF₄]) aqueous solution was used as extraction solvent, and ammonium hexafluorophosphate ([NH₄][PF₆]) was used as ion-pairing agent. 1-Butyl-3-methylimidazolium hexafluorophosphate ([C₄MIM][PF₆]), which is barely soluble in water, was formed in situ, and was used as sample solution. High-performance liquid chromatography (HPLC) was employed for separation and determination of the analytes. The calibration curve showed good linear relationship (r > 0.9998). The recoveries were between 69.71% and 88.33% with RSDs lower than 4.86%. External standard method was adopted in the proposed method, and internal standard method was applied for the evaluation of the proposed method. The two methods were compared and the results indicated that the proposed method was acceptable and simple. The HILME is free of volatile organic solvents, and represents lower expenditures of sample, extraction time and solvent, compared with ultrasonic and Soxhlet extraction. There was no obvious difference in the extraction yields of active constitutions obtained by the three extraction methods.     

GC-MS of volatile components of Schisandra chinensis obtained by supercritical fluid and conventional extraction

In this paper, the volatile compounds of Schisandra chinensis obtained by different extraction techniques including supercritical fluid extraction (SFE), steam distillation (SD), Soxhlet extraction (SE) and ultrasound-assisted extraction (UAE) were investigated for the first time. The sample preparation procedure for GC-MS analysis of the volatile compounds was optimized and then 37, 45, 27 and 37 compounds were identified in the samples obtained by SFE, SD, SE and UAE methods, respectively. As the therapeutic effect of the traditional Chinese medicine is usually based on multifarious essential components or the combination of them instead of only one component, the volatile compounds were compared in groups with the extracts by SE, SD and UAE. This would be more reasonable to evaluate the effects of an alternative technique to extracting multifarious essential components. Among the identified components in the SFE extract, 32 compounds were the same as that by three conventional methods, accounting for 90.5% of the volatile compounds identified. However, as the volatile compounds were classed into groups, it was easy to see that the Schisandra chinensis oil extracted by SFE was made up largely of aromatics and sesquiterpenoids (52.1 and 27.6%, respectively), with less amounts of monoterpenoids and other compounds, distinguishing SFE from the conventional extractions.     

Bioanalytical assay development and validation for simultaneous quantification of five schisandra lignans in rat primary hepatocytes based on LC‐MS/MS: application to a real‐time uptake study for Schisandra Lignan Extract

Schisandra lignans, mainly including schizandrol A, schizandrol B, schisantherin A, schizandrin A, schizandrin B, etc., are the major active ingredients of Schisandra chinensis . In the present study, a robust liquid chromatography–tandem mass spectrometric (LC‐MS/MS) method was developed for the simultaneous quantification of schisandra lignans in rat primary hepatocytes. Lovastatin was used as an internal standard, and chromatographic separation was achieved on a Shimadzu C₁₈ column with a gradient elution at the flow rate of 0.2 mL/min. All of the analytes were detected in multiple reaction monitoring mode with positive electrospray ionization since the sodium adduct ion [M + Na]⁺ was observed as the most intensive peak in the MS spectrum. For schizandrol A, schisantherin A and schizandrin A, the dynamic range was within 2–1000 ng/mg protein, and the linear range of schizandrol B and schizandrin B was from 5 to 1000 ng/mg protein. The intra‐ and inter‐day precision was <15% and the accuracy (relative error) ranged from −15 to 15%. No significant variation was observed in the stability tests. The validated method was then successfully applied to the time‐dependent uptake study for the Schisandra Lignan Extract in rat primary hepatocytes.     

Differentiation of Schisandra chinensis and Schisandra sphenanthera using metabolite profiles based on UPLC-MS and GC-MS

Historically, Schisandra chinensis and S. sphenanthera have been widely used in traditional Chinese medicine. Although both species are in the genus Schisandra, they have dissimilar therapeutic effects that may be attributed to compositional differences in secondary metabolites. We developed a method to compare these metabolites obtained from the above plant species using ultra-performance liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry coupled with multivariate statistical analyses. The critical markers we used to discriminate between both plant species resulted in the identification and quantification of six lignans and seven essential oils. We believe that our approach provided a sensitive, reliable and robust method to conveniently classify medicinal plants that can be used to explore subtle variations among different species or plants from different geographical locations.     

γ-Radiation effect on ionic liquid [bmim][BF4]

The effect of γ radiation on 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF₄]) was investigated in detail. It was found that radiation induced an increase of UV absorption of the ionic liquid but no change in its glass transition point. Raman spectroscopy analysis indicates that the radiolysis of [bmim][BF₄] induces detectable destruction of alkyl-chain and scission of H-atoms of ring of imidizolium cation, and the relatively small changes of BF₄⁻ anion. Viscosities of irradiated [bmim][BF₄] samples were measured at different shear rates and temperatures, and compared with irradiated [bmim][PF₆] samples. The plots of shear stress against shear rate indicates that [bmim][BF₄] is a Newtonian fluid, no matter with irradiation. The viscosity of irradiated [bmim][BF₄] decreased with increasing of temperature and followed an Arrhenius equation. However, radiation caused no change in the viscosity of [bmim][BF₄], but a decrease in the viscosity of [bmim][PF₆] by up to 10%. We conclude that the radiation stability of [bmim][BF₄] is higher than [bmim][PF₆].