Comprehensive analysis of phenolic composition and antioxidant mechanisms in Gymnema sylvestre extracts using LC-MS and column chromatography

Recent studies have highlighted the potential of plant extracts as therapeutic agents for managing oxidative stress and related disorders.This study aims to elucidate the phenolic composition and antioxidant properties of Gymnema sylvestre extracts.Ethanolic reflux extraction followed by column chromatography was employed to isolate phenolic compounds.The total phenolic and flavonoid contents were quantified using the Folin–Ciocalteu and aluminum chloride colorimetric methods,respectively.Antioxidant activities were assessed by DPPH,ABTS scavenging assays and the ferric reducing antioxidant power(FRAP)assay.High-Performance Liquid Chromatography(HPLC)with a C18 column and Thermo TSQ Quantum Access Max(LC-MS)were used to determine the levels of gymnemic acid and identify other potential phenolic compounds.The analysis revealed significant antioxidant activities in the fractions.Fraction A showed the highest DPPH and ABTS scavenging activities,and Fraction C demonstrated the highest ferric reducing power.LC-MS analysis identified several phenolic compounds,indicating that these are major contributors to the antioxidant efficacy of the extract.This study provides a detailed phenolic profile and confirms the strong antioxidant potential of Gymnema sylvestre leaf extract,supporting its therapeutic use and further investigation.

Separation and analysis of six fractions in low temperature coal tar by column chromatography

The low temperature coal tar(CT)is taken as the raw material,and the extraction and column chromatography are used for detailed and accurate characterization in this paper.The n-heptane soluble fraction(CT-HS)and insoluble fraction(CT-HI)were obtained by n-heptane Soxhlet extraction.The extraction rate of CT-HS reached 92.79%(mass),which indicated that there are few heavy compounds in it.Further,different solvents(methylbenzene,benzene,ethyl acetate,methylbenzene-ethanol)were used to elute CT-HS by chromatographic column to obtain five fractions(saturates,aromatics,heteroatoms,phenolics and resins,named CT-SA,CT-AR,CT-HE,CT-PH,CT-RE,respectively).The yields of CTSA,CT-AR,CT-HE,CT-PH,CT-RE are 42.12%,10.43%,2.19%,9.50%and 6.63%(mass),respectively.Gas chromatography-mass spectrometry analysis of eluting components show that alkanes are the main components in CT,followed by polycyclic aromatics,and the corresponding fractions are CT-SA and CT-AR,respectively.The relative content of aliphatics in CT-SA is 76.93%,and the relative content of aromatics in CT-AR is 75.05%.This separation technology effectively separates and enriches different components in CT,and the activation energy required for the pyrolysis process of a single eluting fraction is lower than that of CT,which is expected to provide an important reference for the separation,analysis and conversion of complex oil products such as coal-oil co-processing products,coal tar and other complex heavy carbon oil products.

Optimization of Preparative Separation and Purification of Total Polyphenols from Sargassum tenerrimum by Column Chromatography

Polyphenols from the ethanol extracts of Sargassum tenerrimum （ST） with potent antiallergic effects were studied to optimize separation process through column chromatography. The adsorption and desorption characteristics of three widely used adsorbents： macroporous resin, silica gel, and polyvinylpolypyrrolidone （PVPP）, were critically evaluated respectively and studied for the optimization of preparative separation of polyphenols. Static operations on these adsorbents showed that macroporous resin had the best adsorption and desorption capability among the three adsorbents. Dynamic adsorption and desorption with macroporous resin packed column were also conducted to optimize the parameters such as： with the optimal values shown in brackets, the concen- tration of extract solution （4 times diluted）, pH value （6-7）, adsorption speed （3BVh-1, bed volumes/per hour）, concentration of ethanol （80%）, elution speed （3 BV ht） and elution volume （7 BV）. The chromatographic process so optimized gave a purity of 62.43% from the crude polyphenols, providing a promising basis for large scale preparation of bioactive polyphenols upon further scaling up tests.

Determination of Five Organic Acids in Radix Isatidis by Column Partition Chromatography and Capillary Zone Electrophoresis柱分配色谱-毛细管区带电泳联用分析板蓝根中五种微量有机酸(英文)

Aim To determine five organic acids in Radix Isatidis . Method The extraction method and the column partition chromatographic conditions were studied. Then a capillary zone electrophoretic method was set up for the determination. Results The linear ranges of quinazolinone acid, n anthranilic acid, benzoic acid, salicylic acid, and syringic acid were 5 52-92 0 μg·mL -1 , 5 12-102 μg·mL -1 , 2 28-84 4 μg·mL-1 , 4 78-159 μg·mL -1 , and 1 74-87 0 μg·mL -1 respectively. Conclusion The established method is accurate and simple.

Group separation and analysis of a carbon disulfide-soluble fraction from Shenfu coal by column chromatography

A carbon disulfide-soluble fraction (CDSSF) from Shenfu coal was separated into five fractions by silica-gel column chromatography using hexane and n-hexane/ethyl acetate binary eluent. The five fractions include four clear group fractions and a nonpolar fraction. All the fractions were analyzed by GC/MS. A total of 204 compounds were detected from the original CDSSF and its further separated fractions, with 173 compounds more than those detected by studying the original CDSSF directly. The results demonstrate a clear group separation by column chromatography in coal organic components and a more accessibility to coal components compared with the solvent extraction only.

Separation and purification of deoxynivalenol(DON) mycotoxin from wheat culture using a simple two-step silica gel column chromatography

Deoxynivalenol（DON） is a type B trichothecenes mycotoxin produced by several Fusarium species, often found in foodstuffs for humans and animals. DON is in great demand for the toxicological researches both in vivo and in vitro. In this work, wheat culture was inoculated with a Fusarium graminearum PH-1 strain for DON production. The solvent system for crude extraction was acetonitrile-water（84：16, v/v）. A simple two-step silica gel column chromatography was employed to separate the DON mycotoxin from wheat culture, combined with preparative high performance liquid chromatography（preparative HPLC） to purify the compound. The solvent system for the second silica gel column chromatography was methylene chloride-methanol（17：1, v/v）, which provided a good elution effect selected on thin layer chromatography（TLC）. The target compound was identified by HPLC, and the chemical structure was confirmed by mass spectrometry（MS） and ~1H and ^（13）C nuclear magnetic resonance（NMR） spectroscopy. A total of 433 mg of purified DON was obtained from 1 kg of wheat culture, with a purity of 99.01%. The study had provided an easy-operating and cost-effective method to isolate an expensive compound in a simple way.

Separation of liquefied product of Salix psammophila by column chromatography and structure analysis of its components

The liquefied product of Salixpsammophila wood was separated by thin-layer chromatography （TLC） and column chromatography, and its structure was identified by nuclear magnetic resonance （NMR） spectra in our study. The separation result indicates that the sample of liquefied S. psammophila contained at least two categories of components. The structure of the main components was guaiacyl C-1, C-2 of the hydroxyphenyl propane, i.e., the aromatic nucleus protons of lignin. Degradation and polycondensation reactions occurred when the S. psammophila wood was liquefied in phenol. Polycondensation reactions occurred among the depolymerization products from cellulose, the aromatic depolymerization products from lignin and the products of the displacement reactions between phenoxide ion and cellulose.

Separation of Inorganic Anions Using Methacrylate-Based Monolithic Column Modified with Trimethylamine in Ion Chromatography Capillary System

Methacrylate-based monolithic column was prepared in fused-silica capillary (80 ′ 0.32 mm i.d.) by in situ polymerizetion reaction using glycidyl methacrylate as monomer;ethylene dimethacrylate as crosslinker;1-propanol, 1,4-butanediol, and water as porogenic solvents. The monolith matrix was modified with trimethylamine to create strong anion exchanger via ring opening reaction of epoxy groups. The morphology of the monolithic column was studied by using Scanning Electron Microscope (SEM). This column had good mechanical stability and permeability. The effects of various mobile phases for separation of inorganic anions were investigated. Iodate, bromate, nitrite, bromide, and nitrate were separated within 11 min using100 mMpotassium chloride as mobile phase and detected at 210 nm. This method showed good precision of retention time, acceptable linearity and good sensitivity. Under the optimum condition, the RSD of the retention time was in the range of 1.09%-1.75% (n = 6). The calibration curve showed linear relationships between the peak area and the concentration. The limits of detection (LOD) and the limits of quantitation (LOQ) were between 0.08-0.18 mM and 0.26-0.61 mM, respectively. This method was applied to the determination of inorganic anions in tap water and ground water samples.

Research Progress on the Separation of Alkaloids from Chinese Medicines by Column Chromatography

Alkaloids have a variety of bioactivities and great development value in the fields of pharmaceuticals, cosmetics and health food. Column chromatography is a common method for preparing alkaloids. In this paper, the research status of the separation and purification of alkaloids from Chinese medicines by column chromatography is reviewed, and the factors that influence the refining of alkaloids via a macroporous adsorption resin, ion exchange resin and silica gel are summarized. The thermodynamic and kinetic modeling methods for the static adsorption of adsorbents are also reviewed in this paper. It is suggested that the modeling method of the column chromatography process be deeply studied to establish a more stringent quality control method for sampling liquid and to strengthen the online detection of the chromatography process to improve the refining effect of alkaloids.

Column Chromatography: A Facile and Inexpensive Procedure to Purify the Red Dopant DCJ Applied for OLEDs

DCJ, one of the DCM derivatives, has been used as a laser dye and a red emitter or a red dopant for OLED devices in recent decade. 4-(dicyanomethylene)-2-methyl-6-(julolidyl-9-enyl)-4H-pyran (DCJ) containing julolidine group has been synthesized for use as a red fluorescent dye molecule in organic light-emitting di- odes (OLEDs). In this paper, we reported a facile, simple and inexpensive procedure of purification of DCJ without necessity of HPLC analysis. The maximum absorption, emission, quantum efficiency are increasing in DCJ with the electron-donating of julolidine group.

Determination of petroleum sulfonates in crude oil by column-switching anion-exchange chromatography

A column-switching anion-exchange chromatography method was described for the separation and determination of petroleum monosulfonates （PMS） and petroleum disulfonates （PDS） in crude oil that was simply diluted with the dichloromethane/methanol （60/40）. The high performance liquid chromatography （HPLC） system consisted of a clean-up column and an analytical column, which were connected with two six-port switching valves. Detection of petroleum sulfonates was available and repeatable. This method has been successfully applied to determine PMS and PDS in crude oil samples from Shengli oil field.

Identification of Glyphosate Herbicide with Ion Chromatographic Column Switching Method

[Objective] The paper was to establish the method for quantitative analysis of glyphosate herbicide and identification of salt type. [Method] Using ion chromatographic column switching method,cations( sodion,ammonium ion,potassium ion,dimethonium ion and isopropylamine ion) and glyphosate anion in glyphosate salt were determined with Thermo IonP ac SCS1 cation exchange column and Thermo IonP ac AS14 anion exchange column,and external standard method was used for quantification. [Result] Various components showed good linear relationship within the linearity range,and the correlation coefficient r was greater than 0. 999; the relative standard deviation of retention time and peak area were less than 0. 13% and 1. 22%,respectively; the recovery was 98. 22%-99. 97%.[Conclusion] The method is precise,accurate and simple,and can be used to determine the active ingredients of glyphosate herbicide.

Simultaneous enantioseparation and simulation studies of atenolol,metoprolol and propranolol on Chiralpak^■IG column using supercritical fluid chromatography

Enantioseparation of threeβ-blockers,i.e.,atenolol,metoprolol and propranolol,was studied on amylose tris(3-chloro-5-methylphenylcarbamate)immobilized chiral stationary phase using supercritical fluid chromatography(SFC).The effect of organic modifiers(methanol,isopropanol and their mixture),column temperature and back pressure on chiral separation ofβ-blockers was evaluated.Optimum chromatographic separation with respect to resolution,retention,and analysis time was achieved using a mixture of CO_(2) and 0.1%isopropyl amine in isopropanol:methanol(50:50,V/V),in 75:25(V/V)ratio.Under the optimized conditions,the resolution factors(Rs)and separation factors(a)were greater than3.0 and 1.5,respectively.Further,with increase in temperature(25-45℃)and pressure(100-150 bars)there was corresponding decrease in retention factors(k),a and Rs.However,a reverse trend(a and Rs)was observed for atenolol with increase in temperature.The thermodynamic data from van’t Hoff plots revealed that the enantioseparation was enthalpy driven for metoprolol and propranolol while entropy driven for atenolol.To understand the mechanism of chiral recognition and the elution behavior of the enantiomers,molecular docking studies were performed.The binding energies obtained from simulation studies were in good agreement with the elution order found experimentally and also with the free energy values.The method was validated in the concentration range of 0.5-10μg/m L for all the enantiomers.The limit of detection and limit of quantitation ranged from 0.126 to 0.137μg/m L and 0.376-0.414μg/m L,respectively.The method was used successfully to analyze these drugs in pharmaceutical preparations.

柱前衍生-高效液相色谱法测定巴戟天中氨基酸含量及营养价值评价

建立柱前衍生-高效液相色谱法测定巴戟天中氨基酸含量,采用氨基酸比值系数法评价其营养价值。采用盐酸水解法制得巴戟天氨基酸供试品溶液,以异硫氰酸苯酯和三乙胺为柱前衍生化试剂,采用高效液相色谱法,使用Ultimate Amino Acid色谱柱(4.6 mm×250 mm,5μm)以0.1 mol/L无水乙酸钠-乙腈为流动相,梯度洗脱,柱温40℃,检测波长为254 nm,测定氨基酸含量;通过氨基酸比值、氨基酸比值系数、氨基酸比值系数分等评价其营养价值,并采用系统聚类和主成分分析对其进行分类分析。结果表明,15种氨基酸线性关系良好,相关系数r≥0.9996。16份巴戟天氨基酸总含量为17.87~102.15 mg/g,均检测到15种氨基酸,其中包含6种必需氨基酸,占总氨基酸含量的14.15%~32.06%;8种药用氨基酸,占总氨基酸含量的45.20%~56.31%。限制氨基酸为苏氨酸和亮氨酸,氨基酸比值系数分为33.87~61.31。不同巴戟天样品氨基酸组成相关性显著;主成分分析提取2个主成分,累计方差贡献率为97.085%,可将16批巴戟天分为三类。该实验测定方法简单有效,可同时分离测定15种氨基酸,精密度与重复性良好,有较高的药用价值,可为巴戟天的品质分析和资源开发利用提供参考。

柱前衍生-高效液相色谱法测定化妆品中16种氨基酸的含量

提出了2,4-二硝基氟苯(DNFB)柱前衍生-高效液相色谱法测定化妆品中甘氨酸、亮氨酸、组氨酸、缬氨酸、甲硫氨酸、脯氨酸、半胱氨酸、苏氨酸、谷氨酸、赖氨酸、酪氨酸、精氨酸、异亮氨酸、色氨酸、苯丙氨酸、丙氨酸等16种氨基酸含量的方法。取化妆品样品5 g置于50 mL离心管中,加入5 mL水,超声10 min,加热煮沸15 min,冷却后加入15 mL 35 g·L^(−1)磺基水杨酸溶液,以转速10500 r·min^(−1)离心20 min。取全部上清液,用35 g·L^(−1)磺基水杨酸溶液定容至25 mL。取1 mL样品溶液,加入0.5 mol·L^(−1)碳酸氢钠溶液(pH 9.0)1 mL和1%(体积分数)DNFB衍生溶液1 mL,混匀,于60℃加热10 min,冷却后用0.01 mol·L^(−1)磷酸二氢钾溶液(pH 7.0)定容至5 mL,所得溶液中16种氨基酸经X Bridge C_(18)色谱柱分离,以不同体积比的含1%(体积分数)N,N-二甲基甲酰胺的0.05 mol·L^(−1)乙酸钠缓冲液(pH 6.5)-体积比1∶1的乙腈-水混合溶液为流动相进行梯度洗脱,在360 nm处检测。结果表明:16种氨基酸标准曲线的线性范围均为0.004~40.0 mg·L^(−1),检出限(3S/N)为0.1~0.2 mg·kg^(−1);对空白样品进行3个浓度水平的加标回收试验,回收率为89.0%~105%,测定值的相对标准偏差(n=7)均不大于10%。方法用于11种市售化妆品分析,检出的氨基酸成分多为组氨酸、甘氨酸、甲硫氨酸、谷氨酸。

基于在线柱切换液相色谱技术的红霉素软膏含量测定研究

目的建立在线柱切换高效液相色谱法测定红霉素软膏中主药含量的方法,为相关制剂的质量控制提供有效手段。方法样品经80℃提取后直接进样,柱切换系统下,采用C_(18)(50 mm×2.1 mm,5μm)色谱柱初步分离,2.5 min后转入C_(18)(150 mm×2.1 mm,5μm)柱进行分析,流速0.2 mL·min^(-1),柱温35℃。结果红霉素在1~100μg·mL^(-1)范围内线性关系良好(r=0.9994);平均加样回收率大于96.9%;日内和日间精密度小于1.29%(n=6)。结论本研究改进样品提取方法,并通过在线柱切换完成目标组分的净化和富集,该方法操作简单、准确灵敏、稳定性好,可用于红霉素软膏的含量测定。

荔枝草中乙酸乙酯层化学成分分析

目的:对荔枝草的乙酸乙酯层进行化学成分研究。方法:采用硅胶柱色谱、中压快速色谱和Sephadex-LH凝胶色谱等方法进行分离纯化,运用波谱手段、理化性质和文献对照进行各单体化合物的结构鉴定。结果:从荔枝草的乙酸乙酯层分离出2个单体化合物,分别鉴定为泽兰黄酮和高车前素。结论:采用中压色谱能从荔枝草乙酸乙酯萃取层中快速大量提取泽兰黄酮和高车前素,该方法省时、简便、高效,值得推广应用。

气相色谱-质谱法测定酒店空气中7种苯系物

试验运用气相色谱-质谱法测定扩建装修酒店空气中7种苯系物,采用活性炭管采样和二硫化碳解吸,同时对质谱参数和色谱柱进行优化。结果表明,色谱柱能有效分离苯系物中7种待测组分,实现各组分峰完全分离。苯系物具有良好线性关系,相关系数R^(2)>0.999,检出限介于0.60~2.20μg/L,加标回收率为93.9%~98.2%,相对标准偏差为1.8%~4.0%,准确度和精密度良好。苯系物质量控制样品测定表明,该方法符合质控范围。气相色谱-质谱法可用于检测酒店空气中7种苯系物,方法准确可靠,灵敏度高。

不同超高效液相系统对色谱柱柱效能测定结果的影响

目的探索GB/T 30433⁃2021中柱效能的测试参数,是否适用于高效液相色谱柱。方法比较同一超高效液相系统下,不同甲醇/水溶液流动相比例(40∶60,50∶50,55∶45),不同流量(0.20 mL/min,0.22 mL/min,0.25 mL/min,0.28 mL/min,0.30 mL/min),不同进样量(0.1μL,0.2μL)对高效液相色谱柱柱效能的影响;比较两种超高效液相系统(1290 Infinity II和APUS Plus),在两种不同色谱参数(色谱参数一∶乙腈/水溶液=40∶60,流量=0.5 mL/min,进样量=1.0μL;色谱参数二∶甲醇/水溶液=50∶50,流量=0.20 mL/min,进样量=0.2μL)下,对高效液相色谱柱柱效能每米理论板数的影响。结果同一超高效液相系统,在甲醇/水溶液比例为50∶50,流量为0.20 mL/min,进样量为0.2μL的色谱参数下,高效液相色谱柱柱效能每米理论板数的结果较优;不同超高效液相色谱系统下每米理论板数测试结果差异较大。结论不同超高效液相系统下,柱效能每米理论板数的测定结果除受色谱柱自身性能和色谱参数的影响,还与系统及检测器等柱外硬件相关。

超高效液相色谱在洗洁精表面活性剂检测中的应用

为了能够更加精准地检测洗洁精表面活性剂含量,提出超高效液相色谱在洗洁精表面活性剂检测中的应用研究。考虑到大部分洗洁精应用的表面活性物质均为甜菜碱或氧化胺类物质,设置了以甜菜碱和氧化胺类物质为核心的超高效液相色谱试剂,选择U3000高效液相色谱仪,日本新宇宙XP-302M电雾式检测器以及Acclaim Surfactant Plus分析柱作为具体的测试装置,对测试环境温度和U3000高效液相色谱仪的流速进行定值设置后,按照乙腈洗脱执行梯度对色谱柱进行处理后,将满足线性范畴的数据作为计算洗洁精表面活性剂含量的基础参数,带入到回归方程中,确定各表面活性剂含量,对应的检测结果误差稳定在0.015%以内,单一类别洗洁精表面活性剂含量检测结果误差稳定在0.003%以内。