Isolation and Purification of Unstable Iridoid Glucosides from Traditional Chinese Medicine by Preparative High Performance Liquid Chromatography Coupled with Solid-phase Extraction

An efficient preparative method was successfully developed for isolation and purification of unstable components from medicinal plant extracts, using a combined method of preparative high performance liquid chro-matography(HPLC) and solid-phase extraction(SPE). The aim of this study was to obtain an effective method with high preparative efficiency and importantly to avoid the transformation of unstable compounds. The preparative HPLC system was based on an LC/MS controlled four-channel autopurification system. The SPE method was performed with a C18 packing material to trap the target compounds and to remove the acidic additive derived from the mobile phase. Using this method, the unstable iridoid glucosides(IGs) as model compounds were successfully isolated and purified from the extract of Hedyotis diffusa Willd. Six IGs(including one new minor IG) and one nucleotide compound were simultaneously obtained, each with a purity of 91% as determined by HPLC. The structures of the isolated compounds were identified by UPLC/Q-TOF MS, UV, 1D and/or 2D NMR. It was demonstrated that the combination of preparative HPLC with SPE is a versatile tool for preparative purification of unstable compounds from complex natural products.

A Sensitive Reversed-Phase High-Performance Liquid Chromatography Method for the Quantitative Determination of Milk Xanthine Oxidase Activity

A new reversed-phase high performance liquid chromatography method was developed to quantitate the activity of xanthine oxidase involved in milk fat globule membrane with xanthine as the substrate and the separation of product (uric acid). The increment of uric acid in the reaction system was used to calculate the total activity of XO. The optimized assay conditions, linearity of detection, recovery of uric acid and chromatogram were developed in text, indicating this method is simple, rapid and efficient. It is an alternative potential method for the determination of the activity of XO in milk.

INTERSECTION POINT RULE OF THE RETENTION VALUE AND NORMAL BOILING POINT OF THE HOMOLOGUES IN REVERSED-PHASE HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY

In this paper, a linear relationship between the logarithm of capacity factor k and normal boiling point to of the homologues has been derived, based on the basic retention equation of liquid chromatography according to statistical thermodyoamics proposed by professor Ln Peizhang and others, This equation has been verified by a large number of experimental data, all the strsight lines of lnk- of bumologues for different mobile phass coaiposltion cross each other at the same point, So the intereection point equation van proposed, wbich was used to prodict the retention valu, the result was satisfactory.

INTERSECTION POINT RULE OF THE RETENTION VALUE AND MOBILE PHASE COMPOSITION OF THE HOMOLOGUES IN REVERSED-PHASE HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY

Based on the intersection point rule of the retention value and normal boiling point of homologues in reversed-phase high-performance liquid chromatography(RPLC), the intersection point rule of the retention value of homologues and mobile phase composition has been derived, and was testified by a lot of experimental data from the literature. With this newly proposed equation, we can use the retention value of the compound in one mobile phase composition to predict its retention value in any other mobile phase composition. For fourteen groups of homologues in five mobile phase compositions on five Kinds of columns, the overall average absolute error of 721 data sets is 2.8%.

Quantitative analysis by reversed-phase high-performance liquid chromatography and retinal neuroprotection after topical administration of moxonidine

AIM:To determine moxonidine in aqueous humor and iris-ciliary body by reversed-phase high performance liquid chromatography(RP-HPLC),and to evaluate the retinal neuroprotective effect after topical administration with moxonidine in a high intraocular pressure(IOP)model.METHODS:The eyes of albino rabbits were administered topically and ipsilaterally with 0.2%moxonidine.A RPHPLC method was employed for the identification and quantification of moxonidine between 2 and 480 min,which presented in the aqueous humor and iris-ciliary body.Flash electroretinography(F-ERG)amplitude and superoxide dismutase(SOD)level were measured between day 1 and day 15 after topical administration with moxonidine in a rabbit model of high IOP.Histological and ultrastructural observation underwent to analyze the changes of retinal morphology,the inner retinal layers(IRL)thickness,and retinal ganglion cell(RGC)counting.RESULTS:Moxonidine was detectable between 2 and 480 min after administration,and the peak concentration developed both in the two tissues at 30 min,0.51μg/m Lin aqueous humor and 1.03μg/g in iris-ciliary body.In comparison to control,F-ERG b-wave amplitude in moxonidine eyes were significantly differences between day 3 and day 15(P<0.01)in the high IOP model;SOD levels were significantly higher at all time-points(P<0.01)with a maximum level of 20.29 U/mgprot at day 15;and RGCs were significantly higher(P<0.05).CONCLUSION:Moxonidine is a viable neuroprotective agent with application to high IOP model.All layers of retina,including RGC layer,retinal nerve fiber layer and INL,are more preserved after moxonidine administration.SOD plays a neuroprotective role in ocular hypertension-mediated RGC death.

Advancements in the preparation of high-performance liquid chromatographic organic polymer monoliths for the separation of small-molecule drugs

The various advantages of organic polymer monoliths, including relatively simple preparation processes,abundant monomer availability, and a wide application range of pH, have attracted the attention of chromatographers. Organic polymer monoliths prepared by traditional methods only have macropores and mesopores, and micropores of less than 50 nm are not commonly available. These typical monoliths are suitable for the separation of biological macromolecules such as proteins and nucleic acids, but their ability to separate small molecular compounds is poor. In recent years, researchers have successfully modified polymer monoliths to achieve uniform compact pore structures. In particular, microporous materials with pores of 50 nm or less that can provide a large enough surface area are the key to the separation of small molecules. In this review, preparation methods of polymer monoliths for high-performance liquid chromatography, including ultra-high cross-linking technology, post-surface modification, and the addition of nanomaterials, are discussed. Modified monolithic columns have been used successfully to separate small molecules with obvious improvements in column efficiency.

Quantification of six bioactive compounds in Zhenqi Fuzheng preparation by high-performance liquid chromatography coupled with diode array detector and evaporative light scattering detector

A simple and accurate high-performance liquid chromatography（HPLC）coupled with diode array detector（DAD）and evaporative light scattering detector（ELSD）was established for the determination of six bioactive compounds in Zhenqi Fuzheng preparation（ZFP）.The monitoring wavelengths were 254,275 and 328 nm.Under the optimum conditions,good separation was achieved,and the assay was fully validated in respect of precision,repeatability and accuracy.The proposed method was successfully applied to quantify the six ingredients in 31 batches of ZFP samples and evaluate the variation by hierarchical cluster analysis（HCA）,which demonstrated significant variations on the content of these compounds in the samples from different manufacturers with different preparation procedures.The developed HPLC method can be used as a valid analytical method to evaluate the intrinsic quality of this preparation.

A liquid chromatography with tandem mass spectrometry method for quantitating total and unbound ceritinib in patient plasma and brain tumor

A rapid, sensitive, and robust reversed-phase liquid chromatography with tandem mass spectrometry method was developed and validated for the determination of total and unbound ceritinib, a secondgeneration ALK inhibitor, in patient plasma and brain tumor tissue samples. Sample preparation involved simple protein precipitation with acetonitrile. Chromatographic separation was achieved on a Waters ACQUITY UPLC BEH C_(18) column using a 4-min gradient elution consisting of mobile phase A(0.1% formic acid in water) and mobile phase B(0.1% formic acid in acetonitrile), at a flow rate of 0.4 m L/min. Ceritinib and the internal standard([^(13)C_6]ceritinib) were monitored using multiple reaction monitoring mode under positive electrospray ionization. The lower limit of quantitation(LLOQ) was 1 n M of ceritinib in plasma. The calibration curve was linear over ceritinib concentration range of 1–2000 n M in plasma. The intra-and interday precision and accuracy were within the generally accepted criteria for bioanalytical method( o15%).The method was successfully applied to assess ceritinib brain tumor penetration, as assessed by the unbound drug brain concentration to unbound drug plasma concentration ratio, in patients with brain tumors.

Studies on the Renaturation with Simultaneous Purification of Recombinant Human Proinsulin with Unit of Simultaneous Renaturation and Purification of Protein in Semi-preparative Scale

The renaturation and purification of recombinant human proinsulin (rh-proinsulin) expressed in E. coli with the unit of simultaneous renaturation and purification of protein (USRPP) in semi-preparative scale was studied. The result shows that rh-proinsulin extracted with 8.0 mol/L urea can be renatured and purified simultaneously in 45 minutes with the USRPP (1050 mm ID). The purity of rh-proinsulin was found to be more than 90% and the mass recovery to be more than 80%. The renaturation effect of rh-proinsulin with the USRPP was tested by enzyme cleavage for obtaining insulin. In addition, the result was further confirmed with RPLC, SDS-PAGE electrophoresis, and MALDI-TOF, respectively.

Preparation and Evaluation of Silicon Quantum Dots-Bonded Silica Stationary Phase for Reversed-Phase Chromatography

In this paper,silicon quantum dots(SiQDs)with green fluorescence are synthesized by solvothermal reaction of 3-(2,3-epoxypropoxy)propyltrimethoxysilane(GPTMS)and ethylenediaminetetraacetic acid(EDTA),and then SiQDs are bonded to the surface of silica to obtain a new nano-on-micro stationary phase(SiO_(2)-SiQDs)for reversed-phase chromatography.The successful preparation of SiO_(2)-SiQDs stationary phase is demonstrated by a variety of characterizations,such as transmission electron microscopy,laser confocal microscopy,elemental analysis and Fourier infrared spectroscopy.In addition,the chromatographic performance of the prepared stationary phase is evaluated and it shows good separation performance for non-polar substances such as alkylbenzene,aniline and polycyclic aromatic hydrocarbons in reversed-phase liquid chromatography.It is also verified that the stationary phase has good methyl selectivity and shape selectivity.More interestingly,the separation of prednisolone and hydrocortisone isomers can also be achieved at a low ratio of organic solvents,indicating that this new stationary phase has a good application prospect in isomer separation.

Lysophosphatidylcholine Biomarkers of Lung Cancer Detected by Ultra-performance Liquid Chromatography Coupled with Quadrupole Time-of-flight Mass Spectrometry

Centrifugal ultrafiltration after methanol extraction of whole plasma was used as an optimal condition for the preparation of blood plasma before metabonomic studies. The plasma samples from 102 lung cancer patients and 34 healthy volunteers were prepared with this approach. With ultra-performance liquid chromatography（UPLC） coupled with quadrupole time-of-flight mass spectrometry（Q-TOF MS） analysis, the samples were investigated in order to find potential disease biomarkers. After data acquisition, orthogonal signal correction partial least squares models were built to differentiate the healthy volunteers from lung cancer patients and to identify metabolites that showed significantly different expression between the two groups. Several metabolite ions were identified as potential biomarkers according to the variable importance in the project（VIP） value in both ion modes. Five lysophosphatidylcholines were further identified as specifically lysoPC 16：0, isomer of lysoPC 16：0, lysoPC 18：0, lysoPC 18：1 and lysoPC 18：2. These results suggest that UPLC coupled with Q-TOF MS is an effective technique for the analysis of plasma metabolites in metabonomic studies.

Modifying current thin-film microextraction(TFME)solutions for analyzing prohibited substances:Evaluating new coatings using liquid chromatography

For identifying and quantifying prohibited substances,solid-phase microextraction(SPME)continues to arouse interest as a sample preparation method.However,the practical implementation of this method in routine laboratory testing is currently hindered by the limited number of coatings compatible with the ubiquitous high-performance liquid chromatography(HPLC)systems.Only octadecyl(C18)and polydimethylsiloxane/divinylbenzene ligands are currently marketed for this purpose.To address this situation,the present study evaluated 12 HPLC-compatible coatings,including several chemistries not currently used in this application.The stationary phases of SPME devices in the geometry of thin filmcoated blades were prepared by applying silica particles bonded with various functional ligands(C18,octyl,phenyl-hexyl,3-cyanopropyl,benzenesulfonic acid,and selected combinations of these),as well as unbonded silica,to a metal support.Most of these chemistries have not been previously used as microextraction coatings.The 48 most commonly misused substances were selected to assess the extraction efficacy of each coating,and eight desorption solvent compositions were used to optimize the desorption conditions.All samples were analyzed using an HPLC system coupled with triple quadrupole tandem mass spectrometry.This evaluation enables selection of the best-performing coatings for quantifying prohibited substances and investigates the relationship between extraction efficacy and the physicochemical characteristics of the analytes.Ultimately,using the most suitable coatings is essential for trace-level analysis of chemically diverse prohibited substances.

Ion-pair Reversed-phase×Low-pH Reversed-phase Two-dimensional Liquid Chromatography for In-depth Proteomic Profiling

High-resolution liquid chromatography separation is essential to in-depth proteomic profiling of complex biological samples.Herein,we established an ion-pair reversed-phase×reversed-phase two-dimensional liquid chromatography(IPRP×RP 2DLC)strategy for comprehensive proteomic analysis.Both RPLC separation dimensions were performed at low pH,with trifluoroacetic acid(TFA)and formic acid(FA)as mobile phase addictive,respectively.As the good separation resolution offered by ion-pairing effect of TFA,the fractionation efficiency was greatly improved with 74.0%peptides identified in just one fraction.Comparing with conventional high pH RP fractionation,the overall separation rate of IPRP was about 1.6 times that of high-pH RP,which increased the number of identified peptides by 21%.Further,2169 proteins and 8540 peptides were confidently identified from crude serum sample by our IPRP×RP 2DLC strategy,exhibiting great potential in clinical proteomics in the future.

全自动固相萃取—高效液相色谱法测定现制饮料中7种合成着色剂

目的:建立一种全自动固相萃取—高效液相色谱双波长法测定现制饮料中7种合成着色剂的方法。方法:样品经纯水提取2次,离心后,合并上清液,调节pH至3~4。利用全自动固相萃取装置活化Poly-sery色素专用固相萃取小柱,并上样、淋洗、洗脱。洗脱液氮吹浓缩至200μL,用50%流动相A+50%流动相B混合液定容至1.0 mL。色谱柱采用C 18柱,流动相为20 mmol/L乙酸铵—甲醇,梯度洗脱,流速1.0 mL/min,进样量10μL,检测波长254,628 nm。结果:各物质在0.5~50.0μg/mL范围内相关系数均大于0.9999,方法检出限为0.023~0.179 mg/kg,定量限为0.078~0.598 mg/kg,加标回收率为92.4%~96.8%,相对标准偏差(RSD)为1.2%~4.2%。结论:该方法试剂使用量小,操作步骤简便,自动化程度高,回收率高,重复性好,适合于批量样品测定。

宠物用丹参咀嚼片制备工艺研究及质量标准建立

旨在确定宠物用丹参咀嚼片的制备工艺并建立其质量标准。本试验通过湿法制粒辅料种类、制粒工艺、压片工艺进行考察,确定其制备工艺,采用薄层色谱法、高效液相色谱法(HPLC)对宠物用丹参咀嚼片中丹参酮ⅡA、丹酚酸B分别开展定性和定量研究,建立其质量标准。结果:将丹参喷雾粉加辅料混合均匀,混合时间5 min,转速100 r/min,以10%淀粉浆为黏合剂制成颗粒,干燥温度40~50℃,0.3%硬脂酸镁作为润滑剂,压片速率10~35 r/min;薄层鉴别显示丹参酮ⅡA斑点清晰,分离度良好且专属性强;高效液相色谱显示丹酚酸B在8.0~256.0μg/mL范围内线性关系良好(R^(2)=0.999 9),系统适用性、专属性、精密度、稳定性、重复性、系统耐用性良好,加样回收率为95.0%~105.0%;对6批样品中丹酚酸B进行含量测定,设定含量限度为11.484 1 mg/g。综上,本试验确定的宠物用丹参咀嚼片制备工艺稳定可行,建立的薄层鉴别方法和高效液相色谱含量测定方法可用于宠物用丹参咀嚼片的质量控制。

低渗储层渗吸剂界面性能与组分分离

对石油磺酸盐WPS-D和十八烷基二甲基甜菜碱复配的渗吸剂进行界面张力测试,得出0.3%浓度8∶2比例下的渗吸剂达到超低界面张力(<1.0×10^(-3)mN/m),0.4%和0.5%浓度比例为9∶1的体系接近超低界面张力。采用制备色谱与质谱相结合,对石油磺酸盐WPS-D进行组分分离,并结合界面张力测试结果,考察不同组分的界面活性。结果表明,石油磺酸盐分离出5种结构组成差异较大的不同组分;以重烷基苯磺酸盐为主,C_(17)~C_(19)烷基苯磺酸盐达到超低界面张力并维持,C_(18)~C_(24)的烷基苯磺酸盐接近超低界面张力后反弹,得出提供界面活性的主要组分是C_(17)~C_(19)磺酸盐。

制备高效液相色谱用于纽莫康定杂质B1和B5的纯化

目的开展低含量成分的富集和纯化研究,从Glarea lozoyensis菌体的发酵产物(即纽莫康定B0粗品)中制备出杂质B1和B5,并对其进行结构鉴定。方法建立了基于制备高效液相色谱(prep-HPLC)技术的两步纯化法,第一步使用亲水(HILIC)模式固定相对目标杂质进行富集,第二步采用反相(RPLC)模式固定相对杂质进行制备。得到的两个杂质采用质谱(MS)、核磁(NMR)进行鉴定,确定化合物结构。结果两个杂质为B1和B5,相对分子质量均为1049 Da,色谱纯度分别为97.83%和98.13%。经核磁鉴定,B1为B0的高酪氨酸类似物,B5为B0的鸟氨酸类似物。结论本研究发展的基于prep-HPLC的两步纯化方法为低含量成分制备提供参考,第一步分离实现目标成分富集,第二步利用正交性的色谱柱提高分离选择性,成功制备出杂质B1与B5,有助于B0杂质谱的建立和进一步的质量控制研究。

黑果分散片的制备、质量及体外活性研究

为了探索黑果分散片的制备工艺、质量及其体外活性,通过单因素与正交试验相结合的方式考察了黑果分散片的制备工艺,采用UV法考察了黑果分散片总三萜的含量及其体外活性,采用超高效液相色谱法测定了黑果分散片中没食子酸、儿茶素、表儿茶素的含量.结果发现黑果分散片的优选处方为微晶纤维素作稀释剂、交联聚乙烯吡咯烷酮作崩解剂、75%乙醇为黏合剂、微粉硅胶作润滑剂.分散片中总三萜的含量测定方法显色前后稳定性符合测定要求、仪器精密度和重复性良好,总三萜的加样回收率为99.48%;体外活性试验结果表明,黑果分散片具有一定的清除DPPH和抑制脂质体的能力;超高效液相色谱法测定没食子酸、儿茶素、表儿茶素的加样回收率分别为99.83%、100.69%和99.61%.优选的制剂工艺制备的分散片,其崩解时限符合要求,总三萜的含量为1.42 mg/片,没食子酸、儿茶素、表儿茶素的含量分别为111.15μg/g、940.19μg/g、598.25μg/g.试验结果为黑果分散片的应用提供了理论依据.

头孢克肟制剂中有关物质结构鉴定与定量分析

目的旨在建立头孢克肟制剂中有关物质结构鉴定与定量分析方法。方法采用HPLC-Q-TOF-MS/MS法对主要杂质结构进行分析。建立HPLC法,采用C18色谱柱(250 mm×4.6 mm,5μm),以乙腈-四丁基氢氧化铵溶液为流动相进行梯度洗脱,检测波长为254 nm,柱温为40℃,对头孢克肟制剂进行有关物质检测。结果初步鉴定了头孢克肟制剂中9个杂质,分别为杂质A、B、D、E、F、G、H、头孢克肟亚砜和头孢克肟叔丁酯。在建立的HPLC色谱条件下,头孢克肟及各杂质均能达到基线分离,各有关物质的质量浓度在0.1934~20.03μg·mL^(-1)内线性关系良好,r>0.9990;回收率为98.4%~101.8%(RSD<2.0%)。结论HPLC-Q-TOF-MS/MS技术能初步鉴定头孢克肟制剂的杂质结构,该方法能检测不同厂家头孢克肟片剂、颗粒剂、胶囊剂及干混悬剂中的有关物质。

复方参芪颗粒的制备工艺及其质量控制

目的:优选复方参芪颗粒的最佳配方和制备工艺,并对其质量控制进行初步研究。方法:以颗粒的吸湿率、成型率、流动性和口感为评价指标,按不同权重综合评分,以综合得分为响应值,结合响应面法分析,优选配方和制备工艺;用高效液相色谱法测定黄芪甲苷的含量。结果:浸膏与辅料比例为1∶4,甘露醇与乳糖比例为4∶3,矫味剂用量为0.20%,成型率、吸湿率、休止角分别为96.86%、2.52%、27.60°,颗粒微甜,可接受;黄芪甲苷的线性回归方程为y=1.321 9x+1.113 3,R^(2)=0.999 6。黄芪甲苷在1.994~7.976μg范围内具有良好的线性关系。结论:此方法重现性好,优选的复方参芪颗粒制备工艺切实可行;黄芪甲苷含量测定方法线性关系良好,可用于其质量控制。