A method for rapid and simultaneous determination of imidazolium and pyridinium ionic liquid cations by ion-pair chromatography with ultraviolet detection was developed. Chromatographic separations were performed on a...A method for rapid and simultaneous determination of imidazolium and pyridinium ionic liquid cations by ion-pair chromatography with ultraviolet detection was developed. Chromatographic separations were performed on a reversed-phase silica-based monolithic column using 1-heptanesulfonic acid sodium-acetonitrile as mobile phase. The effects of ion-pair reagent and acetonitrile concentration on retention of the cations were investigated. The retention times of the cations accord with carbon number rule. The method has been successfully applied to the determination of four ionic liquids synthesized by organic chemistry laboratory.展开更多
Troxerutin(TRO)is a mixture of semi-synthetic flavonoids prepared by hydroxyethylation of rutin,and it is commonly used for the treatment of cerebrovascular diseases.The main active ingredient is trishydroxyethyl ruti...Troxerutin(TRO)is a mixture of semi-synthetic flavonoids prepared by hydroxyethylation of rutin,and it is commonly used for the treatment of cerebrovascular diseases.The main active ingredient is trishydroxyethyl rutin.The mother liquor of TRO contains a lot of TRO and other derivatives of hydroxyethylated rutin.In order to make full use of the mother liquor of TRO,an efficient method was developed for recovering high-purity TRO from mother liquor of TRO by combining silica gel column chromatography with semi-preparative liquid chromatography.In the silica gel column chromatographic separation,the ratio of silica gel to sample and eluent composition were investigated to obtain optimum separation effect.The results showed that when the ratio of silica gel to sample was 50,and acetone–ethyl acetate–water–glacial acetic acid(10:10:3:1,v/v/v/v)was used as the eluent,the separation effect of TRO and adjacent impurities was good.Moreover,150 g of TRO with a purity of 80%could be obtained from 1 kg of mother liquor of TRO by the silica gel column chromatographic separation,and the results were consistent with the quality standard of TRO raw material.Subsequently,the semi-preparative HPLC was performed,and 100 g TRO with a purity of up to 98%(w/w)was obtained.Meanwhile,tetrahydroxyethylrutin and tetrahydroxyethylquercetin with purity greater than 98%were obtained.This work proposed the separation and preparation of TRO with high-purity from the production waste of TRO for the first time,which had certain environmental benefits and economic benefits.展开更多
[Objectives]To establish an HPLC method for the quantitative determination of multiple phenolic acid components in Tetracera asiatica medicinal material,providing a basis for establishing its quality standards.[Method...[Objectives]To establish an HPLC method for the quantitative determination of multiple phenolic acid components in Tetracera asiatica medicinal material,providing a basis for establishing its quality standards.[Methods]An Inertsil ODS-C 18 column(250 mm×4.6 mm,5μm)was used.The mobile phase consisted of acetonitrile-0.2% phosphoric acid solution(10:90).The flow rate was 1.0 mL/min.The detection wavelength was 274 nm.The column temperature was 25℃.The injection volume was 10μL.The content of three components,gallic acid,protocatechuic acid,and protocatechualdehyde,was determined in 13 batches of T.asiatica.[Results]Gallic acid showed good linearity within the range of 0.020-6.400μg/mL,protocatechuic acid within 0.201-6.432μg/mL,and protocatechualdehyde within 0.202-6.464μg/mL(r>0.9990).The average recovery rates ranged from 98.61%to 101.17%,with RSD s between 1.21%and 2.69%.[Conclusions]The quantitative determination method established in this study is simple and feasible,and can provide a basis for the quality evaluation of T.asiatica.展开更多
[Objectives]To establish an efficient and environmentally friendly separation and purification method for the large-scale preparation of the major active components-eleutherol,eleutherine,and isoeleutherine-from the e...[Objectives]To establish an efficient and environmentally friendly separation and purification method for the large-scale preparation of the major active components-eleutherol,eleutherine,and isoeleutherine-from the ethnomedicinal plant Eleutherine americana Merr.et K.Heyne.[Methods]The sample of E.americana bulbs was initially extracted with ethanol,followed by three successive extractions with ethyl acetate-water(2:1,V/V)to obtain the target component-enriched fraction.Eight solvent systems were systematically optimized,and a mixture of petroleum ether-ethyl acetate-ethanol-water(5:5:6:4,V/V/V/V)was identified as the optimal solvent system for high-speed counter-current chromatography(HSCCC)separation under conditions of 900 rpm,2 mL/min,and 35℃.The crude HSCCC product was further purified by silica gel column chromatography(200-300 mesh)using gradient elution with a solvent system of n-hexane-dichloromethane-ethyl acetate(varying from 10:5:1 to 4:5:1,V/V/V).UPLC-PDA(Agilent SB-C_(18)column)and nuclear magnetic resonance spectroscopy(600 MHz)were comprehensively employed to assess compound purity and confirm molecular structures.[Results]An optimized technique integrating HSCCC and silica gel column chromatography was established,successfully enabling the large-scale preparation of three bioactive components:eleutherol(purity 99%),eleutherine(purity 98%),and isoeleutherine(purity 98%).Structural identification results were consistent with those reported in the literature.Compared to traditional methods,the new approach demonstrated improved separation efficiency and reduced solvent consumption.[Conclusions]The combined separation method utilizing HSCCC and silica gel column chromatography established in this study demonstrates notable advantages,including high efficiency,environmental friendliness,and cost-effectiveness,enabling the large-scale preparation of the three major active components from E.americana.This approach outperforms conventional methods by offering higher separation efficiency,reduced solvent consumption,and superior product purity,providing a robust technical solution for the development and utilization of bioactive compounds from E.americana.Moreover,it offers a novel methodological reference for the isolation and purification of other natural products.展开更多
As a core power device in strategic industries such as new energy power generation and electric vehicles,the thermal reliability of IGBT modules directly determines the performance and lifetime of the whole system.A s...As a core power device in strategic industries such as new energy power generation and electric vehicles,the thermal reliability of IGBT modules directly determines the performance and lifetime of the whole system.A synergistic optimization structure of“inlet plate-channel spoiler columns”is proposed for the local hot spot problem during the operation of Insulated Gate Bipolar Transistor(IGBT),combined with the inherent defect of uneven flow distribution of the traditional U-type liquid cooling plate in this paper.The influences of the shape,height(H),and spacing from the spoiler column(b)of the plate on the comprehensive heat dissipation performance of the liquid cooling plate are analyzed at different Reynolds numbers,A dual heat source strategy is introduced and the effect of the optimized structure is evaluated by the temperature inhomogeneity coefficient(Φ).The results show that the optimum effect is achieved when the shape of the plate is square,H=4.5 mm,b=2 mm,and u=0.05 m/s,at which the HTPE=1.09 and Φ are reduced by 40%.In contrast,the maximum temperatures of the IGBT and the FWD(Free Wheeling Diode)chips are reduced by 8.7 and 8.4 K,respectively,and ΔP rises by only 1.58 Pa while keeping ΔT not significantly increased.This optimized configuration achieves a significant reduction in the critical chip temperature and optimization of the flow field uniformity with almost no change in the system flow resistance.It breaks through the limitation of single structure optimization of the traditional liquid cooling plate and effectively solves the problem of uneven flow in the U-shaped cooling plate,which provides a new solution with important engineering value for the thermal management of IGBT modules.展开更多
A high-performance liquid chromatography(HPLC)method has been developed using a CAPCELL PAK ADME(150 mm×4.6 mm,5μm)as analytical column and a gradient elution with 15 min using acetonitrile and 0.1%(in volume fr...A high-performance liquid chromatography(HPLC)method has been developed using a CAPCELL PAK ADME(150 mm×4.6 mm,5μm)as analytical column and a gradient elution with 15 min using acetonitrile and 0.1%(in volume fraction)phosphoric acid water(pH=2.2)as the mobile phase.Three active substances in cosmetics were quantitatively detected simultaneously at a detection wavelength of 265 nm.The linear ranges of β-nicotinamide mononucleotides,ergothioneine and nicotinamide are 10~200 mg/L,5~100 mg/L and 5~100 mg/L respectively and the detection limits of three components are 3.0 mg/L,1.5 mg/L and 1.5 mg/L respectively.The recovery rate is 97.1~104.9%,with RSD≤2.0%.The method was applied to quantitative analysis of five samples of cosmetics toner,lotion,cream,essence and gel and three samples of raw materials.The results showed that the results of β-nicotinamide mononucleotide and ergothioneine in five cosmetics were consistent with the product label,while nicotinamide was inconsistent with the label.The purity of the three raw material samples was 99.5%,99.7% and 100.8%respectively.This method offers high precision,accuracy and short analysis time,making it a reliable approach for studying three active ingredients in cosmetics and suitable for quality control of related functional ingredients.展开更多
To address the vibration issues of wind turbine towers,this paper proposes a bidirectional tuned bellow liquid column damper(BTBLCD).The configuration of the proposed BTBLCD is first described in detail,and its energy...To address the vibration issues of wind turbine towers,this paper proposes a bidirectional tuned bellow liquid column damper(BTBLCD).The configuration of the proposed BTBLCD is first described in detail,and its energy dissipation mechanism is derived through theoretical analysis.A refined dynamic model of the wind turbine tower equipped with the BTBLCD is then developed.The vibration energy dissipation performance of the BTBLCD in multiple directions is evaluated through two-way fluid-structure coupling numerical simulations.Finally,a 1/10 scaled model of the wind turbine tower is constructed,and the energy dissipation performance of the BTBLCD is validated using a shaking table test.The results show that the vibration energy dissipation performance of the BTBLCD outperforms that of the bidirectional tuned liquid column damper(BTLCD)in multiple directions.The shaking table test and dynamic response analysis demonstrate a maximum reduction of 61.0%in acceleration and 47.9%in displacement response.Furthermore,the vibration control and energy dissipation performance of the BTBLCD are influenced by the direction and amplitude of vibrations.This study contributes to the development of more effective and versatile vibration mitigation strategies for wind turbine tower structures in various engineering scenarios.展开更多
[Objective]The aim of this work was to establish an analytical method for the determination of deoxynivalenol(DON)in feeds using automatic immunomagnetic beads(IMBs)clean-up coupled with high-performance liquid chroma...[Objective]The aim of this work was to establish an analytical method for the determination of deoxynivalenol(DON)in feeds using automatic immunomagnetic beads(IMBs)clean-up coupled with high-performance liquid chromatography.[Method]Feed samples were extracted using ultra-pure water,purified by automatic IMBs,and subsequently analyzed via high-performance liquid chromatography,employing an external standard method for quantification.[Result]A satisfactory linearity was achieved for DON within the concentration range of 0.05 to 2.0μg/mL,with the corresponding correlation coefficients(R^(2))exceeding 0.9999.The limit of detection(LOD)and limit of quantification(LOQ)for the proposed method were determined to be 0.03 and 0.1 mg/kg,respectively.The average recoveries of the fortified samples(0.1,0.2 and 1.0 mg/kg)were 88.5%−100.6%,with the relative standard deviations(RSD)ranging from 2.1%to 9.7%.[Conclusion]In comparison with the traditional solidphase extraction and immunoaffinity column purification methods,the IMBs technique consolidates the extraction,separation,and purification into a single process.This approach enables fully automated processing,which significantly enhances work efficiency and mitigates result deviations that may arise from manual operations.Consequently,this technique is particularly well-suited for the determination of DON in a large number of feed samples.展开更多
This study investigates the seismic response mitigation of an offshore jacket platform via a novel damping system,the bidirectional tuned liquid column gas damper(BTLCGD).To efficiently model the complex platform stru...This study investigates the seismic response mitigation of an offshore jacket platform via a novel damping system,the bidirectional tuned liquid column gas damper(BTLCGD).To efficiently model the complex platform structure,an equivalent single degree of freedom approach was employed.Since the mass contribution of the first mode of the platform is more than 90%,this simplification significantly reduces the computational burden while maintaining accuracy.Therefore,this structure was modeled and analyzed on a scale of 1 to 36 using the Froudian law.To address the limitations of conventional tuned liquid column gas dampers(TLCGDs),which are susceptible to the directionality of seismic excitations,BTLCGD was proposed.This innovative damper is designed to operate effectively in two orthogonal directions,thereby improving seismic performance.Through numerical simulations,the performance of both TLCGD and BTLCGD was evaluated under seismic loading.The results demonstrated that BTLCGD significantly outperforms TLCGD in terms of reducing structural responses,particularly in the direction where TLCGD is ineffective.Furthermore,BTLCGD offers advantages in terms of installation and space requirements.The results of this research offer valuable perspectives into the design and implementation of effective damping systems for offshore structures,contributing to enhanced structural integrity and safety.展开更多
Background:Polygonum multiflorum-induced liver injury(PM-DILI)has significantly hindered its clinical application and development.Methods:This study investigates the variation in content and toxicity of dian-thrones,t...Background:Polygonum multiflorum-induced liver injury(PM-DILI)has significantly hindered its clinical application and development.Methods:This study investigates the variation in content and toxicity of dian-thrones,the toxic components of P.multiflorum,during different processing cycles.We employed the ultra-high-performance liquid chromatography triple quadrupole mass spectrometry method to quantify six dianthrones in raw P.multiflorum and formulations processed with a method called nine cycles of steaming and sunning.Additionally,toxicity assessments were conducted using human normal liver cell line L02 and zebrafish embryos.Results:Results indicate a gradual reduction in dianthrones content with increasing processing cycles.Processed formulations exhibited significantly reduced cytotoxic-ity in L02 cells and hepatotoxicity in zebrafish embryos.Conclusions:Our findings elucidate the relationship between processing cycles and P.multiflorum toxicity,providing theoretical support for its safe use.展开更多
A high-performance liquid chromatography was describ-ed to measure the concentration of human 3-methylhistidine in urine witho-phthaldialdehyde pre-column derivatization.This assay system resultedin a clear separation...A high-performance liquid chromatography was describ-ed to measure the concentration of human 3-methylhistidine in urine witho-phthaldialdehyde pre-column derivatization.This assay system resultedin a clear separation of 3-methylhistidine derivative from other derivativ-es in urine within 25 min.Linearity,recovery and coefficients of vari-ation were studied.The method has been successfully applied to routineanalysis for clinical studies and diagnosis.展开更多
A flow injection (FI) micro-column system coupled with high performance liquid chromatography (HPLC) was proposed for the pre-separation and determination of active organic component (ecdysterone) in traditional Chine...A flow injection (FI) micro-column system coupled with high performance liquid chromatography (HPLC) was proposed for the pre-separation and determination of active organic component (ecdysterone) in traditional Chinese medicine, Loulu. The factors influencing separation performance were investigated and optimized. Under the optimal conditions, the contents of ecdysterone in Loulu were determined by HPLC system using MeOH-H_2O (40: 60,V/V) as the mobile phase at a flow rate of 1. 0 mL/min. The calibration curve was linear in the range of 0. 5~ 100 mg/L of ecdysterone concentrations. The detection limit of the analyte was 0. 11mol/L(3) with a precision of 0. 38% RSD (n=7 f c= 10. 0 mg/L). The average recovery of the method was 98. 7%. The proposed method has been applied to determine ecdysterone in practical samples, and the determined values by both external standard method and standard addition method were in good agreement. Compared to the traditional solid extraction method, the system proposed has the advantages of simple procedure, good reproducibility, minimum volume requirement, reduction of matrix interference and low contamination risk.展开更多
A sensitive liquid chromatographic mcthod for the detection of andno acids with precolumn fluorescence derivatization with acridone-N-acetyl chloride has been developed. Andno acid derivatives were eluted in 4o ndn wi...A sensitive liquid chromatographic mcthod for the detection of andno acids with precolumn fluorescence derivatization with acridone-N-acetyl chloride has been developed. Andno acid derivatives were eluted in 4o ndn with good reproducibility. The reIative standard deviations (n=6) at an analytical concentration of 50 pmol are < 4%. The method described is also suitable for the analysis of andno acids in different biological samples.展开更多
[Objectives]A method for the detection of monensin in poultry and livestock meat by pre-column derivatization-high performance liquid chromatography was established.[Methods]The sample was extracted with chloroform,de...[Objectives]A method for the detection of monensin in poultry and livestock meat by pre-column derivatization-high performance liquid chromatography was established.[Methods]The sample was extracted with chloroform,derivatized with trichloroacetic acid and 2,4-dinitrophenylhydrazine,and centrifuged to obtain a purified solution.A C18 chromatographic column(4.6 mm×150 mm,5μm)was used for separation with(1.5%)acetic acid water∶methanol(volume ratio)=1∶9 as the mobile phase using a DAD detector for detection,and the external standard method was adopted for peak area quantification.[Results]Monensin had good linearity in the concentration range of 5.00-200 mg/L,with the linear correlation coefficient r 2>0.999;the detection limit was 5.00 mg/kg;the relative standard deviation was smaller than 10%;and the recoveries of standard addition experiment were in the range of 75%-110%.[Conclusions]The method has the advantages of simple pretreatment operation,good derivatization effect and fast detection speed,and is suitable for detecting monensin in poultry and livestock meat.展开更多
Aim To establish a reversed-phase liquid chromatographic (LC) method forsimultaneous determination of tetramethylpyrazine (TMP) and aspirin in a new compound formulation.Methods Chromatographic separation of the two d...Aim To establish a reversed-phase liquid chromatographic (LC) method forsimultaneous determination of tetramethylpyrazine (TMP) and aspirin in a new compound formulation.Methods Chromatographic separation of the two drugs was achieved on a Diamonsil C_(18) column, usinga binary mixture of methanol-1.5% acetic acid (35:65, V/V, pH = 3.1) as mobile phase at a flow rateof 1.0 mL·min^(-1). Results Separation was completed in less than 12 min. Benzoic acid was used asthe internal standard. Recoveries at levels corresponding to 80 % to 120 % of the label claim ofthe formulation ranged from 99.6 to 100.3 % for aspirin and from 99.9 to 101.3% for TMP. The linearrange was 12.6 - 150.9 μg·mL^(-1)(r= 0.9997, n = 5) for aspirin and 25.0- 300.0 μg·mL^(-1) (r =0.9999, n = 5) for TMP. Conclusion The method developed can be used for the simultaneousdetermination of TMP and aspirin in pharmaceutical preparations.展开更多
Abstract： In the presem study, we simultaneously quantified the levels of monoamine neurotransmitters （MANTs） and their metabolites （levodopa, norepinephrine, epinephrine, dopamine, 5-HT, 3,4-dihydroxyphenylacetic...Abstract： In the presem study, we simultaneously quantified the levels of monoamine neurotransmitters （MANTs） and their metabolites （levodopa, norepinephrine, epinephrine, dopamine, 5-HT, 3,4-dihydroxyphenylacetic acid, homovanillic acid and 5-hydroxyindole-3-acetic acid） in different brain subregions of rats using a newly developed simple, sensitive and selective high-performance liquid chromatography with fluorescence detection （HPLC-FLD） method. In this new HPLC-FLD method, analytes were directly extracted and separated without deriveatization step within 20 min. The FLD wavelength was set at 280 nm and 330 nm for excitation and emission, respectively. The analytes were separated on an Agilent Eclipse Plus Cls column （4.6 mm×150 mm, 5.0 μm） equipped with an Agilent XDB-C18 security guard column （4.6 mm×12.5 mm, 5.0 lam）, and the column temperature was maintained at 35 ℃. The mobile phase for elution was isocratic. The mobile phase consisted of citric acid buffer （50 mmol/L citric acid, 50 mmol/L sodium acetate, 0.5 mmol/L octane sulfonic acid sodium salt, 0.5 mmol/L Na2EDTA and 5 mmol/L triethylamine, pH 3.8） and methanol （90：10, v/v） at a flow rate of 1.0 mL/min. The detection limit （DL） was 0.9-23 nM for all the MANTs and their metabolites with a sample volume of 50 μL. The method was shown to be highly reproducible in terms of peak area （intraday, 0.08%-1.85% RSD, n = 5）. The simultaneous measurement of these MANTs and their metabolites improved our understanding of the neurochemistry in the central nervous system （CNS） in relation to different addictive drugs （methamphetamine, heroin and their mixture） in drug-addicted rat models.展开更多
The crude and processed Paeoniae Radix Alba-Atractylodis Macrocephalae Rhizoma herbal pairs, originated from Bai-zhu-shao-yao-san, are used to treat different diseases clinically. In order to evaluate the crude and pr...The crude and processed Paeoniae Radix Alba-Atractylodis Macrocephalae Rhizoma herbal pairs, originated from Bai-zhu-shao-yao-san, are used to treat different diseases clinically. In order to evaluate the crude and processed Paeoniae Radix-Atractylodis Macrocephalae Rhizoma herbal pairs, a simple, easy, and sensitive high-performance liquid chromatography coupled with diode array detectors was developed for simultaneous determination of nine bioactive components in the herbal pairs. The calibration curve exhibited good linearity（r2≥0.9992）. The LODs and LOQs were ≤7.30 and 11.53 μg/m L, respectively. The intra-, inter-day and repeatability RSD values of the nine compounds were less than 3.86%, 2.71%, and 4.29%, respectively. The RSD stability values were less than 3.64%. The recovery of the method was in the range of 96.70%–102.10%, with RSD values less than 3.52%. The developed method can be applied to the intrinsic quality control of crude and processed Paeoniae Radix-Atractylodis Macrocephalae Rhizoma herbal pairs.展开更多
Due to their biological and physiological importance,flavonoids receive considerable attention in the literature. Nowadays,high performance liquid chromatography（HPLC）is the most widely used analytical method.In thi...Due to their biological and physiological importance,flavonoids receive considerable attention in the literature. Nowadays,high performance liquid chromatography（HPLC）is the most widely used analytical method.In this review,we summarize the principle of the choice of HPLC column and mobile phase,discuss and compare the features of various detections such as UV,fluorescence detection,electrochemical detection,chemilummescence detection,UV-MS etc.Recent developments in HPLC including ultra-LC and miniaturization of LC（micro-LC,capillary-LC,and nano-LC）,are also discussed.展开更多
The ginkgo terpenoids including bilobalide and ginkgolides are the main pharmaceutical components in the leaves or extracts of Ginkgo biloba L. In this paper, the analysis of bilobalide and ginkgolides in leaves of Gi...The ginkgo terpenoids including bilobalide and ginkgolides are the main pharmaceutical components in the leaves or extracts of Ginkgo biloba L. In this paper, the analysis of bilobalide and ginkgolides in leaves of Ginkgo biloba L. by high performance liquid chromatography (HPLC)-electrospray ionization (ESI)-mass spectrometry (MS) was carried out. The separation was performed on Inertsil ODS3 column with methanol-water (36:64) as mobile phase, with 1 mL·min -1 of flow rate at 35℃. Then the mass spectrum analysis was conducted by ZMD micromass electrospray ionization (ESI)-mass spectrometer (MS). The HPLC total ion chromatogram and selected ion chromatogram (with 325, 407, 423, 439 of m/z) of the sample and ESI-/MS mass spectra of the peaks in the chromatograms were obtained. So bilobalide, ginkgolide A, B, C and J in Ginkgo biloba L. leaves were identified. The method is easy and rapid, with a good accuracy.展开更多
A sensitive and selective high performance liquid chromatography coupled with electrospray ionization mass spectrometry （LC-MS） was developed for the quantitative determination of ilexgenin A （IA）,a major componen...A sensitive and selective high performance liquid chromatography coupled with electrospray ionization mass spectrometry （LC-MS） was developed for the quantitative determination of ilexgenin A （IA）,a major component in Radix Ilicis Pubescentis,in rat plasma.Chromatographic separation was performed on a C 18 column,with methanol-5 mM ammonium acetate （80：20,v/v） as the mobile phase.Mass spectrometer was set in negative mode with target ions at m/z 501.1→501.1 for IA and m/z 779.4→779.4 for digoxin （internal standard,IS）.Rat plasma was extracted with ethyl acetate after addition of phosphoric solution and the organic layer was evaporated and reconstituted with mobile phase for LC-MS analysis.The proposed method was validated with a linear range of 1.05-525.5 ng/mL for IA with limit of quantitation （LOQ） at 1.05 ng/mL.Intra-and inter-day precision expressed as relative standard deviation （RSD） were less than 10% at LOQ level and overall recovery was over 80%.This validated method was used successfully for the pharmacokinetic study of IA in rats after oral dosing of IA （100 mg/kg） and some main pharmacokinetic parameters of IA in rats were obtained.展开更多
基金supported by the Natural Science Foundation of Heilongjiang Province(No.B200909)the Program for Scientific and Technological Innovation Team Construction in Universities of Heilongjiang Province(No. 2011TD010)
文摘A method for rapid and simultaneous determination of imidazolium and pyridinium ionic liquid cations by ion-pair chromatography with ultraviolet detection was developed. Chromatographic separations were performed on a reversed-phase silica-based monolithic column using 1-heptanesulfonic acid sodium-acetonitrile as mobile phase. The effects of ion-pair reagent and acetonitrile concentration on retention of the cations were investigated. The retention times of the cations accord with carbon number rule. The method has been successfully applied to the determination of four ionic liquids synthesized by organic chemistry laboratory.
基金Shaanxi science and technology hall project(Grant No.2018JM7060)Provincial Key Discipline Construction Project of pharmacy of Xi’an Medical University(Grant No.2016YXXK08)。
文摘Troxerutin(TRO)is a mixture of semi-synthetic flavonoids prepared by hydroxyethylation of rutin,and it is commonly used for the treatment of cerebrovascular diseases.The main active ingredient is trishydroxyethyl rutin.The mother liquor of TRO contains a lot of TRO and other derivatives of hydroxyethylated rutin.In order to make full use of the mother liquor of TRO,an efficient method was developed for recovering high-purity TRO from mother liquor of TRO by combining silica gel column chromatography with semi-preparative liquid chromatography.In the silica gel column chromatographic separation,the ratio of silica gel to sample and eluent composition were investigated to obtain optimum separation effect.The results showed that when the ratio of silica gel to sample was 50,and acetone–ethyl acetate–water–glacial acetic acid(10:10:3:1,v/v/v/v)was used as the eluent,the separation effect of TRO and adjacent impurities was good.Moreover,150 g of TRO with a purity of 80%could be obtained from 1 kg of mother liquor of TRO by the silica gel column chromatographic separation,and the results were consistent with the quality standard of TRO raw material.Subsequently,the semi-preparative HPLC was performed,and 100 g TRO with a purity of up to 98%(w/w)was obtained.Meanwhile,tetrahydroxyethylrutin and tetrahydroxyethylquercetin with purity greater than 98%were obtained.This work proposed the separation and preparation of TRO with high-purity from the production waste of TRO for the first time,which had certain environmental benefits and economic benefits.
基金Supported by Regional Science Foundation of China,National Natural Science Foundation(No.82160820)General Program of Guizhou Provincial Natural Science Foundation[QianKeHe Foundation-ZK(2023)General153].
文摘[Objectives]To establish an HPLC method for the quantitative determination of multiple phenolic acid components in Tetracera asiatica medicinal material,providing a basis for establishing its quality standards.[Methods]An Inertsil ODS-C 18 column(250 mm×4.6 mm,5μm)was used.The mobile phase consisted of acetonitrile-0.2% phosphoric acid solution(10:90).The flow rate was 1.0 mL/min.The detection wavelength was 274 nm.The column temperature was 25℃.The injection volume was 10μL.The content of three components,gallic acid,protocatechuic acid,and protocatechualdehyde,was determined in 13 batches of T.asiatica.[Results]Gallic acid showed good linearity within the range of 0.020-6.400μg/mL,protocatechuic acid within 0.201-6.432μg/mL,and protocatechualdehyde within 0.202-6.464μg/mL(r>0.9990).The average recovery rates ranged from 98.61%to 101.17%,with RSD s between 1.21%and 2.69%.[Conclusions]The quantitative determination method established in this study is simple and feasible,and can provide a basis for the quality evaluation of T.asiatica.
基金Supported by Natural Science Foundation of Tibet Autonomous Region,Science and Technology Department of Tibet(XZ202501ZR0118).
文摘[Objectives]To establish an efficient and environmentally friendly separation and purification method for the large-scale preparation of the major active components-eleutherol,eleutherine,and isoeleutherine-from the ethnomedicinal plant Eleutherine americana Merr.et K.Heyne.[Methods]The sample of E.americana bulbs was initially extracted with ethanol,followed by three successive extractions with ethyl acetate-water(2:1,V/V)to obtain the target component-enriched fraction.Eight solvent systems were systematically optimized,and a mixture of petroleum ether-ethyl acetate-ethanol-water(5:5:6:4,V/V/V/V)was identified as the optimal solvent system for high-speed counter-current chromatography(HSCCC)separation under conditions of 900 rpm,2 mL/min,and 35℃.The crude HSCCC product was further purified by silica gel column chromatography(200-300 mesh)using gradient elution with a solvent system of n-hexane-dichloromethane-ethyl acetate(varying from 10:5:1 to 4:5:1,V/V/V).UPLC-PDA(Agilent SB-C_(18)column)and nuclear magnetic resonance spectroscopy(600 MHz)were comprehensively employed to assess compound purity and confirm molecular structures.[Results]An optimized technique integrating HSCCC and silica gel column chromatography was established,successfully enabling the large-scale preparation of three bioactive components:eleutherol(purity 99%),eleutherine(purity 98%),and isoeleutherine(purity 98%).Structural identification results were consistent with those reported in the literature.Compared to traditional methods,the new approach demonstrated improved separation efficiency and reduced solvent consumption.[Conclusions]The combined separation method utilizing HSCCC and silica gel column chromatography established in this study demonstrates notable advantages,including high efficiency,environmental friendliness,and cost-effectiveness,enabling the large-scale preparation of the three major active components from E.americana.This approach outperforms conventional methods by offering higher separation efficiency,reduced solvent consumption,and superior product purity,providing a robust technical solution for the development and utilization of bioactive compounds from E.americana.Moreover,it offers a novel methodological reference for the isolation and purification of other natural products.
基金supported by Tianjin Science and Technology Planning Project(22YDTPJC0020).
文摘As a core power device in strategic industries such as new energy power generation and electric vehicles,the thermal reliability of IGBT modules directly determines the performance and lifetime of the whole system.A synergistic optimization structure of“inlet plate-channel spoiler columns”is proposed for the local hot spot problem during the operation of Insulated Gate Bipolar Transistor(IGBT),combined with the inherent defect of uneven flow distribution of the traditional U-type liquid cooling plate in this paper.The influences of the shape,height(H),and spacing from the spoiler column(b)of the plate on the comprehensive heat dissipation performance of the liquid cooling plate are analyzed at different Reynolds numbers,A dual heat source strategy is introduced and the effect of the optimized structure is evaluated by the temperature inhomogeneity coefficient(Φ).The results show that the optimum effect is achieved when the shape of the plate is square,H=4.5 mm,b=2 mm,and u=0.05 m/s,at which the HTPE=1.09 and Φ are reduced by 40%.In contrast,the maximum temperatures of the IGBT and the FWD(Free Wheeling Diode)chips are reduced by 8.7 and 8.4 K,respectively,and ΔP rises by only 1.58 Pa while keeping ΔT not significantly increased.This optimized configuration achieves a significant reduction in the critical chip temperature and optimization of the flow field uniformity with almost no change in the system flow resistance.It breaks through the limitation of single structure optimization of the traditional liquid cooling plate and effectively solves the problem of uneven flow in the U-shaped cooling plate,which provides a new solution with important engineering value for the thermal management of IGBT modules.
文摘A high-performance liquid chromatography(HPLC)method has been developed using a CAPCELL PAK ADME(150 mm×4.6 mm,5μm)as analytical column and a gradient elution with 15 min using acetonitrile and 0.1%(in volume fraction)phosphoric acid water(pH=2.2)as the mobile phase.Three active substances in cosmetics were quantitatively detected simultaneously at a detection wavelength of 265 nm.The linear ranges of β-nicotinamide mononucleotides,ergothioneine and nicotinamide are 10~200 mg/L,5~100 mg/L and 5~100 mg/L respectively and the detection limits of three components are 3.0 mg/L,1.5 mg/L and 1.5 mg/L respectively.The recovery rate is 97.1~104.9%,with RSD≤2.0%.The method was applied to quantitative analysis of five samples of cosmetics toner,lotion,cream,essence and gel and three samples of raw materials.The results showed that the results of β-nicotinamide mononucleotide and ergothioneine in five cosmetics were consistent with the product label,while nicotinamide was inconsistent with the label.The purity of the three raw material samples was 99.5%,99.7% and 100.8%respectively.This method offers high precision,accuracy and short analysis time,making it a reliable approach for studying three active ingredients in cosmetics and suitable for quality control of related functional ingredients.
基金support for the research,authorship,and/or publication of this paper:This study is supported by the National Science Foundation of China(Grant No.52368074)the Science Fund for Distinguished Young Scholars of Gansu Province(No.21JR7RA267)Hongliu Outstanding Young Talents Program of Lanzhou University of Technology.
文摘To address the vibration issues of wind turbine towers,this paper proposes a bidirectional tuned bellow liquid column damper(BTBLCD).The configuration of the proposed BTBLCD is first described in detail,and its energy dissipation mechanism is derived through theoretical analysis.A refined dynamic model of the wind turbine tower equipped with the BTBLCD is then developed.The vibration energy dissipation performance of the BTBLCD in multiple directions is evaluated through two-way fluid-structure coupling numerical simulations.Finally,a 1/10 scaled model of the wind turbine tower is constructed,and the energy dissipation performance of the BTBLCD is validated using a shaking table test.The results show that the vibration energy dissipation performance of the BTBLCD outperforms that of the bidirectional tuned liquid column damper(BTLCD)in multiple directions.The shaking table test and dynamic response analysis demonstrate a maximum reduction of 61.0%in acceleration and 47.9%in displacement response.Furthermore,the vibration control and energy dissipation performance of the BTBLCD are influenced by the direction and amplitude of vibrations.This study contributes to the development of more effective and versatile vibration mitigation strategies for wind turbine tower structures in various engineering scenarios.
基金Supported by National Key Research and Development Program of China(2023YFD1301001)Central Public-interest Scientific Institution Basal Research Fund(1610072023005)Agricultural Science and Technology Innovation Program of CAAS(CAAS-ASTIP-IQSTAP-04).
文摘[Objective]The aim of this work was to establish an analytical method for the determination of deoxynivalenol(DON)in feeds using automatic immunomagnetic beads(IMBs)clean-up coupled with high-performance liquid chromatography.[Method]Feed samples were extracted using ultra-pure water,purified by automatic IMBs,and subsequently analyzed via high-performance liquid chromatography,employing an external standard method for quantification.[Result]A satisfactory linearity was achieved for DON within the concentration range of 0.05 to 2.0μg/mL,with the corresponding correlation coefficients(R^(2))exceeding 0.9999.The limit of detection(LOD)and limit of quantification(LOQ)for the proposed method were determined to be 0.03 and 0.1 mg/kg,respectively.The average recoveries of the fortified samples(0.1,0.2 and 1.0 mg/kg)were 88.5%−100.6%,with the relative standard deviations(RSD)ranging from 2.1%to 9.7%.[Conclusion]In comparison with the traditional solidphase extraction and immunoaffinity column purification methods,the IMBs technique consolidates the extraction,separation,and purification into a single process.This approach enables fully automated processing,which significantly enhances work efficiency and mitigates result deviations that may arise from manual operations.Consequently,this technique is particularly well-suited for the determination of DON in a large number of feed samples.
文摘This study investigates the seismic response mitigation of an offshore jacket platform via a novel damping system,the bidirectional tuned liquid column gas damper(BTLCGD).To efficiently model the complex platform structure,an equivalent single degree of freedom approach was employed.Since the mass contribution of the first mode of the platform is more than 90%,this simplification significantly reduces the computational burden while maintaining accuracy.Therefore,this structure was modeled and analyzed on a scale of 1 to 36 using the Froudian law.To address the limitations of conventional tuned liquid column gas dampers(TLCGDs),which are susceptible to the directionality of seismic excitations,BTLCGD was proposed.This innovative damper is designed to operate effectively in two orthogonal directions,thereby improving seismic performance.Through numerical simulations,the performance of both TLCGD and BTLCGD was evaluated under seismic loading.The results demonstrated that BTLCGD significantly outperforms TLCGD in terms of reducing structural responses,particularly in the direction where TLCGD is ineffective.Furthermore,BTLCGD offers advantages in terms of installation and space requirements.The results of this research offer valuable perspectives into the design and implementation of effective damping systems for offshore structures,contributing to enhanced structural integrity and safety.
基金National Natural Science Foundation of China,Grant/Award Number:81973476Chinese Society of Toxicology,Grant/Award Number:CST2021CT101。
文摘Background:Polygonum multiflorum-induced liver injury(PM-DILI)has significantly hindered its clinical application and development.Methods:This study investigates the variation in content and toxicity of dian-thrones,the toxic components of P.multiflorum,during different processing cycles.We employed the ultra-high-performance liquid chromatography triple quadrupole mass spectrometry method to quantify six dianthrones in raw P.multiflorum and formulations processed with a method called nine cycles of steaming and sunning.Additionally,toxicity assessments were conducted using human normal liver cell line L02 and zebrafish embryos.Results:Results indicate a gradual reduction in dianthrones content with increasing processing cycles.Processed formulations exhibited significantly reduced cytotoxic-ity in L02 cells and hepatotoxicity in zebrafish embryos.Conclusions:Our findings elucidate the relationship between processing cycles and P.multiflorum toxicity,providing theoretical support for its safe use.
文摘A high-performance liquid chromatography was describ-ed to measure the concentration of human 3-methylhistidine in urine witho-phthaldialdehyde pre-column derivatization.This assay system resultedin a clear separation of 3-methylhistidine derivative from other derivativ-es in urine within 25 min.Linearity,recovery and coefficients of vari-ation were studied.The method has been successfully applied to routineanalysis for clinical studies and diagnosis.
基金Education Ministy Foundation for Chinese Returned Scholars and Nature Science Foundation of Hubeiprovince!98J054
文摘A flow injection (FI) micro-column system coupled with high performance liquid chromatography (HPLC) was proposed for the pre-separation and determination of active organic component (ecdysterone) in traditional Chinese medicine, Loulu. The factors influencing separation performance were investigated and optimized. Under the optimal conditions, the contents of ecdysterone in Loulu were determined by HPLC system using MeOH-H_2O (40: 60,V/V) as the mobile phase at a flow rate of 1. 0 mL/min. The calibration curve was linear in the range of 0. 5~ 100 mg/L of ecdysterone concentrations. The detection limit of the analyte was 0. 11mol/L(3) with a precision of 0. 38% RSD (n=7 f c= 10. 0 mg/L). The average recovery of the method was 98. 7%. The proposed method has been applied to determine ecdysterone in practical samples, and the determined values by both external standard method and standard addition method were in good agreement. Compared to the traditional solid extraction method, the system proposed has the advantages of simple procedure, good reproducibility, minimum volume requirement, reduction of matrix interference and low contamination risk.
文摘A sensitive liquid chromatographic mcthod for the detection of andno acids with precolumn fluorescence derivatization with acridone-N-acetyl chloride has been developed. Andno acid derivatives were eluted in 4o ndn with good reproducibility. The reIative standard deviations (n=6) at an analytical concentration of 50 pmol are < 4%. The method described is also suitable for the analysis of andno acids in different biological samples.
文摘[Objectives]A method for the detection of monensin in poultry and livestock meat by pre-column derivatization-high performance liquid chromatography was established.[Methods]The sample was extracted with chloroform,derivatized with trichloroacetic acid and 2,4-dinitrophenylhydrazine,and centrifuged to obtain a purified solution.A C18 chromatographic column(4.6 mm×150 mm,5μm)was used for separation with(1.5%)acetic acid water∶methanol(volume ratio)=1∶9 as the mobile phase using a DAD detector for detection,and the external standard method was adopted for peak area quantification.[Results]Monensin had good linearity in the concentration range of 5.00-200 mg/L,with the linear correlation coefficient r 2>0.999;the detection limit was 5.00 mg/kg;the relative standard deviation was smaller than 10%;and the recoveries of standard addition experiment were in the range of 75%-110%.[Conclusions]The method has the advantages of simple pretreatment operation,good derivatization effect and fast detection speed,and is suitable for detecting monensin in poultry and livestock meat.
文摘Aim To establish a reversed-phase liquid chromatographic (LC) method forsimultaneous determination of tetramethylpyrazine (TMP) and aspirin in a new compound formulation.Methods Chromatographic separation of the two drugs was achieved on a Diamonsil C_(18) column, usinga binary mixture of methanol-1.5% acetic acid (35:65, V/V, pH = 3.1) as mobile phase at a flow rateof 1.0 mL·min^(-1). Results Separation was completed in less than 12 min. Benzoic acid was used asthe internal standard. Recoveries at levels corresponding to 80 % to 120 % of the label claim ofthe formulation ranged from 99.6 to 100.3 % for aspirin and from 99.9 to 101.3% for TMP. The linearrange was 12.6 - 150.9 μg·mL^(-1)(r= 0.9997, n = 5) for aspirin and 25.0- 300.0 μg·mL^(-1) (r =0.9999, n = 5) for TMP. Conclusion The method developed can be used for the simultaneousdetermination of TMP and aspirin in pharmaceutical preparations.
基金National Natural Science Foundation(Grant No.813 73372)the Open Foundation of State Key Laboratory of Natural and Biomimetic Drugs(Grant No.SKL2012004)Specialized Research Fund for the Doctoral Program of Higher Education of China(Grant No.20110001110021 and 20130001110059)
文摘Abstract： In the presem study, we simultaneously quantified the levels of monoamine neurotransmitters （MANTs） and their metabolites （levodopa, norepinephrine, epinephrine, dopamine, 5-HT, 3,4-dihydroxyphenylacetic acid, homovanillic acid and 5-hydroxyindole-3-acetic acid） in different brain subregions of rats using a newly developed simple, sensitive and selective high-performance liquid chromatography with fluorescence detection （HPLC-FLD） method. In this new HPLC-FLD method, analytes were directly extracted and separated without deriveatization step within 20 min. The FLD wavelength was set at 280 nm and 330 nm for excitation and emission, respectively. The analytes were separated on an Agilent Eclipse Plus Cls column （4.6 mm×150 mm, 5.0 μm） equipped with an Agilent XDB-C18 security guard column （4.6 mm×12.5 mm, 5.0 lam）, and the column temperature was maintained at 35 ℃. The mobile phase for elution was isocratic. The mobile phase consisted of citric acid buffer （50 mmol/L citric acid, 50 mmol/L sodium acetate, 0.5 mmol/L octane sulfonic acid sodium salt, 0.5 mmol/L Na2EDTA and 5 mmol/L triethylamine, pH 3.8） and methanol （90：10, v/v） at a flow rate of 1.0 mL/min. The detection limit （DL） was 0.9-23 nM for all the MANTs and their metabolites with a sample volume of 50 μL. The method was shown to be highly reproducible in terms of peak area （intraday, 0.08%-1.85% RSD, n = 5）. The simultaneous measurement of these MANTs and their metabolites improved our understanding of the neurochemistry in the central nervous system （CNS） in relation to different addictive drugs （methamphetamine, heroin and their mixture） in drug-addicted rat models.
基金The National Natural Science Foundation of China(Grant No.81202918)the Open Project of National First-Class Key Discipline for Science of Chinese Materia Medica,Nanjing University of Chinese Medicine(Grant No.2011ZYX2-006)+2 种基金the Science and Technology Project of Hangzhou,China(Grant No.20130533B68 and 20131813A23)the Chinese Medicine Research Program of Zhejiang Province,China(Grant No.2014ZQ008 and 2015ZQ011)the Science Foundation of Zhejiang Chinese Medical University(Grant No.2011ZY25 and 2013ZZ12)
文摘The crude and processed Paeoniae Radix Alba-Atractylodis Macrocephalae Rhizoma herbal pairs, originated from Bai-zhu-shao-yao-san, are used to treat different diseases clinically. In order to evaluate the crude and processed Paeoniae Radix-Atractylodis Macrocephalae Rhizoma herbal pairs, a simple, easy, and sensitive high-performance liquid chromatography coupled with diode array detectors was developed for simultaneous determination of nine bioactive components in the herbal pairs. The calibration curve exhibited good linearity（r2≥0.9992）. The LODs and LOQs were ≤7.30 and 11.53 μg/m L, respectively. The intra-, inter-day and repeatability RSD values of the nine compounds were less than 3.86%, 2.71%, and 4.29%, respectively. The RSD stability values were less than 3.64%. The recovery of the method was in the range of 96.70%–102.10%, with RSD values less than 3.52%. The developed method can be applied to the intrinsic quality control of crude and processed Paeoniae Radix-Atractylodis Macrocephalae Rhizoma herbal pairs.
基金Administration Bureau of Traditional Chinese Medicine(2007-2008)for Scientific Research Program of TCM (Grant No.HL07057)
文摘Due to their biological and physiological importance,flavonoids receive considerable attention in the literature. Nowadays,high performance liquid chromatography（HPLC）is the most widely used analytical method.In this review,we summarize the principle of the choice of HPLC column and mobile phase,discuss and compare the features of various detections such as UV,fluorescence detection,electrochemical detection,chemilummescence detection,UV-MS etc.Recent developments in HPLC including ultra-LC and miniaturization of LC（micro-LC,capillary-LC,and nano-LC）,are also discussed.
文摘The ginkgo terpenoids including bilobalide and ginkgolides are the main pharmaceutical components in the leaves or extracts of Ginkgo biloba L. In this paper, the analysis of bilobalide and ginkgolides in leaves of Ginkgo biloba L. by high performance liquid chromatography (HPLC)-electrospray ionization (ESI)-mass spectrometry (MS) was carried out. The separation was performed on Inertsil ODS3 column with methanol-water (36:64) as mobile phase, with 1 mL·min -1 of flow rate at 35℃. Then the mass spectrum analysis was conducted by ZMD micromass electrospray ionization (ESI)-mass spectrometer (MS). The HPLC total ion chromatogram and selected ion chromatogram (with 325, 407, 423, 439 of m/z) of the sample and ESI-/MS mass spectra of the peaks in the chromatograms were obtained. So bilobalide, ginkgolide A, B, C and J in Ginkgo biloba L. leaves were identified. The method is easy and rapid, with a good accuracy.
文摘A sensitive and selective high performance liquid chromatography coupled with electrospray ionization mass spectrometry （LC-MS） was developed for the quantitative determination of ilexgenin A （IA）,a major component in Radix Ilicis Pubescentis,in rat plasma.Chromatographic separation was performed on a C 18 column,with methanol-5 mM ammonium acetate （80：20,v/v） as the mobile phase.Mass spectrometer was set in negative mode with target ions at m/z 501.1→501.1 for IA and m/z 779.4→779.4 for digoxin （internal standard,IS）.Rat plasma was extracted with ethyl acetate after addition of phosphoric solution and the organic layer was evaporated and reconstituted with mobile phase for LC-MS analysis.The proposed method was validated with a linear range of 1.05-525.5 ng/mL for IA with limit of quantitation （LOQ） at 1.05 ng/mL.Intra-and inter-day precision expressed as relative standard deviation （RSD） were less than 10% at LOQ level and overall recovery was over 80%.This validated method was used successfully for the pharmacokinetic study of IA in rats after oral dosing of IA （100 mg/kg） and some main pharmacokinetic parameters of IA in rats were obtained.
