High Performance Liquid Chromatography (HPLC) experiments have been performed on nine steviol glycosides namely rebaudioside A, steviolbioside, stevioside, rubusoside, rebaudioside B, rebaudioside C, rebaudioside D, r...High Performance Liquid Chromatography (HPLC) experiments have been performed on nine steviol glycosides namely rebaudioside A, steviolbioside, stevioside, rubusoside, rebaudioside B, rebaudioside C, rebaudioside D, rebaudioside F, and dulcoside A isolated from the leaves of Stevia rebaudiana using Reversed-Phase (RP) column. Using RP-HPLC method, the individual retention times for nine naturally occurring ent-kaurane diterpene glycosides of S. rebaudiana reported in JECFA have been determined at four different temperatures: 20℃, 40℃, 60℃, and 79℃. Also, calculated the relative retention times of the eight steviol glycosides steviolbioside, stevioside, rubusoside, rebaudioside B, rebaudioside C, rebaudioside D, rebaudioside F, and dulcoside A against the major steviol glycoside rebaudioside A. HPLC results suggested that temperatures 40℃ and 60℃ would be ideal conditions for better separation of steviol glycosides.展开更多
A direct enantio-,diastereo-,and chemo-selective high-performance liquid chromatographic method was developed for determining the content,enantiomeric purity,and related substances of the chiral antidepressant drug se...A direct enantio-,diastereo-,and chemo-selective high-performance liquid chromatographic method was developed for determining the content,enantiomeric purity,and related substances of the chiral antidepressant drug sertraline HCl in a single chromatographic run.The separation was achieved on a chiral stationary phase based on amylose tris(3-chloro-5-methylphenylcarbamate)under reversed-phase conditions.The method was optimized by evaluating the influence of the temperature and mobile phase composition on the retention and selectivity.The application of the single-run approach allowed to baseline resolve all investigated species in less than 15 min,without using buffers or tandem-coupled columns.The chromatographic method was validated according to the guidelines of the Official Medicines Control Laboratory and applied to control the content of sertraline HCl and related chiral substances in a generic antidepressant formulation.展开更多
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 o...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.展开更多
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 ...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.展开更多
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 ...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%.展开更多
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...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.展开更多
The present paper covers the actional mechanism of trifluoroacetic acid for the separation of biopolymers investigated by using the parameters of stoichiometric displacement model for retention(SDM-R) in reversed-phas...The present paper covers the actional mechanism of trifluoroacetic acid for the separation of biopolymers investigated by using the parameters of stoichiometric displacement model for retention(SDM-R) in reversed-phase liquid chromatography. It was found that the trifluoroacetic acid(TFA) may participate in, or stimulate the association among displacing agent molecules in mobile phase, and decrease the affinity of both the associate molecules of the displacing agent and the TFA-protein ion-pairing. The former dominates over the separation selectivity of biopolymers as the concentration of TFA is lower than a given value, and the two contrary functions partly offset to each other and the latter dominates as its concentration is greater than the given value.展开更多
Reversed-phase paper chromatography technique is used for study on the extraction mechanism and sep- aration of rare earth elements.As the stationary phase,chromatographic paper strips are impregnated with a solution ...Reversed-phase paper chromatography technique is used for study on the extraction mechanism and sep- aration of rare earth elements.As the stationary phase,chromatographic paper strips are impregnated with a solution of monomyristyl phosphoric acid (MPA) in chloroform.Mineral acids are used as developers. The effect of concentration of acids and/or salts upon R_f has been investigated.According to the re- sults of R_f values for a given rare earth element in various acids,the order of extraction ability is HCl>HNO_3>H_2SO_4.A tetrad effect is clearly observed.for the R_f value of rare earth elements.The effects of other parameters on the R_f value,such as the quantities of extractant retained by the paper and the temperature are also examined.Based on the determination of the molar ratio of MPA to rare earth elements and the number of H^+ ions released in extraction reaction,a reasonable mechanism is proposed.The mutual separation of heavy rare earth elements will be better than that of the light rare earth group because of the larger separation coefficient of the former.A mixture of Ho-Er-Tm-Lu is successfully separated by the present method.展开更多
The development of facile and rapid quantification of biologically active biomolecules such as isotretitoin in therapeutic drugs contained in many generic formu- lations is necessary for determining their efficiency a...The development of facile and rapid quantification of biologically active biomolecules such as isotretitoin in therapeutic drugs contained in many generic formu- lations is necessary for determining their efficiency and their quality to improve the human health care. Isotretritoin finds its applications in the maintenance of epithelial tissues. Different processes to date such as normal phase HPLC, or gas chromatrography am- ong others are able to separate and quantify isote- troin. However, the extraction is quite complex and in the case of HPLC, the analysis requires long retention times. In such context, an isocratic reversed- phase high-performance liquid chromatography (HP- LC) technique coupled with an UV-vis detector is described here for easy separation and quantification of 13-cis-retinoic (isotretinoin) from soft gelatin capsule formulations. The isotretinoin was extracted from three different commercial drug samples with tetrahydrofuran (THF) solvent by a procedure that can be completed in less than 10 minutes. Subsequent separation and quantification were accomplished in less than 5 minutes under isocratic reversed-phase conditions on a Lichrospher RP18 column and a mobile phase consisting of 0.01% TFA/acetonitrile (15/85, v/v) at a flow rate of 1.0 mL/min. Isotretoin was detected for the three samples via its UV-vis absorbance at 342 nm. The method was validated and the results showed good linearity, precision and accuracy for sensitive and selective quantitative determination of isotretinoin in the different pharmaceutical formulations. We found that the average isotretinoin content in two of the three commercial pro- ducts fell outside the 90-110% United States Pha- rmacopeia specifications. Consequently, the facile extraction and the precise method for the biomole- cule quantification open up tremendous possibilities in improving the quality control of drugs which can exist as different generic brands.展开更多
Covalent organic frameworks(COFs)have numerous advantages,including high specific surface area,good stability,and ease of modification.These features have generated significant interest in utilizing COFs as chromatogr...Covalent organic frameworks(COFs)have numerous advantages,including high specific surface area,good stability,and ease of modification.These features have generated significant interest in utilizing COFs as chromatographic stationary phase materials.Herein,two monomers,1,3,5-tris-(4-aminophenyl)triazine(TAPT)and 1,3,5-benzenetricarboxaldehyde,are selected to construct the COF material.A novel core-shell type composite material named SiO_(2)@COF was prepared with the covalent triazine framework layer grafted on the silica by in situ growth method,and then the C18 chain was post-modifi ed on the SiO_(2)@COF material,named SiO_(2)@COF-C18.Multiple methods have been employed to illustrate the morphological and structural characteristics of the SiO_(2)@COF-C18 material.Then,several analytes,including anilines,polycyclic aromatic hydrocarbons(PAHs),alkylbenzenes,and positional isomers,were selected to study the separation mechanism of the SiO_(2)@COF-C18 column,which demonstrated that these analytes were separated on the SiO_(2)@COF-C18 column under chromatographic modes of hydrophobic interaction,π-πinteraction,steric hindrance eff ect,etc.The prepared chromatographic column had excellent repeatability and high separation efficiency,and it was used to determine acetaminophen tablets under reversed-phase conditions.These results open a new avenue for the post-modification of hydrophobic groups on COF materials for pharmaceutical analysis.展开更多
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 ar...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.展开更多
KOVATS index is the most precise index system reflecting the interaction between the molecules of solutes and stationary phase in gas chromatography at present. Large quantity of Kovats in dex data have been published...KOVATS index is the most precise index system reflecting the interaction between the molecules of solutes and stationary phase in gas chromatography at present. Large quantity of Kovats in dex data have been published. It is a good way to use Kováts index in gas chromatography to predict the retention value in liquid chromatography, which is significant in theory and apphcation.展开更多
Ⅰ. INTRODUCTIONReversed-phase ion-pair liquid chromatography is widely used in the separation of ionized organic compounds. In recent years, the separation of inorganic ions by the reversedphase ion-pair liquid chrom...Ⅰ. INTRODUCTIONReversed-phase ion-pair liquid chromatography is widely used in the separation of ionized organic compounds. In recent years, the separation of inorganic ions by the reversedphase ion-pair liquid chromatography with indirect UV detection or conductivity展开更多
The interaction index c which was derived from the fundamental retention equationlogk’ =a + cC_B in reversed--phase high--performancc liquid chromatography (RP-HPLC) quan-titatively describes the difference in the in...The interaction index c which was derived from the fundamental retention equationlogk’ =a + cC_B in reversed--phase high--performancc liquid chromatography (RP-HPLC) quan-titatively describes the difference in the interaction between solute--strong. solvent andsolute--weak solvent; it has shown to be a constant for a specific solute even when columnsystems with different C18 packings are used. The theoretical basis for peak identificationby using interaction index has been proposed, which was based on the a,c values on stan-dard C18 column by utilizing linear a-a plots on column pairs and the linear relationship be-tween parameters a and c for the structural related compounds. Through the establishmentof parameters a,c data based on the standard C18 column for a certain type of compounds,the retention of thesc compounds on various C18 columns can be predicted. Typical exam-ples have been given to verify the correctness of this method.展开更多
A computer-assisted retention prediction system (RPS) of fifteen O-ethyl O-aryl N-iso- propyl phosphoramidothioates (1) in reversed-phase HPLC was investigated. The system is based on the use of four physicochemical p...A computer-assisted retention prediction system (RPS) of fifteen O-ethyl O-aryl N-iso- propyl phosphoramidothioates (1) in reversed-phase HPLC was investigated. The system is based on the use of four physicochemical parameters (hydrophobicity , electric effect σ, field effect F and steric effect ) which is closely related to the retention mechanism in reversed-phase HPLC. The system was evaluated by comparing the measured retention data with the predicted ones. The predicted values were consistent with the measured values within a relative error of 11.5%.展开更多
A method is presented for the computer-assisted optimization of mobile phase selection for the separation of a synthetic intermediate of unknown composition by reversed- phase HPLC.The method is based on recognition o...A method is presented for the computer-assisted optimization of mobile phase selection for the separation of a synthetic intermediate of unknown composition by reversed- phase HPLC.The method is based on recognition of the order of the peaks by comparison of peak area ratio and followed by the BSOS-L(Binary Solvent Optimization System for HPLC)method.Excellent agreement was obtained between predicted data and experimental results.展开更多
Two polysaccharide-based chiral stationary phase columns were evaluated to improve the previous partial chiral peak separation to a baseline-resolved separation of the INGREZZA® drug substance and its diastereome...Two polysaccharide-based chiral stationary phase columns were evaluated to improve the previous partial chiral peak separation to a baseline-resolved separation of the INGREZZA® drug substance and its diastereomers. Moreover, the tailing factor (Tf) variation was studied to investigate chiral column degradation and regeneration and to optimize chiral column performance and efficiency.展开更多
Flavonoids were the most important secondary metabolites in celery （Apium graveolens L.）.In this study,the flavonoid （apigenin and luteolin） contents of leaves and petioles in 44 Chinese celery varieties,an Americ...Flavonoids were the most important secondary metabolites in celery （Apium graveolens L.）.In this study,the flavonoid （apigenin and luteolin） contents of leaves and petioles in 44 Chinese celery varieties,an American celery variety ‘Ventura＇ and an European celery variety ‘Princer＇ were assayed by reversed-phase high-perfor mance liquid chromatography （RP-HPLC）.The results showed that significant differences in the apigenin and luteolin contents of the leaves and petioles were found among 46 celery varieties,and the variation coefficients of leaf apigenin content,leaf luteolin content,leaf flavonoid content,petiole apigenin content,petiole luteolin content and petiole flavonoid content were 30％,10％,30％,20％,30％ and 20％,respectively.There was no correlation between the leaf flavonoid content and petiole flavonoid content.The apigenin content was about 18 to 50 times of luteolin in celery leaf and about 19 to 40 times of luteolin in celery petiole.The flavonoids in most of the Chinese celery varieties were higher than in ‘Ventura＇ and ‘Princer＇.The flavonoid contents of Chinese celery varieties from the Yangtze Valley and southern China were higher than those from northern China.Our results suggested that Chinese celery varieties with high petiole apigenin contents could be used for vegetable breeding because the petiole was the main edible part,and Chinese celery varieties with high leaf apigenin contents could be used for apigenin production.展开更多
文摘High Performance Liquid Chromatography (HPLC) experiments have been performed on nine steviol glycosides namely rebaudioside A, steviolbioside, stevioside, rubusoside, rebaudioside B, rebaudioside C, rebaudioside D, rebaudioside F, and dulcoside A isolated from the leaves of Stevia rebaudiana using Reversed-Phase (RP) column. Using RP-HPLC method, the individual retention times for nine naturally occurring ent-kaurane diterpene glycosides of S. rebaudiana reported in JECFA have been determined at four different temperatures: 20℃, 40℃, 60℃, and 79℃. Also, calculated the relative retention times of the eight steviol glycosides steviolbioside, stevioside, rubusoside, rebaudioside B, rebaudioside C, rebaudioside D, rebaudioside F, and dulcoside A against the major steviol glycoside rebaudioside A. HPLC results suggested that temperatures 40℃ and 60℃ would be ideal conditions for better separation of steviol glycosides.
文摘A direct enantio-,diastereo-,and chemo-selective high-performance liquid chromatographic method was developed for determining the content,enantiomeric purity,and related substances of the chiral antidepressant drug sertraline HCl in a single chromatographic run.The separation was achieved on a chiral stationary phase based on amylose tris(3-chloro-5-methylphenylcarbamate)under reversed-phase conditions.The method was optimized by evaluating the influence of the temperature and mobile phase composition on the retention and selectivity.The application of the single-run approach allowed to baseline resolve all investigated species in less than 15 min,without using buffers or tandem-coupled columns.The chromatographic method was validated according to the guidelines of the Official Medicines Control Laboratory and applied to control the content of sertraline HCl and related chiral substances in a generic antidepressant formulation.
文摘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.
文摘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.
文摘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%.
基金Supported by the Key Science and Technology Program of Shaanxi Province,China(No.2015SF146).
文摘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.
基金Supported by the National Natrual Science Foundation of China
文摘The present paper covers the actional mechanism of trifluoroacetic acid for the separation of biopolymers investigated by using the parameters of stoichiometric displacement model for retention(SDM-R) in reversed-phase liquid chromatography. It was found that the trifluoroacetic acid(TFA) may participate in, or stimulate the association among displacing agent molecules in mobile phase, and decrease the affinity of both the associate molecules of the displacing agent and the TFA-protein ion-pairing. The former dominates over the separation selectivity of biopolymers as the concentration of TFA is lower than a given value, and the two contrary functions partly offset to each other and the latter dominates as its concentration is greater than the given value.
文摘Reversed-phase paper chromatography technique is used for study on the extraction mechanism and sep- aration of rare earth elements.As the stationary phase,chromatographic paper strips are impregnated with a solution of monomyristyl phosphoric acid (MPA) in chloroform.Mineral acids are used as developers. The effect of concentration of acids and/or salts upon R_f has been investigated.According to the re- sults of R_f values for a given rare earth element in various acids,the order of extraction ability is HCl>HNO_3>H_2SO_4.A tetrad effect is clearly observed.for the R_f value of rare earth elements.The effects of other parameters on the R_f value,such as the quantities of extractant retained by the paper and the temperature are also examined.Based on the determination of the molar ratio of MPA to rare earth elements and the number of H^+ ions released in extraction reaction,a reasonable mechanism is proposed.The mutual separation of heavy rare earth elements will be better than that of the light rare earth group because of the larger separation coefficient of the former.A mixture of Ho-Er-Tm-Lu is successfully separated by the present method.
文摘The development of facile and rapid quantification of biologically active biomolecules such as isotretitoin in therapeutic drugs contained in many generic formu- lations is necessary for determining their efficiency and their quality to improve the human health care. Isotretritoin finds its applications in the maintenance of epithelial tissues. Different processes to date such as normal phase HPLC, or gas chromatrography am- ong others are able to separate and quantify isote- troin. However, the extraction is quite complex and in the case of HPLC, the analysis requires long retention times. In such context, an isocratic reversed- phase high-performance liquid chromatography (HP- LC) technique coupled with an UV-vis detector is described here for easy separation and quantification of 13-cis-retinoic (isotretinoin) from soft gelatin capsule formulations. The isotretinoin was extracted from three different commercial drug samples with tetrahydrofuran (THF) solvent by a procedure that can be completed in less than 10 minutes. Subsequent separation and quantification were accomplished in less than 5 minutes under isocratic reversed-phase conditions on a Lichrospher RP18 column and a mobile phase consisting of 0.01% TFA/acetonitrile (15/85, v/v) at a flow rate of 1.0 mL/min. Isotretoin was detected for the three samples via its UV-vis absorbance at 342 nm. The method was validated and the results showed good linearity, precision and accuracy for sensitive and selective quantitative determination of isotretinoin in the different pharmaceutical formulations. We found that the average isotretinoin content in two of the three commercial pro- ducts fell outside the 90-110% United States Pha- rmacopeia specifications. Consequently, the facile extraction and the precise method for the biomole- cule quantification open up tremendous possibilities in improving the quality control of drugs which can exist as different generic brands.
基金the Project of Sichuan Department of Science and Technology(2022NSFSC0622)the Scientifi c Research Project of Southwest Medical University(2021ZKMS043)+1 种基金the Science and Technology Project of Luzhou(2021-JYJ-74)the National Natural Science Foundation of China(21974015)。
文摘Covalent organic frameworks(COFs)have numerous advantages,including high specific surface area,good stability,and ease of modification.These features have generated significant interest in utilizing COFs as chromatographic stationary phase materials.Herein,two monomers,1,3,5-tris-(4-aminophenyl)triazine(TAPT)and 1,3,5-benzenetricarboxaldehyde,are selected to construct the COF material.A novel core-shell type composite material named SiO_(2)@COF was prepared with the covalent triazine framework layer grafted on the silica by in situ growth method,and then the C18 chain was post-modifi ed on the SiO_(2)@COF material,named SiO_(2)@COF-C18.Multiple methods have been employed to illustrate the morphological and structural characteristics of the SiO_(2)@COF-C18 material.Then,several analytes,including anilines,polycyclic aromatic hydrocarbons(PAHs),alkylbenzenes,and positional isomers,were selected to study the separation mechanism of the SiO_(2)@COF-C18 column,which demonstrated that these analytes were separated on the SiO_(2)@COF-C18 column under chromatographic modes of hydrophobic interaction,π-πinteraction,steric hindrance eff ect,etc.The prepared chromatographic column had excellent repeatability and high separation efficiency,and it was used to determine acetaminophen tablets under reversed-phase conditions.These results open a new avenue for the post-modification of hydrophobic groups on COF materials for pharmaceutical analysis.
基金supported by National Natural Science Foundation of China(22074154)Longyuan Youth Innovation and Entrepreneurship Talent(Team)Project(E20492SC)+2 种基金Lanzhou talent innovation and Entrepreneurship Project(2021-RC-35)Science and Technology Project of Science and Technology Bureau of Chengguan District in Lanzhou City(2020JSCX0033)Youth Innovation Promotion Association CAS(2021420)
文摘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.
文摘KOVATS index is the most precise index system reflecting the interaction between the molecules of solutes and stationary phase in gas chromatography at present. Large quantity of Kovats in dex data have been published. It is a good way to use Kováts index in gas chromatography to predict the retention value in liquid chromatography, which is significant in theory and apphcation.
文摘Ⅰ. INTRODUCTIONReversed-phase ion-pair liquid chromatography is widely used in the separation of ionized organic compounds. In recent years, the separation of inorganic ions by the reversedphase ion-pair liquid chromatography with indirect UV detection or conductivity
文摘The interaction index c which was derived from the fundamental retention equationlogk’ =a + cC_B in reversed--phase high--performancc liquid chromatography (RP-HPLC) quan-titatively describes the difference in the interaction between solute--strong. solvent andsolute--weak solvent; it has shown to be a constant for a specific solute even when columnsystems with different C18 packings are used. The theoretical basis for peak identificationby using interaction index has been proposed, which was based on the a,c values on stan-dard C18 column by utilizing linear a-a plots on column pairs and the linear relationship be-tween parameters a and c for the structural related compounds. Through the establishmentof parameters a,c data based on the standard C18 column for a certain type of compounds,the retention of thesc compounds on various C18 columns can be predicted. Typical exam-ples have been given to verify the correctness of this method.
文摘A computer-assisted retention prediction system (RPS) of fifteen O-ethyl O-aryl N-iso- propyl phosphoramidothioates (1) in reversed-phase HPLC was investigated. The system is based on the use of four physicochemical parameters (hydrophobicity , electric effect σ, field effect F and steric effect ) which is closely related to the retention mechanism in reversed-phase HPLC. The system was evaluated by comparing the measured retention data with the predicted ones. The predicted values were consistent with the measured values within a relative error of 11.5%.
基金Project supported by the National Natural Science Foundation of China.
文摘A method is presented for the computer-assisted optimization of mobile phase selection for the separation of a synthetic intermediate of unknown composition by reversed- phase HPLC.The method is based on recognition of the order of the peaks by comparison of peak area ratio and followed by the BSOS-L(Binary Solvent Optimization System for HPLC)method.Excellent agreement was obtained between predicted data and experimental results.
文摘Two polysaccharide-based chiral stationary phase columns were evaluated to improve the previous partial chiral peak separation to a baseline-resolved separation of the INGREZZA® drug substance and its diastereomers. Moreover, the tailing factor (Tf) variation was studied to investigate chiral column degradation and regeneration and to optimize chiral column performance and efficiency.
基金Supported by Shanghai Green Vegetable Industrial Technology SystemKey Scienceand Technology Research Program of Science and Technology Commission of Shanghai Municipality(12391900900)+1 种基金Innovation Project of Science and Technology Foundation of Pudong New District(PKQ2012-03)Special Fund for Agro-scientific Research in the Public Interest(201403032)~~
文摘Flavonoids were the most important secondary metabolites in celery （Apium graveolens L.）.In this study,the flavonoid （apigenin and luteolin） contents of leaves and petioles in 44 Chinese celery varieties,an American celery variety ‘Ventura＇ and an European celery variety ‘Princer＇ were assayed by reversed-phase high-perfor mance liquid chromatography （RP-HPLC）.The results showed that significant differences in the apigenin and luteolin contents of the leaves and petioles were found among 46 celery varieties,and the variation coefficients of leaf apigenin content,leaf luteolin content,leaf flavonoid content,petiole apigenin content,petiole luteolin content and petiole flavonoid content were 30％,10％,30％,20％,30％ and 20％,respectively.There was no correlation between the leaf flavonoid content and petiole flavonoid content.The apigenin content was about 18 to 50 times of luteolin in celery leaf and about 19 to 40 times of luteolin in celery petiole.The flavonoids in most of the Chinese celery varieties were higher than in ‘Ventura＇ and ‘Princer＇.The flavonoid contents of Chinese celery varieties from the Yangtze Valley and southern China were higher than those from northern China.Our results suggested that Chinese celery varieties with high petiole apigenin contents could be used for vegetable breeding because the petiole was the main edible part,and Chinese celery varieties with high leaf apigenin contents could be used for apigenin production.
