The hydroxyl radical （·OH） plays a central role in the oxidation and removal of many atmospheric compounds. Measurement of atmospheric ·OH is very difficult because of its high reactivity and low atmospher...The hydroxyl radical （·OH） plays a central role in the oxidation and removal of many atmospheric compounds. Measurement of atmospheric ·OH is very difficult because of its high reactivity and low atmospheric abundance. In this article, a simple and highly sensitive method, high performance liquid chromatography coupled with coulometric detection （HPLC-CD）, was developed to determine ·OH indirectly by determining its reaction products with salicylic acid （SAL）, 2,3-dihydroxybenzoic acid （2,3-DHBA）, and 2,5-dihydroxybenzoic acid （2,5-DHBA）. Under the optimum conditions for its determination, 2,3-DHBA and 2,5-DHBA could be well separated and the detection limits for 2,3-DHBA were 3 ×10^-10 mol/L and for 2,5-DHBA were 1.5 ×10^-10 mol/L, which were lower than most previous reports. This method was also applied to measure atmospheric hydroxyl radical levels and demonstrated the feasibility in clean and polluted air.展开更多
Aflatoxins are the potential lethal toxin produced by Aspergillus sp. important health hazard throughout the world. In this study, 26 Aspergillus sp. have been isolated from 50 samples of red chilli collected througho...Aflatoxins are the potential lethal toxin produced by Aspergillus sp. important health hazard throughout the world. In this study, 26 Aspergillus sp. have been isolated from 50 samples of red chilli collected throughout the country. These 26 isolates were grown primarily on agar media to identify the aflatoxin producing species. It is possible to distinguish A. flavus strains from other Aspergillus sp. developing orange colour on the reverse of the plates. The Coconut Cream Agar (CCA) is used to detect aflatoxin producer strains having blue fluorescence when exposed to a UV-light. Several other media were used for morphological characteristics of Aspergillus sp. Out of 26 isolates, four isolates were confirmed as Aspergillus sp. These isolates were subjected to cross contamination with freshly ground, sterile maize and after 15 days of incubation the contaminated maize were analyzed by HPLC and found aflatoxin in each of the sample containing 186 ppb (max.). This study was conducted to assay the ability to produce aflatoxins by the Aspergillus spp. isolated from red chilli (Capsicum annuum L. Solanaceae) available throughout the country. The results found in the experiment are much more behind the acceptable limit according to some international standard. As red chilli is a widely used spice in Bangladesh, the proper controlling measures may be taken for controlling the surveillance of aflatoxinic fungi like as use of bio-pesticides, proper drying method and storage conditions.展开更多
[ Objective] To detect the praziquantel content in praziquantel injection by HPLC. [ Methods ] Chromatographic conditions were as follows： chromato- graphic colmnn was Diamonsil Cls column （ 150 mm x 4.6 mm, 5 μm）...[ Objective] To detect the praziquantel content in praziquantel injection by HPLC. [ Methods ] Chromatographic conditions were as follows： chromato- graphic colmnn was Diamonsil Cls column （ 150 mm x 4.6 mm, 5 μm） ; column temperature was 25 ℃ ; mobile phase was acetonitrile-water （60：40） ; flow rate was 1.0 mL/min ; UV detection wavelength was 210 nm; and injection volume was 20 μL. [ Results ] Praziquantel showed good linear relationship within the con- centration of 6.037 - 90.55 g/L （ r = 0. 999 4） ; the average recovery rate was 99.24%, and RSD was 0. 769%. [Condusions ] This method was simple, rap- id, sensitive and repeatable, and could be used for the quality control of praziquantel injection.展开更多
New HPLC method was developed for determination of amlodipine and valsartan in their binary mixture as a part of routine control of combined formulations. The method was validated to meet official requirements includi...New HPLC method was developed for determination of amlodipine and valsartan in their binary mixture as a part of routine control of combined formulations. The method was validated to meet official requirements including selectivity, stability, linearity, precision and accuracy. Chromatography was carried out using a LiChrospher RP-18 column, a mixture containing acetonitrile, phosphate buffer of pH 3.5 and methanol (45:45:10, v/v/v) and new fluorescence detection at 255 nm for excitation and 448 nm for emission. The effect of methanol content, pH of the buffer, flow rate, detection wavelengths and column temperature was estimated in robustness study, according to a plan defined by the Plackett-Burman design. For identification of significant effects, both graphical and statistical methods were used. Ro-bustness for dissolution test was checked estimating the effects of paddle speed, temperature and pH of dissolution medium. The method was proved to complying with all official guidelines. Therefore, it is suitable for determination of amlodipine and valsartan in their binary mixtures for different analytical and pharmaceutical purposes.展开更多
Glycerides are first separated to classes of triglycerides(TGs), diglycerides(DGs) and monoglycerides(MGs) by normal phase HPLC on silica gel column. Individual triglyceride separation is then achieved by non-aqueous ...Glycerides are first separated to classes of triglycerides(TGs), diglycerides(DGs) and monoglycerides(MGs) by normal phase HPLC on silica gel column. Individual triglyceride separation is then achieved by non-aqueous reversed phase(NARP) HPLC on C_(18) column with UV detection at 215nm.展开更多
Amino acid neurotransmitters facilitate the transmission of nerve messages across the synapses and play essential roles in the control and regulation of a variety of functions in the central and peripheral nervous sys...Amino acid neurotransmitters facilitate the transmission of nerve messages across the synapses and play essential roles in the control and regulation of a variety of functions in the central and peripheral nervous system. In this study, we developed a sensitive and efficient method using high-performance liquid chromatography （HPLC） with fluorescence detection for the assay of five important amino acid n After derivatization with o-phthaldialdehyde （OPA）, aspartate （Asp）, glutamic acid （Glu）, glycine （Gly）, taurine （Tau） and ）,-aminobutyric acid （GABA） were simultaneously detected in the presence of the internal standard homoserine （Hse）. Precise separation of these five amino acids was achieved using isocratic elution within 24 min. Good linearity was found over the concentration range with correlation coefficients （r2） not less than 0.9998. The limit of detection （LOD） values were no more than 10 nmol/L. The intra- and inter-day reproducibility was adequate with the relative standard deviation （RSD） of 10.5% or below. This method has also been applied to the analysis of amino acids in the substantia nigra and striatum samples obtained from C57BL/6 mice.展开更多
[Objective] This study aimed to optimize the chromatographic conditions for detecting ellagic acid in pomegranate peels using HPLC method. [Method] By using 0.2 mg/ml ellagic acid standard solution, on the basis of si...[Objective] This study aimed to optimize the chromatographic conditions for detecting ellagic acid in pomegranate peels using HPLC method. [Method] By using 0.2 mg/ml ellagic acid standard solution, on the basis of single-factor experiment and orthogonal experiment, chromatographic conditions （mobile phase ratio, flow rate, col- umn temperature） for detecting ellagic acid using HPLC were optimized. Based on the optimal chromatographic conditions, the ellagic acid content in experimental pomegranate peels was determined. [Resull] The optimal chromatographic conditions for detecting ellagic acid in pomegranate peels using HPLC method are： 1.2% phos- phoric acid：acetonitrile=85：15, column temperature of 35 ℃, and flow rate of 1.0 ml/min. The linear regression equation of ellagic acid is： y=2.9e＋0.6x＋4.4e＋5 （FF=9 999）. Ac- cording to the standard addition recovery test, the average recovery rate of ellagic acid is 98.20%, and RSD is 0.60%. Under above optimized chromatographic condi- tions, ellagic acid can be well separated from other interfering components in pomegranate peels, with shorter peak time and ideal effect, which is convenient for the detection in production practices. [Conclusion] This study laid the foundation for detecting ellagic acid in pomegranate peels using HPLC method.展开更多
Aim To develop an HPLC method with fluorescence detection for the assay ofDL111-IT in rabbit plasma. Methods DL111-IT and internal standard glybenzcyclamide in rabbit plasmawere extracted with chloroform. The determin...Aim To develop an HPLC method with fluorescence detection for the assay ofDL111-IT in rabbit plasma. Methods DL111-IT and internal standard glybenzcyclamide in rabbit plasmawere extracted with chloroform. The determination was performed on a Diamonsil ODS-C_(18) column(150 mm x 4.6 mm, 5 μm) with a mobile phase of acetonitrile and 0.025 mol·L^(-1) diammoniumhydrogen phosphate buffer (pH 5.0, adjusted by phosphoric acid) (60:40, V/V) at a flow-rate of 1.0mL·min^(-1) . Fluorescence detector was operated at excitation wavelength of 250 nm and emissionwavelength of 332 nm. Results The calibration curve in plasma was linear from 1.00 - 20.00ng·mL^(-1) ( r = 0.999 6, n = 5). The method afforded average extracting recoveries of 85.3% ±1.3%, 84.9% ± 2.7% and 85.8% ± 1.8%, and the average method recoveries were 99.5% ±0.4%, 102.1%± 1.8% and 101.3% ± 2.4% for the high (20.00 ng·mL^(-1)) , middle (10.00 ng·mL^(-1)) and low (1.00 ng·mL^(-1)) check samples, respectively. The intra-day (n = 5) and inter-day (n = 5) precisions(RSD) were less than 3.0% and 7.0%, respectively. The limit of detection and quantitation for themethod were 0.3 ng·mL^(-1) (S/N = 3) and 1 ng·mL^(-1) (S/N = 10, RSD<7.0%) plasma sample,respectively. Conclusion The developed method was accurate, sensitive, simple and could be used forpharmacokinetic study of DL111- IT.展开更多
A post-column reaction chemiluminescence detection method in ion chromatography is described in this paper.The chemiluminescence system was indigo cramine-hydrogen peroxide. The chemiluminescence reaction conditions a...A post-column reaction chemiluminescence detection method in ion chromatography is described in this paper.The chemiluminescence system was indigo cramine-hydrogen peroxide. The chemiluminescence reaction conditions and the separation conditions of Co and Cu in chromatography were presented.The detection limits were 1.0 and 2.0×10-8 g/mL for Co and Cu respectively.展开更多
In this paper, a high-performance liquid chromatography coupled with ultraviolet detection and Fourier transform-ion cyclotron resonance mass spectrometry （HPLC-UV/FrICRMS） method was described for the investigation...In this paper, a high-performance liquid chromatography coupled with ultraviolet detection and Fourier transform-ion cyclotron resonance mass spectrometry （HPLC-UV/FrICRMS） method was described for the investigation of impurity profile in moxifloxacin （MOX） drug substance and chemical reference substance. Ten impurities were detected by HPLC-UV, while eight impurities were identified by using the high accurate molecular mass combined with multiple-stage mass spectrometric data and fragmentation rules. In addition, to our knowledge, five impurities were founded for the first time in MOX drug substance.展开更多
基金This work was supported by the National Natural Science Foundation of China(No.40075026).
文摘The hydroxyl radical （·OH） plays a central role in the oxidation and removal of many atmospheric compounds. Measurement of atmospheric ·OH is very difficult because of its high reactivity and low atmospheric abundance. In this article, a simple and highly sensitive method, high performance liquid chromatography coupled with coulometric detection （HPLC-CD）, was developed to determine ·OH indirectly by determining its reaction products with salicylic acid （SAL）, 2,3-dihydroxybenzoic acid （2,3-DHBA）, and 2,5-dihydroxybenzoic acid （2,5-DHBA）. Under the optimum conditions for its determination, 2,3-DHBA and 2,5-DHBA could be well separated and the detection limits for 2,3-DHBA were 3 ×10^-10 mol/L and for 2,5-DHBA were 1.5 ×10^-10 mol/L, which were lower than most previous reports. This method was also applied to measure atmospheric hydroxyl radical levels and demonstrated the feasibility in clean and polluted air.
文摘Aflatoxins are the potential lethal toxin produced by Aspergillus sp. important health hazard throughout the world. In this study, 26 Aspergillus sp. have been isolated from 50 samples of red chilli collected throughout the country. These 26 isolates were grown primarily on agar media to identify the aflatoxin producing species. It is possible to distinguish A. flavus strains from other Aspergillus sp. developing orange colour on the reverse of the plates. The Coconut Cream Agar (CCA) is used to detect aflatoxin producer strains having blue fluorescence when exposed to a UV-light. Several other media were used for morphological characteristics of Aspergillus sp. Out of 26 isolates, four isolates were confirmed as Aspergillus sp. These isolates were subjected to cross contamination with freshly ground, sterile maize and after 15 days of incubation the contaminated maize were analyzed by HPLC and found aflatoxin in each of the sample containing 186 ppb (max.). This study was conducted to assay the ability to produce aflatoxins by the Aspergillus spp. isolated from red chilli (Capsicum annuum L. Solanaceae) available throughout the country. The results found in the experiment are much more behind the acceptable limit according to some international standard. As red chilli is a widely used spice in Bangladesh, the proper controlling measures may be taken for controlling the surveillance of aflatoxinic fungi like as use of bio-pesticides, proper drying method and storage conditions.
基金Supported by the Planning Program for Science and Technology Development of Taizhou City(TG1126)the Research Project of Jiangsu Agri-animal Husbandry Vocational College(NSFFH1307)
文摘[ Objective] To detect the praziquantel content in praziquantel injection by HPLC. [ Methods ] Chromatographic conditions were as follows： chromato- graphic colmnn was Diamonsil Cls column （ 150 mm x 4.6 mm, 5 μm） ; column temperature was 25 ℃ ; mobile phase was acetonitrile-water （60：40） ; flow rate was 1.0 mL/min ; UV detection wavelength was 210 nm; and injection volume was 20 μL. [ Results ] Praziquantel showed good linear relationship within the con- centration of 6.037 - 90.55 g/L （ r = 0. 999 4） ; the average recovery rate was 99.24%, and RSD was 0. 769%. [Condusions ] This method was simple, rap- id, sensitive and repeatable, and could be used for the quality control of praziquantel injection.
文摘New HPLC method was developed for determination of amlodipine and valsartan in their binary mixture as a part of routine control of combined formulations. The method was validated to meet official requirements including selectivity, stability, linearity, precision and accuracy. Chromatography was carried out using a LiChrospher RP-18 column, a mixture containing acetonitrile, phosphate buffer of pH 3.5 and methanol (45:45:10, v/v/v) and new fluorescence detection at 255 nm for excitation and 448 nm for emission. The effect of methanol content, pH of the buffer, flow rate, detection wavelengths and column temperature was estimated in robustness study, according to a plan defined by the Plackett-Burman design. For identification of significant effects, both graphical and statistical methods were used. Ro-bustness for dissolution test was checked estimating the effects of paddle speed, temperature and pH of dissolution medium. The method was proved to complying with all official guidelines. Therefore, it is suitable for determination of amlodipine and valsartan in their binary mixtures for different analytical and pharmaceutical purposes.
文摘Glycerides are first separated to classes of triglycerides(TGs), diglycerides(DGs) and monoglycerides(MGs) by normal phase HPLC on silica gel column. Individual triglyceride separation is then achieved by non-aqueous reversed phase(NARP) HPLC on C_(18) column with UV detection at 215nm.
文摘Amino acid neurotransmitters facilitate the transmission of nerve messages across the synapses and play essential roles in the control and regulation of a variety of functions in the central and peripheral nervous system. In this study, we developed a sensitive and efficient method using high-performance liquid chromatography （HPLC） with fluorescence detection for the assay of five important amino acid n After derivatization with o-phthaldialdehyde （OPA）, aspartate （Asp）, glutamic acid （Glu）, glycine （Gly）, taurine （Tau） and ）,-aminobutyric acid （GABA） were simultaneously detected in the presence of the internal standard homoserine （Hse）. Precise separation of these five amino acids was achieved using isocratic elution within 24 min. Good linearity was found over the concentration range with correlation coefficients （r2） not less than 0.9998. The limit of detection （LOD） values were no more than 10 nmol/L. The intra- and inter-day reproducibility was adequate with the relative standard deviation （RSD） of 10.5% or below. This method has also been applied to the analysis of amino acids in the substantia nigra and striatum samples obtained from C57BL/6 mice.
文摘[Objective] This study aimed to optimize the chromatographic conditions for detecting ellagic acid in pomegranate peels using HPLC method. [Method] By using 0.2 mg/ml ellagic acid standard solution, on the basis of single-factor experiment and orthogonal experiment, chromatographic conditions （mobile phase ratio, flow rate, col- umn temperature） for detecting ellagic acid using HPLC were optimized. Based on the optimal chromatographic conditions, the ellagic acid content in experimental pomegranate peels was determined. [Resull] The optimal chromatographic conditions for detecting ellagic acid in pomegranate peels using HPLC method are： 1.2% phos- phoric acid：acetonitrile=85：15, column temperature of 35 ℃, and flow rate of 1.0 ml/min. The linear regression equation of ellagic acid is： y=2.9e＋0.6x＋4.4e＋5 （FF=9 999）. Ac- cording to the standard addition recovery test, the average recovery rate of ellagic acid is 98.20%, and RSD is 0.60%. Under above optimized chromatographic condi- tions, ellagic acid can be well separated from other interfering components in pomegranate peels, with shorter peak time and ideal effect, which is convenient for the detection in production practices. [Conclusion] This study laid the foundation for detecting ellagic acid in pomegranate peels using HPLC method.
文摘Aim To develop an HPLC method with fluorescence detection for the assay ofDL111-IT in rabbit plasma. Methods DL111-IT and internal standard glybenzcyclamide in rabbit plasmawere extracted with chloroform. The determination was performed on a Diamonsil ODS-C_(18) column(150 mm x 4.6 mm, 5 μm) with a mobile phase of acetonitrile and 0.025 mol·L^(-1) diammoniumhydrogen phosphate buffer (pH 5.0, adjusted by phosphoric acid) (60:40, V/V) at a flow-rate of 1.0mL·min^(-1) . Fluorescence detector was operated at excitation wavelength of 250 nm and emissionwavelength of 332 nm. Results The calibration curve in plasma was linear from 1.00 - 20.00ng·mL^(-1) ( r = 0.999 6, n = 5). The method afforded average extracting recoveries of 85.3% ±1.3%, 84.9% ± 2.7% and 85.8% ± 1.8%, and the average method recoveries were 99.5% ±0.4%, 102.1%± 1.8% and 101.3% ± 2.4% for the high (20.00 ng·mL^(-1)) , middle (10.00 ng·mL^(-1)) and low (1.00 ng·mL^(-1)) check samples, respectively. The intra-day (n = 5) and inter-day (n = 5) precisions(RSD) were less than 3.0% and 7.0%, respectively. The limit of detection and quantitation for themethod were 0.3 ng·mL^(-1) (S/N = 3) and 1 ng·mL^(-1) (S/N = 10, RSD<7.0%) plasma sample,respectively. Conclusion The developed method was accurate, sensitive, simple and could be used forpharmacokinetic study of DL111- IT.
文摘A post-column reaction chemiluminescence detection method in ion chromatography is described in this paper.The chemiluminescence system was indigo cramine-hydrogen peroxide. The chemiluminescence reaction conditions and the separation conditions of Co and Cu in chromatography were presented.The detection limits were 1.0 and 2.0×10-8 g/mL for Co and Cu respectively.
基金the Ministry of Public Health of the People's Republic of China(No200802038) for financial support
文摘In this paper, a high-performance liquid chromatography coupled with ultraviolet detection and Fourier transform-ion cyclotron resonance mass spectrometry （HPLC-UV/FrICRMS） method was described for the investigation of impurity profile in moxifloxacin （MOX） drug substance and chemical reference substance. Ten impurities were detected by HPLC-UV, while eight impurities were identified by using the high accurate molecular mass combined with multiple-stage mass spectrometric data and fragmentation rules. In addition, to our knowledge, five impurities were founded for the first time in MOX drug substance.
