[ Objective] To develop an efficient and practical method for detecting avermectin residue in animal-derived food. [ Method ] Acetonitrile was used as the extraction fluid. After the removal of moisture, trifluoroacet...[ Objective] To develop an efficient and practical method for detecting avermectin residue in animal-derived food. [ Method ] Acetonitrile was used as the extraction fluid. After the removal of moisture, trifluoroacetic anhydride and N-methyl imidazole were used for derivatization and mixed well. After complete derivatization, high-performance liquid chromatography （HPLC） with C18 column was used for accurate qualitative and quantitative analysis of the detected substance using methanol aqueous solution （92： 8, V/ V）. [ Result] The detection limit of HPLC connected with a fluorescence detector was up to 0.1 ug/L. When the standard was added to the substrate at a final concentration in the range of 0.1 -20.0 lag/L, the recoveries were in the range of 80% -108% and the relative deviation was in the range of 4.1% -11.4%. [ Conclusion] The developed HPLC con- nected with a fluorescence detector is simple, practical, highly sensitive and resistant to interference, and it thus can meet the needs for determina- tion of biological toxin residues of avermectins in animal-derived food in laboratory.展开更多
Raspberry ketone {RK, 4-(4-hydroxyphenyl)butan-2-one} is a natural compound contained in raspberry, and is added to cosmetics for skin whitening. It is very important to measure the RK level in cosmetics for quality a...Raspberry ketone {RK, 4-(4-hydroxyphenyl)butan-2-one} is a natural compound contained in raspberry, and is added to cosmetics for skin whitening. It is very important to measure the RK level in cosmetics for quality assessment, since RK structurally resembles 4-(4-hydroxyphenyl)-2-butanol, which causes leukoderma on consumers’ skin. Here, we present a simple HPLC-fluorescence method for determination of RK in a fragrance mist by pre-column derivatization with 4-hydrazino-7-nitro-2,1,3-benzoxadiazole hydrazine (NBD-H), which reacts with the carbonyl group of RK. The NBD-RK derivative was eluted from a reversed-phase ODS column, and detected with excitation at 470 nm and emission at 550 nm. The retention time of NBD-RK derivative obtained by reaction with NBD-H at 80°C for 20 min was 10.3 min. The standard curve was linear in the range of 0.2 to 10 μg/mL, with a correlation coefficient (r<sup>2</sup>) value of 0.9980. The lower limit of detection was 0.018 μg/mL (absolute amount of 1.8 pmol). The coefficients of variation were less than 8.1%. The content of RK in fragrance mist (1.00 mL) was 1.18 ± 0.07 mg (range: 1.12 to 1.28 mg, n = 5). Recovery tests were satisfactory (83.9% ± 3.9%;range: 79.6 to 88.8%, n = 5).展开更多
The stereochemistry of two 6, 9-oxygen bridge dibenzocyclooctadiene lignans from Kadsura coccinea, are difficult to separate and very unstable. The present study was designed to develop a high-performance liquid chrom...The stereochemistry of two 6, 9-oxygen bridge dibenzocyclooctadiene lignans from Kadsura coccinea, are difficult to separate and very unstable. The present study was designed to develop a high-performance liquid chromatography using circular dichroism detection for the analysis of the stereochemistry. A new 6, 9-oxygen bridge dibenzocyclooctadiene lignans named Kadsulignan Q was firstly found with an S-biphenyl configuration. The other compound was identified as Kadsulignan L with an R- biphenyl configuration. In order to obtain kinetic data on their reversible interconversion, the stability was measured at different deuterated solvents such as deuterated methanol, deuterated chloroform and deuterated dimethylsulfoxide. The lignans were more unstable and converted more easily in deuterated methanol than in deuterated chloroform and deuterated dimethylsulfoxide.展开更多
Ceramides are important signaling molecules involved in a variety of cellular processes, including cell growth, differentiation, and apoptosis. Currently, different methods are used for ceramide analysis, some of whic...Ceramides are important signaling molecules involved in a variety of cellular processes, including cell growth, differentiation, and apoptosis. Currently, different methods are used for ceramide analysis, some of which are insensitive or cumbersome. This paper described methods utilizing thin layer chromatography (TLC) and high-performance liquid chromatography (HPLC) followed by evaporative light scattering detection (ELSD) to detect ceramide directly in cell extracts without derivatization, which was proved to be efficient and reproducible. Five kinds of ceramides were used as standards. Both TLC and normal-phase HPLC/ELSD results indicate that yeast contains several kinds of ceramides.展开更多
文摘[ Objective] To develop an efficient and practical method for detecting avermectin residue in animal-derived food. [ Method ] Acetonitrile was used as the extraction fluid. After the removal of moisture, trifluoroacetic anhydride and N-methyl imidazole were used for derivatization and mixed well. After complete derivatization, high-performance liquid chromatography （HPLC） with C18 column was used for accurate qualitative and quantitative analysis of the detected substance using methanol aqueous solution （92： 8, V/ V）. [ Result] The detection limit of HPLC connected with a fluorescence detector was up to 0.1 ug/L. When the standard was added to the substrate at a final concentration in the range of 0.1 -20.0 lag/L, the recoveries were in the range of 80% -108% and the relative deviation was in the range of 4.1% -11.4%. [ Conclusion] The developed HPLC con- nected with a fluorescence detector is simple, practical, highly sensitive and resistant to interference, and it thus can meet the needs for determina- tion of biological toxin residues of avermectins in animal-derived food in laboratory.
文摘Raspberry ketone {RK, 4-(4-hydroxyphenyl)butan-2-one} is a natural compound contained in raspberry, and is added to cosmetics for skin whitening. It is very important to measure the RK level in cosmetics for quality assessment, since RK structurally resembles 4-(4-hydroxyphenyl)-2-butanol, which causes leukoderma on consumers’ skin. Here, we present a simple HPLC-fluorescence method for determination of RK in a fragrance mist by pre-column derivatization with 4-hydrazino-7-nitro-2,1,3-benzoxadiazole hydrazine (NBD-H), which reacts with the carbonyl group of RK. The NBD-RK derivative was eluted from a reversed-phase ODS column, and detected with excitation at 470 nm and emission at 550 nm. The retention time of NBD-RK derivative obtained by reaction with NBD-H at 80°C for 20 min was 10.3 min. The standard curve was linear in the range of 0.2 to 10 μg/mL, with a correlation coefficient (r<sup>2</sup>) value of 0.9980. The lower limit of detection was 0.018 μg/mL (absolute amount of 1.8 pmol). The coefficients of variation were less than 8.1%. The content of RK in fragrance mist (1.00 mL) was 1.18 ± 0.07 mg (range: 1.12 to 1.28 mg, n = 5). Recovery tests were satisfactory (83.9% ± 3.9%;range: 79.6 to 88.8%, n = 5).
基金supported by the PAPD(Priority Academic Program Development)of Jiangsu Higher Education Institutions,University Science Research Project of Jiangsu Province(No.09KJB350002)National Key Technology R&D Program(No.2012BAI30B02),National Natural Science Foundation of China(No.30901853)Hepatic Fibrosis Innovative Medicine-Research and Development of Fructus Schisandrae capsule(No.F12-157-9-00)
文摘The stereochemistry of two 6, 9-oxygen bridge dibenzocyclooctadiene lignans from Kadsura coccinea, are difficult to separate and very unstable. The present study was designed to develop a high-performance liquid chromatography using circular dichroism detection for the analysis of the stereochemistry. A new 6, 9-oxygen bridge dibenzocyclooctadiene lignans named Kadsulignan Q was firstly found with an S-biphenyl configuration. The other compound was identified as Kadsulignan L with an R- biphenyl configuration. In order to obtain kinetic data on their reversible interconversion, the stability was measured at different deuterated solvents such as deuterated methanol, deuterated chloroform and deuterated dimethylsulfoxide. The lignans were more unstable and converted more easily in deuterated methanol than in deuterated chloroform and deuterated dimethylsulfoxide.
文摘Ceramides are important signaling molecules involved in a variety of cellular processes, including cell growth, differentiation, and apoptosis. Currently, different methods are used for ceramide analysis, some of which are insensitive or cumbersome. This paper described methods utilizing thin layer chromatography (TLC) and high-performance liquid chromatography (HPLC) followed by evaporative light scattering detection (ELSD) to detect ceramide directly in cell extracts without derivatization, which was proved to be efficient and reproducible. Five kinds of ceramides were used as standards. Both TLC and normal-phase HPLC/ELSD results indicate that yeast contains several kinds of ceramides.
