Coenzyme Q10 and vitamin E are among the most widely consumed nutritional supplements in China owing to their antioxidant and other health-promoting properties.This study aimed to establish an accurate and efficient a...Coenzyme Q10 and vitamin E are among the most widely consumed nutritional supplements in China owing to their antioxidant and other health-promoting properties.This study aimed to establish an accurate and efficient analytical method for the simultaneous determination of these two compounds in commercial softgel capsules,which is essential for rigorous quality control.Herein,a proton nuclear magnetic resonance(1H NMR)method was developed and validated using coumarin as an internal standard.Characteristic signals at 3.997 ppm for coenzyme Q10 and 2.621 ppm for vitamin E were selected for quantification.The method demonstrated excellent performance in terms of precision(relative standard deviation<2%),specificity(resolution>1.5),and stability(24-h variation<3%).The validation results complied with the China Food and Drug Administration guidelines,demonstrating high accuracy.Application to products from four different manufacturers showed compound contents ranging from 98.2%to 102.4%of label amounts.These findings support^(1)H NMR spectroscopy as a rapid,precise,and reliable approach for the simultaneous quality assessment of coenzyme Q10 and vitamin E formulations.展开更多
The rhodium-phosphine complex catalyst Rh(CO)(acac)(PPh3)(Ⅰ) for 1-hexene hydroformylation was studied under the following reaction conditions: CO/H2=1(mole rate), pressure 1.0 MPa, temperature 25-120℃, by using the...The rhodium-phosphine complex catalyst Rh(CO)(acac)(PPh3)(Ⅰ) for 1-hexene hydroformylation was studied under the following reaction conditions: CO/H2=1(mole rate), pressure 1.0 MPa, temperature 25-120℃, by using the pres surized in-situ 1H NMR technique. Experimental results indicated that the formation of a rhodium hydride complex from (Ⅰ) began at room temperature and its amount increased with increasing of reaction temperature. This intermediate complex began to decompose at 100℃ and disapeared completely at 120℃ The intensity change of the proton signal was parallel to catalytical activity in hydroformylation of olefins. Under pure CO pressure the proton signal of Rh-H bond was not observed. There was a 0.2 ppm difference in proton chemical shifts of Rh-H bond under pure H2 pressure and under H2+CO pressure. The results showed that the rhodium-hydride carbonyl complex is the active intermediate in the industrial hydroformylation process.展开更多
Astaxanthin(AX)and vitamin E(VE)are widely consumed nutritional supplements in China,with its beneficial effects predominantly attributed to all-trans AX and VE.The aim of this study is to develop and validate a rapid...Astaxanthin(AX)and vitamin E(VE)are widely consumed nutritional supplements in China,with its beneficial effects predominantly attributed to all-trans AX and VE.The aim of this study is to develop and validate a rapid and accurate method for quantifying the content of AX and VE in nutritional supplement products using highly sensitive1H NMR method.Coumarin was chosen as the internal standard.Specific signals from AX was optimal at H-7,7'in the chemical shift range ofδ6.17–6.24 ppm,whereas the signals of VE atδ2.59 ppm.To demonstrate the reliability of this analytical approach the proposed method underwent rigorous validation,specificity,limit of detection(LOD),limit of quantitation(LOQ),linearity,accuracy,precision,and recovery.The accuracy of the validation method was 3.10%for AX and 1.99%for VE.The results indicated that the method was precise and reliable.The method has been successfully applied to simultaneous quantification of AX and VE in nutritional supplements products.展开更多
The recycled oil from coal liquefaction was separated into three fractions(saturates,aromatics and polar fraction) by liquid chromatograph according to group composition.Each fraction was analyzed qualitatively by 1H-...The recycled oil from coal liquefaction was separated into three fractions(saturates,aromatics and polar fraction) by liquid chromatograph according to group composition.Each fraction was analyzed qualitatively by 1H-NMR spectra,then the aromatic fraction was characterized using gas chromatograph/mass spectrometer(GC-MS).It shows that liquid chromatograph is well used to separate coal liquefaction oil with high repeatability and high recovery yield.Aromatic fraction with carbon number from C10 to C21 mainly includes dicyclic-,tricyclic-and tetracyclic-hydrogenation aromatic compounds such as tetrahydronaphthalene,hydrophenanthrene,hydropyrene and their alkyl substitution compounds and so on.展开更多
基金supported by the Open Research Fund Program of the Shandong Provincial Key Laboratory of Glycoscience and Glycotechnology(Ocean University of China)。
文摘Coenzyme Q10 and vitamin E are among the most widely consumed nutritional supplements in China owing to their antioxidant and other health-promoting properties.This study aimed to establish an accurate and efficient analytical method for the simultaneous determination of these two compounds in commercial softgel capsules,which is essential for rigorous quality control.Herein,a proton nuclear magnetic resonance(1H NMR)method was developed and validated using coumarin as an internal standard.Characteristic signals at 3.997 ppm for coenzyme Q10 and 2.621 ppm for vitamin E were selected for quantification.The method demonstrated excellent performance in terms of precision(relative standard deviation<2%),specificity(resolution>1.5),and stability(24-h variation<3%).The validation results complied with the China Food and Drug Administration guidelines,demonstrating high accuracy.Application to products from four different manufacturers showed compound contents ranging from 98.2%to 102.4%of label amounts.These findings support^(1)H NMR spectroscopy as a rapid,precise,and reliable approach for the simultaneous quality assessment of coenzyme Q10 and vitamin E formulations.
文摘The rhodium-phosphine complex catalyst Rh(CO)(acac)(PPh3)(Ⅰ) for 1-hexene hydroformylation was studied under the following reaction conditions: CO/H2=1(mole rate), pressure 1.0 MPa, temperature 25-120℃, by using the pres surized in-situ 1H NMR technique. Experimental results indicated that the formation of a rhodium hydride complex from (Ⅰ) began at room temperature and its amount increased with increasing of reaction temperature. This intermediate complex began to decompose at 100℃ and disapeared completely at 120℃ The intensity change of the proton signal was parallel to catalytical activity in hydroformylation of olefins. Under pure CO pressure the proton signal of Rh-H bond was not observed. There was a 0.2 ppm difference in proton chemical shifts of Rh-H bond under pure H2 pressure and under H2+CO pressure. The results showed that the rhodium-hydride carbonyl complex is the active intermediate in the industrial hydroformylation process.
基金the Fundamental Research Funds for the Central Universities(No.202351011)。
文摘Astaxanthin(AX)and vitamin E(VE)are widely consumed nutritional supplements in China,with its beneficial effects predominantly attributed to all-trans AX and VE.The aim of this study is to develop and validate a rapid and accurate method for quantifying the content of AX and VE in nutritional supplement products using highly sensitive1H NMR method.Coumarin was chosen as the internal standard.Specific signals from AX was optimal at H-7,7'in the chemical shift range ofδ6.17–6.24 ppm,whereas the signals of VE atδ2.59 ppm.To demonstrate the reliability of this analytical approach the proposed method underwent rigorous validation,specificity,limit of detection(LOD),limit of quantitation(LOQ),linearity,accuracy,precision,and recovery.The accuracy of the validation method was 3.10%for AX and 1.99%for VE.The results indicated that the method was precise and reliable.The method has been successfully applied to simultaneous quantification of AX and VE in nutritional supplements products.
文摘The recycled oil from coal liquefaction was separated into three fractions(saturates,aromatics and polar fraction) by liquid chromatograph according to group composition.Each fraction was analyzed qualitatively by 1H-NMR spectra,then the aromatic fraction was characterized using gas chromatograph/mass spectrometer(GC-MS).It shows that liquid chromatograph is well used to separate coal liquefaction oil with high repeatability and high recovery yield.Aromatic fraction with carbon number from C10 to C21 mainly includes dicyclic-,tricyclic-and tetracyclic-hydrogenation aromatic compounds such as tetrahydronaphthalene,hydrophenanthrene,hydropyrene and their alkyl substitution compounds and so on.
