Crosslink polymerization kinetics of poly（acrylic acid-co-2-acrylamido-2-methylpropane sulfonic acid）,AA/AMPS hydrogels,was investigated by using dilatometry in the presence of sodium persulfate as initiator and N,N...Crosslink polymerization kinetics of poly（acrylic acid-co-2-acrylamido-2-methylpropane sulfonic acid）,AA/AMPS hydrogels,was investigated by using dilatometry in the presence of sodium persulfate as initiator and N,N＇-methylene bis（acrylamide） as crosslinker.It was found that the reaction for the crosslink polymerization of AA/AMPS hydrogels had orders of 0.58,1.14,and 0.86 with respect to the initiator,AMPS,and AA,respectively.From the Arrhenius plots,the activation energy of the crosslink polymerization was found to be about 140 and 89 kJ·mol-1 in the presence and absence of the crosslinker,respectively,in the temperature range from 45 to 65 °C.It was noted that the crosslinker had effects on the reaction order of the initiator and the activation energy due to the formation of cross-linked networks,which was verified by Fourier transfer infrared （FTIR） spectrum.To further confirm the influences of the cross-linked network structure on kinetic parameters of the crosslink polymerization,a mechanism was proposed,which highlights the different termination routes between free radical polymerization and crosslink polymerization.These results suggest that dilatometry provides a convenient tool for crosslink polymeri-zation study,and confirm that the cross-linked networks are formed in the crosslink polymerization.展开更多
Liquid chromatography coupled with the triple quadrupole mass spectrometry(LC-QQQ MS)technique is the most commonly used technique for quantitative analysis.It is widely used in pharmacology,targeted metabolomics,Chin...Liquid chromatography coupled with the triple quadrupole mass spectrometry(LC-QQQ MS)technique is the most commonly used technique for quantitative analysis.It is widely used in pharmacology,targeted metabolomics,Chinese medicine quality control,and other research fields.The technique monitors only characteristic precursors and product ions through multiple reaction monitoring(MRM)mode and can detect targeted molecules in complex matrix with high specificity and sensitivity.In the present study,a diarylamide derivative diuretic was used as an example to introduce the method establishment and parameter optimization of this liquid chromatography-mass spectrometry technique.Diuretic and its internal standard could be completely separated within a 5-min gradient,and the quantitative linear range was 1–1000 ng/mL with R2=0.9996 in practical samples.This study showed that the key to the method development for LC-QQQ MS was the selection of the LC mobile phase,the elution gradient,the declustering potential,and the collision energy of compounds in MS.展开更多
基金Supported by the National Natural Science Foundation of China（20176007 20376087）
文摘Crosslink polymerization kinetics of poly（acrylic acid-co-2-acrylamido-2-methylpropane sulfonic acid）,AA/AMPS hydrogels,was investigated by using dilatometry in the presence of sodium persulfate as initiator and N,N＇-methylene bis（acrylamide） as crosslinker.It was found that the reaction for the crosslink polymerization of AA/AMPS hydrogels had orders of 0.58,1.14,and 0.86 with respect to the initiator,AMPS,and AA,respectively.From the Arrhenius plots,the activation energy of the crosslink polymerization was found to be about 140 and 89 kJ·mol-1 in the presence and absence of the crosslinker,respectively,in the temperature range from 45 to 65 °C.It was noted that the crosslinker had effects on the reaction order of the initiator and the activation energy due to the formation of cross-linked networks,which was verified by Fourier transfer infrared （FTIR） spectrum.To further confirm the influences of the cross-linked network structure on kinetic parameters of the crosslink polymerization,a mechanism was proposed,which highlights the different termination routes between free radical polymerization and crosslink polymerization.These results suggest that dilatometry provides a convenient tool for crosslink polymeri-zation study,and confirm that the cross-linked networks are formed in the crosslink polymerization.
基金National Natural Science Foundation of China(Grant No.22004004 and 81620108029).
文摘Liquid chromatography coupled with the triple quadrupole mass spectrometry(LC-QQQ MS)technique is the most commonly used technique for quantitative analysis.It is widely used in pharmacology,targeted metabolomics,Chinese medicine quality control,and other research fields.The technique monitors only characteristic precursors and product ions through multiple reaction monitoring(MRM)mode and can detect targeted molecules in complex matrix with high specificity and sensitivity.In the present study,a diarylamide derivative diuretic was used as an example to introduce the method establishment and parameter optimization of this liquid chromatography-mass spectrometry technique.Diuretic and its internal standard could be completely separated within a 5-min gradient,and the quantitative linear range was 1–1000 ng/mL with R2=0.9996 in practical samples.This study showed that the key to the method development for LC-QQQ MS was the selection of the LC mobile phase,the elution gradient,the declustering potential,and the collision energy of compounds in MS.
