Infrared(IR)absorption spectroscopy has been widely used for dynamic characterization of catalysts and mechanism of catalytic reactions.However,due to the strong infrared absorption of heterogeneous catalysts(mainly o...Infrared(IR)absorption spectroscopy has been widely used for dynamic characterization of catalysts and mechanism of catalytic reactions.However,due to the strong infrared absorption of heterogeneous catalysts(mainly oxides,or supported metal and metal oxides,etc.)below 1200 cm^(-1),and the intensity of regular infrared light source rapidly decays at low-wavenumber range,most in-situ infrared spectroscopy studies are limited to the detection of surface adsorbates in the range of 4000-900 cm^(-1).The change of catalytically active component itself(M-O,M-M bond,etc.,1200-50 cm^(-1))during the reaction is hard to be tracked under reaction conditions by in-situ IR.In this work,a home-made in-situ IR reactor was designed and a sample preparing method was developed.With such progresses,the changes of reactants,products,surface adsorbates,and catalysts themselves can be measured under the same reaction conditions with a spectral range of 4000-400 cm^(-1),providing a new opportunity for in-situ characterization of heterogeneous catalysis.CO oxidation on Pd/SiO_(2) and Cu/SiO_(2) catalysts were taken as examples,since both the two catalytic systems were extensively used commercially,and moreover reduction and oxidation of palladium and copper occur during the examined reaction conditions.The characteristic bands of Pd^(2+)-O(670,608 cm^(-1)),Cu^(+)-O(635 cm^(-1))and Cu^(2+)-O(595,535 cm^(-1))were observed by IR,and the changes during CO oxidation reaction were successfully monitored by IR.The oxidation/reduction of palladium and copper were also confirmed by ex-situ XPS.Moreover,Pd^(0) in Pd/SiO_(2) and Cu^(+)in Cu/SiO_(2) were found as the thermal dynamically stable phases under the examined conditions for CO oxidation.展开更多
For optimization of production processes and product quality,often knowledge of the factors influencing the process outcome is compulsory.Thus,process analytical technology(PAT)that allows deeper insight into the proc...For optimization of production processes and product quality,often knowledge of the factors influencing the process outcome is compulsory.Thus,process analytical technology(PAT)that allows deeper insight into the process and results in a mathematical description of the process behavior as a simple function based on the most important process factors can help to achieve higher production efficiency and quality.The present study aims at characterizing a well-known industrial process,the transesterification reaction of rapeseed oil with methanol to produce fatty acid methyl esters(FAME)for usage as biodiesel in a continuous micro reactor set-up.To this end,a design of experiment approach is applied,where the effects of two process factors,the molar ratio and the total flow rate of the reactants,are investigated.The optimized process target response is the FAME mass fraction in the purified nonpolar phase of the product as a measure of reaction yield.The quantification is performed using attenuated total reflection infrared spectroscopy in combination with partial least squares regression.The data retrieved during the conduction of the DoE experimental plan were used for statistical analysis.A non-linear model indicating a synergistic interaction between the studied factors describes the reactor behavior with a high coefficient of determination(R^(2))of 0.9608.Thus,we applied a PAT approach to generate further insight into this established industrial process.展开更多
Compared to small molecule process analytical technology （PAT） applications, biotechnology product PAT applications have certain unique challenges and opportunities. Understanding process dynamics of bioreactor cell...Compared to small molecule process analytical technology （PAT） applications, biotechnology product PAT applications have certain unique challenges and opportunities. Understanding process dynamics of bioreactor cell culture process is essential to establish an appropriate process control strategy for biotechnology product PAT applications. Inline spectroscopic techniques for real time monitoring of bioreactor cell culture process have the distinct potential to develop PAT approaches in manufac- turing biotechnology drug products. However, the use of inline Fourier transform infrared （FTIR） spectroscopic techniques for bioreactor cell culture process monitoring has not been reported. In this work, real time inline FTIR Spectroscopy was applied to a lab scale bioreactor mAb IgG3 cell culture fluid biomolecular dynamic model. The technical feasibility of using FTIR Spectroscopy for real time tracking and monitoring four key cell culture metabolites （including glucose, glutamine, lactate, and ammonia） and protein yield at increasing levels of complexity （simple binary system, fully formulated media, actual bioreactor cell culture process） was evaluated via a stepwise approach. The FTIR fingerprints of the key metabolites were identified. The multivariate partial least squares （PLS） calibration models were established to correlate the process FTIR spectra with the concentrations of key metabolites and protein yield of in-process samples, either individually for each metabolite and protein or globally for all four metabolites simultaneously. Applying the 2＇ld derivative pre-processing algorithm to the FTIR spectra helps to reduce the number of PLS latent variables needed significantly and thus simplify the interpretation of the PLS models. The validated PLS models show promise in predicting the concentration profiles of glucose, glutamine, lactate, and ammonia and protein yield over the course of the bioreactor cell culture process. Therefore, this work demonstrated the technical feasibility of real time monitoring of the bioreactor cell culture process via FTIR spectroscopy. Its implications for enabling cell culture PAT were discussed.展开更多
The penetration behavior of topical substances in the skin not only relates to the transdermal delivery efficiency but also involves the safety and therapeutic effect of topical products,such as sunscreen and hair gro...The penetration behavior of topical substances in the skin not only relates to the transdermal delivery efficiency but also involves the safety and therapeutic effect of topical products,such as sunscreen and hair growth products.Researchers have tried to illustrate the transdermal process with diversified theories and technologies.Directly observing the distribution of topical substances on skin by characteristic imaging is the most convincing approach.Unfortunately,fluorescence labeling imaging,which is commonly used in biochemical research,is limited for transdermal research for most topical substances with a molecular mass less than 500 Da.Label-free imaging technologies possess the advantages of not requiring any macromolecular dyes,no tissue destruction and an extensive substance detection capability,which has enabled rapid development of such technologies in recent years and their introduction to biological tissue analysis,such as skin samples.Through the specific identification of topical substances and endogenous tissue components,label-free imaging technologies can provide abundant tissue distribution information,enrich theoretical and practical guidance for transdermal drug delivery systems.In this review,we expound the mechanisms and applications of the most popular label-free imaging technologies in transdermal research at present,compare their advantages and disadvantages,and forecast development prospects.展开更多
A comprehensive understanding of the microscopic reaction mechanisms at the gas-solid-liquid electrochemical interfaces is urgently required for the development of advanced electrocatalysts applied in burgeoning susta...A comprehensive understanding of the microscopic reaction mechanisms at the gas-solid-liquid electrochemical interfaces is urgently required for the development of advanced electrocatalysts applied in burgeoning sustainable energy conversion systems. In-situ synchrotron radiation Fourier transform infrared(SR-FTIR) spectroscopy is one of the most powerful techniques for investigating the evolving dynamics of reactive intermediates during electrocatalytic reactions. In this review, we methodically summarize the recent progress in the research of dynamic mechanisms for valuable electrocatalytic reactions based on in-situ SR-FTIR methodology. Moreover, the merits and drawbacks of SRFTIR spectroscopy, the design principles of infrared beam setups and in-situ cells, as well as the in-situ measurement criteria are also discussed in detail. Lastly, the potential challenges and opportunities in this field are prudently stated. This review is expected to stimulate a broad interest in the material science and electrochemistry communities for exploring the dynamic mechanisms of prominent catalysis at the atomic/molecular level by using SR-based spectroscopy.展开更多
目的利用拉曼光谱与中红外光谱的数据融合技术实现对食用酒精乙醇浓度(酒精度)的快速定量检测。方法首先,分别采集不同浓度食用酒精水溶液的拉曼光谱与中红外光谱。其次,采用多元散射校正(multiplicative scatter correction,MSC)、卷...目的利用拉曼光谱与中红外光谱的数据融合技术实现对食用酒精乙醇浓度(酒精度)的快速定量检测。方法首先,分别采集不同浓度食用酒精水溶液的拉曼光谱与中红外光谱。其次,采用多元散射校正(multiplicative scatter correction,MSC)、卷积平滑(Savitzky-Golay,S-G)、一阶求导的方法对原始数据进行预处理。然后,基于自举软缩减法(bootstrapping soft shrinkage,BOSS)和无信息变量消除算法(uninformative variable elimination,UVE)分别对预处理后的光谱数据进行特征提取,并利用X-Y距离样本集划分法(sample set partitioning based on joint X-Y distance,SPXY)将光谱数据划分为校正集和预测集。最后,建立基于拉曼光谱-中红外光谱数据融合的偏最小二乘回归(partial least squares regression,PLSR)食用酒精乙醇浓度预测模型,并利用麻雀搜寻算法优化的混合核极限学习机算法(sparrow search algorithm-optimized hybrid kernel extreme learning machine,SSA-HKELM)提升预测性能,实现对不同浓度食用酒精的快速、准确定量检测。结果与拉曼光谱数据、中红外光谱数据以及中红外与拉曼光谱的数据层融合构建的预测模型相比,中红外光谱与拉曼光谱特征层融合数据构建的预测模型具有更好的预测性能。其中,最优模型的校正集均方根误差(root mean squared error of calibration set,RMSEC)为0.98314,校正集决定系数(R_(c)^(2))为0.99634,预测集均方根误差(root mean squared error of prediction set,RMSEP)为1.03256,预测集决定系数(R_(p)^(2))为0.99036。结论中红外光谱与拉曼光谱特征层融合预测模型可以实现对不同浓度食用酒精的高效定量检测,为食用酒精的质量检测提供了有效的理论支持与技术保障。展开更多
A direct aqueous supercritical fluid extraction （SFE） system using carbon dioxide provides a sustainable means by which a vast range of industries may continue to depend on well established infrared （IR） technique...A direct aqueous supercritical fluid extraction （SFE） system using carbon dioxide provides a sustainable means by which a vast range of industries may continue to depend on well established infrared （IR） techniques to determine oil-in-water. The SFE-IR method provides an environmentally friendly substitute for current national standard IR reference methods for measuring oil-in-water that rely on using increasingly restricted ozone depleting solvents whose manufacture is being phased out in accordance with international law. The SFE-IR analysis of a 500 mL water sample can be accomplished in 15 min. A rapid on-line SFE-IR calibration method has been implemented. With this calibration method, SFE-IR accuracy for determining diesel oil in 500 mL spiked water samples using single wave number measurement was 86.0%-98.8% with precision （RSD） ranging from 2.5%-7.0%. Using a general purpose calculation which involves measuring infrared absorbance values at three different wave numbers, SFE-IR method accuracy for determining diesel oil in 500 mL spiked water samples was 83.7%-92.2% with RSD 1.0%-9.3%. Data is presented that indicates current long established national standard IR reference methods involving three wave number calculations should be reviewed since, without careful consideration, the inclusion of calculated aromatic hydrocarbon species contributions to final oil-in-water concentration values may provide less accurate results.展开更多
文摘Infrared(IR)absorption spectroscopy has been widely used for dynamic characterization of catalysts and mechanism of catalytic reactions.However,due to the strong infrared absorption of heterogeneous catalysts(mainly oxides,or supported metal and metal oxides,etc.)below 1200 cm^(-1),and the intensity of regular infrared light source rapidly decays at low-wavenumber range,most in-situ infrared spectroscopy studies are limited to the detection of surface adsorbates in the range of 4000-900 cm^(-1).The change of catalytically active component itself(M-O,M-M bond,etc.,1200-50 cm^(-1))during the reaction is hard to be tracked under reaction conditions by in-situ IR.In this work,a home-made in-situ IR reactor was designed and a sample preparing method was developed.With such progresses,the changes of reactants,products,surface adsorbates,and catalysts themselves can be measured under the same reaction conditions with a spectral range of 4000-400 cm^(-1),providing a new opportunity for in-situ characterization of heterogeneous catalysis.CO oxidation on Pd/SiO_(2) and Cu/SiO_(2) catalysts were taken as examples,since both the two catalytic systems were extensively used commercially,and moreover reduction and oxidation of palladium and copper occur during the examined reaction conditions.The characteristic bands of Pd^(2+)-O(670,608 cm^(-1)),Cu^(+)-O(635 cm^(-1))and Cu^(2+)-O(595,535 cm^(-1))were observed by IR,and the changes during CO oxidation reaction were successfully monitored by IR.The oxidation/reduction of palladium and copper were also confirmed by ex-situ XPS.Moreover,Pd^(0) in Pd/SiO_(2) and Cu^(+)in Cu/SiO_(2) were found as the thermal dynamically stable phases under the examined conditions for CO oxidation.
文摘For optimization of production processes and product quality,often knowledge of the factors influencing the process outcome is compulsory.Thus,process analytical technology(PAT)that allows deeper insight into the process and results in a mathematical description of the process behavior as a simple function based on the most important process factors can help to achieve higher production efficiency and quality.The present study aims at characterizing a well-known industrial process,the transesterification reaction of rapeseed oil with methanol to produce fatty acid methyl esters(FAME)for usage as biodiesel in a continuous micro reactor set-up.To this end,a design of experiment approach is applied,where the effects of two process factors,the molar ratio and the total flow rate of the reactants,are investigated.The optimized process target response is the FAME mass fraction in the purified nonpolar phase of the product as a measure of reaction yield.The quantification is performed using attenuated total reflection infrared spectroscopy in combination with partial least squares regression.The data retrieved during the conduction of the DoE experimental plan were used for statistical analysis.A non-linear model indicating a synergistic interaction between the studied factors describes the reactor behavior with a high coefficient of determination(R^(2))of 0.9608.Thus,we applied a PAT approach to generate further insight into this established industrial process.
文摘Compared to small molecule process analytical technology （PAT） applications, biotechnology product PAT applications have certain unique challenges and opportunities. Understanding process dynamics of bioreactor cell culture process is essential to establish an appropriate process control strategy for biotechnology product PAT applications. Inline spectroscopic techniques for real time monitoring of bioreactor cell culture process have the distinct potential to develop PAT approaches in manufac- turing biotechnology drug products. However, the use of inline Fourier transform infrared （FTIR） spectroscopic techniques for bioreactor cell culture process monitoring has not been reported. In this work, real time inline FTIR Spectroscopy was applied to a lab scale bioreactor mAb IgG3 cell culture fluid biomolecular dynamic model. The technical feasibility of using FTIR Spectroscopy for real time tracking and monitoring four key cell culture metabolites （including glucose, glutamine, lactate, and ammonia） and protein yield at increasing levels of complexity （simple binary system, fully formulated media, actual bioreactor cell culture process） was evaluated via a stepwise approach. The FTIR fingerprints of the key metabolites were identified. The multivariate partial least squares （PLS） calibration models were established to correlate the process FTIR spectra with the concentrations of key metabolites and protein yield of in-process samples, either individually for each metabolite and protein or globally for all four metabolites simultaneously. Applying the 2＇ld derivative pre-processing algorithm to the FTIR spectra helps to reduce the number of PLS latent variables needed significantly and thus simplify the interpretation of the PLS models. The validated PLS models show promise in predicting the concentration profiles of glucose, glutamine, lactate, and ammonia and protein yield over the course of the bioreactor cell culture process. Therefore, this work demonstrated the technical feasibility of real time monitoring of the bioreactor cell culture process via FTIR spectroscopy. Its implications for enabling cell culture PAT were discussed.
文摘The penetration behavior of topical substances in the skin not only relates to the transdermal delivery efficiency but also involves the safety and therapeutic effect of topical products,such as sunscreen and hair growth products.Researchers have tried to illustrate the transdermal process with diversified theories and technologies.Directly observing the distribution of topical substances on skin by characteristic imaging is the most convincing approach.Unfortunately,fluorescence labeling imaging,which is commonly used in biochemical research,is limited for transdermal research for most topical substances with a molecular mass less than 500 Da.Label-free imaging technologies possess the advantages of not requiring any macromolecular dyes,no tissue destruction and an extensive substance detection capability,which has enabled rapid development of such technologies in recent years and their introduction to biological tissue analysis,such as skin samples.Through the specific identification of topical substances and endogenous tissue components,label-free imaging technologies can provide abundant tissue distribution information,enrich theoretical and practical guidance for transdermal drug delivery systems.In this review,we expound the mechanisms and applications of the most popular label-free imaging technologies in transdermal research at present,compare their advantages and disadvantages,and forecast development prospects.
基金supported by the National Natural Science Foundation of China (Nos. 1932212, U1932109, 11875257)。
文摘A comprehensive understanding of the microscopic reaction mechanisms at the gas-solid-liquid electrochemical interfaces is urgently required for the development of advanced electrocatalysts applied in burgeoning sustainable energy conversion systems. In-situ synchrotron radiation Fourier transform infrared(SR-FTIR) spectroscopy is one of the most powerful techniques for investigating the evolving dynamics of reactive intermediates during electrocatalytic reactions. In this review, we methodically summarize the recent progress in the research of dynamic mechanisms for valuable electrocatalytic reactions based on in-situ SR-FTIR methodology. Moreover, the merits and drawbacks of SRFTIR spectroscopy, the design principles of infrared beam setups and in-situ cells, as well as the in-situ measurement criteria are also discussed in detail. Lastly, the potential challenges and opportunities in this field are prudently stated. This review is expected to stimulate a broad interest in the material science and electrochemistry communities for exploring the dynamic mechanisms of prominent catalysis at the atomic/molecular level by using SR-based spectroscopy.
文摘目的利用拉曼光谱与中红外光谱的数据融合技术实现对食用酒精乙醇浓度(酒精度)的快速定量检测。方法首先,分别采集不同浓度食用酒精水溶液的拉曼光谱与中红外光谱。其次,采用多元散射校正(multiplicative scatter correction,MSC)、卷积平滑(Savitzky-Golay,S-G)、一阶求导的方法对原始数据进行预处理。然后,基于自举软缩减法(bootstrapping soft shrinkage,BOSS)和无信息变量消除算法(uninformative variable elimination,UVE)分别对预处理后的光谱数据进行特征提取,并利用X-Y距离样本集划分法(sample set partitioning based on joint X-Y distance,SPXY)将光谱数据划分为校正集和预测集。最后,建立基于拉曼光谱-中红外光谱数据融合的偏最小二乘回归(partial least squares regression,PLSR)食用酒精乙醇浓度预测模型,并利用麻雀搜寻算法优化的混合核极限学习机算法(sparrow search algorithm-optimized hybrid kernel extreme learning machine,SSA-HKELM)提升预测性能,实现对不同浓度食用酒精的快速、准确定量检测。结果与拉曼光谱数据、中红外光谱数据以及中红外与拉曼光谱的数据层融合构建的预测模型相比,中红外光谱与拉曼光谱特征层融合数据构建的预测模型具有更好的预测性能。其中,最优模型的校正集均方根误差(root mean squared error of calibration set,RMSEC)为0.98314,校正集决定系数(R_(c)^(2))为0.99634,预测集均方根误差(root mean squared error of prediction set,RMSEP)为1.03256,预测集决定系数(R_(p)^(2))为0.99036。结论中红外光谱与拉曼光谱特征层融合预测模型可以实现对不同浓度食用酒精的高效定量检测,为食用酒精的质量检测提供了有效的理论支持与技术保障。
文摘A direct aqueous supercritical fluid extraction （SFE） system using carbon dioxide provides a sustainable means by which a vast range of industries may continue to depend on well established infrared （IR） techniques to determine oil-in-water. The SFE-IR method provides an environmentally friendly substitute for current national standard IR reference methods for measuring oil-in-water that rely on using increasingly restricted ozone depleting solvents whose manufacture is being phased out in accordance with international law. The SFE-IR analysis of a 500 mL water sample can be accomplished in 15 min. A rapid on-line SFE-IR calibration method has been implemented. With this calibration method, SFE-IR accuracy for determining diesel oil in 500 mL spiked water samples using single wave number measurement was 86.0%-98.8% with precision （RSD） ranging from 2.5%-7.0%. Using a general purpose calculation which involves measuring infrared absorbance values at three different wave numbers, SFE-IR method accuracy for determining diesel oil in 500 mL spiked water samples was 83.7%-92.2% with RSD 1.0%-9.3%. Data is presented that indicates current long established national standard IR reference methods involving three wave number calculations should be reviewed since, without careful consideration, the inclusion of calculated aromatic hydrocarbon species contributions to final oil-in-water concentration values may provide less accurate results.
