The Experts below are selected from a list of 201 Experts worldwide ranked by ideXlab platform
Xinsheng Chai - One of the best experts on this subject based on the ideXlab platform.
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determination of activity of denitrifying enzyme in soil samples by a headspace gas Chromatographic Technique
Journal of Chromatography A, 2021Co-Authors: Xubo Zhang, Xinsheng Chai, Guangzhi Zhong, Xiao OuyangAbstract:Abstract This paper reported a headspace gas chromatography (HS-GC) for the determination of denitrifying enzyme activity in soil samples. It was based on measuring the NO2 signal in a set of closed/air-free vials containing soil samples that incubated at the designated conditions. The results showed that the method has a good measurement precision (RSD
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Determination of the softening point of rosin by a simple and automated headspace gas Chromatographic Technique
Journal of separation science, 2018Co-Authors: Yi Dai, Jian-bo Zhan, Bao-shan Yue, Xie Jiao, Wang Hao, Xinsheng ChaiAbstract:We report a simple and automated headspace gas Chromatographic Technique for the determination of the softening point of rosin. A lumpy solid of rosin is added into a headspace vial, then an automated stepwise temperature ramping and headspace sampling was performed at each temperature stage and gas chromatography measurement. By plotting the gas chromatography signal for an impurity in rosin versus the temperature, a transition point (corresponding to the rosin softening point) was determined. The results show that the present method has a good precision (
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determination of the softening point of rosin by a simple and automated headspace gas Chromatographic Technique
IEEE Journal of Solid-state Circuits, 2018Co-Authors: Yi Dai, Jian-bo Zhan, Bao-shan Yue, Jiao Xie, Hao Wang, Xinsheng ChaiAbstract:We report a simple and automated headspace gas Chromatographic Technique for the determination of the softening point of rosin. A lumpy solid of rosin is added into a headspace vial, then an automated stepwise temperature ramping and headspace sampling was performed at each temperature stage and gas chromatography measurement. By plotting the gas chromatography signal for an impurity in rosin versus the temperature, a transition point (corresponding to the rosin softening point) was determined. The results show that the present method has a good precision (<0.76%), and good accuracy (the relative differences compared to the ring and ball method was <4.0%). The present method is simple, accurate, and automated. It is practical and suitable for testing the softening of rosin and derivatives in mills.
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a high throughput headspace gas Chromatographic Technique for the determination of nitrite content in water samples
Journal of Chromatography A, 2018Co-Authors: Shuxin Zhang, Xinsheng Chai, Rong Peng, Ran Jiang, Donald G BarnesAbstract:Abstract This paper reports on a high-throughput headspace gas Chromatographic method (HS-GC) for the determination of nitrite content in water sample, based on GC measurement of cyclohexene produced from the reaction between nitrite and cyclamate in a closed vial. The method has a relative standard deviation of
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efficient determination of specific surface area of shale samples using a tracer based headspace gas Chromatographic Technique
Analytical Chemistry, 2017Co-Authors: Xinsheng Chai, Hui Tian, Xianming Xiao, Donald G BarnesAbstract:This paper reports on a novel method for determining the specific surface area (SSA) of shale via headspace gas chromatography (HS-GC). The method is based on the water adsorption on the surface of shale sample after achieving phase equilibrium at an elevated temperature (i.e., heating at 125 °C for 48 h). A mathematical model shows that the SSA can be determined from the signal of the vapor water released during HS-GC analysis. The results obtained by this method correlated well (R2 = 0.992) with data obtained by the reference BET method. Because the phase equilibrium step for multiple samples can be conducted simultaneously, and because the phase re-equilibrium step is much faster in the HS-GC measurement, the present method is more efficient for batch sample testing.
Yi-xian Gong - One of the best experts on this subject based on the ideXlab platform.
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an efficient headspace gas Chromatographic Technique for determining humic acid content in fertilizer
Journal of Chromatography A, 2019Co-Authors: Wei-qi Xie, Yi-xian GongAbstract:A fast, convenient and commercially available approach for analyzing humic acid content in fertilizer using headspace gas chromatography (HS-GC) is presented in this paper. Humic acid is converted into carbon dioxide based on the oxidation of humic acid in strong acidic medium and can be measured via automatic HS-GC. Conditions for the alkaline extraction and the humic acid oxidation process are also optimized. The new Technique proved to be precise (RSD ≤ 3.59%) and accurate (relative errors≤9.46% as compared with the spectrophotometric approach). The newly established Technique presents a practical tool to routinely analyze humic acid content in fertilizer during the fertilizer production.
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a fast and simple headspace gas Chromatographic Technique for quantitatively analyzing urea in human urine
Analytical Biochemistry, 2019Co-Authors: Wei-qi Xie, Yi-xian GongAbstract:A fast and convenient headspace gas Chromatographic (HS-GC) approach was described for the estimation of urea in human urine. The HS-GC could detect the generated carbon dioxide derived from the urease-catalyzed hydrolysis of urea. It was found that the hydrolysis of urea catalyzed by urease was completed within 40 min at 35 °C. The results proved the great accuracy (relative errors ≤ 8.48%) and precision (RSD ≤ 2.66%) of the HS-GC approach. Moreover, the recoveries ranged from 97.9% to 101.5%. The new approach is rapid and automated, which provides a new way to routinely analyze urea in urine for the control of metabolic disease.
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determination of iodate in iodized edible salt based on a headspace gas Chromatographic Technique
Journal of Chromatography A, 2019Co-Authors: Wei-qi Xie, Yi-xian GongAbstract:This paper introduces a convenient approach for determining iodate in iodized salt by headspace gas chromatography (HS-GC). The analytical Technique can measure the generated carbon dioxide from the redox reaction between iodate and sodium oxalate in the presence of strong acid. The formed carbon dioxide from this reaction in a closed vial is measured by GC. It was observed that the redox reaction in the vial was completed in 40 min at 95 °C. The results indicated that this analytical Technique is precise (RSD ≤ 2.69%) and accurate (relative errors ≤ 7.21%). The present approach is fast and simple, providing a robust avenue to the routine estimation of iodate in iodized salt in a wide variety of applications from processing to quality monitoring.
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Measurement of water absorption capacity in wheat flour by a headspace gas Chromatographic Technique
Journal of separation science, 2018Co-Authors: Wei-qi Xie, Yi-xian GongAbstract:The purpose of this work is to introduce a new method for quantitatively analyzing water absorption capacity in wheat flour by a headspace gas Chromatographic Technique. This headspace gas Chromatographic Technique was based on measuring the water vapor released from a series of wheat flour samples with different contents of water addition. According to the different trends between the vapor and wheat flour phase before and after the water absorption capacity in wheat flour, a turning point (corresponding to water absorption capacity in wheat flour) can be obtained by fitting the data of the water gas chromatography peak area from different wheat flour samples. The data showed that the phase equilibrium in the vial can be achieved in 25 min at desired temperature (35°C). The relative standard deviation of the reaction headspace gas Chromatographic Technique in water absorption capacity determination was within 3.48%, the relative differences has been determined by comparing the water absorption capacity obtained from this new analytical Technique with the data from the reference Technique (i.e., the filtration method), which are less than 8.92%. The new headspace gas Chromatographic method is automated, accurate and be a reliable tool for quantifying water absorption capacity in wheat flour in both laboratory research and mill applications.
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determination of total sugar content in lignocellulosic hydrolysates by using a reaction headspace gas Chromatographic Technique
Cellulose, 2017Co-Authors: Wei-qi Xie, Yi-xian GongAbstract:This paper investigates a new analytical Technique for the quantitative detection of total sugar content in lignocellulosic hydrolysates by reaction headspace gas chromatography (HS-GC). By detecting the carbon dioxide (CO2) generated from the reaction between sugars in lignocellulosic hydrolysates and potassium dichromate, the total sugar content in lignocellulosic hydrolysates can be quantified. The data illustrate that the conversion of sugars in lignocellulose hydrolysates can be achieved under the given conditions (at 90 °C for 30 min), the relative standard deviation of this HS-GC Technique in the total sugar content determination was within 3.35%, and the measured total sugar content in 15 lignocellulose hydrolysate samples closely matched those measured by the reference spectrophotometric Technique (relative differences <7.69%). The present Technique is efficient, reliable and suitable to be used in the total sugar content quantification in lignocellulose hydrolysate related research and process control.
Yi Dai - One of the best experts on this subject based on the ideXlab platform.
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Determination of the softening point of rosin by a simple and automated headspace gas Chromatographic Technique
Journal of separation science, 2018Co-Authors: Yi Dai, Jian-bo Zhan, Bao-shan Yue, Xie Jiao, Wang Hao, Xinsheng ChaiAbstract:We report a simple and automated headspace gas Chromatographic Technique for the determination of the softening point of rosin. A lumpy solid of rosin is added into a headspace vial, then an automated stepwise temperature ramping and headspace sampling was performed at each temperature stage and gas chromatography measurement. By plotting the gas chromatography signal for an impurity in rosin versus the temperature, a transition point (corresponding to the rosin softening point) was determined. The results show that the present method has a good precision (
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determination of the softening point of rosin by a simple and automated headspace gas Chromatographic Technique
IEEE Journal of Solid-state Circuits, 2018Co-Authors: Yi Dai, Jian-bo Zhan, Bao-shan Yue, Jiao Xie, Hao Wang, Xinsheng ChaiAbstract:We report a simple and automated headspace gas Chromatographic Technique for the determination of the softening point of rosin. A lumpy solid of rosin is added into a headspace vial, then an automated stepwise temperature ramping and headspace sampling was performed at each temperature stage and gas chromatography measurement. By plotting the gas chromatography signal for an impurity in rosin versus the temperature, a transition point (corresponding to the rosin softening point) was determined. The results show that the present method has a good precision (<0.76%), and good accuracy (the relative differences compared to the ring and ball method was <4.0%). The present method is simple, accurate, and automated. It is practical and suitable for testing the softening of rosin and derivatives in mills.
Wei-qi Xie - One of the best experts on this subject based on the ideXlab platform.
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an efficient headspace gas Chromatographic Technique for determining humic acid content in fertilizer
Journal of Chromatography A, 2019Co-Authors: Wei-qi Xie, Yi-xian GongAbstract:A fast, convenient and commercially available approach for analyzing humic acid content in fertilizer using headspace gas chromatography (HS-GC) is presented in this paper. Humic acid is converted into carbon dioxide based on the oxidation of humic acid in strong acidic medium and can be measured via automatic HS-GC. Conditions for the alkaline extraction and the humic acid oxidation process are also optimized. The new Technique proved to be precise (RSD ≤ 3.59%) and accurate (relative errors≤9.46% as compared with the spectrophotometric approach). The newly established Technique presents a practical tool to routinely analyze humic acid content in fertilizer during the fertilizer production.
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a fast and simple headspace gas Chromatographic Technique for quantitatively analyzing urea in human urine
Analytical Biochemistry, 2019Co-Authors: Wei-qi Xie, Yi-xian GongAbstract:A fast and convenient headspace gas Chromatographic (HS-GC) approach was described for the estimation of urea in human urine. The HS-GC could detect the generated carbon dioxide derived from the urease-catalyzed hydrolysis of urea. It was found that the hydrolysis of urea catalyzed by urease was completed within 40 min at 35 °C. The results proved the great accuracy (relative errors ≤ 8.48%) and precision (RSD ≤ 2.66%) of the HS-GC approach. Moreover, the recoveries ranged from 97.9% to 101.5%. The new approach is rapid and automated, which provides a new way to routinely analyze urea in urine for the control of metabolic disease.
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determination of iodate in iodized edible salt based on a headspace gas Chromatographic Technique
Journal of Chromatography A, 2019Co-Authors: Wei-qi Xie, Yi-xian GongAbstract:This paper introduces a convenient approach for determining iodate in iodized salt by headspace gas chromatography (HS-GC). The analytical Technique can measure the generated carbon dioxide from the redox reaction between iodate and sodium oxalate in the presence of strong acid. The formed carbon dioxide from this reaction in a closed vial is measured by GC. It was observed that the redox reaction in the vial was completed in 40 min at 95 °C. The results indicated that this analytical Technique is precise (RSD ≤ 2.69%) and accurate (relative errors ≤ 7.21%). The present approach is fast and simple, providing a robust avenue to the routine estimation of iodate in iodized salt in a wide variety of applications from processing to quality monitoring.
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Measurement of water absorption capacity in wheat flour by a headspace gas Chromatographic Technique
Journal of separation science, 2018Co-Authors: Wei-qi Xie, Yi-xian GongAbstract:The purpose of this work is to introduce a new method for quantitatively analyzing water absorption capacity in wheat flour by a headspace gas Chromatographic Technique. This headspace gas Chromatographic Technique was based on measuring the water vapor released from a series of wheat flour samples with different contents of water addition. According to the different trends between the vapor and wheat flour phase before and after the water absorption capacity in wheat flour, a turning point (corresponding to water absorption capacity in wheat flour) can be obtained by fitting the data of the water gas chromatography peak area from different wheat flour samples. The data showed that the phase equilibrium in the vial can be achieved in 25 min at desired temperature (35°C). The relative standard deviation of the reaction headspace gas Chromatographic Technique in water absorption capacity determination was within 3.48%, the relative differences has been determined by comparing the water absorption capacity obtained from this new analytical Technique with the data from the reference Technique (i.e., the filtration method), which are less than 8.92%. The new headspace gas Chromatographic method is automated, accurate and be a reliable tool for quantifying water absorption capacity in wheat flour in both laboratory research and mill applications.
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determination of total sugar content in lignocellulosic hydrolysates by using a reaction headspace gas Chromatographic Technique
Cellulose, 2017Co-Authors: Wei-qi Xie, Yi-xian GongAbstract:This paper investigates a new analytical Technique for the quantitative detection of total sugar content in lignocellulosic hydrolysates by reaction headspace gas chromatography (HS-GC). By detecting the carbon dioxide (CO2) generated from the reaction between sugars in lignocellulosic hydrolysates and potassium dichromate, the total sugar content in lignocellulosic hydrolysates can be quantified. The data illustrate that the conversion of sugars in lignocellulose hydrolysates can be achieved under the given conditions (at 90 °C for 30 min), the relative standard deviation of this HS-GC Technique in the total sugar content determination was within 3.35%, and the measured total sugar content in 15 lignocellulose hydrolysate samples closely matched those measured by the reference spectrophotometric Technique (relative differences <7.69%). The present Technique is efficient, reliable and suitable to be used in the total sugar content quantification in lignocellulose hydrolysate related research and process control.
Qing Chen - One of the best experts on this subject based on the ideXlab platform.
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Developments in high-speed countercurrent chromatography and its applications in the separation of terpenoids and saponins.
Journal of separation science, 2016Co-Authors: Hua Song, Jianhong Lin, Xuan Zhu, Qing ChenAbstract:High-speed countercurrent chromatography is a liquid-liquid separation Chromatographic Technique, which has the unique feature of eliminating irreversible adsorption using liquid support medium, and is widely used in research and development of traditional Chinese medicine, biochemistry, food, environment analysis, and so on. In this review, some new developments of countercurrent chromatography, for instance cross-axis countercurrent chromatography, dual countercurrent chromatography, foam countercurrent chromatography, and pH-zone-refining countercurrent chromatography are presented. Furthermore, the research and progress in high-speed countercurrent chromatography Techniques and its application in the separation and purification of terpenoids and saponins are reviewed.