The molecular weight distribution (MWD) of dissolved organic matter (DOM) in lake waters from Lake Hongfeng was examined using high performance size exclusion chromatography (HPSEC) with UV-vis absorbance and fluoresc...The molecular weight distribution (MWD) of dissolved organic matter (DOM) in lake waters from Lake Hongfeng was examined using high performance size exclusion chromatography (HPSEC) with UV-vis absorbance and fluorescence detection. The elution curves obtained by absorbance and fluorescence techniques expressed similar patterns, with the exception of diminishing of large fraction and the peaks behind several seconds in fluorescence chromatograms. According to its molecular weight (MW), DOM in water samples is divided into several fractions: large ({>3.5} kDa); medium-large ({3.5}-{2.0} kDa); medium ({2.0}-{1.0} kDa) and small ({<1.0} kDa). The average molecular weight was calculated using the elution curve detected by UV-vis absorbance and fluorescence detection techniques. The results showed that the weight-average molecular weight (Mw) and number-average molecular weight (Mn) calculated by UV-vis absorbance techniques range from 1750 to 2050 Dalton and from 1450 to 1850 Dalton, respectively. And the Mw and Mn obtained by fluorescence detection are lower by 50 to 400 Dalton. As a reference, the molecular weight of Fluka humic acid (FHA) is larger than that of water samples by about 200 Dalton. The average molecular weight of DOM for water samples collected in March and July was compared. The results revealed that the molecular weight is lower for water samples obtained in July than that obtained in March, indicating the ambient environment has an influence on the molecular weight, including photo-degradation and biological activity.展开更多
This study of renaturation by dilution and size exclusion chromatogra phy (SEC) addition of urea to improve yield as well as the initial and final pro tein concentrations showed that although urea decreased the rate o...This study of renaturation by dilution and size exclusion chromatogra phy (SEC) addition of urea to improve yield as well as the initial and final pro tein concentrations showed that although urea decreased the rate of lysozyme ref o lding, it could suppress protein aggregation to sustain the pathway of correct r efolding at high protein concentration; and that there existed an optimum urea c oncentration in renaturation buffer. Under the above conditions, lysozyme was su ccessfully refolded from initial concentration of up to 40 mg/mL by dilution and 100 mg/mL by SEC, with the yield of the former being more than 40% and that of the latter being 34.8%. Especially, under the condition of 30 min interval time, i.e. τ>2(t_R2 -t_R1 ), the efficiency was increased by 25% and the renaturation buffe r could be recycled for SEC refolding in continuous operation of downstream proc ess.展开更多
Base on the principle of absolute quantification of size exclusion chromatography （SEC）, a light scattering （LS） detector coupled with a concentration detector （refractive index detector） is utilized to determin...Base on the principle of absolute quantification of size exclusion chromatography （SEC）, a light scattering （LS） detector coupled with a concentration detector （refractive index detector） is utilized to determine the compositions of complicated binary mixtures. A theoretical analysis predicts that the response factors for both LS and RI detectors are linear functions with the composition of any specified polymer mixtures in the binary polymer mixtures. Two pairs of complicated binary mixtures were used to test the theory mentioned in the present paper, and the experimental results show an excellent accordance with the theory.展开更多
The synthesis and characterization of a novel macroporous silica derived size exclusion chromatography （SEC） packing for quantitative analysis of high molecular weight （MW） polyacrylamide （PAM） are presented. Us...The synthesis and characterization of a novel macroporous silica derived size exclusion chromatography （SEC） packing for quantitative analysis of high molecular weight （MW） polyacrylamide （PAM） are presented. Using this packing, a fast, sensitive and reproducible approach for quantitation of super high-MW PAM in demanding enhanced oil recovery （EOR） waters was developed and the effect of synthesis parameters on the properties of resultant materials was investigated. These parameters include salt addition, reaction temperature and duration, activation condition of functional groups on the silica surface, as well as the reaction cycles required for optimal silica modification. Moreover, SEC analysis conditions, such as mobile phase composition, flow rate, detection and sample preparation, were also explored and an optimal analysis protocol was developed. Under this optimized SEC analysis conditions, the synthesized macroporous materials proved satisfactory for quantification of PAM with average MW up to 22 million Daltons. An SEC analysis required less than few minutes with a detection limit of 1 ng, a linear response range of 0.1 to 75 mg/L with squared R value of 0.99 and reproducibility better than 9.2% RSD （relative standard deviation）. The analysis of PAM in highly saline oilfield production water containing interfering high MW polymeric surfactants indicated the recovery ranges from 92.5% to 110.1% for 1.0 mg/L PAM and 94.2% to 103.8% for 50 mg/L PAM solution. This study presented for the ftrst time that the reliable quantization of high MW PAM in highly demanding EOR waters can be achieved by SEC.展开更多
目的分离纯化碧根果致敏原Car i 1,并对其结构进行表征鉴定。方法以新鲜碧根果果仁为原料,通过粉碎、脱脂、浸提、粗分级、凝胶过滤层析,对碧根果致敏原蛋白Car i 1进行分离纯化。结合十二烷基硫酸钠-聚丙烯酰胺凝胶电泳、液相色谱-串...目的分离纯化碧根果致敏原Car i 1,并对其结构进行表征鉴定。方法以新鲜碧根果果仁为原料,通过粉碎、脱脂、浸提、粗分级、凝胶过滤层析,对碧根果致敏原蛋白Car i 1进行分离纯化。结合十二烷基硫酸钠-聚丙烯酰胺凝胶电泳、液相色谱-串联质谱法和免疫印迹法3种方法对Cari1进行鉴定,并通过圆二色谱仪与紫外分光光度计表征其二、三级结构。结果本方法纯化获得碧根果致敏原Cari1,单轮制备量可达5 mg以上,且纯度大于95%,蛋白质高级结构未被破坏,能够被全部3名碧根果过敏患者的血清准确识别。结论该纯化方法技术路线简单、设备要求低且单次制备量高,总得率可达65%,操作便捷,为碧根果致敏原Car i 1的相关研究奠定了物质基础。展开更多
Edible plant derived exosome-like nanoparticles(ELNs)have been shown to have multiple nutraceutical functions.However,the diversity of plant materials makes the plant derived ELN study challenging.More efforts are sti...Edible plant derived exosome-like nanoparticles(ELNs)have been shown to have multiple nutraceutical functions.However,the diversity of plant materials makes the plant derived ELN study challenging.More efforts are still needed to explore the feasible isolation methods of edible plant derived ELNs and the possible roles of food-derived ELNs in improving human health.In this study,a size exclusion chromatography based method was compared with the traditional ultracentrifugation method to isolate blueberry derived ELNs(B-ELNs),and the miRNA profile of B-ELNs was analyzed by high-throughput sequencing.A total of 36 miRNAs were found to be enriched in B-ELNs compared with berry tissue,and their potential cross-kingdom human gene targets were further predicted.Results showed that size exclusion chromatography was effective for B-ELN isolation.The most abundant miRNAs in B-ELNs mainly belonged to the miR166 family and miR396 family.Target gene prediction indicated that B-ELNs could potentially regulate pathways related to the human digestive system,immune system and infectious diseases.展开更多
Accurate quantification of dissolved organic nitrogen(DON) has been a challenge due to the cumulative analytical errors in the conventional method via subtracting dissolved inorganic nitrogen species(DIN) from total d...Accurate quantification of dissolved organic nitrogen(DON) has been a challenge due to the cumulative analytical errors in the conventional method via subtracting dissolved inorganic nitrogen species(DIN) from total dissolved nitrogen(TDN). Size exclusion chromatography coupled with an organic nitrogen detector(SEC-OND) has been developed as a direct method for quantification and characterization of DON. However, the applications of SECOND method still subject to poor separations between DON and DIN species and unsatisfied N recoveries of macromolecules. In this study, we packed a series of SEC columns with different lengths and resin materials for separation of different N species and designed an independent vacuum ultraviolet(VUV) oxidation device for complete oxidation converting N species to nitrate. To guarantee sufficient N recoveries, the operation conditions were optimized as oxidation time ≥ 30 min, injection mass(sample concentration × injection volume) < 1000 μL × mg-N/L for macromolecular proteins, and neutral p H mobile eluent. The dissolved O_(2)concentration in SEC mobile phase determined the upper limit of VUV oxidation at a specific oxidation time. Compared to conventional HW50S column(20 × 250 mm),HW40S column(20 × 350 mm) with mobile phase comprising of 1.5 g/L Na2HPO_(4)·2H_(2)O + 2.5g/L KH_(2)PO_(4)(p H = 6.85) could achieve a better separation of DON, nitrite, nitrate, and ammonia. When applied to river water, lake water, wastewater effluent, groundwater, and landfill leachate, the SEC-OND method could quantify DON as well as DIN species accurately and conveniently even the DIN/TDN ratio reached 0.98.展开更多
文摘The molecular weight distribution (MWD) of dissolved organic matter (DOM) in lake waters from Lake Hongfeng was examined using high performance size exclusion chromatography (HPSEC) with UV-vis absorbance and fluorescence detection. The elution curves obtained by absorbance and fluorescence techniques expressed similar patterns, with the exception of diminishing of large fraction and the peaks behind several seconds in fluorescence chromatograms. According to its molecular weight (MW), DOM in water samples is divided into several fractions: large ({>3.5} kDa); medium-large ({3.5}-{2.0} kDa); medium ({2.0}-{1.0} kDa) and small ({<1.0} kDa). The average molecular weight was calculated using the elution curve detected by UV-vis absorbance and fluorescence detection techniques. The results showed that the weight-average molecular weight (Mw) and number-average molecular weight (Mn) calculated by UV-vis absorbance techniques range from 1750 to 2050 Dalton and from 1450 to 1850 Dalton, respectively. And the Mw and Mn obtained by fluorescence detection are lower by 50 to 400 Dalton. As a reference, the molecular weight of Fluka humic acid (FHA) is larger than that of water samples by about 200 Dalton. The average molecular weight of DOM for water samples collected in March and July was compared. The results revealed that the molecular weight is lower for water samples obtained in July than that obtained in March, indicating the ambient environment has an influence on the molecular weight, including photo-degradation and biological activity.
文摘This study of renaturation by dilution and size exclusion chromatogra phy (SEC) addition of urea to improve yield as well as the initial and final pro tein concentrations showed that although urea decreased the rate of lysozyme ref o lding, it could suppress protein aggregation to sustain the pathway of correct r efolding at high protein concentration; and that there existed an optimum urea c oncentration in renaturation buffer. Under the above conditions, lysozyme was su ccessfully refolded from initial concentration of up to 40 mg/mL by dilution and 100 mg/mL by SEC, with the yield of the former being more than 40% and that of the latter being 34.8%. Especially, under the condition of 30 min interval time, i.e. τ>2(t_R2 -t_R1 ), the efficiency was increased by 25% and the renaturation buffe r could be recycled for SEC refolding in continuous operation of downstream proc ess.
基金supported by the National Natural Science Foundation of China(No.50633030)
文摘Base on the principle of absolute quantification of size exclusion chromatography （SEC）, a light scattering （LS） detector coupled with a concentration detector （refractive index detector） is utilized to determine the compositions of complicated binary mixtures. A theoretical analysis predicts that the response factors for both LS and RI detectors are linear functions with the composition of any specified polymer mixtures in the binary polymer mixtures. Two pairs of complicated binary mixtures were used to test the theory mentioned in the present paper, and the experimental results show an excellent accordance with the theory.
文摘The synthesis and characterization of a novel macroporous silica derived size exclusion chromatography （SEC） packing for quantitative analysis of high molecular weight （MW） polyacrylamide （PAM） are presented. Using this packing, a fast, sensitive and reproducible approach for quantitation of super high-MW PAM in demanding enhanced oil recovery （EOR） waters was developed and the effect of synthesis parameters on the properties of resultant materials was investigated. These parameters include salt addition, reaction temperature and duration, activation condition of functional groups on the silica surface, as well as the reaction cycles required for optimal silica modification. Moreover, SEC analysis conditions, such as mobile phase composition, flow rate, detection and sample preparation, were also explored and an optimal analysis protocol was developed. Under this optimized SEC analysis conditions, the synthesized macroporous materials proved satisfactory for quantification of PAM with average MW up to 22 million Daltons. An SEC analysis required less than few minutes with a detection limit of 1 ng, a linear response range of 0.1 to 75 mg/L with squared R value of 0.99 and reproducibility better than 9.2% RSD （relative standard deviation）. The analysis of PAM in highly saline oilfield production water containing interfering high MW polymeric surfactants indicated the recovery ranges from 92.5% to 110.1% for 1.0 mg/L PAM and 94.2% to 103.8% for 50 mg/L PAM solution. This study presented for the ftrst time that the reliable quantization of high MW PAM in highly demanding EOR waters can be achieved by SEC.
文摘目的分离纯化碧根果致敏原Car i 1,并对其结构进行表征鉴定。方法以新鲜碧根果果仁为原料,通过粉碎、脱脂、浸提、粗分级、凝胶过滤层析,对碧根果致敏原蛋白Car i 1进行分离纯化。结合十二烷基硫酸钠-聚丙烯酰胺凝胶电泳、液相色谱-串联质谱法和免疫印迹法3种方法对Cari1进行鉴定,并通过圆二色谱仪与紫外分光光度计表征其二、三级结构。结果本方法纯化获得碧根果致敏原Cari1,单轮制备量可达5 mg以上,且纯度大于95%,蛋白质高级结构未被破坏,能够被全部3名碧根果过敏患者的血清准确识别。结论该纯化方法技术路线简单、设备要求低且单次制备量高,总得率可达65%,操作便捷,为碧根果致敏原Car i 1的相关研究奠定了物质基础。
基金supported by the National Natural Science Foundation of China(31701561)。
文摘Edible plant derived exosome-like nanoparticles(ELNs)have been shown to have multiple nutraceutical functions.However,the diversity of plant materials makes the plant derived ELN study challenging.More efforts are still needed to explore the feasible isolation methods of edible plant derived ELNs and the possible roles of food-derived ELNs in improving human health.In this study,a size exclusion chromatography based method was compared with the traditional ultracentrifugation method to isolate blueberry derived ELNs(B-ELNs),and the miRNA profile of B-ELNs was analyzed by high-throughput sequencing.A total of 36 miRNAs were found to be enriched in B-ELNs compared with berry tissue,and their potential cross-kingdom human gene targets were further predicted.Results showed that size exclusion chromatography was effective for B-ELN isolation.The most abundant miRNAs in B-ELNs mainly belonged to the miR166 family and miR396 family.Target gene prediction indicated that B-ELNs could potentially regulate pathways related to the human digestive system,immune system and infectious diseases.
基金supported by the Basic Research Program of Jiangsu Province (No.BK20211557)the National Key R&D Program (No.2016YFE0112300)+1 种基金the National Natural Science Foundation of China (No.51708279)the High-level Talent Team Project of Quanzhou City (No. 2018CT006)。
文摘Accurate quantification of dissolved organic nitrogen(DON) has been a challenge due to the cumulative analytical errors in the conventional method via subtracting dissolved inorganic nitrogen species(DIN) from total dissolved nitrogen(TDN). Size exclusion chromatography coupled with an organic nitrogen detector(SEC-OND) has been developed as a direct method for quantification and characterization of DON. However, the applications of SECOND method still subject to poor separations between DON and DIN species and unsatisfied N recoveries of macromolecules. In this study, we packed a series of SEC columns with different lengths and resin materials for separation of different N species and designed an independent vacuum ultraviolet(VUV) oxidation device for complete oxidation converting N species to nitrate. To guarantee sufficient N recoveries, the operation conditions were optimized as oxidation time ≥ 30 min, injection mass(sample concentration × injection volume) < 1000 μL × mg-N/L for macromolecular proteins, and neutral p H mobile eluent. The dissolved O_(2)concentration in SEC mobile phase determined the upper limit of VUV oxidation at a specific oxidation time. Compared to conventional HW50S column(20 × 250 mm),HW40S column(20 × 350 mm) with mobile phase comprising of 1.5 g/L Na2HPO_(4)·2H_(2)O + 2.5g/L KH_(2)PO_(4)(p H = 6.85) could achieve a better separation of DON, nitrite, nitrate, and ammonia. When applied to river water, lake water, wastewater effluent, groundwater, and landfill leachate, the SEC-OND method could quantify DON as well as DIN species accurately and conveniently even the DIN/TDN ratio reached 0.98.
