[Objective] The aim was to study the flavonoid content of Fagopyrum megaspartanium leaves by water bath and ultrasonic extractions.[Method] By using water bath extraction and ultrasonic extraction,the total flavonoid ...[Objective] The aim was to study the flavonoid content of Fagopyrum megaspartanium leaves by water bath and ultrasonic extractions.[Method] By using water bath extraction and ultrasonic extraction,the total flavonoid content in buckwheat leaves was measured with UV spectrophotometer.[Result] The optimum wavelength for determination of the content of flavonoid extracted from buckwheat leaves was 420 nm;the content of total flavonoid extracted by ultrasonic extraction and water bath extraction from buckwheat were 5.26% and 5.40% respectively;and the average total flavonoid content by water bath extraction was significantly higher than that by ultrasonic extraction.[Conclusion] The result is significant for the improvement of flavonoid content measurement of buckwheat.展开更多
The procedure of enzymatic aqueous extraction of soybean oil was assessed when two-step controlled enzymatic hydrolysis was applied. With aqueous extraction of soybean oil-containing protein, the highest yield of oil ...The procedure of enzymatic aqueous extraction of soybean oil was assessed when two-step controlled enzymatic hydrolysis was applied. With aqueous extraction of soybean oil-containing protein, the highest yield of oil was 96.1% at the optimized conditions studied. Soybean oil-containing protein was hydrolyzed and resulted in releasing part of oil. The separated protein that contained 40% oil was enriched due to its adsorption capacity of released oil, the average oil extraction yeild reached 93.5%. Then the high oil content protein was hydrolyzed again to release oil by enzyme, the oil extraction yeild was 80.4%. As a result, high quality of soybean oil was obtained and the content of total oil yield was 74.4%.展开更多
The kinetics of forward extraction of boric acid from salt lake brine by 2-ethyl-1,3-hexanediol in toluene was investigated using the single drop technique. The factors affecting the extraction rate include interfacia...The kinetics of forward extraction of boric acid from salt lake brine by 2-ethyl-1,3-hexanediol in toluene was investigated using the single drop technique. The factors affecting the extraction rate include interfacial area between aqueous phase and organic phase, initial concentration of boric acid in aqueous phase, initial concentration of 2-ethyl-1,3-hexanediol in organic phase, and extraction temperature. The experimental results show that the extraction rate increases with the increase of the initial concentration of boric acid and2-ethyl-1,3-hexanediol, interfacial area of two phases, and temperature. With the temperature-dependence study, it is showed that the extraction is a diffusion-controlled process. The kinetic equation is presented for pH 1.0 in the aqueous phase and temperature of 318 K.展开更多
Suspended particulate matter (SPM) collected in the Changjiang (Yangtze River) estuary in June 2006 was separated into five fractions via water elutriation: clay-very fme silt (〈8 μm), fine silt (8-16 μm),...Suspended particulate matter (SPM) collected in the Changjiang (Yangtze River) estuary in June 2006 was separated into five fractions via water elutriation: clay-very fme silt (〈8 μm), fine silt (8-16 μm), medium silt (16--32 μm), coarse silt (32~53 μm) and sand (〉63 μm). The SPM and fractionated particles were sequentially analyzed by a modified SEDEX sequential extraction method to obtain six species of phosphorus: exchangeable or loosely-sorbed P, organic P, Fe-bound P, authigenic P, detrital P and refractory P. The results indicated that all particulate phosphorus species except for detrital P were negatively correlated to particle size; a high detrital P content was found in coarse silt and very coarse silt. From the inside of the river mouth to the gate of the fiver mouth, organic P, Fe-bound P and refractory P in the suspended particles decreased and a higher amount of exchangeable P appeared around the gate of the fiver mouth. From the gate of the river mouth to the sea, exchangeable P and organic P in suspended panicles increased distinctly. The total particulate P flux into the estuary from the Changjiang River was about 45.45×10^8μmol/s during sampling. Of this, about 8.27×10^8μmol/s was associated with the "truly suspended" fraction. The bio-available particulate P flux was about 13.58×10^8μmol/s. Of this, about 4.24 ×10^8μmol/s w as transported by "truly suspended" particles.展开更多
[Objective] To compare the extraction results of several different methods. [Method] The dietary fiber was extracted from sweet potato respectively by the sieve method, the enzymatic process and enzyme-alkali method. ...[Objective] To compare the extraction results of several different methods. [Method] The dietary fiber was extracted from sweet potato respectively by the sieve method, the enzymatic process and enzyme-alkali method. The extraction results of the three methods were optimized and compared. [Result] The extraction rate of dietary fiber by enzymatic method was the highest, which could reach 38% of total potato residue. The properties of dietary fiber extracted by the three methods were compared, the results indicated that the dietary fiber extracted by enzymatic method had good water-holding capacity, soil absorption and expansion. [Conclusion] The enzymatic method is the best for extracting dietary fiber from sweet potato.展开更多
A flow-based iodometric extraction method for the determination of selenium sulfide was developed and applied to cosmeceutical products. Iodine which was generated from the reduction of selenium(IV) ions by iodide i...A flow-based iodometric extraction method for the determination of selenium sulfide was developed and applied to cosmeceutical products. Iodine which was generated from the reduction of selenium(IV) ions by iodide ion was on-line extracted using a polypropylene HFM (hollow fiber membrane) liquid extraction technique. The HFM extraction unit was constructed and used to support an organic solvent (hexane) and separate between the organic phase and aqueous phase. The resulting purple extract was carried to a fiber optic spectrophotometric detector for the measurement at 521 nm. Parameters which affected the extraction efficiency, sensitivity and sample throughput such as iodide (selenium molar ratio, extraction time and washing time between the cycles) were investigated and optimized. A linear dynamic range of 80-373 mg.Lt selenium solution was obtained with an extraction time of 60 sec. The total analysis time including washing was about 180 sec which provided a sample throughput of approximately 20 samples'hr1 and excluded the sample pre-treatment. The recoveries for the determination of selenium in the forms of selenium dioxide and selenium sulfide were in the range of 103%-104% with 1%-3% RSD (relative standard deviation). The relative errors of this method which was applied for determination of selenium sulfide levels in an anti-dandruff shampoo and a cosmeceutical bead sample were both less than 2.5%.展开更多
Luvisols, Stagnogleys and Cambisols, although less fertile, are used intensively for mixed farming, grazing and as forestland. Therefore we aimed our study at determination of total organic carbon (TOC) content, hum...Luvisols, Stagnogleys and Cambisols, although less fertile, are used intensively for mixed farming, grazing and as forestland. Therefore we aimed our study at determination of total organic carbon (TOC) content, humic substances (HS) content, humic acids (HA) content, fulvic acids (FA), hot water extractable carbon (Chw) content and content total and labile trace elements content. Humic substances quality was assessed by HA/FA ratio and by coloured indexes measured in ultraviolet and visible UV-VIS spectral range. The total and labile contents of Zn, Cd, Cu, Co, Pb, Mo and Se were determined by flame or electro-thermal atomic absorption spectrometry after extraction of the soil samples in the aqua regia (total content) and in the solution of 0.01 M CaCI2. Total and labile trace elements content was correlated with determined carbon fractions and soil reaction. Results showed that studied soils content low amount of TOC and had low quality of humic substances. HA/FA ratio was less than 1 and colour indexes were higher than 4. All determined carbon fractions correlated with labile form of Zn and Cd. Correlation between soil reaction and total zinc content was found. Significant effect of humic substances content on to water-soluble forms of heavy metals was detected.展开更多
Aiming at the problems of high time-consuming, low accuracy and weak versatility of the existing methods of wa- ter extraction based on TM image, this paper combines principal component analysis (PCA) with the modif...Aiming at the problems of high time-consuming, low accuracy and weak versatility of the existing methods of wa- ter extraction based on TM image, this paper combines principal component analysis (PCA) with the modified normalized difference water index (MNDWI) which was improved by XU Han-qiu to construct a false color composite image that could separate water from others easily. This method can realize the water extraction based on TM image by analyzing the spectral characteristics of water in this false color image and establishing a water extraction model. This paper also compares the effi- ciency of this method with MNDWI, (TM2 + TM3) - (TM4 + TM5) and new water index (NWI), which were applied in the city and mountain of Taiyuan, respectively. The results show that the proposed method can extract water body from TM im- age more rapidly and efficiently and its accuracy is up to 94.03 %. In addition, this method does not require a manual selec- tion threshold, which meets the research reuuirement of high automaticm.展开更多
A beta spectrometric method for the rapid determination of strontium-90 (90Sr) in water samples was developed and tested. 90Sr is extracted directly from the water samples by means of a scintillator cocktail, contai...A beta spectrometric method for the rapid determination of strontium-90 (90Sr) in water samples was developed and tested. 90Sr is extracted directly from the water samples by means of a scintillator cocktail, containing the crown ether dicyclohexano-18-crown-6 as an extracting agent (STRONEX). Minimal clean-up is necessary when other beta nuclides are present, such as barium-140. These nuclides are eliminated by a barium chromate scavenge, prior to the extraction step. The method presented here allows for the investigation of at least 12 water samples a day and is therefore a suitable tool for emergency analysis.展开更多
Biomass as a sustainable and renewable energy source is starting to gain momentum, especially as more economical energy extraction methods prevail. SCWBG (supercritical water biomass gasification) is one of the more...Biomass as a sustainable and renewable energy source is starting to gain momentum, especially as more economical energy extraction methods prevail. SCWBG (supercritical water biomass gasification) is one of the more promising methods to extract energy from biomass in a gaseous form due to its lower temperature and simpler setup. In this work, two biomass and two bio-waste samples are gasified in SCW (supercritical water) under two temperatures (hence water densities). As temperature increases and water density decreases, combustible gas yields tend to increase due to changes in reaction pathways and reaction rates. An analytical comparison is also made between the four different types of biomass in terms of the combustible gases produced and hence the energy value. As a result of this analysis beet skin produces the most methane and corn silage yields the most hydrogen. The two bio-waste samples (straw and beet skin) are found to have the highest HHV (higher heating values).展开更多
A rapid, precise, sensitive and simple method has been developed for the extraction and determination of TPT (triphenyltin), DPT (diphenyltin) and MPT (monophenyltin) in seawater samples. The procedure is based ...A rapid, precise, sensitive and simple method has been developed for the extraction and determination of TPT (triphenyltin), DPT (diphenyltin) and MPT (monophenyltin) in seawater samples. The procedure is based on the use of the dual functionalization of mesoporous silica with diol and Cl6 alkane groups for the collection of TPT and its derivatives, DPT and MPT, from seawater samples, followed by ethylation of the target matrices using sodium tetraethylborate (NaBEt4) and quantification by gas chromatography with pulsed flame photometric detection. The modified extraction method replaces conventional solid- and liquid-phase extraction with solid dispersion of silica nanoparticles. The partitioning of the analyte between a carefully size-selected silica nanoparticles (solid phase) and a liquid phase occurs as the solid moves through the sample as a colloidal sol. By tailoring the size of the particles to approximately 250 nm in diameter, they can be easily dispersed in aqueous solution, without the need for any mechanical or hand shaking and the solid can then be readily recovered, together with the analytes, by simple filtration or centrifugation. Recoveries of TPT, DPT and MPT chloride spiked matrices rang from 87.3±1.1 to 98.1±1.3 in seawater samples (n = I 1 samples). The limit of detection obtained was typically in the range of 0.1-3 ng Sn/L. The proposed method shows excellent linearity in the range of 0.5-2 ng Sn/L and good repeatability (RSD 〈 5% at 0.02 ng TPT (as Sn)/L). The method performance is demonstrated with real seawater samples.展开更多
Isolation and purification of single-walled carbon nanotubes (SWCNTs) are prerequisites for their implementation in various applications. In this work, we present a fast (-5 min), low-cost, and easily scalable ben...Isolation and purification of single-walled carbon nanotubes (SWCNTs) are prerequisites for their implementation in various applications. In this work, we present a fast (-5 min), low-cost, and easily scalable bench-top approach to the extraction of high-quality isolated SWCNTs from bundles and impurities in an aqueous dispersion. The extraction procedure, based on aqueous two-phase (ATP) separation, is widely applicable to any SWCNT source (tested on samples up to 1.7 nm in diameter) and independent of defect density, purity, diameter, and length. The extracted dispersions demonstrate that the removal of large aggregates, small bundles, and impurities is comparable to that by density gradient ultracentrifugation, but without the need for high-end instrumentation. Raman and fluorescence-excitation spectroscopy, single-nanotube fluorescence imaging, atomic force and transmission electron microscopy, and thermogravimetric analysis all confirm the high purity of the isolated SWCNTs. By predispersing the SWCNTs without sonication (only gentle stirring), full-length, pristine SWCNTs can be isolated (tested up to 20 μm). Hence, this simple ATP method will find immediate application in the generation of SWCNT materials for all levels of nanotube research and applications, from fundamental studies to high-performance devices.展开更多
基金Supported by National Key Technology Research and Development Program(2006BAD02B06)National Natural Science Foundation of China(31060207)+1 种基金Agricultural Research Project of Guizhou Province[NY(2010)3094]Special Program of Plant and Animal Breeding of Guizhou Province[No.(2010)023]~~
文摘[Objective] The aim was to study the flavonoid content of Fagopyrum megaspartanium leaves by water bath and ultrasonic extractions.[Method] By using water bath extraction and ultrasonic extraction,the total flavonoid content in buckwheat leaves was measured with UV spectrophotometer.[Result] The optimum wavelength for determination of the content of flavonoid extracted from buckwheat leaves was 420 nm;the content of total flavonoid extracted by ultrasonic extraction and water bath extraction from buckwheat were 5.26% and 5.40% respectively;and the average total flavonoid content by water bath extraction was significantly higher than that by ultrasonic extraction.[Conclusion] The result is significant for the improvement of flavonoid content measurement of buckwheat.
文摘The procedure of enzymatic aqueous extraction of soybean oil was assessed when two-step controlled enzymatic hydrolysis was applied. With aqueous extraction of soybean oil-containing protein, the highest yield of oil was 96.1% at the optimized conditions studied. Soybean oil-containing protein was hydrolyzed and resulted in releasing part of oil. The separated protein that contained 40% oil was enriched due to its adsorption capacity of released oil, the average oil extraction yeild reached 93.5%. Then the high oil content protein was hydrolyzed again to release oil by enzyme, the oil extraction yeild was 80.4%. As a result, high quality of soybean oil was obtained and the content of total oil yield was 74.4%.
基金Supported by the Natural Science Foundation of the Education Department Hebei Province(2009426)Educational Commission of Hebei Province(ZH2011221)
文摘The kinetics of forward extraction of boric acid from salt lake brine by 2-ethyl-1,3-hexanediol in toluene was investigated using the single drop technique. The factors affecting the extraction rate include interfacial area between aqueous phase and organic phase, initial concentration of boric acid in aqueous phase, initial concentration of 2-ethyl-1,3-hexanediol in organic phase, and extraction temperature. The experimental results show that the extraction rate increases with the increase of the initial concentration of boric acid and2-ethyl-1,3-hexanediol, interfacial area of two phases, and temperature. With the temperature-dependence study, it is showed that the extraction is a diffusion-controlled process. The kinetic equation is presented for pH 1.0 in the aqueous phase and temperature of 318 K.
基金Supported by the National Natural Science Foundation of China (Nos.40976044,40920164004 and 30490232)the National Basic Research Program of China (973 Program) (Nos.2002CB12405 and 2005CB422305)
文摘Suspended particulate matter (SPM) collected in the Changjiang (Yangtze River) estuary in June 2006 was separated into five fractions via water elutriation: clay-very fme silt (〈8 μm), fine silt (8-16 μm), medium silt (16--32 μm), coarse silt (32~53 μm) and sand (〉63 μm). The SPM and fractionated particles were sequentially analyzed by a modified SEDEX sequential extraction method to obtain six species of phosphorus: exchangeable or loosely-sorbed P, organic P, Fe-bound P, authigenic P, detrital P and refractory P. The results indicated that all particulate phosphorus species except for detrital P were negatively correlated to particle size; a high detrital P content was found in coarse silt and very coarse silt. From the inside of the river mouth to the gate of the fiver mouth, organic P, Fe-bound P and refractory P in the suspended particles decreased and a higher amount of exchangeable P appeared around the gate of the fiver mouth. From the gate of the river mouth to the sea, exchangeable P and organic P in suspended panicles increased distinctly. The total particulate P flux into the estuary from the Changjiang River was about 45.45×10^8μmol/s during sampling. Of this, about 8.27×10^8μmol/s was associated with the "truly suspended" fraction. The bio-available particulate P flux was about 13.58×10^8μmol/s. Of this, about 4.24 ×10^8μmol/s w as transported by "truly suspended" particles.
文摘[Objective] To compare the extraction results of several different methods. [Method] The dietary fiber was extracted from sweet potato respectively by the sieve method, the enzymatic process and enzyme-alkali method. The extraction results of the three methods were optimized and compared. [Result] The extraction rate of dietary fiber by enzymatic method was the highest, which could reach 38% of total potato residue. The properties of dietary fiber extracted by the three methods were compared, the results indicated that the dietary fiber extracted by enzymatic method had good water-holding capacity, soil absorption and expansion. [Conclusion] The enzymatic method is the best for extracting dietary fiber from sweet potato.
文摘A flow-based iodometric extraction method for the determination of selenium sulfide was developed and applied to cosmeceutical products. Iodine which was generated from the reduction of selenium(IV) ions by iodide ion was on-line extracted using a polypropylene HFM (hollow fiber membrane) liquid extraction technique. The HFM extraction unit was constructed and used to support an organic solvent (hexane) and separate between the organic phase and aqueous phase. The resulting purple extract was carried to a fiber optic spectrophotometric detector for the measurement at 521 nm. Parameters which affected the extraction efficiency, sensitivity and sample throughput such as iodide (selenium molar ratio, extraction time and washing time between the cycles) were investigated and optimized. A linear dynamic range of 80-373 mg.Lt selenium solution was obtained with an extraction time of 60 sec. The total analysis time including washing was about 180 sec which provided a sample throughput of approximately 20 samples'hr1 and excluded the sample pre-treatment. The recoveries for the determination of selenium in the forms of selenium dioxide and selenium sulfide were in the range of 103%-104% with 1%-3% RSD (relative standard deviation). The relative errors of this method which was applied for determination of selenium sulfide levels in an anti-dandruff shampoo and a cosmeceutical bead sample were both less than 2.5%.
文摘Luvisols, Stagnogleys and Cambisols, although less fertile, are used intensively for mixed farming, grazing and as forestland. Therefore we aimed our study at determination of total organic carbon (TOC) content, humic substances (HS) content, humic acids (HA) content, fulvic acids (FA), hot water extractable carbon (Chw) content and content total and labile trace elements content. Humic substances quality was assessed by HA/FA ratio and by coloured indexes measured in ultraviolet and visible UV-VIS spectral range. The total and labile contents of Zn, Cd, Cu, Co, Pb, Mo and Se were determined by flame or electro-thermal atomic absorption spectrometry after extraction of the soil samples in the aqua regia (total content) and in the solution of 0.01 M CaCI2. Total and labile trace elements content was correlated with determined carbon fractions and soil reaction. Results showed that studied soils content low amount of TOC and had low quality of humic substances. HA/FA ratio was less than 1 and colour indexes were higher than 4. All determined carbon fractions correlated with labile form of Zn and Cd. Correlation between soil reaction and total zinc content was found. Significant effect of humic substances content on to water-soluble forms of heavy metals was detected.
文摘Aiming at the problems of high time-consuming, low accuracy and weak versatility of the existing methods of wa- ter extraction based on TM image, this paper combines principal component analysis (PCA) with the modified normalized difference water index (MNDWI) which was improved by XU Han-qiu to construct a false color composite image that could separate water from others easily. This method can realize the water extraction based on TM image by analyzing the spectral characteristics of water in this false color image and establishing a water extraction model. This paper also compares the effi- ciency of this method with MNDWI, (TM2 + TM3) - (TM4 + TM5) and new water index (NWI), which were applied in the city and mountain of Taiyuan, respectively. The results show that the proposed method can extract water body from TM im- age more rapidly and efficiently and its accuracy is up to 94.03 %. In addition, this method does not require a manual selec- tion threshold, which meets the research reuuirement of high automaticm.
文摘A beta spectrometric method for the rapid determination of strontium-90 (90Sr) in water samples was developed and tested. 90Sr is extracted directly from the water samples by means of a scintillator cocktail, containing the crown ether dicyclohexano-18-crown-6 as an extracting agent (STRONEX). Minimal clean-up is necessary when other beta nuclides are present, such as barium-140. These nuclides are eliminated by a barium chromate scavenge, prior to the extraction step. The method presented here allows for the investigation of at least 12 water samples a day and is therefore a suitable tool for emergency analysis.
文摘Biomass as a sustainable and renewable energy source is starting to gain momentum, especially as more economical energy extraction methods prevail. SCWBG (supercritical water biomass gasification) is one of the more promising methods to extract energy from biomass in a gaseous form due to its lower temperature and simpler setup. In this work, two biomass and two bio-waste samples are gasified in SCW (supercritical water) under two temperatures (hence water densities). As temperature increases and water density decreases, combustible gas yields tend to increase due to changes in reaction pathways and reaction rates. An analytical comparison is also made between the four different types of biomass in terms of the combustible gases produced and hence the energy value. As a result of this analysis beet skin produces the most methane and corn silage yields the most hydrogen. The two bio-waste samples (straw and beet skin) are found to have the highest HHV (higher heating values).
文摘A rapid, precise, sensitive and simple method has been developed for the extraction and determination of TPT (triphenyltin), DPT (diphenyltin) and MPT (monophenyltin) in seawater samples. The procedure is based on the use of the dual functionalization of mesoporous silica with diol and Cl6 alkane groups for the collection of TPT and its derivatives, DPT and MPT, from seawater samples, followed by ethylation of the target matrices using sodium tetraethylborate (NaBEt4) and quantification by gas chromatography with pulsed flame photometric detection. The modified extraction method replaces conventional solid- and liquid-phase extraction with solid dispersion of silica nanoparticles. The partitioning of the analyte between a carefully size-selected silica nanoparticles (solid phase) and a liquid phase occurs as the solid moves through the sample as a colloidal sol. By tailoring the size of the particles to approximately 250 nm in diameter, they can be easily dispersed in aqueous solution, without the need for any mechanical or hand shaking and the solid can then be readily recovered, together with the analytes, by simple filtration or centrifugation. Recoveries of TPT, DPT and MPT chloride spiked matrices rang from 87.3±1.1 to 98.1±1.3 in seawater samples (n = I 1 samples). The limit of detection obtained was typically in the range of 0.1-3 ng Sn/L. The proposed method shows excellent linearity in the range of 0.5-2 ng Sn/L and good repeatability (RSD 〈 5% at 0.02 ng TPT (as Sn)/L). The method performance is demonstrated with real seawater samples.
文摘Isolation and purification of single-walled carbon nanotubes (SWCNTs) are prerequisites for their implementation in various applications. In this work, we present a fast (-5 min), low-cost, and easily scalable bench-top approach to the extraction of high-quality isolated SWCNTs from bundles and impurities in an aqueous dispersion. The extraction procedure, based on aqueous two-phase (ATP) separation, is widely applicable to any SWCNT source (tested on samples up to 1.7 nm in diameter) and independent of defect density, purity, diameter, and length. The extracted dispersions demonstrate that the removal of large aggregates, small bundles, and impurities is comparable to that by density gradient ultracentrifugation, but without the need for high-end instrumentation. Raman and fluorescence-excitation spectroscopy, single-nanotube fluorescence imaging, atomic force and transmission electron microscopy, and thermogravimetric analysis all confirm the high purity of the isolated SWCNTs. By predispersing the SWCNTs without sonication (only gentle stirring), full-length, pristine SWCNTs can be isolated (tested up to 20 μm). Hence, this simple ATP method will find immediate application in the generation of SWCNT materials for all levels of nanotube research and applications, from fundamental studies to high-performance devices.