An online method using continuous flow isotope ratio mass spectrometry （CF-IRMS） interfaced with a Gasbench Ⅱ was presented to determine chlorine stable isotope composition. Silver chloride （AgCl） was quantitativ...An online method using continuous flow isotope ratio mass spectrometry （CF-IRMS） interfaced with a Gasbench Ⅱ was presented to determine chlorine stable isotope composition. Silver chloride （AgCl） was quantitatively derived from chloride by using silver nitrate （AgNO3）, and then was reacted with iodomethane （CH3Ⅰ） to produce methyl chloride （CH3Cl）. A GasBench Ⅱ equipped with a PoraPlot Q column was used to separate CH3Cl from any other gas species. Finally, chlorine stable isotope analysis was carried out on CH3Cl introduced to the IRMS in a helium stream via an active open split. The minimum amount of Cl used in this method is of the order of 1.4 μmol. Inter-laboratory and inter-technique comparisons show that the total uncertainty incorporating both the precision and accuracy of this method is better than 0.007%. Furthermore, ten seawaters sampled from different locations have a narrow δ37Cl value range from -0.008% to 0.010%, with a mean value of （0.000±0.006）%. This supports the assumption that any seawater can be representative of standard mean ocean chloride （SMOC） and used as an international reference material.展开更多
Bivalve shell fossils,cemented by authigenic carbonates,are widely spread in the Haima cold seep,Qiongdongnan Basin of the South China Sea(SCS).In this study,we examined an element profile of Gigantidas platifrons in ...Bivalve shell fossils,cemented by authigenic carbonates,are widely spread in the Haima cold seep,Qiongdongnan Basin of the South China Sea(SCS).In this study,we examined an element profile of Gigantidas platifrons in the Haima cold seeps at a water depth of 1381 m.Based on the scanning electron microscope(SEM)analyses,the prismatic layer and nacreous layer were identified,which are characterized by prismatic structure and stratified structure,respectively.In addition,the profile can be subdivided into two parts:altered and unaltered zones.Laser inductively coupled plasma mass spectrometry(LA-ICP-MS)mapping shows that the element concentrations of the altered zones were influenced by the authigenic carbonate rocks,whereas the element concentrations of unaltered zones remain stable.In-situ X-ray diffraction(XRD)analyses show that the mineral constituent of the prismatic layer is mainly composed of aragonite.Along with the growth profile,Mg/Ca ratios of unaltered zones have minor variations,ranging 0.72-0.97 mmol/mol(mean=0.87 mmol/mol),with estimated temperatures of 3.8-4.1℃,indicating that the temperature of the surrounding seawater remains constant and agree with the measured data of 3.9℃which was conducted by a conductivity-temperature-depth system(CTD).The minor variations of Ba/Ca ratios(0.01-0.06 mmol/mol;mean=0.04 mmol/mol)indicate a relatively stabilized salinity of the surrounding seawater.S/Ca ratios show large variations of 0.04-4.15 mmol/mol(mean=1.37 mmol/mol).S/Ca ratios have regular variations which generally correspond to the variations of the Mg/Ca ratios,highlighting that the S/Ca ratios of bivalve shells show the potential to reflect the growth rate of the Gigantides.However,further studies should be carried out on the understanding of the links between the S/Ca ratios and seepage intensity of cold-seep fluids.展开更多
目的探究不同肉酱比对鹿肉酱中挥发性有机化合物(volatile organic compounds,VOCs)影响的差异性,并筛选不同肉酱比的关键性VOCs。方法利用电子鼻结合气相色谱-离子迁移谱法(gas chromatography-ion mobility spectrometry,GC-IMS)检测...目的探究不同肉酱比对鹿肉酱中挥发性有机化合物(volatile organic compounds,VOCs)影响的差异性,并筛选不同肉酱比的关键性VOCs。方法利用电子鼻结合气相色谱-离子迁移谱法(gas chromatography-ion mobility spectrometry,GC-IMS)检测不同肉酱比加工的鹿肉酱样品中的香气类别及VOCs成分,通过计算偏最小二乘法判别(partial least squares discriminant analysis,PLS-DA)和正交-偏最小二乘法判别(orthogonal partial least squares discriminant analysis,OPLS-DA)分析变量重要性因子(variable important for the projection,VIP),筛选可区分不同肉酱比的鹿肉酱样品中差异性影响最关键的变量敏感物质及VOCs(VIP>1)。结果电子鼻传感器S3、S7、S9和S10对应的氨类、芳香族、硫化物和萜烯类、芳香族、硫化氢类、烷烃类等敏感物质是不同肉酱比的鹿肉酱样品中最关键的挥发类特征性气味;利用GC-IMS共检测出82种主要VOCs,筛选出33种关键差异性特征VOCs(VIP>1),与电子鼻的关键特征性香气检测结果一致。结论基于电子鼻和GC-IMS的主要特征香气标志物的聚类分析能够有效、全面、客观地对不同肉酱比的鹿肉酱中关键挥发性性气味和VOCs进行区分和评价。展开更多
[Objective] This study was to establish a method for the rapid and accurate detection of the coupling ratio of artificial antigen. [Method] Artificial synthetic antigen of citrinin （CIT） was first conjugated with ve...[Objective] This study was to establish a method for the rapid and accurate detection of the coupling ratio of artificial antigen. [Method] Artificial synthetic antigen of citrinin （CIT） was first conjugated with vector protein bovine serum albumin （BSA） and then identified by SDS-PAGE electrophoresis,and its coupling ratio was measured by UV absorption and mass spectrometry. [Result] The identification result showed that artificial antigen of CIT was successfully coupled,and the coupling ratio was 8.4 by UV absorption while 6.0 by mass spectrometry. [Conclusion] The comparison experiment showed that mass spectrometry could rapidly identify the artificial antigen and accurately detect its coupling ratio. This study provided basis for the preparation of CIT antigen as well as the establishment of an for enzyme-linked immunosorbent assay （ELISA） for citrinin determination.展开更多
该文建立液相色谱-稳定同位素比值质谱联用(liquid chromatography-stable isotope ratio mass spectrometry,LC-IRMS)检测抗坏血酸δ^(13)C值的分析方法,用于鉴别针叶樱桃粉中抗坏血酸天然来源的真实性。样品中抗坏血酸经液相色谱在线...该文建立液相色谱-稳定同位素比值质谱联用(liquid chromatography-stable isotope ratio mass spectrometry,LC-IRMS)检测抗坏血酸δ^(13)C值的分析方法,用于鉴别针叶樱桃粉中抗坏血酸天然来源的真实性。样品中抗坏血酸经液相色谱在线分离纯化,优化后色谱条件为:Syncronis C18(250 mm×4.6 mm,5μm)色谱柱,流动相为水-pH 2的硫酸溶液(90∶10,体积比),流速0.250 mL/min,色谱柱温度30℃,进样量10μL,通过LC-IsoLink实现目标物全部氧化为CO_(2)气体,最终以气态形式进入稳定同位素质谱仪,直接检测样品中抗坏血酸的δ^(13)C,该方法结果稳定、准确。分别测定了7个合成来源的维生素C片和19个针叶樱桃粉,结果表明,天然来源抗坏血酸δ^(13)C值为-25.00‰~-22.01‰,合成来源抗坏血酸δ^(13)C值为-11.74‰~-10.28‰,两者分布显著性差异,该方法可用于抗坏血酸产品标识的真实性鉴别研究。展开更多
A new, simple and fast separation method for Fe using an extraction chromatographic resin, Aliquat 336 (commercially available as TEVA resin) has been developed. A one milliliter column containing 0.33 mL TEVA resin o...A new, simple and fast separation method for Fe using an extraction chromatographic resin, Aliquat 336 (commercially available as TEVA resin) has been developed. A one milliliter column containing 0.33 mL TEVA resin on 0.67 mL CG-71C was used.Iron was adsorbed with 6mol·L-1 HCl + H2O2 on TEVA resin, and recovered with 2 mol·L-1HNO3. The recovery yield and total blank were 93.5 ± 6.5% and 6 ng, respectively. Theseparation method is simple, and takes < 2 hours. For evaluation of the Fe separation, Fe isotope ratios were measured by a double-spike method employing multicollector inductively coupled plasma source mass spectrometry (MC-ICP-MS) with repeatability of 0.06‰ (SD) for the standard solution and ~0.05‰ for the silicate samples. Therefore, the column chemistry developed in this study is a viable option for Fe isotope ratio measurement by MC-ICP-MS.展开更多
Alpha spectrometry using pulse height analysis has been used for the determination of uranium concentrations in different environmental samples. The concentration of 238U was measured by both destructive and non-destr...Alpha spectrometry using pulse height analysis has been used for the determination of uranium concentrations in different environmental samples. The concentration of 238U was measured by both destructive and non-destructive techniques with a detection limit of less than 1.8 mBq/kg. However, because of the extremely low 234U concentrations in environmental samples, it was necessary to use a destructive technique to separate U from the sample matrices as well as remove interfering elements from the sample solution to determine 238U/234U ratio. In this study, the uranium was separated from the environmental samples using anion exchangers in (Dowex 1 × 8 Cl? form) and purified via co-precipitation with Lanthanum fluorides (LaF3) and the alpha source prepared by electrodeposition. The results obtained were validated using some certified reference samples.展开更多
基金Projects(40772156, 41072179) supported by the National Natural Science Foundation of China
文摘An online method using continuous flow isotope ratio mass spectrometry （CF-IRMS） interfaced with a Gasbench Ⅱ was presented to determine chlorine stable isotope composition. Silver chloride （AgCl） was quantitatively derived from chloride by using silver nitrate （AgNO3）, and then was reacted with iodomethane （CH3Ⅰ） to produce methyl chloride （CH3Cl）. A GasBench Ⅱ equipped with a PoraPlot Q column was used to separate CH3Cl from any other gas species. Finally, chlorine stable isotope analysis was carried out on CH3Cl introduced to the IRMS in a helium stream via an active open split. The minimum amount of Cl used in this method is of the order of 1.4 μmol. Inter-laboratory and inter-technique comparisons show that the total uncertainty incorporating both the precision and accuracy of this method is better than 0.007%. Furthermore, ten seawaters sampled from different locations have a narrow δ37Cl value range from -0.008% to 0.010%, with a mean value of （0.000±0.006）%. This supports the assumption that any seawater can be representative of standard mean ocean chloride （SMOC） and used as an international reference material.
基金Supported by the Key Research and Development Project of Guangdong Province(No.2020B1111510001)the National Natural Science Foundation of China(No.U2244224)+1 种基金the PI Project of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(No.GML2020GD0802)the Guangdong Special Support Team Program(No.2019BT02H594)。
文摘Bivalve shell fossils,cemented by authigenic carbonates,are widely spread in the Haima cold seep,Qiongdongnan Basin of the South China Sea(SCS).In this study,we examined an element profile of Gigantidas platifrons in the Haima cold seeps at a water depth of 1381 m.Based on the scanning electron microscope(SEM)analyses,the prismatic layer and nacreous layer were identified,which are characterized by prismatic structure and stratified structure,respectively.In addition,the profile can be subdivided into two parts:altered and unaltered zones.Laser inductively coupled plasma mass spectrometry(LA-ICP-MS)mapping shows that the element concentrations of the altered zones were influenced by the authigenic carbonate rocks,whereas the element concentrations of unaltered zones remain stable.In-situ X-ray diffraction(XRD)analyses show that the mineral constituent of the prismatic layer is mainly composed of aragonite.Along with the growth profile,Mg/Ca ratios of unaltered zones have minor variations,ranging 0.72-0.97 mmol/mol(mean=0.87 mmol/mol),with estimated temperatures of 3.8-4.1℃,indicating that the temperature of the surrounding seawater remains constant and agree with the measured data of 3.9℃which was conducted by a conductivity-temperature-depth system(CTD).The minor variations of Ba/Ca ratios(0.01-0.06 mmol/mol;mean=0.04 mmol/mol)indicate a relatively stabilized salinity of the surrounding seawater.S/Ca ratios show large variations of 0.04-4.15 mmol/mol(mean=1.37 mmol/mol).S/Ca ratios have regular variations which generally correspond to the variations of the Mg/Ca ratios,highlighting that the S/Ca ratios of bivalve shells show the potential to reflect the growth rate of the Gigantides.However,further studies should be carried out on the understanding of the links between the S/Ca ratios and seepage intensity of cold-seep fluids.
文摘目的探究不同肉酱比对鹿肉酱中挥发性有机化合物(volatile organic compounds,VOCs)影响的差异性,并筛选不同肉酱比的关键性VOCs。方法利用电子鼻结合气相色谱-离子迁移谱法(gas chromatography-ion mobility spectrometry,GC-IMS)检测不同肉酱比加工的鹿肉酱样品中的香气类别及VOCs成分,通过计算偏最小二乘法判别(partial least squares discriminant analysis,PLS-DA)和正交-偏最小二乘法判别(orthogonal partial least squares discriminant analysis,OPLS-DA)分析变量重要性因子(variable important for the projection,VIP),筛选可区分不同肉酱比的鹿肉酱样品中差异性影响最关键的变量敏感物质及VOCs(VIP>1)。结果电子鼻传感器S3、S7、S9和S10对应的氨类、芳香族、硫化物和萜烯类、芳香族、硫化氢类、烷烃类等敏感物质是不同肉酱比的鹿肉酱样品中最关键的挥发类特征性气味;利用GC-IMS共检测出82种主要VOCs,筛选出33种关键差异性特征VOCs(VIP>1),与电子鼻的关键特征性香气检测结果一致。结论基于电子鼻和GC-IMS的主要特征香气标志物的聚类分析能够有效、全面、客观地对不同肉酱比的鹿肉酱中关键挥发性性气味和VOCs进行区分和评价。
基金Supported by National High Technology Research and Development Program of China (863 Program) (2007AA10Z426-1)~~
文摘[Objective] This study was to establish a method for the rapid and accurate detection of the coupling ratio of artificial antigen. [Method] Artificial synthetic antigen of citrinin （CIT） was first conjugated with vector protein bovine serum albumin （BSA） and then identified by SDS-PAGE electrophoresis,and its coupling ratio was measured by UV absorption and mass spectrometry. [Result] The identification result showed that artificial antigen of CIT was successfully coupled,and the coupling ratio was 8.4 by UV absorption while 6.0 by mass spectrometry. [Conclusion] The comparison experiment showed that mass spectrometry could rapidly identify the artificial antigen and accurately detect its coupling ratio. This study provided basis for the preparation of CIT antigen as well as the establishment of an for enzyme-linked immunosorbent assay （ELISA） for citrinin determination.
文摘A new, simple and fast separation method for Fe using an extraction chromatographic resin, Aliquat 336 (commercially available as TEVA resin) has been developed. A one milliliter column containing 0.33 mL TEVA resin on 0.67 mL CG-71C was used.Iron was adsorbed with 6mol·L-1 HCl + H2O2 on TEVA resin, and recovered with 2 mol·L-1HNO3. The recovery yield and total blank were 93.5 ± 6.5% and 6 ng, respectively. Theseparation method is simple, and takes < 2 hours. For evaluation of the Fe separation, Fe isotope ratios were measured by a double-spike method employing multicollector inductively coupled plasma source mass spectrometry (MC-ICP-MS) with repeatability of 0.06‰ (SD) for the standard solution and ~0.05‰ for the silicate samples. Therefore, the column chemistry developed in this study is a viable option for Fe isotope ratio measurement by MC-ICP-MS.
文摘Alpha spectrometry using pulse height analysis has been used for the determination of uranium concentrations in different environmental samples. The concentration of 238U was measured by both destructive and non-destructive techniques with a detection limit of less than 1.8 mBq/kg. However, because of the extremely low 234U concentrations in environmental samples, it was necessary to use a destructive technique to separate U from the sample matrices as well as remove interfering elements from the sample solution to determine 238U/234U ratio. In this study, the uranium was separated from the environmental samples using anion exchangers in (Dowex 1 × 8 Cl? form) and purified via co-precipitation with Lanthanum fluorides (LaF3) and the alpha source prepared by electrodeposition. The results obtained were validated using some certified reference samples.
