Organic aerosol (OA) is a crucial component of atmospheric fine particles. To achieve a better understanding of the chemical characteristics and sources of OA in Beijing, the size-resolved chemical composition of subm...Organic aerosol (OA) is a crucial component of atmospheric fine particles. To achieve a better understanding of the chemical characteristics and sources of OA in Beijing, the size-resolved chemical composition of submicron aerosols were measured in-situ using a High-Resolution Time-of-Flight Aerosol Mass Spectrometer in the winter of 2010, with a high time resolution of 5 min. During this study, the mean OA mass concentration was 20.9±25.3 μg/m3, varying between 1.9 and 284.6 μg/m3. Elemental analysis showed that the average H/C, O/C and N/C (molar ratio) were 1.70, 0.17, and 0.005, respectively, corresponding to an OM/OC ratio (mass ratio of organic matter to organic carbon) of 1.37. The average mass-based size distributions of OA present a promi- nent accumulation mode peaking at approximately 450 nm. The prominent presence of ultrafine particles (Dva < 100 nm) was mainly from the fresh emissions of combustion sources. A Positive Matrix Factorisation (PMF) analysis of the organic mass spectral dataset differentiated the OA into three components, including hydrocarbon-like (HOA), cooking-related (COA), and oxygenated (OOA) organic aerosols, which, on average, accounted for 26.9%, 49.7% and 23.4%, respectively, of the total organic mass. The HOA and COA likely corresponded to primary organic aerosol (POA) associated with combustion-related and cooking emissions, respectively, and the OOA components corresponded to aged secondary organic aerosol (SOA).展开更多
目的建立超高效液相色谱-高分辨质谱法检测调味品中19种非食用物质的分析方法。方法样品经乙酸乙酯-环己烷提取,采用凝胶渗透色谱(gel permeation chromatography,GPC)净化与在线定量浓缩,然后经C_(18)色谱柱分离,乙腈和5 mmol/L乙酸铵(...目的建立超高效液相色谱-高分辨质谱法检测调味品中19种非食用物质的分析方法。方法样品经乙酸乙酯-环己烷提取,采用凝胶渗透色谱(gel permeation chromatography,GPC)净化与在线定量浓缩,然后经C_(18)色谱柱分离,乙腈和5 mmol/L乙酸铵(含0.1%甲酸)溶液梯度洗脱后经超高效液相色谱-线性离子阱/静电场轨道阱高分辨质谱(ultra performance liquid chromatography-linear ion trap-orbitrap high resolution mass spectrometry,UPLC-LTQ-orbitrap MS)测定。结果 19种目标物在15 min内实现良好分离,线性相关系数均≥0.996,定量限(limit of quantitation,LOQ)为5~15μg/kg,加标回收率在61.9%~105.8%之间,相对标准偏差(relative standard deviation,RSD)为2.3%~12.9%。结论本研究建立的方法准确、简单,可适用于调味品中19种非食用物质的定性定量及确证分析。展开更多
The status of PCDDs and PCDFs content in retail foods from a certain area by Isotope Dilution HRGC-HRMS was surveyed and the local population PCDD/Fs exposure from diverse foods and health risk was evaluated.PCDD/Fs w...The status of PCDDs and PCDFs content in retail foods from a certain area by Isotope Dilution HRGC-HRMS was surveyed and the local population PCDD/Fs exposure from diverse foods and health risk was evaluated.PCDD/Fs was extracted from samples by Soxhlet extraction,concentrated and purified by FMS column chromatograph,carbon column enrichment.Confirmation and quantitative analysis at pg/g level of PCDD/Fs was performed by HRGC/HRMS using multiple ion detection mode(MID).TEQ concentration was calculated by WHO-TEF multiplying by concentration of seventeen PCDD/Fs congener.Median of PCDD/Fs concentration for fish,livestock,poultry,egg,vegetable oil,milk,vegetable totally 100 samples for ten diverse foods didn’t exceed the limit standards by EU.The level of PCDD/Fs for different food in the certain area was lower or comparable to the data reported by developed country in the world.The total weekly intake and monthly intake for local population or national population was 3.44,14.8 WHO-TEQ/kg BW and 1.5,6.42 pg WHO-TEQ/kg BW respectively,the value was lower than the Tolerable Weekly Intake of 14 pg WHO TEQ/kg BW for PCDDs,PCDFs and dioxin-like PCBs established by EU Scientific Committee for Food.The dietary PCDD/Fs intake for local people was higher than national population.And animal food was the dominant contributor to the total dietary intake,which accounted for more than 70 percent.These levels of consumption of diverse food containing typical levels of PCDD/Fs doesn’t present a risk to the health of the local population.But integrative dietary intake could be evaluated including of PCBs intake for population in the future.展开更多
Labeled polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/Fs)were extracted by three different methods,i.e.,soxhlet extraction,hot extraction and accelerated solvent extraction(ASE).The PCDD/Fs were detected by...Labeled polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/Fs)were extracted by three different methods,i.e.,soxhlet extraction,hot extraction and accelerated solvent extraction(ASE).The PCDD/Fs were detected by high resolution gas chromatography-high resolution mass spectrometry.Comparisons of the three methods were carried out by recovery of PCDD/Fs,solvent consumption and extraction time.The results showed that all of the method could extract labeled PCDD/Fs efficiently.ASE was a time saving procedure with lowest consumption of solvents compared with the other two methods.展开更多
A rapid pretreatment method of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in soil and analysis by high resolution gas chromatograph-high resolution mass spectrometry was present.The extraction and a...A rapid pretreatment method of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in soil and analysis by high resolution gas chromatograph-high resolution mass spectrometry was present.The extraction and alumina clean up of PCDD/Fs in soil was achieved by accelerated solvent extractor.Then the multi-layer silica-gel column was used for further clean up.The whole method has been evaluated on certified reference soil and farm soil.Accuracy and precision of this method was tested with satisfactory results.展开更多
文摘Organic aerosol (OA) is a crucial component of atmospheric fine particles. To achieve a better understanding of the chemical characteristics and sources of OA in Beijing, the size-resolved chemical composition of submicron aerosols were measured in-situ using a High-Resolution Time-of-Flight Aerosol Mass Spectrometer in the winter of 2010, with a high time resolution of 5 min. During this study, the mean OA mass concentration was 20.9±25.3 μg/m3, varying between 1.9 and 284.6 μg/m3. Elemental analysis showed that the average H/C, O/C and N/C (molar ratio) were 1.70, 0.17, and 0.005, respectively, corresponding to an OM/OC ratio (mass ratio of organic matter to organic carbon) of 1.37. The average mass-based size distributions of OA present a promi- nent accumulation mode peaking at approximately 450 nm. The prominent presence of ultrafine particles (Dva < 100 nm) was mainly from the fresh emissions of combustion sources. A Positive Matrix Factorisation (PMF) analysis of the organic mass spectral dataset differentiated the OA into three components, including hydrocarbon-like (HOA), cooking-related (COA), and oxygenated (OOA) organic aerosols, which, on average, accounted for 26.9%, 49.7% and 23.4%, respectively, of the total organic mass. The HOA and COA likely corresponded to primary organic aerosol (POA) associated with combustion-related and cooking emissions, respectively, and the OOA components corresponded to aged secondary organic aerosol (SOA).
文摘目的建立超高效液相色谱-高分辨质谱法检测调味品中19种非食用物质的分析方法。方法样品经乙酸乙酯-环己烷提取,采用凝胶渗透色谱(gel permeation chromatography,GPC)净化与在线定量浓缩,然后经C_(18)色谱柱分离,乙腈和5 mmol/L乙酸铵(含0.1%甲酸)溶液梯度洗脱后经超高效液相色谱-线性离子阱/静电场轨道阱高分辨质谱(ultra performance liquid chromatography-linear ion trap-orbitrap high resolution mass spectrometry,UPLC-LTQ-orbitrap MS)测定。结果 19种目标物在15 min内实现良好分离,线性相关系数均≥0.996,定量限(limit of quantitation,LOQ)为5~15μg/kg,加标回收率在61.9%~105.8%之间,相对标准偏差(relative standard deviation,RSD)为2.3%~12.9%。结论本研究建立的方法准确、简单,可适用于调味品中19种非食用物质的定性定量及确证分析。
文摘The status of PCDDs and PCDFs content in retail foods from a certain area by Isotope Dilution HRGC-HRMS was surveyed and the local population PCDD/Fs exposure from diverse foods and health risk was evaluated.PCDD/Fs was extracted from samples by Soxhlet extraction,concentrated and purified by FMS column chromatograph,carbon column enrichment.Confirmation and quantitative analysis at pg/g level of PCDD/Fs was performed by HRGC/HRMS using multiple ion detection mode(MID).TEQ concentration was calculated by WHO-TEF multiplying by concentration of seventeen PCDD/Fs congener.Median of PCDD/Fs concentration for fish,livestock,poultry,egg,vegetable oil,milk,vegetable totally 100 samples for ten diverse foods didn’t exceed the limit standards by EU.The level of PCDD/Fs for different food in the certain area was lower or comparable to the data reported by developed country in the world.The total weekly intake and monthly intake for local population or national population was 3.44,14.8 WHO-TEQ/kg BW and 1.5,6.42 pg WHO-TEQ/kg BW respectively,the value was lower than the Tolerable Weekly Intake of 14 pg WHO TEQ/kg BW for PCDDs,PCDFs and dioxin-like PCBs established by EU Scientific Committee for Food.The dietary PCDD/Fs intake for local people was higher than national population.And animal food was the dominant contributor to the total dietary intake,which accounted for more than 70 percent.These levels of consumption of diverse food containing typical levels of PCDD/Fs doesn’t present a risk to the health of the local population.But integrative dietary intake could be evaluated including of PCBs intake for population in the future.
文摘Labeled polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/Fs)were extracted by three different methods,i.e.,soxhlet extraction,hot extraction and accelerated solvent extraction(ASE).The PCDD/Fs were detected by high resolution gas chromatography-high resolution mass spectrometry.Comparisons of the three methods were carried out by recovery of PCDD/Fs,solvent consumption and extraction time.The results showed that all of the method could extract labeled PCDD/Fs efficiently.ASE was a time saving procedure with lowest consumption of solvents compared with the other two methods.
文摘A rapid pretreatment method of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in soil and analysis by high resolution gas chromatograph-high resolution mass spectrometry was present.The extraction and alumina clean up of PCDD/Fs in soil was achieved by accelerated solvent extractor.Then the multi-layer silica-gel column was used for further clean up.The whole method has been evaluated on certified reference soil and farm soil.Accuracy and precision of this method was tested with satisfactory results.
