Intermediate and semi-volatility organic compounds(I/SVOCs)are crucial precursors for secondary organic aerosols(SOA).Vehicles are major sources of I/SVOCs,yet their emission profiles remain insufficiently characteriz...Intermediate and semi-volatility organic compounds(I/SVOCs)are crucial precursors for secondary organic aerosols(SOA).Vehicles are major sources of I/SVOCs,yet their emission profiles remain insufficiently characterized.We conducted dynamometer tests on eight in-use gasoline and diesel vehicles(DVs),employing non-targeted analysis with comprehensive two-dimensional gas chromatography coupled with high-resolution mass spectrometry(GC×GC-TOFMS)to investigate vehicular I/SVOC emissions at the molecular level.A total of 438 and 424 compounds were identified and(semi)-quantified in the gas and particle phases,respectively.DVs exhibited higher emission factors(376.7±74.9 mg/(kg·fuel))compared to gasoline vehicles(GVs)(114.4±42.1 mg/(kg·fuel))across both phases.Alkanes(29.7%-41.9%),single-ring aromatics(2.6%-29.8%),and cycloalkanes(1.0%-13.1%)were dominant I/SVOCs groups.Oxygenated I/SVOCs were more abundant in particulate phases(40.3%-56.8%)than in gas phases(14.4%-15.3%).Upgrading emission standards reduced organic emissions by 89.2%from China IV to China VI for DVs,particularly in the particle phase.Coldstart conditions resulted in higher I/SVOC emissions(528.4 mg/(kg·fuel))than hot-starts(224.8 mg/(kg·fuel))due to reduced combustion efficiency and suboptimal after-treatment performance at low temperatures.Our composition-based SOA estimation method improved SOA predictions by 1.5 and 1.2 times for diesel and GVs,respectively,compared to the traditional bin approach.These findings provide valuable insights into the molecular composition of vehicular I/SVOCs and their environmental impacts.展开更多
The characteristic flavor of the enzymatic hydrolysate of Lentinus edodes,which was involved in the Maillard reaction by xylose,fructose,glucose,sucrose,mannose,maltose,vitamin C(VC)and L-arabinose,was determined and ...The characteristic flavor of the enzymatic hydrolysate of Lentinus edodes,which was involved in the Maillard reaction by xylose,fructose,glucose,sucrose,mannose,maltose,vitamin C(VC)and L-arabinose,was determined and analyzed by gas chromatography-ion mobility spectroscopy(GC-IMS).The characteristic flavor fingerprints of Maillard reaction products(MRPs)of L.edodes enzymatic hydrolysate were constructed.The differences in the characteristic flavors of Maillard reaction with different reducing sugars and VC were compared.The main characteristic flavor,characteristic peak,characteristic marker substance and content were determined,a principal component analysis(PCA)of volatile organic compounds(VOCs)was carried out.The results showed that there were 42 kinds of monomers and some dimers of volatile compounds in the samples including 17 aldehydes,5 alcohols,7 ketones,2 esters,2 acids,7 other compounds and 2 ethers.The volatile VOCs of the sample with added sucrose,VC and L-arabinose were significantly higher than those of the enzymatic hydrolysate of L.edodes.After the Maillard reaction,the flavor of the hydrolysate was significantly improved,and the main components changed significantly.展开更多
基金supported by the National Key Research and Development Program of China(Nos.2023YFC3706201 and 2022YFE0135000)the National Natural Science Foundation of China(Nos.42175123 and 42311530112)the Fundamental Research Funds for the Central Universities of China(Nos.63241318,63241322,and 63243126).
文摘Intermediate and semi-volatility organic compounds(I/SVOCs)are crucial precursors for secondary organic aerosols(SOA).Vehicles are major sources of I/SVOCs,yet their emission profiles remain insufficiently characterized.We conducted dynamometer tests on eight in-use gasoline and diesel vehicles(DVs),employing non-targeted analysis with comprehensive two-dimensional gas chromatography coupled with high-resolution mass spectrometry(GC×GC-TOFMS)to investigate vehicular I/SVOC emissions at the molecular level.A total of 438 and 424 compounds were identified and(semi)-quantified in the gas and particle phases,respectively.DVs exhibited higher emission factors(376.7±74.9 mg/(kg·fuel))compared to gasoline vehicles(GVs)(114.4±42.1 mg/(kg·fuel))across both phases.Alkanes(29.7%-41.9%),single-ring aromatics(2.6%-29.8%),and cycloalkanes(1.0%-13.1%)were dominant I/SVOCs groups.Oxygenated I/SVOCs were more abundant in particulate phases(40.3%-56.8%)than in gas phases(14.4%-15.3%).Upgrading emission standards reduced organic emissions by 89.2%from China IV to China VI for DVs,particularly in the particle phase.Coldstart conditions resulted in higher I/SVOC emissions(528.4 mg/(kg·fuel))than hot-starts(224.8 mg/(kg·fuel))due to reduced combustion efficiency and suboptimal after-treatment performance at low temperatures.Our composition-based SOA estimation method improved SOA predictions by 1.5 and 1.2 times for diesel and GVs,respectively,compared to the traditional bin approach.These findings provide valuable insights into the molecular composition of vehicular I/SVOCs and their environmental impacts.
基金This work was supported by the Innovative Engineering project of Shandong Academy of Agricultural Sciences(CXGC2022A36)Modern Agricultural Industry Technology System of Shandong Province(SDAIT-07-09).
文摘The characteristic flavor of the enzymatic hydrolysate of Lentinus edodes,which was involved in the Maillard reaction by xylose,fructose,glucose,sucrose,mannose,maltose,vitamin C(VC)and L-arabinose,was determined and analyzed by gas chromatography-ion mobility spectroscopy(GC-IMS).The characteristic flavor fingerprints of Maillard reaction products(MRPs)of L.edodes enzymatic hydrolysate were constructed.The differences in the characteristic flavors of Maillard reaction with different reducing sugars and VC were compared.The main characteristic flavor,characteristic peak,characteristic marker substance and content were determined,a principal component analysis(PCA)of volatile organic compounds(VOCs)was carried out.The results showed that there were 42 kinds of monomers and some dimers of volatile compounds in the samples including 17 aldehydes,5 alcohols,7 ketones,2 esters,2 acids,7 other compounds and 2 ethers.The volatile VOCs of the sample with added sucrose,VC and L-arabinose were significantly higher than those of the enzymatic hydrolysate of L.edodes.After the Maillard reaction,the flavor of the hydrolysate was significantly improved,and the main components changed significantly.
