Single particle-inductively coupled plasma mass spectrometry (SP-ICP-MS) is a powerful tool for size-characterization of metal-containing nanoparticles (MCNs) at environmentally relevant concentrations,however,coexist...Single particle-inductively coupled plasma mass spectrometry (SP-ICP-MS) is a powerful tool for size-characterization of metal-containing nanoparticles (MCNs) at environmentally relevant concentrations,however,coexisting dissolved metal ions greatly interfere with the accuracy of particle size analysis.The purpose of this study is to develop an online technique that couples hollow fiber ultrafiltration (HFUF) with SP-ICP-MS to improve the accuracy and size detection limit of MCNs by removing metal ions from suspensions of MCNs.Through systematic optimization of conditions including the type and concentration of surfactant and complexing agent,carrier pH,and ion cleaning time,HFUF completely removes metal ions but retains the MCNs in suspension.The optimal conditions include using a mixture of 0.05 vol.%FL-70 and 0.5 mmol/L Na2S2O_(3)(pH=8.0) as the carrier and 4 min as the ion cleaning time.At these conditions,HFUF-SP-ICP-MS accurately determines the sizes of MCNs,and the results agree with the size distribution determined by transmission electron microscopy,even when metal ions also are present in the sample.In addition,reducing the ionic background through HFUF also lowers the particle size detection limit with SP-ICP-MS (e.g.,from 28.3 to 14.2 nm for gold nanoparticles).This size-based ion-removal principle provided by HFUF is suitable for both cations (e.g.,Ag+) and anions (e.g.,AuCl_(4)^(-)) and thus has good versatility compared to ion exchange purification and promising prospects for the removal of salts and macromolecules before single particle analysis.展开更多
The overwhelming magnitude of coal-fired power plants has caused an inevitable release of metal-containing nanoparticles(MNPs)into the atmosphere,which may be inhaled into the respiratory system and cause oxidative st...The overwhelming magnitude of coal-fired power plants has caused an inevitable release of metal-containing nanoparticles(MNPs)into the atmosphere,which may be inhaled into the respiratory system and cause oxidative stress.In this study,MNPs and oxidative potential(OP)were analyzed in<1μm fractions of 56 coal fly ashes collected from Chinese CFPPs.The particle number concentrations(PNCs)of Fe-and Ti-containing NPs,as the dominant MNPs in CFAs,were in the range of 1.5×10^(9)to 9.4×10^(10)and 6.4×10^(8)to 4.1×10^(10)particles/mg,with average particle sizes of 87 and 89 nm,respectively.Average OP values of<1μm fractions were 1.4−2.2 nmol AA min^(−1)μg^(−1)for three simulated lung fluids,which were 2−3 orders of magnitude higher than those of urban atmospheric PM_(2.5).According to structural equation model analysis,metal concentrations in<1μm fractions,PNCs of Fe-/Ti-containing NPs,and their corresponding dissolved Fe/Ti(including NPs with minute sizes)can regulate OP of<1μm fractions in CFAs.Elevated PNCs of MNPs in CFAs can be produced by CFPPs burning low-rank coals and with a low combustion efficiency boiler(e.g.,circulating fluidized-bed boiler).Once entering lung fluids,they likely release more dissolved metals or tiny corresponding NPs,thus generating greater OP.This study provides the first comprehensive investigation of OP generated by MNPs in CFAs.展开更多
基金supported by the National Key Research and Development Project (No.2020YFA0907400)Strategic Priority Research Program of the Chinese Academy of Sciences (No.XDPB2005)+2 种基金National Natural Science Foundation of China(No.21777178)the National Young Top-Notch Talents (No.W03070030)Youth Innovation Promotion Association of the Chinese Academy of Sciences (No.Y202011)。
文摘Single particle-inductively coupled plasma mass spectrometry (SP-ICP-MS) is a powerful tool for size-characterization of metal-containing nanoparticles (MCNs) at environmentally relevant concentrations,however,coexisting dissolved metal ions greatly interfere with the accuracy of particle size analysis.The purpose of this study is to develop an online technique that couples hollow fiber ultrafiltration (HFUF) with SP-ICP-MS to improve the accuracy and size detection limit of MCNs by removing metal ions from suspensions of MCNs.Through systematic optimization of conditions including the type and concentration of surfactant and complexing agent,carrier pH,and ion cleaning time,HFUF completely removes metal ions but retains the MCNs in suspension.The optimal conditions include using a mixture of 0.05 vol.%FL-70 and 0.5 mmol/L Na2S2O_(3)(pH=8.0) as the carrier and 4 min as the ion cleaning time.At these conditions,HFUF-SP-ICP-MS accurately determines the sizes of MCNs,and the results agree with the size distribution determined by transmission electron microscopy,even when metal ions also are present in the sample.In addition,reducing the ionic background through HFUF also lowers the particle size detection limit with SP-ICP-MS (e.g.,from 28.3 to 14.2 nm for gold nanoparticles).This size-based ion-removal principle provided by HFUF is suitable for both cations (e.g.,Ag+) and anions (e.g.,AuCl_(4)^(-)) and thus has good versatility compared to ion exchange purification and promising prospects for the removal of salts and macromolecules before single particle analysis.
基金study was funded by the National Natural Science Foundation of China(42125102)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB40000000)。
文摘The overwhelming magnitude of coal-fired power plants has caused an inevitable release of metal-containing nanoparticles(MNPs)into the atmosphere,which may be inhaled into the respiratory system and cause oxidative stress.In this study,MNPs and oxidative potential(OP)were analyzed in<1μm fractions of 56 coal fly ashes collected from Chinese CFPPs.The particle number concentrations(PNCs)of Fe-and Ti-containing NPs,as the dominant MNPs in CFAs,were in the range of 1.5×10^(9)to 9.4×10^(10)and 6.4×10^(8)to 4.1×10^(10)particles/mg,with average particle sizes of 87 and 89 nm,respectively.Average OP values of<1μm fractions were 1.4−2.2 nmol AA min^(−1)μg^(−1)for three simulated lung fluids,which were 2−3 orders of magnitude higher than those of urban atmospheric PM_(2.5).According to structural equation model analysis,metal concentrations in<1μm fractions,PNCs of Fe-/Ti-containing NPs,and their corresponding dissolved Fe/Ti(including NPs with minute sizes)can regulate OP of<1μm fractions in CFAs.Elevated PNCs of MNPs in CFAs can be produced by CFPPs burning low-rank coals and with a low combustion efficiency boiler(e.g.,circulating fluidized-bed boiler).Once entering lung fluids,they likely release more dissolved metals or tiny corresponding NPs,thus generating greater OP.This study provides the first comprehensive investigation of OP generated by MNPs in CFAs.
