Ozone（O3） is an important atmospheric oxidant. Black carbon（BC） particles released into the atmosphere undergo an aging process via O3 oxidation. O3-aged BC particles may change their uptake ability toward trace r...Ozone（O3） is an important atmospheric oxidant. Black carbon（BC） particles released into the atmosphere undergo an aging process via O3 oxidation. O3-aged BC particles may change their uptake ability toward trace reducing gases such as SO2 in the atmosphere,leading to different environmental and health effects. In this paper, the heterogeneous reaction process between O3-aged BC and SO2 was explored via in-situ diffuse reflectance infrared Fourier transform spectroscopy（DRIFTS）. Combined with ion chromatography（IC）,DRIFTS was used to qualitatively and quantitatively analyze the sulfate product. The results showed that O3-aged BC had stronger SO2 oxidation ability than fresh BC, and the reactive species/sites generated on the surface had an important role in the oxidation of SO2.Relative humidity or 254 nm UV（ultraviolet） light illumination enhanced the oxidation uptake of SO2 on O3-aged BC. The oxidation potentials of the BC particles were detected via dithiothreitol（DTT） assay. The DTT activity over BC was decreased in the process of SO2 reduction, with the consumption of oxidative active sites.展开更多
为解决农药残留测定时检测项目不全面、部分农药易吸附和降解等导致的回收率偏低的现象,提出了题示方法,并对净化条件和保护剂的种类及用量进行优化。样品经粉碎后,分取(3±0.05)g,加入1.0mol·L^(-1)二硫苏糖醇溶液100μL和1%...为解决农药残留测定时检测项目不全面、部分农药易吸附和降解等导致的回收率偏低的现象,提出了题示方法,并对净化条件和保护剂的种类及用量进行优化。样品经粉碎后,分取(3±0.05)g,加入1.0mol·L^(-1)二硫苏糖醇溶液100μL和1%(体积分数)乙酸溶液15mL,浸泡30min。加入15mL乙腈,振荡5min,加入质量比4∶1的无水硫酸镁和无水硫酸钠混合粉末7.5g,振荡3min,于冰浴中冷却10min,离心5min。分取上清液9mL,用装有无水硫酸镁900mg、N-丙基乙二胺300mg、十八烷基硅烷键合硅胶(C_(18))300mg、硅胶300mg的净化管净化,振荡5min,离心5min。分取上清液5mL,于40℃氮吹浓缩至约0.4mL,加入150μL水,用乙腈稀释至1mL,涡旋混匀后过0.22μm滤膜,滤液进入超高效液相色谱仪,在ZORBAX Eclipse plus C_(18)色谱柱上用不同体积比的含0.1%(体积分数)甲酸的10mmol·L^(-1)甲酸铵溶液和乙腈的混合溶液进行梯度洗脱,分离后的30种农药在串联质谱仪的电喷雾离子源正离子模式和多反应监测模式下检测,以基质匹配法定量。结果显示:以去除了石墨化碳黑(GCB)的QuEChERS吸附剂作净化剂可有效降低氯磺隆、胺苯磺隆、甲磺隆和杀虫脒的吸附损失,以二硫苏糖醇作保护剂可降低内吸磷、甲拌磷砜和苯线磷等有机磷类农药的降解损失;30种农药可在20min内完成分离,标准曲线的线性范围为10~150μg·L^(-1),检出限为0.001~0.005mg·kg^(-1);对空白样品进行加标回收试验,回收率为81.3%~110%,测定值的相对标准偏差(n=6)为1.3%~11%;方法用于实际样品分析,仅在一份样品中检出灭线磷,检出量为0.012mg·kg^(-1)。展开更多
基金the financial support provided by the National Natural Science Foundation of China(Nos.21277004,21190051,41121004)the Beijing Natural Science Foundation(No.8132035)+1 种基金the Fujitsu Laboratories Limited Foundation(No.k120400)the Special Fund of State Key Joint Laboratory of Environmental Simulation and Pollution Control(2015)
文摘Ozone（O3） is an important atmospheric oxidant. Black carbon（BC） particles released into the atmosphere undergo an aging process via O3 oxidation. O3-aged BC particles may change their uptake ability toward trace reducing gases such as SO2 in the atmosphere,leading to different environmental and health effects. In this paper, the heterogeneous reaction process between O3-aged BC and SO2 was explored via in-situ diffuse reflectance infrared Fourier transform spectroscopy（DRIFTS）. Combined with ion chromatography（IC）,DRIFTS was used to qualitatively and quantitatively analyze the sulfate product. The results showed that O3-aged BC had stronger SO2 oxidation ability than fresh BC, and the reactive species/sites generated on the surface had an important role in the oxidation of SO2.Relative humidity or 254 nm UV（ultraviolet） light illumination enhanced the oxidation uptake of SO2 on O3-aged BC. The oxidation potentials of the BC particles were detected via dithiothreitol（DTT） assay. The DTT activity over BC was decreased in the process of SO2 reduction, with the consumption of oxidative active sites.
文摘为解决农药残留测定时检测项目不全面、部分农药易吸附和降解等导致的回收率偏低的现象,提出了题示方法,并对净化条件和保护剂的种类及用量进行优化。样品经粉碎后,分取(3±0.05)g,加入1.0mol·L^(-1)二硫苏糖醇溶液100μL和1%(体积分数)乙酸溶液15mL,浸泡30min。加入15mL乙腈,振荡5min,加入质量比4∶1的无水硫酸镁和无水硫酸钠混合粉末7.5g,振荡3min,于冰浴中冷却10min,离心5min。分取上清液9mL,用装有无水硫酸镁900mg、N-丙基乙二胺300mg、十八烷基硅烷键合硅胶(C_(18))300mg、硅胶300mg的净化管净化,振荡5min,离心5min。分取上清液5mL,于40℃氮吹浓缩至约0.4mL,加入150μL水,用乙腈稀释至1mL,涡旋混匀后过0.22μm滤膜,滤液进入超高效液相色谱仪,在ZORBAX Eclipse plus C_(18)色谱柱上用不同体积比的含0.1%(体积分数)甲酸的10mmol·L^(-1)甲酸铵溶液和乙腈的混合溶液进行梯度洗脱,分离后的30种农药在串联质谱仪的电喷雾离子源正离子模式和多反应监测模式下检测,以基质匹配法定量。结果显示:以去除了石墨化碳黑(GCB)的QuEChERS吸附剂作净化剂可有效降低氯磺隆、胺苯磺隆、甲磺隆和杀虫脒的吸附损失,以二硫苏糖醇作保护剂可降低内吸磷、甲拌磷砜和苯线磷等有机磷类农药的降解损失;30种农药可在20min内完成分离,标准曲线的线性范围为10~150μg·L^(-1),检出限为0.001~0.005mg·kg^(-1);对空白样品进行加标回收试验,回收率为81.3%~110%,测定值的相对标准偏差(n=6)为1.3%~11%;方法用于实际样品分析,仅在一份样品中检出灭线磷,检出量为0.012mg·kg^(-1)。
