大气臭氧被动采样方法及其Δ^(17)O测定的研究  

Passive Sampling of Atmospheric Ozone and Determination of Δ^(17 )O

作　　者：李裕文 赵祝钰 曹芳 周雨辰[1,2] 周苇菁 杨笑影 俞浩然 章炎麟 LI Yu-Wen;ZHAO Zhu-Yu;CAO Fang;ZHOU Yu-Chen;ZHOU Wei-Jing;YANG Xiao-Ying;YU Hao-Ran;ZHANG Yan-Lin(School of Applied Meteorology,Nanjing University of Information Science and Technology,Nanjing 210044,China;Atmospheric Environment Center,Joint Laboratory for International Cooperation on Climate and Environmental Change,Ministry of Education,Nanjing University of Information Science and Technology.Nanjing 210044,China)

机构地区：[1]南京信息工程大学应用气象学院,南京210044 [2]南京信息工程大学教育部气候与环境变化国际合作联合实验室,大气环境中心,南京210044

出　　处：《分析化学》2022年第5期801-809,共9页Chinese Journal of Analytical Chemistry

基　　金：国家自然科学基金项目(Nos.41977305,41977185);江苏省双创团队项目(2018);江苏省自然科学基金项目(No.BK20180040);江苏省“333人才工程”项目(No.RRA2020068)资助。

摘　　要：基于被动采样方法,使用亚硝酸盐涂覆的被动采样器,对大气中臭氧(O_(3))进行采集,采样周期为1周。将大气O_(3)转化为吸附膜上的硝酸盐,通过加入一定浓度的氨基磺酸将剩余的亚硝酸盐去除后,加入适量NaOH中和,调节溶液pH值,最后采用反硝化细菌法将硝酸盐转化为N_(2) O,进入800℃金管高温裂解为N_(2)和O_(2),将测定的δ18 O和δ^(17)O值换算为Δ^(17)O(Δ^(17)O=δ^(17)O-0.52δ^(18) O),根据国际标准样品(USGS34和USGS35)建立的标准曲线获取硝酸盐的Δ^(17)O真实值,并进一步换算为大气中O_(3)的Δ^(17)O值。研究结果表明,加入0.5 mL氨基磺酸(1 mol/L),振荡15 min可完全去除亚硝酸盐,且对硝酸盐同位素值测定无影响;使用99.999%NaNO_(2)可更好地降低试剂中NO-3导致的空白效应,从而减小对同位素值测定的影响;O_(3)转化生成的硝酸盐含量应高于6μg NO-3-N,此时测得Δ^(17)O的标准偏差为0.29‰(n=3)。通过本方法对南京市春季的大气被动采集O_(3)样品进行分析,换算得到O_(3)的Δ^(17)O=26.59‰±1.41‰,与主动采集样品的值基本一致。被动采集方法具有成本低、仪器便携性好、耗能小等优点,其同位素值测量结果表明,被动采样是一种可行性高的采样方法,可用于大气O_(3)氧同位素异常值研究。As an air pollutant,tropospheric ozone(O_(3)) is also a precursor of atmospheric nitrate.Its oxygen isotope abnormal(Δ^(17)O)can be used to trace atmospheric nitrate and other atmospheric chemical processes.This research was based on the passive sampling method,and the O_(3) in the atmosphere was collected using a passive sampler coated with nitrite.The sampling period was one week.The atmospheric O_(3) was converted into nitrate on the adsorption filter membrane,the remaining nitrite was removed by adding a certain concentration of sulfamic acid,and then the corresponding concentration of sodium hydroxide was added to neutralize the pH of the solution.Nitrate was converted into N_(2)O by the denitrifying bacteria method,and the produced N_(2)O entered the gold tube at 800℃to be pyrolyzed into N_(2)and O_(2).The δ^(18) O and δ^(17)O values of oxygen were measured and converted to Δ^(17)O(Δ^(17)O=δ^(17)O-0.52δ18 O).With the help of international samples with knownΔ^(17)O values(USGS34 and USGS35),aΔ^(17)O standard curve was established to convert theΔ^(17)O of real nitrates,and finally converted to the value ofΔ^(17)O in atmospheric ozone.The research results showed that adding 0.5 mL of sulfamic acid(1 mol/L)to the reaction and shaking for 15 min could completely remove nitrite without affecting the isotope value of nitrate.The use of 99.999%sodium nitrite could better reduce the blank effect caused by nitrate in the drug,thereby reducing the impact on the isotope value.The content of nitrate generated by O_(3)conversion should be higher than 6μg of NO_(3)-N,and the standard deviation ofΔ^(17)O measured at this time was 0.29‰(n=3).This method was used to analyze the passively collected O_(3)samples in Nanjing spring,and theΔ^(17)O value of O_(3)was 26.59‰±1.41‰,which was consistent with the actively collected value and similar to previous research results.Passive sampling method had many advantages such as low price,good portability and low energy consumption.Its isotope value measurement r

关 键 词：大气臭氧 被动采样 硝酸盐 氧同位素异常值 

分 类 号：X831[环境科学与工程—环境工程]