被动采样-UV法测定环境空气中的臭氧浓度

Passive sampling incorporating UV method for measuring ozone concentrations in ambient air

研究被动采样 -UV法测定臭氧浓度。以 Na NO2 作为诱捕试剂 ,用被动采样器吸收 O3,然后在紫外分光光度计上进行测定。通过测定所生成的 NO- 3浓度 ,间接计算出臭氧浓度。结果表明 ,测得臭氧浓度范围在 2 0～ 10 0 μg/m3,NO- 3浓度线性范围在 0～ 0 .6mmol/L。在测定 NO- 3浓度时 ,NO- 2 会造成很大的干扰 ,但在实验中 ,NO- 2 浓度在 0～ 0 .8mmol/L,氨基磺酸都能有效地去除其干扰。该方法是简单、灵敏。

The present paper aims at introducing the passive sampling incorporating UV method for measuring ozone concentrations in ambient air. It is a common sense that sodium nitrite can be used for measuring the performance of an ozone passive sampler as a trapping reagent, which can in turn be used by UV method. What the passive sampling has to measure is the daily average ozone concentration. Our measuring results show that the extent of measured ozone concentration is from 20 to 100 μg/m^3 and the linear extent of nitrate concentration is from 0 to 0.6 mmol/L. Since the excessive sodium nitrite is added to the absorbing aqua, both nitrite and nitrate have the absorption at 220 nm with UV method. When nitrate concentrations are measured, nitrite can be a source of serious interference. However sulfamic acid can offset its interference effectively, as shown in our experiment, in so far as the nitrite concentration is within 0 to 0.8 mmol/L. Thus, the experiments demonstrate that our method is suitable for measuring ozone inside and outside under all climatic conditions.