Method for determining content of nitrogen oxide in air byalkali absorption-Raman spectrometry

Abstract

The invention discloses a method for determining the content of nitrogen oxide in air byan alkali absorption-Raman spectrometry, and in particularrelates to a Raman spectrometry utilizing alkali to absorb nitrogen oxideand thus calculating the content of nitrogen oxide. The method comprises the following steps: the air continuously flowing through a two-way parallel alkali absorption pipelineat the same flow rate and at the same time to absorb the nitrogen oxide, quantitatively calculating the content of nitrogen oxide in the air by comparing the contents of nitrate in two parts of absorption solutions formed by whether an oxidant solution is introduced through detection. The NO<3+> detection method is the Raman spectroscopy, comprising the steps: taking 717 plus or minus 2cm<-1> as a reference peak,setting the corresponding intensity to 5000, normalizing the linear function of a spectrogram, and determining by using an external standard method according to a corresponding relationship between the nitrate in a sample and relative intensity after normalizing at 1049 plus or minus 2cm<-1>. Compared with the existing method, the method provided by the invention has the advantages of quick sample preparation, repeatability, goodsystem stability, easy obtaining of used reagents, non-toxicity, highdetection anti-interference ability, good specificity, high accuracy and the like.

Description

technical field [0001] The invention relates to the field of analytical chemistry, in particular to a method for measuring the content of nitrogen oxides in air by using lye absorption-Raman spectroscopy. Background technique [0002] Nitrogen oxides include a variety of compounds. Except for nitrogen dioxide, other nitrogen oxides are extremely unstable and easily turn into nitrogen dioxide and nitric oxide when exposed to light, humidity or heat, and nitric oxide will be oxidized to nitrogen dioxide. Therefore, nitrogen oxides in the air are mainly nitrogen dioxide and nitrogen monoxide, and mainly nitrogen dioxide. [0003] As air pollutants, nitrogen oxides pose a potential threat to the ecological environment and human health. They are not only the main cause of photochemical smog and acid rain, but also the main culprit in the destruction of the ozone layer. Nitrogen oxides in the air dissolve in water to form nitrate compounds that, at high levels, can cause nitros...

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Problems solved by technology

However, the above-mentioned method has many disadvantages, such as cumbersome operation, high cost, long time, low accuracy, poor specificity, low detector sensitivity, and the long-term exposure of the absorption liquid to the air will increase the blank value, etc., which cannot fully satisfy need

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