荧光猝灭法测定空气中二氧化氮和一氧化氮

Fluorescence quenching method for the determination of nitrogen dioxide and nitrogen monoxide in air

NO2可被藏红T溶液吸收并转变为亚硝酸根，并且在酸性介质中，亚硝酸根可以使藏红T发生荧光猝灭，据此建立了荧光光度法测定亚硝酸根进而间接测定空气中NO2和NO的新方法。研究了硫酸，藏红T用量，柠檬酸钠用量对测定体系的影响。在最佳实验条件下，NO2^-的浓度在0．023-0．276μg／mL范围内与荧光信号的降低值呈良好的线性关系，相关系数为0．9978。该方法用于测定空气中NO2和NO时的检出限分别为0．0004mg／m^3和0．0006mg／m^3。该方法简单、快速、检出限低，可为环境评估提供一个参考方法。

NO2 could be absorbed and transformed into nitrite in a safranine T solution, and in acidic medium, the fluorescence of safranine T solution could be quenched by nitrite. Accordingly , a fluorescence spectrometry method was proposed to determine NO2 and NO in air through determining NO2. The influence of sulfuric acid, dosage of safranine T and sodium citrate were studied. Under the optimal experimental conditions, the concentration of NO2^- in the range of 0. 023--0. 276 μg/mL was linearly correlated to the decreasing of fluorescence intensity, with a correlation coefficient of 0. 997 8. The detection limits for NO2 and NO were 0. 000 4 mg/m^3 and 0. 000 6 mg/m^3, respectively. The method was simple,rapid and its detection limit was low. It can provide a reference method for environmental assessment.