title: Fluorimetric determination of nitrogen oxides in the air by a novel red-region fluorescent reagent.
abstract: A sensitive fluorimetric method for the determination of nitrogen oxides (NO(x): NO+NO(2)) in air is described. Nitrogen dioxide (nitrogen monoxide was previously converted to nitrogen dioxide in oxide tubes) was aspirated through a fritted glass bubble at a flow rate of 500 ml min(-1) for 120 min and fixed as nitrite, using 0.1 N NaOH as a trapping solution with the empirical absorption efficiency 0.74 and the stoichiometric factor 0.5. The method is based on the fluorescence quenching of a red-region fluorescent reagent, tetra-substituted amino aluminum phthalocyanine (TAAlPc), after being diazotized by nitrite. Under optimal conditions the linear range of the calibration curve for nitrite is 1-40 ng ml(-1) (NO(2) 0.24-9.6 ppb, v/v). The detection limit is 0.34 ng ml(-1) for nitrite (NO(2) 0.08 ppb, v/v) and the relative standard deviation for six replicate measurements of 15 ng ml(-1) nitrite is 3.2%. The method has been applied to the determination of nitrogen oxides in the air with satisfactory results. Typical gaseous co-pollutants such as SO(2), H(2)S and HCHO did not interference the determination.
authors.affiliation: Department of Chemistry of Zhangzhou Teacher's College, Zhangzhou 363000, Fujian, People's Republic of China.
authors.forename: Xin-Qi
authors.initials: XQ
authors.lastname: Zhan
authors.forename: Dong-Hui
authors.initials: DH
authors.lastname: Li
authors.forename: Hong
authors.initials: H
authors.lastname: Zheng
authors.forename: Jin-Gou
authors.initials: JG
authors.lastname: Xu
authors.forename: Yi-Qun
authors.initials: YQ
authors.lastname: Zhou