title: Spectrofluorimetric determination of trace nitrite with a novel fluorescent probe.
abstract: A simple, sensitive and selective fluorimetric determination for trace nitrites was developed using an unsymmetrical rhodamine with a high fluorescence quantum yield and large Stokes shift. The method is based on the reaction of the unsymmetrical rhodamine with nitrite in an acidic medium to form a nitroso product, which has much lower fluorescence because the electron-withdrawing effect of the nitroso group influences the system of p-pi conjugation between N atom and benzene ring. Under optimum conditions, the fluorescence quenching intensity is linear over a nitrite concentration range of 1.0 x 10(-8) to 3.5 x 10(-7)M. The detection limit is 2.0 x 10(-10)M (S/N=3). The method was applied to the determination of nitrite in tap water and lake water with satisfactory results. The mechanism for the reaction is also reported.
authors.affiliation: School of Chemical Engineering and Technology, Tianjin University, Weijin Road, Tianjin 300072, China.
authors.forename: Qing-Hao
authors.initials: QH
authors.lastname: Liu
authors.forename: Xi-Long
authors.initials: XL
authors.lastname: Yan
authors.forename: Jin-Chun
authors.initials: JC
authors.lastname: Guo
authors.forename: Dong-Hua
authors.initials: DH
authors.lastname: Wang
authors.forename: Lei
authors.initials: L
authors.lastname: Li
authors.forename: Fan-Yong
authors.initials: FY
authors.lastname: Yan
authors.forename: Li-Gong
authors.initials: LG
authors.lastname: Chen
mesh_terms: D005456:Fluorescent Dyes / Q000032:analysis / Q000138:chemical synthesis / Q000737:chemistry*; D005618:Fresh Water / Q000032:analysis*; D006851:Hydrochloric Acid / Q000737:chemistry; D016014:Linear Models; D015394:Molecular Structure; D009573:Nitrites / Q000032:analysis* / Q000737:chemistry; D012235:Rhodamines / Q000032:analysis / Q000138:chemical synthesis / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence / Q000379:methods*; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000032:analysis*
chemical_list: D005456:Fluorescent Dyes; D009573:Nitrites; D012235:Rhodamines; D014867:Water; D006851:Hydrochloric Acid