Spectrofluorimetric determination of trace nitrite with a novel fluorescent probe.
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.
Liu
Qing-Hao
QH
School of Chemical Engineering and Technology, Tianjin University, Weijin Road, Tianjin 300072, China.
Yan
Xi-Long
XL
Guo
Jin-Chun
JC
Wang
Dong-Hua
DH
Li
Lei
L
Yan
Fan-Yong
FY
Chen
Li-Gong
LG
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*
D005456:Fluorescent Dyes; D009573:Nitrites; D012235:Rhodamines; D014867:Water; D006851:Hydrochloric Acid