Quantitative detection of nitric oxide in exhaled human breath by extractive electrospray ionization mass spectrometry.
Exhaled nitric oxide (eNO) is a useful biomarker of various physiological conditions, including asthma and other pulmonary diseases. Herein a fast and sensitive analytical method has been developed for the quantitative detection of eNO based on extractive electrospray ionization mass spectrometry (EESI-MS). Exhaled NO molecules selectively reacted with 2-phenyl-4, 4, 5, 5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO) reagent, and eNO concentration was derived based on the EESI-MS response of 1-oxyl-2-phenyl-4, 4, 5, 5-tetramethylimidazoline (PTI) product. The method allowed quantification of eNO below ppb level (~0.02 ppbv) with a relative standard deviation (RSD) of 11.6%. In addition, eNO levels of 20 volunteers were monitored by EESI-MS over the time period of 10 hrs. Long-term eNO response to smoking a cigarette was recorded, and the observed time-dependent profile was discussed. This work extends the application of EESI-MS to small molecules (<30 Da) with low proton affinity and collision-induced dissociation efficiency, which are usually poorly visible by conventional ion trap mass spectrometers. Long-term quantitative profiling of eNO by EESI-MS opens new possibilities for the research of human metabolism and clinical diagnosis.
Jiangxi Key Laboratory for Mass Spectrometry and Instrumentation, East China Institute of Technology, Nanchang, Jiangxi Province 330013, P. R. China.
Susu
S
Pan
State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, P. R. China.
Yong
Y
Tian
National Institute of Metrology, Beijing 100013, P. R. China.
Ming
M
Li
Department of Respiratory Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province 330006, P. R. China.
Jiuyan
J
Zhao
Department of Respiratory Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province 330006, P. R. China.
Lanlan
L
Zhu
Department of Respiratory Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province 330006, P. R. China.
Wei
W
Zhang
Jiangxi Key Laboratory for Mass Spectrometry and Instrumentation, East China Institute of Technology, Nanchang, Jiangxi Province 330013, P. R. China.
Haiwei
H
Gu
Jiangxi Key Laboratory for Mass Spectrometry and Instrumentation, East China Institute of Technology, Nanchang, Jiangxi Province 330013, P. R. China.
Haidong
H
Wang
State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, P. R. China.
Jianbo
J
Shi
National Institute of Metrology, Beijing 100013, P. R. China.
Xiang
X
Fang
Jiangxi Key Laboratory for Mass Spectrometry and Instrumentation, East China Institute of Technology, Nanchang, Jiangxi Province 330013, P. R. China.
Penghui
P
Li
Jiangxi Key Laboratory for Mass Spectrometry and Instrumentation, East China Institute of Technology, Nanchang, Jiangxi Province 330013, P. R. China.
Huanwen
H
Chen
D000465:Algorithms; D001944:Breath Tests / Q000379:methods; D003497:Cyclic N-Oxides / Q000737:chemistry; D045853:Exhalation; D006801:Humans; D007093:Imidazoles / Q000737:chemistry; D008956:Models, Chemical; D009569:Nitric Oxide / Q000032:analysis* / Q000737:chemistry; D012907:Smoking; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
D003497:Cyclic N-Oxides; D007093:Imidazoles; C079391:2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide; D009569:Nitric Oxide