title: Development of a novel running buffer for the simultaneous determination of nitrate and nitrite in human serum by capillary zone electrophoresis.
abstract: In order to improve NO2- peak height and obtain a convenient buffer system for the assay of nitrogen monooxide metabolites, we developed a novel running buffer for the simultaneous determination of nitrite and nitrate in human serum by capillary electrophoresis. The addition of cetyltrimethylammonium chloride to the running buffer resulted in high-speed separation using reverse electroosmotic flow. Highly sensitive determination was also achieved using stacking with 10-fold diluted sample solutions. The samples were injected hydrodynamically for 100 s into a 50 cm x 75 microm I.D. capillary. The separation voltage was 10 kV (negative polarity). UV detection was performed at 214 nm. We obtained complete separation of nitrite and nitrate in deproteinized human serum within 6 min with optimum analytical conditions. Linear calibration curves for nitrite and nitrate for both peak height and peak area were obtained with standard addition method. The limits of detection obtained at a signal-to-noise ratio of 3 for nitrite and nitrate were 4.1 and 2.0 microM, while the values of relative standard deviation of peak height were 2.4 and 2.6%, respectively.
authors.affiliation: Human Stress Signal Research Center, National Institute of Advanced Industrial Science and Technology, AIST Kansai, 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Miyado
authors.forename: Hidenori
authors.initials: H
authors.lastname: Nagai
authors.forename: Sahori
authors.initials: S
authors.lastname: Takeda
authors.forename: Keiitsu
authors.initials: K
authors.lastname: Saito
authors.forename: Keiichi
authors.initials: K
authors.lastname: Fukushi
authors.forename: Yasukazu
authors.initials: Y
authors.lastname: Yoshida
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Wakida
authors.forename: Etsuo
authors.initials: E
authors.lastname: Niki
mesh_terms: D002021:Buffers; D019075:Electrophoresis, Capillary / Q000379:methods*; D009566:Nitrates / Q000097:blood*; D009573:Nitrites / Q000097:blood*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D002021:Buffers; D009566:Nitrates; D009573:Nitrites