Simultaneous determination of nitrite and nitrate ions by air-segmented amplitude-modulated multiplexed flow analysis.
The concept of amplitude-modulated multiplexed flow analysis has been extended to the simultaneous determination of multiple analytes in a sample. A sample solution containing nitrite and nitrate ions is delivered from two channels, but the flow rates are varied at different frequencies. One of the channels has a reduction column for converting nitrate ions to nitrite ions. Downstream, the absorbance of the diazo-coupling product is monitored after the merging of both solutions with a Griess reagent. The signal is analyzed by a fast Fourier transform (FFT) in real time. From the thus-obtained amplitude, a µmol dm(-3) level of the ions can be determined. The introduction of air bubbles is effective to reduce any axial dispersion, and hence to improve the sensitivity.
Faculty of Pharmaceutical Sciences, Tokushima University, Japan.
Haruka
H
Yoshida
Koji
K
Inui
Masaki
M
Takeuchi
Hideji
H
Tanaka
D000388:Air; D017022:Flow Injection Analysis; D007477:Ions / Q000032:analysis; D009566:Nitrates / Q000032:analysis*; D009573:Nitrites / Q000032:analysis*
D007477:Ions; D009566:Nitrates; D009573:Nitrites