Determination of nitrite by sequential injection analysis of electrokinetic flow analysis system

A new sequential injection analysis (SIA) method of an electrokinetic flow analysis (EKFA) system for the determination of nitrite-nitrogen is presented in this paper. The proposed system mainly consisted of an electroosmotic pump, two solenoid valves and a spectrophotometer etc. All the pump and valves were controlled by a personal computer automatically. The determination method of nitrite-nitrogen was based on the reaction among nitrite, sulfanilamide and naphthylethylenediamine to form a colored compound, which was measured at 540 nm. The linear calibration range of nitrite-nitrogen was 10–800 μg l−1. The detection limit was 1 μg l−1 (K=3, n=11). The analytical method can provide a throughput of 33 samples per h.