Simultaneous speciation analysis of inorganic nitrogen with the use of ion chromatography in highly salinated...

We present the development of a method for the simultaneous determination of inorganic nitrogen species in oxidized (NO2 (-) , NO3 (-) ) and reduced (NH4 (+) ) forms using ion chromatography with diode-array detection (205, 208, and 425 nm, respectively). The oxidized forms were determined directly after the separation in the anion exchanger, while the reduced form was determined in the column hold-up time after derivatization with the Nessler reagent. The use of an appropriate modifier (Seignette reagent) and mobile phase (NaCl) enabled the determination of inorganic nitrogen species in highly salinated environmental samples (water, sediments). Moreover, low detection limits were obtained of 0.04 mg/L for NH4 (+) and 0.006 and 0.005 mg/L for NO2 (-) and NO3 (-) , respectively. The analysis of environmental samples indicated NH4 (+) contents of up to 1161 ± 47 mg/kg and NO3 (-) of up to 148 ± 6 mg/kg for sediment samples, as well as the NH4 (+) concentrations of up to 0.98 ± 0.10 mg/L, NO2 (-) of up to 24 ± 1 mg/L and NO3 (-) of up to 20 ± 1 mg/L for water samples.