Application of SPE technique using a newly obtained sorbent based on silica gel covered with polyaniline to simultaneous determination of Nitrate (III) and Nitrate (V) anions in water samples

Nitrate (III) and nitrate (V) often occur together in many environmental samples; however, high concentrations of other ions, especially chloride, make difficult the correct integration of the peaks. The newly obtained sorbent, based on silica gel modified with polyaniline, was successfully used as a solid phase in SPE technique to remove the undesirable matrix effect. Commercially available bottled water samples with various contents of mineral components after purification on SPE column were determined using an ion chromatograph DX-500 IC (Dionex USA) with a conductometric detector. As eluent, aqueous solution containing 3.5 mM (0.37 g/L) of Na2CO3 and 1 mM (0.084 g/L) of NaHCO3 was used. Amounts of anions in all investigated samples of water ranged from 1.71 to 22.33 mg/L for nitrate (V) and 0.04-0.10 mg/L for nitrate (III). These values were within Polish standards.