Simultaneous Ion Chromatographic Detection of NO₂^- and NO₃^- in Dairy Products

A simple and rapid method for determination of NO₂^- and NO₃^- by ion chromatography with conductivity detection was studied.The anions were tested on AS18(4×250 mm) anion exchange column using 32 mmol/L KOH as eluant.The flow rate of mobile phase was 1.0 mL/min.The correction coefficients were 0.9997 and 0.999 6 for NO₂^- and NO₃^- respectively.Detection limits(3S/N) were found to be 0.001 and 0.004 mg/L.Recoveries tested by the standard addition method were in the range of 90.0%～103.4%.