Abstract: This paper presents a method to detect nitrate and nitrite simultaneously in fruits, vegetables and meat products using high performance capillary electrophoresis (HPCE). We focused on optimizing the detection conditions and eliminating the interfering ions. The separation was carried out in a capillary column with an internal diameter (ID) and an effective length of 30 cm (total length = 40 cm) and the analytes were detected by capillary zone electrophoresis-direct UV detection at 214 nm. The effects of buffer pH and concentration, the electroosmotic flow modifier cetyl trimethyl ammonium bromide (CTAB), elimination of chloride ion interference and separation voltage on separation efficiency were investigated. The method was validated in terms of recovery, linearity, limit of detection (LOD) and precision. Results showed that NO3- and NO2- at concentrations below 500 mmol/L were separated well in 6 min. The recoveries of this method were in the range of 81.82%–100.91%, and it showed a wide linear range with a correlation coefficient above 0.99. The LODs for nitrate and nitrite were 0.69 and 0.50 μg/mL, respectively, and the precision (expressed as relative standard deviation) was less than 3.2% for both salts. This method proved to simple, fast, accurate and environmental friendly and would provide a scientific basis for rapid monitoring of nitrate and nitrite residues in fruits, vegetables and meat products.

Key words: capillary electrophoresis, fruits, vegetables and meat products, nitrate, nitrite, Cl- interference