Simultaneous Determination of Nitrate, Nitrite and Bromate by Capillary Zone Electrophoresis in Tea Infusions Grown in the Black Sea Region of Turkey

Abstract

A quick method for the simultaneous determination of nitrate, nitrite and bromate ions in tea infusions using capillary zone electrophoresis was developed. A three-factor full factorial design was applied for the determination of optimal conditions. Prior to the full factorial analysis, a number of experiments were conducted. A 50 mM phosphate buffer solution with pH 3.5 was selected. A capillary temperature of 40 degrees C, -20 kV applied voltage, 61.5 cm total capillary length (53.5 cm effective length) with 50 mu m i.d., and 50 mbar injection pressure for 30 s were used. The limits of detection for nitrate, nitrite, and bromate were 0.60, 0.99, and 2.14 mg/L, respectively. The anions could be detected by the method with good resolution within 7 min with average spike recovery ranging between 91.6 and 105.5% (n = 3).