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 °C, −20 kV applied voltage, 61.5 cm total capillary length (53.5 cm effective length) with 50 μm 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).

Application of Capillary Electrophoresis to the Analysis of Bioactive Compounds in Herbal Raw Materials

“…Moreover, this techniques was used to determinate organic acids in sage [ 48 ], Pterocephalus hookeri [ 49 ] and chamomile, linden, and mint [ 50 ]. Moreover, CE-UV was used to identify alkaloids in tea [ 51 ], Sophora tonkinensis [ 52 ], Chelidonium majus [ 53 ], Cortex Phellodendri Chinensis [ 54 ], Nelumbo nucifera [ 55 ], anthraquinones in slimming tea [ 56 ], coumarins in Cacalia Tangutica [ 57 ], and nitrate, nitrite, and bromate in tea infusions [ 30 ].…”

“…In turn, the undeniable advantages of CE include high efficiency, low consumption of reagents, small sample volumes, short analysis times, and the possibility of measuring in a wide range of pH [ 27 , 28 ]. However, an extremely important factor that determines the choice of using CE is that it enables the simultaneous determination of cations and anions [ 28 , 29 , 30 ]. Due to the use of capillaries with very small diameters, the volume of the introduced sample may reach several nL.…”