Determination of nitrites and nitrates in plasma-activated deionized water by microchip capillary electrophoresis

In this work, we present the application of a fast and sensitive microanalytical method, microchip capillary electrophoresis (MCE), for the determination of NO(2)(-)and NO(3)(-)ions in deionized water treated by atmospheric pressure plasma jet (APPJ). The MCE technique consisted of an online combination of isotachophoresis with zone electrophoresis, both performed on the microchip. The argon plasma has been characterized by optical emission spectroscopy (OES) and Fourier transform infrared spectroscopy (FTIR). OES confirmed the presence of argon excited species (Ar I) emission (4p -> 4s) lines, N(2)emission bands (second positive system C-3 pi(u) -> B-3 pi(g)), and OH band (A(2) n-ary sumation (+) -> X-2 pi Delta v= 0), as well as the presence of NO and excited NO2. The presence of NO(2)molecules was also confirmed by FTIR absorption spectroscopy. The performance of the developed MCE method was evaluated for linearity, limit of detection, limit of quantitation, precision, and accuracy, and the concentration of NO(2)(-)and NO(3)(-)in the water as a function of the water treatment time was monitored.