Configuration for kHz plasma jet: Voltage: 18.3 ± 0.2 kV (peak-to-peak); Frequency: 24.9 kHz; Return current: 4 - 7 mA; Distance between electrodes: 20 mm; Distance from nozzle to sample: 10 mm; Reactor flush time: 20 s; Plasma exposure time: 60 s; Total feed gas flow: 2 L/min