The influence of the experimental variables (frequency, amplitude, pulse height, deposition potential and deposition time) which were involved in the SWASV determination of paraquat was investigated (Fig. 2). The effect of frequency (υ) on the current intensity (Ip) of paraquat on Chit-CPE was evaluated in the range from 5 to 50 Hz. The signal increased up to 50 Hz. Nevertheless, the maximum acceptable value to be in a SWASV program, which is 50 Hz and which corresponds to 0.02 s of duration for each step, was used in the present experimental study. The amplitude influence was investigated in the range from 1 to 100 mV.