The aim of this study was to determine the presence of para-chloroaniline  (PCA) obtained by the mixture of 5,25% sodium hypochlorite (NaOCl) and 2% chlorhexidine (CHX), evaluated by nuclear magnetic resonance spectroscopy (NMR-H-1) at 600MHz. Initially a  commercial sample of 98% PCA (group 1: GPCA) was analyzed by NMRH-1 combining it with dimethylsulfoxide perdeuterated as solvent, in order to obtain the basal spectra.  Ten samples were then prepared by combining equal amounts of  5,25%NaOCl and 2%CHX (group 2:GHC) (PROPORTION 1:1 v/v) by manual stirring. Each sample was then spinned for 10 minutes at 25Cº, in order to eliminate the supernatant and to obtain the precipitate, which was prepared at dry vacuum to finally isolate the solid precipitate. The precipitate was again dissolved in d6-DMSO to perform the NMR.H-1 analysis. Commercial PCA showed a distinctive spectra, with  a characteristic double sign at 7.02-7.03 ppm and 6.58-6.59 ppm. Experimental samples lack of this distinctive  spectra, instead, they all showed a complex combination of signs, which none correspond to pure PCA.