Author(s)

Miriam Muñoz Arratia¹, María de Lourdes Lanzagorta Rebollo¹, Francisco Javier Pérez Flores², Rodolfo García Contreras³, José Luis Molinari Soriano⁴, Ana María Fernández Presas^1,3*

¹Instituto de Estudios Avanzados en Odontología “Yury Kutler”, Mexico City, Mexico.
²Instituto de Química, Universidad Nacional Autónoma de México, Mexico City, Mexico.
³Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico.
⁴Departamento de Bioquímica y Biología Estructural, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México City, Mexico.

5.1% of sodium hypochlorite (NaOCl) mixed with 2% of chlorhexidine (CHX) forms a brown precipitate that corresponds to para-chloroaniline (PCA), whether PCA is formed after the combination of NaOCl, CHX, and ethylenediaminetetraacetic acid (EDTA) by means of electron impact (high resolution and interlaced scanning) and ionization by fast atom bombardment (FAB), was analyzed. The brown precipitate, showed signals 127 and 153 Da, corresponding to p-chloroaniline and p-chlorophenyl isocyanate, respectively. These results were analyzed and compared with signals from the interlaced scanning program and confirmed with high resolution mass spectrometry analysis and compared with the NIST database. The mass spectra of this precipitated after different days confirmed the evolution of byproducts with the presence of a peak m/z = 127, due to the decrease of the fragment m/z = 153, which disappeared after 180 days. A blue and a white precipitate were observed by the addition of CHX (2%) with or without polyethylene glycol, respectively, EDTA (17%) and NaOCl (5.1%) precipitates contain chlorhexidine (m/z = 505), but no PCA was detected. We confirmed that PCA is not formed directly as a byproduct of CHX oxidation, but through the formation of the para-chlorophenyl isocyanate intermediate, which degrades slowly to PCA.

Chlorhexidine, Para-Chloroaniline, Para-Chlorophenyl Isocyanate, EDTA, Sodium Hypochlorite

Arratia, M. , Rebollo, M. , Flores, F. , Contreras, R. , Soriano, J. and Presas, A. (2019) Detection of Para-Chloroaniline Resulting from the Interaction between Sodium Hypochlorite and Chlorhexidine Analyzed by Mass Spectrometry. American Journal of Analytical Chemistry, 10, 629-640. doi: 10.4236/ajac.2019.1012044.