title: Determination of 4-chloroaniline and its derivatives formed in the interaction of sodium hypochlorite and chlorhexidine by using gas chromatography.
abstract: BACKGROUND
  The combination of sodium hypochlorite (NaOCl) and chlorhexidine (CHX) results in the formation of a precipitate. In a previous study, we demonstrated the formation of 4-chloroaniline (PCA) in the precipitate by using x-ray photon spectroscopy (XPS) and time of flight secondary ion mass spectrometry (TOF-SIMS). The TOF-SIMS results showed a peak at 127 amu, which is characteristic of 4-chloroaniline. However, this could also be characteristic of other isomers of 4-chloroaniline such as 2-chloroaniline and 3-chloroaniline.
  
  
  OBJECTIVE
  The aim of this study was to further identify the precipitate by using gas chromatography-mass spectrometry (GC-MS).
  
  
  RESULTS
  The results showed an absence of other aniline derivatives in the precipitate. Only PCA was found.
  
  
  CONCLUSIONS
  Further investigations of the precipitate should address the bioavailability of PCA leaching out from dentin and its cytotoxicity. Until the precipitate is studied further, it would appear prudent to minimize its formation by avoiding the use of CHX together with NaOCl.
authors.affiliation: Department of Endodontics, Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada. bettina.basrani@dentistry.utoronto.ca
authors.forename: Bettina R
authors.initials: BR
authors.lastname: Basrani
authors.forename: Sheela
authors.initials: S
authors.lastname: Manek
authors.forename: Dan
authors.initials: D
authors.lastname: Mathers
authors.forename: Edward
authors.initials: E
authors.lastname: Fillery
authors.forename: Rana N S
authors.initials: RN
authors.lastname: Sodhi
mesh_terms: D000814:Aniline Compounds / Q000032:analysis*; D011232:Chemical Precipitation; D002710:Chlorhexidine / Q000737:chemistry*; D004347:Drug Interactions; D008401:Gas Chromatography-Mass Spectrometry; D012388:Root Canal Irrigants / Q000737:chemistry*; D012973:Sodium Hypochlorite / Q000737:chemistry*
chemical_list: D000814:Aniline Compounds; D012388:Root Canal Irrigants; D012973:Sodium Hypochlorite; D002710:Chlorhexidine; C004658:4-chloroaniline