Regioselective chloride ion loss from chlorine-37 enriched polychlorodibenzofurans by negative-ion mass spectrometry

Regiospecific chlorine-37 enriched dichloro-, trichloro-, tetrachloro-, and pentachlorodibenzofuran isomers were investigated under electron capture negative-ion mass spectrometry (ECNIMS) conditions. The relative chloride ion loss from the enriched positions was determined from the chloride-37 and chloride-35 ion abundances after correcting for the isotopic enrichment. Regioselective chloride anion losses were observed with the carbon 3-chlorine bond (beta-chlorine) generally found to be the most labile. The carbon-chlorine bond cleavages can be loosely associated with calculated carbon-chlorine bond residual charges.