Electron capture negative ion (ECNI) mass spectrometry of complex mixtures of chlorinated decanes and dodecanes: An approach to ECNI mass spectra of chlorinated paraffins in technical mixtures

The electron capture negative ion (ECNI) mass spectra of two complex mixtures of polychlorinated decanes (PCDe) and polychlorinated dodecanes (PCDo) are presented. The number of isomers in these mixtures is still high but is drastically reduced in comparison to technical products of chlorinated paraffins (CP), due to their fixed chain length. As a result, the mass spectra are simplified and less complex. Different modes of negative ion formation were observed in the spectra of the PCDe and PCDo. [M+Cl]^– adduct ions were the most abundant ions in the spectra of lower chlorinated molecules. Higher chlorinated isomers formed prominently [M-Cl]^– and [M-HCl]^– fragments besides [M+Cl]^–. Possible consequences for the determination of chlorinated paraffins by ECNI-MS that result from the variation in ion formation are addressed.