DART-MS Negative Ionization of Vinylidene Fluoride (VDF) Telomers Reveals the Importance of [M + HCO₃]⁻ and [M + HCO₄]⁻ Association.

RATIONALE: Direct analysis in real time (DART) is an open-air ion source that does not require a sample preparation step. Only a few studies have focused on the negative-ion formation processes for low-polarity molecules. In this study, an ω-iodo oligo (vinylidene fluoride) telomer of known composition was investigated to elucidate the involved DART ionization mechanisms. METHODS: A DART ionization source was coupled to a Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS), whose high m/z measurement accuracy enabled the unambiguous assignment of molecular formulas to the detected ions. Tandem MS experiments were performed to confirm these assignments. Data interpretation and visualization were carried out using Kendrick plots. RESULTS: were emphasized. These results demonstrated the need to reinterpret data obtained in a previous DART-MS study on PVDF samples with unknown end groups. CONCLUSIONS: adducts were found to play a significant role in the ionization of iodinated PVDF.