A mechanism study of positive ionization processes in flowing atmospheric-pressure afterglow (FAPA) ambient ion source with controlled plasma and ambient conditions

Although plasma based ambient desorption/ionization (ADI) sources have been widely used for direct analysis of complex samples, mass spectrometric imaging, high throughput screening etc., the ionization mechanism of plasma-based ADI remains a mystery by now. In this report, a targeted study was conducted aiming at a better understanding of the ionization processes of plasma-based ambient desorption ionization source. As a representative of...