A Karsa-led study, in collaboration with the University of Helsinki and Tampere University, demonstrates a breakthrough in chemical ionization mass spectrometry (CIMS). The team introduced uronium chemical ionization (CI), generated by X-ray desorption of solid urea, as a safe and sustainable reagent ion source.
Unlike conventional approaches that rely on reactive or toxic gases, this method uses only solid-state precursors, eliminating handling risks and ensuring long-term stability. The uronium source operates continuously for months without maintenance, a significant advantage for both laboratory and field deployments.
One of the study’s highlights is shown in Figure 6a. Oxidation products of α-pinene were detected using three complementary solid-state reagent ions — uronium, nitrate, and fluoranthenium. Together, these reagents provided broad coverage across compound classes, from highly oxygenated products to basic and moderately oxygenated molecules.
This demonstrates, for the first time, that comprehensive trace-gas detection can be achieved entirely with solid precursors, opening the door to simpler, safer, and more sustainable mass spectrometry systems.
Uronium CI complements existing ionization schemes and is especially powerful for detecting bases such as amines and ammonia, which are critical to atmospheric new-particle formation but notoriously difficult to measure. Its stability, sensitivity, and sustainability make it a promising tool for:
This work is published open access in Analytical Chemistry.
