Detection of nitroxyl (HNO) by membrane inlet mass spectrometry.

Membrane inlet (or introduction) mass spectrometry (MIMS) was used to detect nitroxyl (HNO) in aqueous solution for the first time. The common HNO donors Angeli's salt (AS) and Piloty's acid (PA), along with a newly developed donor, 2-bromo-N-hydroxybenzenesulfonamide (2-bromo-Piloty's acid, 2BrPA), were examined by this technique. MIMS experiments revealed that under physiological conditions 2BrPA is an essentially pure HNO donor, but AS produces a small amount of nitric oxide (NO). In addition, MIMS experiments also confirmed that PA is susceptible to oxidation and NO production, but that 2BrPA is not as prone to oxidation.