Detection of nitroxyl (HNO) by membrane inlet mass spectrometry

Oxidation of N-hydroxy-l-arginine by hypochlorous acid to form nitroxyl (HNO)

“…It has proven useful for the study of NO in aqueous and blood solutions [51,[55][56][57]. Recently, we have reported its utility for the study of HNO in aqueous solutions [13]. Although the low intensity of the parent m/z 31 MIMS signal for HNO currently precludes its unambiguous detection, its EI fragmentation product can be detected at m/z 30 (NO + [22].…”

“…In previous work, to rule out the possibility that the observed m/z 30 MIMS signal is not due to the parent ion of NO (rather than HNO fragmentation) we have used selective chemical traps for HNO (e.g., thiols under anaerobic conditions or phosphines under anaerobic or aerobic conditions) [13]. Unfortunately, we were unable to use the thiols or phosphines used previously because they react readily with HOCl.…”

“…Given its inherent reactivity, HNO has proven difficult to detect directly. Recent methods have been developed for HNO detection [8][9][10][11][12][13][14][15]; however, due to a lack of sensitivity and/or selectivity, HNO has not yet been observed in vivo.…”

Controlled release of HNO from chemical donors for biological applications

“…Bromo-Piloty's acid is a derivative of Piloty's acid, and is reported to produce HNO, but not NO, by spontaneous decomposition under physiological conditions, as determined by membrane-inlet mass spectrometry [33]. IPA-NO is a NONOate-type NO donor, but it also produces HNO [14], so it can be considered as a "dual" donor for NO and HNO.…”

Physical and structural properties of [Cu(BOT1)Cl]Cl, a fluorescent imaging probe for HNO

“…They include HNO trapping techniques using metalloporphyrins [9], thiols [6], and phosphines [10]. Membrane inlet mass spectrometry (MIMS) has been used to measure submicromolar concentrations of HNO in aqueous media [11]. A number of fluorescent detection methods have also been implemented, including a metallopolymer approach [12] as well as a fluorescently labeled nitroxide radical probe [13].…”