Evidence for a mechanism that involves secondary electron capture in the liquid secondary ionization mass spectrometry beam-induced dehalogenation of organic compounds

Abstract

The effect of the analyte electron affinity on the liquid secondary ionization mass spectrometry beam-induced dehalogenation of simple bromoaromatic compounds in a glycerol matrix was investigated. The results show a definite trend of decreasing dehalogenation with increasing analyte electron affinity. At high analyte electron affinity (≥ 1.0 eV), no dehalogenation was observed. These results are consistent with electrochemical and pulse radiolysis studies where one electron reduction was shown to be responsible for dehalogenation. A chloroaromatic compound with high electron affinity, 4-(4-chloro-benzoyl)pyridine, exhibited reduction by hydrogen addition but not dehalogenation. The radiation chemistry of alcohols was used to elaborate a scheme of the reactive species generated in the glycerol matrix by kiloelectronvolt particle bombardment. The possible role of those species in reduction processes such as dehalogenation was evaluated. The observation that dehalogenation decreases with analyte electron affinity is mechanistically consistent with the proposition that secondary electron production is an intrinsic part of the bombardment process.

Determination of β2-Agonists in Porcine Urine by Molecularly Imprinted Solid Phase Extraction Followed Ultra-Performance Liquid Chromatography–Tandem Mass Spectrometry Detection

“…Matrix effect (ME) is often observed in LC-MS=MS analysis for complicated sample including urine samples, which could enhance or suppress the signal response of target analytes (Theberge and Bertrand 1996;Jones et al 2007). SPE with mixed phase mode sorbent was often used to extract and clean the b 2 -agonists in a complicated sample matrix to decrease the sample matrix effect (Ramos et al 2000;Haasnoot et al 1998;Nielen et al 2008) due to its association of apolar and ionic mechanisms (Chen et al 1992).…”

Deiodination of iodinated aromatic compounds with electrospray ionization mass spectrometry

“…Additional reports of dehalogenation with CI have also appeared . Dehalogenation has also been observed with 252 Cf plasma desorption, thermospray, fast‐atom bombardment (FAB), and liquid secondary ionization mass spectrometry (FAB‐LSIMS) …”

“…[13] Dehalogenation has also been observed with 252 Cf plasma desorption, [14] thermospray, [15] fast-atom bombardment (FAB), [16,17] and liquid secondary ionization mass spectrometry (FAB-LSIMS). [18][19][20] For determination of ICM in environmental samples, liquid chromatography (LC)/MS has been the preferred method for sensitive determination of these compounds. Electrospray ionization (ESI)-MS, usually operated in the positive-ion mode, has been the method of choice.…”