Benzidine photodegradation: a mass spectrometry and UV spectroscopy combined study

Abstract

The benzidine photodegradation process was studied using UV/Vis spectroscopy and electrospray ionization mass spectrometry (ESI-MS) combined with collision-induced dissociation (CID) and tandem mass spectrometry (MS/MS). Mass spectrometry was used to characterize benzidine and to identify and characterize possible degradation products and intermediates. The MS data showed that benzidine is quite persistent in aqueous medium. Moreover, the MS analysis enabled us to propose the following three degradation products/intermediates: 4 0 -nitro-4-biphenylamine, tetrahydroxybiphenyl and 4,4 0 -dinitrobiphenyl. For the benzidine molecular ion and protonated molecule and for the protonated molecules of the degradation products/intermediates detected, fragmentation patterns are proposed based on CID and MS/MS data. For the photodegradation process different catalysts were used, namely the commercial TiO 2 Degussa P25, and the laboratory-prepared ZnO, TiO 2 anatase and a titanium-zinc oxide with a perovskite type structure. Comparison of the different catalysts showed that degradation was favoured with the commercial TiO 2 . Nevertheless, the other catalysts appear to be promising and economic alternatives for potential future remediation studies.

Degradation of food dyes by zero-valent metals exposed to ultrasonic irradiation in water medium: optimization and electrospray ionization mass spectrometry monitoring

“…30 Recent examples have shown that ESI-MS, in conjunction with ESI-MS/MS, can be successfully applied to monitor a number of processes, including the environmentally-relevant ones, furnishing novel and significant information about them. [31][32][33][34][35][36][37][38][39][40][41] In this work, ESI(-)-MS (electrospray ionization mass spectrometry in the negative ion mode), in conjunction with ultraviolet-visible spectrophotometry (UV-Vis) and total organic carbon (TOC) techniques, were employed to monitor the reductive degradation of four prototype food dyes: Amaranth (1), Sunset Yellow (2), Red 40 (3) and Brilliant Blue (4) (Figure 1). The reactions were Figure 1.…”

Ozonation of ethinylestradiol in aqueous-methanolic solution: direct monitoring by electrospray ionization mass spectrometry

“…[27][28][29] Electrospray ionization mass spectrometry (ESI-MS), because of its appealing and unique attributes, has rapidly becoming an alternative approach suitably employed to a direct monitoring of a increasing number of relevant environmental processes. [30][31][32][33][34][35][36][37][38][39][40] In these inquiries, the information provided by the MS (the m/z values of the ionic species) and MS/MS data (the fragmentation profiles of a given mass-selected ion) are meticulously evaluated aiming to propose chemical structures of products (and in some cases transient intermediates) likely formed in the condensed phase. 41 The identification of by-products arising from oxidative treatments, which can be more risky than the own precursors indeed, 42 is an important point that must be taken into consideration for the evaluation of the overall performance of a given process.…”

Combination of advanced oxidation processes and biological treatment for the removal of benzidine‐derived dyes

“…The color perception is due the maximum wavelenght at which the chromophore is excited [16]. nm, 281 nm for benzidine, 254 nm and 222 nm for naphtalene and bencene ring, respectively [17]. nm, 281 nm for benzidine, 254 nm and 222 nm for naphtalene and bencene ring, respectively [17].…”