N-nitrosodimethylamine formation during treatment with strong oxidants of dimethylamine containing water

Abstract

The aim of the paper is the evaluation of the possibility of NDMA formation, as a result of strong oxidants reacting with DMA. Summarized results of investigations on N-nitrosodimethylamine formation as a result of dimethylamine reactions with chlorine dioxide, ozone and hydrogen peroxide are presented. Preliminary results of experiments on NDMA formation as a result of DMA reactions with permanganate are also shown. The experiments on dimethylamine reactions with chlorine dioxide, hydrogen peroxide and permanganate were carried out at room temperature under static conditions. Ozonation experiments were carried out at room temperature in a semi-continuous mode. Water samples from all experiments described above were collected during the experiment itself and subsequently analyzed with HPLC-IE with UV-Vis detector at 230 nm. NDMA formation was also confirmed by GC-LRMS. NDMA forms as a result of chlorine dioxide, ozone, hydrogen peroxide or permanganate reactions with dimethylamine. both in the presence as well as in the absence of ammonia ions. The presence of nitrites and nitrates in a post-reaction mixture suggests that NDMA are formed as the result of DMA reactions with nitrites. Thus the mechanism of NDMA formation with these oxidants is different than that described by Mitch et al. and Choi et al. The results also showed a conversion ratio of DMA to NDMA of even up to a single percent (with relation to amines), a simultaneous decrease of NDMA formation potential with a decrease of pH, however, in the case of chlorine dioxide application, a maximum conversion ratio was observed, as well the NDMA formation potential is strongly dependent on the oxidant/DMA ratio.

Nitrosamines and water

“…The general belief that oxidation decreases nitrosamine formation potential is based on the results of two papers by Lee et al [93,94], where several NDMA suspected precursors (organic compounds with dimethylamine-or trimethylamine groups) were oxidized with relatively high doses of oxidants (ozone, chlorine dioxide, ferrate and hydroxyl radicals) and then reacted with chloramine. However, there are several reports that state that oxidation of DMA may lead to the formation of NDMA [41,95,96], particularly at a higher pH. Zhao et al [39] have also shown that raw water oxidation with chlorine dioxide or ozone may increase NDMA content in treated waters.…”

“…Chlorination and chloramination are the main sources of NDMA in wastewaters and drinking waters. However, there have been several reports of NDMA formation upon the application of other strong oxidants, such as ozone, chlorine dioxide, KMnO 4 or ferrate (VI) [16,39,41,42,[87][88][89]95,96]. In general, when oxidants are in contact with dimethylamine, part of the DMA is oxidized to nitrites and nitrates (formaldehyde and formic acids are also commonly detected).…”

Catalytic Impact of Activated Carbon on the Formation of Nitrosamines from Different Amine Precursors

“…Several studies have shown that other oxidants including ozone (O 3 ), chlorine dioxide (ClO 2 ) and permanganate (23)(24)(25)(26)(27)(28)(29) can oxidize amines to produce low levels of nitrosamines. Andrzejewski et al (24,27) linked nitrosamine formation during ozonation to the formaldehyde-catalyzed nitrosation since formaldehyde is a common product of ozonation.…”

“…Several studies have shown that other oxidants including ozone (O 3 ), chlorine dioxide (ClO 2 ) and permanganate (23)(24)(25)(26)(27)(28)(29) can oxidize amines to produce low levels of nitrosamines. Andrzejewski et al (24,27) linked nitrosamine formation during ozonation to the formaldehyde-catalyzed nitrosation since formaldehyde is a common product of ozonation. In contrast, Yang et al (30) proposed two other pathways: (i) secondary amine precursors reacting with hydroxylamine to form unsymmetrical dialkylhydrazine intermediates, which are further oxidized to their relevant nitrosamines; and (ii) a nitrosation pathway in which N 2 O 4 acts as the nitrosating reagent, to be responsible.…”

A Practical LC-MS/MS Method for the Detection of NDMA at Nanogram per Liter Concentrations in Multiple Water Matrices

“…Measurement of low concentrations of NDMA in different water matrices can be achieved by using highly sensitive and selective instrumental methods such as GC-MS/MS (Mitch and Sedlak 2002;Schmidt and Brauch 2008;Hu et al 2008;Andrzejewski and Nawrocki 2007;Planas et al 2008;Charrois et al 2007;Grebel et al 2006;Cheng et al 2006;Charrois et al 2004;Mitch et al 2003b;Taguchi et al 1994;Yoon et al 2011) and LC-MS/MS Ripolles et al 2011;Wang et al 2010;Kosaka et al 2009;Plumlee et al 2008;Krauss and Hollender 2008;Kodamatani et al 2009;Zhao et al 2006). However, the measurement of low concentrations of NDMA not only depends on the analytical detection limit of the LC or GC employed but also on the techniques (i.e., liquidliquid extraction (LLE) or solid-phase extraction (SPE)) that are used for the recovery and concentration of NDMA from the samples and for the elimination of matrix effects.…”