N-Nitrosomethylethylamine (NMEA) and N-nitrosodiethylamine (NDEA), two new potential disinfection byproducts; formation during water disinfection with chlorine

Abstract

(NMEA) and N-nitrosodiethylamine (NDEA) are highly mutagenic compounds that are
 suspected of carcinogenic activity to the human body.
 The aim of the paper is the evaluation of the possibility of N-nitrosomethylethylamine and
 N-nitrosodiethylamine formation as a result of the reaction of methylethylamine (MEA) or
 diethylamine (DEA) respectively with chlorine in the presence of ammonia ions. The
 optimal conditions of NMEA and NDEA formation were identified as a result of an
 experiment carried out using different molar ratios of the substrates of reaction.
 As the primary aim of the research was the evaluation of the possibility of NMEA and
 NDEA formation as a result of the reaction of methylethylamine or diethylamine
 respectively with chlorine in the presence of ammonia ions, a successful result obtained
 after GC-LRMS analysis was fundamental to the further research. Analytes from postreaction
 mixtures were concentrated, according to the modified procedure proposed by
 Mitch et al., by means of liquid/liquid extraction with the usage of methylene chloride. The
 N-nitrosomethylethylamine and N-nitrosodiethylamine were found in the analyzed
 extracts of post-reaction mixtures. Apart from NMEA and NDEA identification, the
 verification of other products with the usage of mass spectra library was also undertaken.
 The results indicated that the changes in the relative ratio of the substrates influence the
 concentration of NMEA and NDEA.
 The obtained results revealed that NMEA and NDEA are only two of the many products
 of the reaction taking place in the aqueous solution, which contained methylethylamine or
 diethylamine and ammonia ions, and was disinfected with chlorine. The other identified
 products are: ethyl(methyl)formamide and 3-ethyl(methyl)aminopropanenitrile. Therefore
 N-nitrosomethylethylamine and N-nitrosodiethylamine can be treated as new disinfection
 by-products similar to THMs, HAAs, MX or NDMA.