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

(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.