Analytical Sciences

Contamination, Decomposition, and Formation of N-Nitrosodimethylamine in Water Samples at the ng/L Level of Determination

Hitoshi KODAMATANI, Kenta SUGIHARA, Taketo TANISUE, Ryo KANZAKI, and Takashi TOMIYASU

Division of Earth and Environmental Science, Graduate School of Science and Engineering, Kagoshima University, 1-21-35 Korimoto, Kagoshima 890-0065, Japan

An ultra-sensitive analytical system that can determine the concentration of N-nitrosamines at the ng/L level without preconcentration was used to investigate the contamination, decomposition, and formation of N-nitrosodimethylamine (NDMA) and other N-nitrosamines in water samples during general analytical procedures. A preliminary experiment was performed to estimate the NDMA concentrations in ambient air. Since the air samples contained NDMA at concentrations in the range of 2.0 – 10.7 ng/m³, ambient air was identified as the source of NDMA contamination in water samples. We directly confirmed that the concentration of aqueous 10-ng/L NDMA samples stored in clear glass bottles decreased upon exposure to sunlight. Thus, to maintain the N-nitrosamine concentration, such samples must always be protected from sunlight during sampling. The existence of N-nitrosamines in experimental reagents, such as ranitidine and sodium hypochlorite solutions, was also confirmed, as was the formation of NDMA on an activated carbon solid-phase extraction cartridge.

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