NNitrosodimethylamine

NDMA, or N-nitrosodimethylamine, is a chemical compound in the nitrosamine family. It has the formula C2H6N2O and is encountered as a contaminant in environmental sources and in some pharmaceutical products. It is a volatile, colorless liquid at room temperature with a faint odor and is soluble in water and organic solvents.

NDMA forms when secondary amines such as dimethylamine react with nitrosating agents like nitrites under acidic conditions. This can occur during food processing, for example in meat curing or high-temperature cooking, in water treatment as a byproduct of disinfection or nitrosation, and during pharmaceutical manufacturing. It is also present in tobacco smoke.

NDMA is a potent carcinogen in laboratory animals and is classified by the International Agency for Research on Cancer as a Group 2A probable carcinogen to humans. Human data are limited, but long-term exposure is a concern and risk depends on dose and duration. Primary exposure is typically through ingestion of contaminated water or food; inhalation and dermal exposure can also occur.

Regulators treat NDMA as a contaminant of concern in drinking water and foods, with very low permissible levels in many jurisdictions. Water treatment approaches to reduce NDMA include activated carbon and advanced oxidation processes. In pharmaceutical manufacturing, controls aim to minimize formation, and NDMA contamination has led to recalls of certain medicines.

Analytical detection commonly relies on gas or liquid chromatography with mass spectrometric detection, often after sample concentration and cleanup.