James F. Barbour

N-Nitrosodimethylamine in beer

Abstract Commercially-available bottled and canned beer was analysed for volatile nitrosamines using a chemiluminescence detector. N -Nitrosodimethylamine, the only volatile nitrosamine found, was detected in 23 of 25 samples analysed. The range of levels was 0–14 ppb (μg/kg) while the mean was 5·9 ppb. The identity of N -nitrosodimethylamine was confirmed by mass spectrometry.

N-nitrosodimethylamine in Spanish beers

A survey of 21 beers produced in Spain during 1994 was conducted to assess contamination with volatile N-nitrosamines. N-Nitrosodimethylamine (NDMA), the only volatile N-nitrosamine detected, was found in 52% of Spanish beers at or above the detection level (0.05 microgram/kg). The mean NDMA level for all samples was 0.11 microgram/kg, and the range was from not detected to 0.55 microgram/kg. No differences in the NDMA content were observed between the different beer types. Individual daily intake of NDMA may reach up to 0.021 microgram/person/day for Spanish people.

N-Nitrosodimethylamine in dried dairy products

Abstract Commercially available non-fat dried milk and dried buttermilk were analysed for volatile nitrosamines using a chemiluminescence detector. N-Nitrosodimethylamine, the only volatile nitrosamine that could be confirmed to be present by mass spectrometry, was detected in eight out of nine samples analysed. The range of levels was 0 to 4·5 ppb (μg/kg) while the mean was 1·9 ppb. The identity of N-nitrosodimethylamine was confirmed by mass spectrometry in five of the samples.

Isolation and characterization of products from the nitrosation of the alkaloid gramine

The nitrosation of gramine, a tertiary amine alkaloid present in barley malt, was carried out by reaction with sodium nitrite in buffered acetic acid (pH 3.4) for 1 hr at room temperature. Two major non-volatile products of the nitrosation reaction were isolated by preparative HPLC and characterized as indole-3-carboxylic acid and N1-nitroso-3-nitromethylindole. This interpretation was supported by spectral data. The nature of these products indicated that gramine did not undergo nitrosation by the expected mechanism of nitrosative dealkylation. A mechanism is offered to explain the labile nature of the dimethylamino group found in gramine.