N-nitrosodimethylamine in domestic beer in China.

Samples of domestic (Chinese) beer were analysed for N-nitrosamines using gas chromatography--high resolution mass spectrometry with a peak-matching technique. Of 26 samples tested, 20 (77%) were found to be contaminated with N-nitrosodimethylamine (NDMA)L. The mean content of these samples was 2.7 micrograms/litre, without correction for recovery of NDMA from beer (74% with a coefficient of variance of 18%). The remaining six samples contained less than 0.5 micrograms/litre, the lower limit of detection.