Determination of N-nitrosomethylaniline and methylaniline in the gas phase

Determination of 4-(Methylnitrosamino)-1-(3-Pyridyl)-1-Butanone (NNK) arising from tobacco smoke in airborne particulate matter

The most important tobacco-specific nitrosamine found in cigarette smoke and formed in ageing smoke after cigarettes are extinguished is 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). It is formed from nitrosation of nicotine, under particular conditions both in indoor and outdoor environments. NNK has been classified as a potent lung carcinogen which is expected to be found primarily in the particle-phase and to be stable in particulate matter. In this study tests have been carried out to show that a bisulfate-treated filter is more efficient than an untreated filter to collect both nicotine and NNK, and that the latter is stable in outdoor particulate matter. To characterize NNK in the outdoor environment, airborne samples were collected from 11 cities in USA, UK, Hong Kong and Malta with characteristics varying from low to high population densities and from urban to suburban to rural, and with desert characteristics and distinct climates. It has been shown that airborne particle + gas phase nicotine and particle-phase NNK behave in a linearly correlated manner. A seasonal analysis was carried out on a subset of data available from five sites in California, where the load of NNK in PM10 is driven by long range transport of the air masses passing over densely populated cities. In the winter season, the load of NNK in PM is higher than in summer in a statistically significant manner. The contamination of PM with NNK shows variability, but is observed at all sites. This paper highlights the potential risk of chronic exposure to NNK in particulate matter by the inhalation pathway.

Effect of catechin liposomes on the nitrosamines and quality of traditional Chinese bacon

Liposomes are capable of increasing the nitrosamine inhibition of catechins in traditional Chinese bacon after long-term storage.

Seasonal variations of particle-associated nitrosamines by gas chromatography-mass spectrometry in the atmospheric environment of Zonguldak, Turkey

A gas chromatography-mass spectrometry method has been proposed for the determination of low-level mutagenic and carcinogenic nitrosamines in particulate matter. The method includes the collection of particulate matters (PM2.5 and PM10) using a dichotomous Partisol 2025 sampler and extraction of the compounds from aqueous solution with dichloromethane/2-propanol after sonication with a slightly basic water solution prior to their GC-MS analysis in electron impact mode. The obtained recoveries of nitrosamines ranged from 92.4 to 99.2 %, and the precision of this method, as indicated by the relative standard deviations, was within the range of 0.95-2.46 %. The detection limits obtained from calculations using the GC-MS results based on S/N=3 were found within the range from 4 to 22 pg/m(3). The predominant nitrosamines determined in particulate matter were N-nitrosodimethylamine, N-nitrosodiethylamine, N-nitrosodibutylamine and N-nitrosomorpholine. Furthermore, N-mono- and dinitrosopiperazine and N-nitrosoethylbutylamine were also determined. N-dinitrosopiperazine was detected in PM2.5 samples at the highest concentrations of up to 22.85 ng/m(3) and in PM2.5-10 samples at concentrations up to 7.60 ng/m(3) in winter, whereas it was found in PM2.5 samples up to 5.15 ng/m(3) and in PM2.5-10 samples up to 3.12 ng/m(3) in summer. The total concentrations of nitrosamines were up to 161.4 ng/m(3) in fine and 53.90 ng/m(3) in coarse fractions in winter, whereas in summer were up to 35.24 and 12.60 ng/m(3), respectively. The concentration levels of nitrosamines fluctuated significantly within a year, with higher means and peak concentrations in the winter compared to that in the summertime. The seasonal variations of particle-associated nitrosamine concentrations were investigated together with their relationships with meteorological parameters using Pearson's correlation analysis in the winter and summer periods. Analysis of variance was used to determine which concentrations of nitrosamines were statistically different from one another and, together with meteorological parameters and discriminant analysis, was used to classify the particle samples by particle size according to seasons. The classification results of the particle samples in different seasons were very satisfactory, allowing 99.5 % of cases to be correctly grouped.