Terry A. Gough

Volatile nitrosamines in salt-preserved fish before and after cooking.

Abstract Uncooked, steamed and fried samples of salted fish were analysed for volatile nitrosamines by gas chromatography with detection by chemiluminescence and some were also analysed by combined gas chromatography and high-resolution mass spectrometry. N-Nitrosodimethylamine (NDMA) was detected in all of the samples that were analysed, whether cooked or uncooked. It was also detected in the aqueous phases derived from the steamed samples, and in the oil from frying in two out of three batches. In one of these the NDMA level was the highest encountered in the present study. N-Nitrosodiethylamine (NDEA), on the other hand, was detected in more batches of the steamed fish than of the uncooked or fried fish. It was not detected in the oil used for frying. In half of the steamed batches NDEA was detected only in the aqueous phases and in one batch it was detected only in the steamed fish. N-Nitrosodi-n-propylamine (NDPA) was detected in both the steamed and fried samples and N-nitrosodi-n-butylamine (NDBA) in only the fried samples. Neither was detected in the uncooked samples. N-Nitrosomorpholine (NMOR) occurred in the uncooked samples. Salted fish heads are sometimes used by southern Chinese to prepare soup. NDMA and NDEA occurred in both uncooked fish heads and in the soups prepared from them. The results confirm that certain nitrosamines are formed from precursors during cooking. A possible relationship between salted fish and certain cancers that are particularly prevalent among southern Chinese populations is discussed.

Illicitly imported heroin products: some physical and chemical features indicative of their origin.

Samples taken from over 200 seizures of imported illicit heroin preparations of known geographical origin have been examined by gas liquid chromatography (GLC). The chromatographic characteristics were considered in conjunction with the physical appearance of the materials and it was found possible in many instances to discriminate between samples of different origin. Thus by carrying out GLC and HPLC and a visual inspection on a sample of unknown provenance, it may be possible to give an opinion as to its geographical origin.

Illicitly Imported Heroin Products: Some Physical and Chemical Features Indicative of Their Origin. Part II

Samples taken from seizures of imported illicit heroin preparations of known geographical origin have been examined. The typology developed in a previous survey of illicit heroin products is applicable to virtually all the samples studied in this work. On the basis of these observations it is possible to give an opinion as to the origin of some samples of illicit heroin of unknown provenance. The observation in the previous survey that unrelated samples of illicit heroin possess unique chemical profiles has been confirmed by the present results.

Volatile nitrosamines from ion-exchange resins.

Abstract Deionized water was analysed for volatile nitrosamines, and was found to contain minute amounts of these compounds. Ion-exchange resins, including those used in water deionization plants, were examined and the anion exchangers were identified as the source of the nitrosamines. Gas chromatography combined with chemiluminescence and mass spectrometry was used to identify and quantify the nitrosamines. The relevance of these observations to food analysis is discussed.

The rapid determination of cocaine and other local anesthetics using field tests and chromatography.

The application of field tests and chromatography to the detection of cocaine and some other local anesthetics that have been used to adulterate cocaine is described. Initial screening of samples by field tests, followed by concurrent TLC and GC, enables rapid identification of these compounds to be achieved. In particular, the use of flow-programmed GC shortens the time for analysis compared with conventional GC and requires negligible equilibration time between consecutive runs [12]. The method gives reliable quantitative data.