A rapid gas chromatographic procedure with an analysis time of 5 min was developed for the determination of environmental nicotine collected on sorbent tubes containing XAD-4 resin. In validating this procedure, severe temporal losses of nicotine were observed for solutions in glass sample vials waiting in a queue in an autosampler tray for analysis. These losses were traced to adsorptive interactions of nicotine with the glass surface of the vials. The use of N-ethylnornicotine as the internal standard or the addition of triethylamine to all solutions were both successful in producing constant response ratios of nicotine to internal standard. Owing to the limited availability and expense of N-ethylnornicotine, our current procedure calls for the addition of triethylamine to all nicotine solutions at the 0.01% V/V level and the use of quinoline as internal standard.

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Two gas chromatographicmass spectrometric methods, one based on chemical derivatisation and the other on analytical pyrolysis, were employed for the characterisation of a diverse group of bacteria. The muramic acid content of some Gram-positive and Gram-negative bacteria (including legionellae) was determined by aldononitrile acetate derivativisation and capillary GC -MS analysis. Muramic acid levels were generally higher in Gram-positive than in Gram-negative bacteria. When applied to the same set of bacteria, pyrolysis GC -MS and non-linear mapping were also able to distinguish Gram-negative from Gram-positive bacteria. The potential of GC -MS techniques for the direct chemical characterisation of bacteria is discussed.