Reproducible pyrolysis-gas chromatography of micro-organisms with solid stationary phases and isothermal oven temperatures.

Eight solid stationary phases were examined for their suitability for pyrolysis-gas chromatography (Py-GC) of micro-organisms. With temperature programming these phases offered little advantage over the traditional liquid phase Carbowax 20M, but at an isothermal analysis temperature of 100 degrees C their use solved many technical problems. Pyrograms were produced containing small numbers of baseline-resolved peaks which eluted within 8 to 25 min. Four to six specimens per hour could be examined with two pyrolysers attached to one chromatograph oven. When a control organism was used to derive normalized results, pyrograms were reproducible with a second column and a second pyrolyser, suggesting that inter-laboratory reproducibility may be possible. Five different bacterial genera were well discriminated and some differentiation was achieved between different isolates of Streptococcus mutans, but similarity between pyrograms with was unrelated to orthodox taxonomic grouping. The best discrimination was achieved with Chromosorb 104, followed by Chromosorb 101 and Tenax-GC. With solid phases and isothermal oven temperatures Py-GC is a promising technique for microbial identification.