Volatile compounds in the blood of fire fatalities
An attempt was made to evaluate the importance of smoke and toxic gas inhalation in fires by comparing the volatile constituents in blood taken from fire fatalities with those of normal healthy and post-mortem controls. At the initial stage of the project, particular attention was given to the measurement of carbonyl compounds which represent a series of toxic and strongly irritant thermal degradation products from many polymeric materials. Three analytical methods, namely, i) gas chromatographic analysis of carbonyls after conversion to their corresponding 2,4-dinitrophenyl hydrazone derivatives, ii) direct static headspace gas chromatography, and iii) dynamic headspace gas chromatography, were compared for their applicability to the measurement of carbonyls in blood. Problems associated with binding of carbonyls to blood proteins were experienced in the first two methods which precluded their use for this application. The latter method was found to be most suitable in this respect since the bound carbonyls were released during the purging process. The method was also the most sensitive and when used in conjunction with a mass spectrometer, a detection limit in the nanogram per millilitre range was obtained. Volatiles in blood were extracted by purging the samples (1 ml) with 0.6 litre of helium and collecting the components on a small Tenax-GC column. The volatiles were then thermally desorbed and analysed by gas chromatography-mass spectrometry using a 100 m x 0.5 mm i.d. Carbowax 20M SCOT column. The sorption technique was found to extract a wide range of volatile components from blood enabling a comparison of volatile profiles to be made. Thus initially organic nitriles as well as the carbonyl compounds were quantified. Volatile components were identified by comparison of their retention indices and mass spectra with those of authentic standards. Where the latter were not available, tentative identifications were made 9n the basis of their mass spectral data only. Quantification of carbonyls and nitriles was achieved by comparing their response ratios to those from an external standard under identical conditions. During the period from August 1981 to May 1982, thirty-one blood volatile profiles were studied. These included four normal healthy controls and six post-mortem controls. In general, more complex profiles were found in fire fatalities than those of the controls. Over 140 chemical species have been identified in these! profiles and these include series of carbonyls, nitriles, alcohols, esters, aliphatic and aromatic hydrocarbons, halogenated hydrocarbons, heterocyclic compounds and sulphur-containing compounds. A detailed examination of the profiles has indicated that those compounds which might be of significance fell into two main catagories: those which were strong sensory and respiratory irritants, and those which were depressants of the central nervous system. Quantitative measurements of carbonyls in blood have shown that the mean levels of 2-butanone, butandione, 2-pentanone, cyclopentanone, cyclohexanone and hexanal were higher in fire fatalities than those in the controls. Of particular concern were the very high levels of acetonitrile and the presence of acrolein Ca highly toxic and strong sensory irritant) in the blood of some of the fire fatalities. Although the toxicological significance of these gaseous toxicants in causing fire fatalities has yet to be established, the results have clearly demonstrated that most of the fire deaths included in this exposed to a wide range of toxicants. these compounds may have played a vital incapacitation during the fire.