Expert significance of evaluating volatile non-metal combustion products in analysis of blood from subjects dead in fire

Qualitative and quantitative composition and time course of formation of toxic substances during burning of polymers have been studied for two polymers, P-53-P and STBO. The most toxic gaseous products of nitrogen combustion are listed: hydrogen cyanide, nitrites, acid nitriles, aldehydes, aromatic carbohydrates, alkanes, and carbon oxide. Two expert conclusions are presented, including analysis of blood and viscera from subjects who died during fire. The following toxic substances were detected: carbon oxide, hydrogen cyanide, nitrites, acrylonitrile, acetonitrile, benzene, and methane in one case and the same products except carbon oxide in the other. The author considers that the list of tested toxic substances should be extended, particularly in cases with negative results of blood testing for carbon oxide and carboxyhemoglobin.     

Forensic chemical testing of cadaveric material for acetonitrile

Gas chromatographic conditions for qualitative and quantitative evaluation of acetonitrile in biological material were determined, including those for reactive gas chromatography. Absolute and relative time of acetonitrile and concomitant substances retention in three columns of different polarity was determined. Study of the time of acetonitrile retention in biological material showed that acetonitrile concentration in the blood virtually did not change in cadaveric material stored in a hermetically closed flask for 2 weeks at 20 +/- 3 degrees C, while its concentration in the stomach decreased by 10-15%. Distribution of acetonitrile in human viscera in lethal poisoning was studied; the agent was evenly distributed in the gastric wall, intestine, liver, and kidney, while its concentrations in the lung and brain were 2-3 times higher. Forensic chemical expert analyses of the blood, urine, and viscera from corpses of humans dead from lethal acetonitrile poisoning showed that lethal concentration in the blood was 28.3-57.0 mg and in the urine 23.2-40.6 mg/100 ml.     

The gas chromatographic detection of acetylene in cadaveric material]

Acetylene traces were detected by gas chromatography in the cadaveric right crural muscle of a 30-year-old man dead from an explosion of an acetylene reservoir at a plant. Acetylene was identified using the absolute calibration method on 3 standard gas chromatographic columns, reaction gas chromatography, and acetylene "deduction" by silver sulfate on silicagel.     

A gas chromatographic method for detecting nitrites in the blood and stomach contents

Ethyl nitrite method is proposed as the tentative test for nitrites in studies of the blood and gastric contents. The sensitivity of the method in "pure" solutions is 17 micrograms/sample. The method is specific and its sensitivity is not inferior to routine chemical analyses of biological materials for nitrites.     

Forensic and chemical determination of methane in cadaveric samples

Conditions were elaborated for the determination of methane, through gas chromatography, in blood and the lung by using a 2% methanol solution as an internal standard and with the below gas-chromatography column being applied: dimensions--200 x 0.3 cm, 15% di-2-ethylhexyl sebacate on Dinochrome II (0.16 x 0.21 mm) at 110 0 degree C. The detector is of the flame-ionization type. The normal content of methane was determined for blood and for the lung--0.122 +/- 0.0074 microgram/ml and 0.20 +/- 0.04 microgram/g, respectively. Biological samples from cadavers of other persons who died due to trauma were suggested for use as controls. The method was used to examine expertise objects, blood and the lung from the cadavers of peoples who died in fire.     

Preservation of methanol in cadaveric material

Duration of preservation of methanol in cadaveric material at 20 +/- 3 degrees C during 4-13 months was studied on 19 model and expert objects of cadaveric material (muscle tissue, kidney, blood, urine). Exponential relationship between methanol concentration and duration of storage of the object was detected. Methanol concentration decreased by 30-70% during the first weeks, after which the process decelerated to 5-10% a month. Toxicologically significant concentrations of endogenous methanol were not revealed in any case.     

Gas chromatography in quantitative analysis of hydrocyanic acid and its salts in cadaveric blood

A direct gas chromatography method was designed for the quantitative determination of cyanides (prussic acid) in cadaveric blood. Its sensitivity is 0.05 mg/ml. The routine volatile products, including substances, which emerge due to putrefaction of organic matters, do not affect the accuracy and reproducibility of the method; the exception is H-propanol that was used as the internal standard. The method was used in legal chemical expertise related with acute cyanide poisoning (suicide) as well as with poisoning of products of combustion of nonmetals (foam-rubber). The absolute error does not exceed 10% with a mean quadratic deviation of 0.0029-0.0033 mg.     

Gas chromatographic method of quantitative determination of carbon monoxide in cadaver blood

A gas chromatographic method has been developed for measurement of carbon monoxide in cadaveric blood on a chromatographer with thermal conductivity detector and air oxygen as the internal standard. The error of the method is no more than 4% with the mean quadratic deviation +/- 0.18-0.33 min. The method was studied on 10 model and 30 expert blood samples. Putrefactive products did not influence the accuracy of analysis.     

Unified gas chromatography method for the detection of volatile toxicants in biological samples

A method was designed to identify and quantify the volatile toxicants in cadaveric samples; it is based on analyzing the equilibrium of the gas-vapor phase. A system comprising 3 gas chromatography columns with different polarities and without preliminary isolation of an analyzed substance is used in toxicants' identification. 0.2% n-propanol solution was used in quantification of fresh biological samples, while methanol solution was used in cases of purulence-affected materials. The method sensitivity provides for detecting some of the toxicants, like acetaldehydes, acetone as well as ethyl and higher alcohols at the level of their natural content. The method has been tested for as long as 15 years at expertise objects.     

Detection of chlorinated carbohydrates in putrefactive biological material

Carbochlorohydrates were separated from putrefaction products of organic substances and volatile solvents by gas chromatographic column packed with CaA 5 A. A 100 x 0.4 cm column, used for forensic chemical analysis of fresh and putrefactive cadaveric material, proved to be highly effective. The data were confirmed by results of chemical analysis of distillates from the viscera.