Detection of acetic acid in cadavers by gas chromatography

A simple technique of sample preparation for gas chromatographic test for acetic acid in cadaveric material has been developed. The background concentration of natural content of acetates in the stomach, liver and kidneys are determined. The error of the method is no more than 10% with standard deviation +/- 0.04-0.13.     

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.     

Characteristics of alphacypermethrin isolation from biological material

Methanol is proposed as an isolating agent for isolation of alphacypermethrin from biological material. Optimal conditions of isolating alphacipermetrin from human cadaveric liver tissue with methanol are determined and quantitative estimation of isolation results is provided.     

The analysis of tiapride in cadaveric material

To optimize conditions of tiapride isolation from cadaveric organs, we compared the results of conventional methods by Stas-Otto, A.A. Vasilyeva and V.F. Kramarenko which provide tiapride isolation up to 50% and a new precise and reproducible method providing 60 +/- 2% tiapride isolation. Identification of tiapride isolated from cadaveric material was made with thin-layer chromatography and high performance liquid chromatography. The latter assay employed the method of external standard. The original techniques proposed identify and measure tiapride in hepatic samples in the presence of unidentified endogenic compounds. The techniques are rapid, selective, sensitive and reproducible.     

The determination of ethylene glycol in blood and urine

Method of ethylene glycol isolation from blood and urine with subsequent gas-chromatographic determination was developed. The method makes it possible to extract 60-80% of ethylene glycol and to detect its toxic concentration in the cadaveric blood and urine.     

The detection of isoniazide in the cadaveric blood and plasma by high performance liquid chromatography with a diode matrix detector

The authors describe the analytical procedure for the rapid detection of isoniazide in the cadaveric blood and plasma using high performance liquid chromatography with a diode matrix detector (HPLC-DAD). The method is designed for toxicological and forensic medical analyses. The preliminary preparation of the samples includes protein precipitation with trichloroacetic acid, formation of isoniazide derivatives with cinnamic aldehyde, and chromatographic analysis on an Eclipse XDB-C18 column with registration of absorption at a wavelength of 340 nm. The mobile phase is a mixture of methanol and 0.05 M ammonium acetate buffer (50:50 v/v), pH 3.8. The detection limit is 0.5 mcg/ml in plasma and 1 mcg/ml in blood hemolizate. The qualitative determination is possible in a concentration range from 2 to 200 mcg/ml. Mean square deviation does not exceed 12% in a concentration interval from 2 to 50 mcg/ml.     

Changes in the concentration of carboxyhemoglobin in the blood under the action of high temperatures

Changes in carboxyhemoglobin concentrations are studied in 18 specimens of cadaveric blood 1-2 h and 3 days after heating to 50, 65, 70, 75, 80, and 90 degrees C for 5, 10, and 20 min. The concentration of carboxyhemoglobin decreased to 15% after heating at 70-75 degrees C for 10 and 20 min. Heating to 80-90 degrees makes the measurements impossible. Five-min heating at 50-65 degrees C did not change the concentration of carboxyhemoglobin in the blood.     

The use of circular dichroism and spectrophotometric methods in establishing the time of death

Dynamics of destruction of metal-containing proteins in skeletal muscles depending on storage duration (up to 30 days) of cadaveric material was studied in vitro using spectra of circular dichroism and absorption in visible spectrum area. Dichroic absorption diminishes gradually with increase of storage duration of cadaveric material.     

The isolation of amitriptyline from cadaveric material using acetonitrile

Method of amitriptyline isolation from the cadaveric material using acetonitrile as extractant is suggested. This method makes it possible to extract in average 76.09% of substance previously added in quantity of 1 mg to 25 g of the liver. Method was successfully used in analysis of expert material.     

Relationship between the concentration of ethanol and methanol in blood samples from Swedish drinking drivers

Headspace gas chromatography was used to determine the concentration of ethanol and methanol in blood samples from 519 individuals suspected of drinking and driving in Sweden where the legal alcohol limit is 0.50 mg/g in whole blood (11 mmol/l). The concentration of ethanol in blood ranged from 0.01 to 3.52 mg/g with a mean of 1.83 +/- 0.82 mg/g (+/- S.D.). The frequency distribution was symmetrical about the mean but deviated from normality. A plot of the same data on normal probability paper indicated that it might be composed of two subpopulations (bimodal). The concentration of methanol in the same blood specimens ranged from 1 to 23 mg/l with a mean of 7.3 +/- 3.6 mg/l (+/- S.D.) and this distribution was markedly skew (+). The concentration of ethanol (x) and methanol (y) were positively correlated (r = 0.47, P less than 0.001) and implies that 22% (r2) of the variance in blood-methanol can be attributed to its linear regression on blood-ethanol. The regression equation was y = 3.6 + 2.1 x and the standard error estimate was 0.32 mg/l. This large scatter precludes making reliable estimates of blood-methanol concentration from measurements of blood-ethanol concentration and the regression equation. But higher blood-methanol concentrations are definitely associated with higher blood-ethanol in this sample of Swedish drinking drivers. Frequent exposure to methanol and its toxic products of metabolism, formaldehyde and formic acid, might constitute an additional health risk associated with heavy drinking in predisposed individuals. The determination of methanol in blood of drinking drivers in addition to ethanol could indicate long-standing ethanol intoxication and therefore potential problem drinkers or alcoholics.     

The determination of phoxim in cadaveric material by gas-liquid chromatography]

The developed gas-liquid chromatographic procedure for forensic chemical detection and measurement of phoxim in cadaveric material permits the detection in 25 g of an organ of 44 to 52% of added phoxim. The threshold of phoxim measurement in 100 g of the liver is 0.04 mg, the least volume of phoxim detectable being 0.02 g. The developed gas-liquid chromatographic technique should be used as an additional method together with thin-layer chromatography, for a more objective evaluation of the results of forensic chemical analysis of cadaveric material for phoxim.     

An evaluation of methods for isolating antiparkinson preparations from cadaveric material

Methods of amedine, amyzyl, and tropacine isolation from cadaveric material, blood and urine were developed. They ensure higher output of the given substances as compared with conventional methods of isolation of toxicologically significant substances. An extraction-photometric method was developed for estimation of amedine, amyzyl, and tropacine in the cadaveric material.     

Gas chromatography with mass-selective detector in testing blood for amitriptyline and nortriptyline

The article describes the method of simultaneous detection of amitriptiline and nortriptilin in cadaveric blood using gas chromatography with mass-selective detection. Preparation includes liquid-liquid extraction and derivation with trifluoroacetic anhydride. Nortriptilin threshold of detectability in the blood is 0.02 mcg/ml, amitriptilin one--0.05 mcg/ml. The range of detectability--0.05-3.0 mcg/ml for both compounds. Maximal error of the compounds detectability was under 12.9% for concentrations 0.10 mcg/ml and 10.6% for concentrations 2.0 mcg/ml. The method was tested on expert material in forensic chemical examinations.     

Gas-chromatographic detection of acetic acid in cadaveric specimens

Data on Liquid Gas Chromatographic method for detection of the acetic acid after etherification in the cadaveric organs are presented. The results of quantitative acetic acid determination in the cadaveric organs by LGC method after etherification are influenced upon by its "background" values. Acetic acid concentration in the cadaveric organs of subjects who died from the cause other than acetic acid poisoning is within the limits 0.1-0.21 g (mean value 0.17 g) in 100 g of the stomach and 0.07-0.13 g (mean value 0.11 g) in 100 g of the liver. Method may be used in expert practice to determine acetic acid poisoning with due regard for its "background" concentrations in the organs.     

The gas chromatographic determination of carbophos in cadaveric material

The authors developed a method of malathion insecticide determination in the cadaveric material (blood and wall of the stomach) including extraction of 5 ml of blood (5 g of fragmented tissue of stomach wall) by hexan; preparative chromatographic purification of extract on silicagel layer L 5/40 mkm in hexan-diethyl ether system 10:2; Gas-liquid chromatographic investigation on column with 5% SE-30 and 5% XE-60 (Chromatograph "Colour-106" with thermionic detector). This method makes it possible to detect 72-76% of malathion added.     

The detection and separation of antiparkinson preparations in cadaveric material by gas-liquid chromatography

Method of gas-chromatographic detection of anti-parkinsonism substances (amedine, amysile, dinesine, midantane, tropazine and cyclodole) isolated from the cadaveric material is suggested. Conditions for separation of anti-parkinsonism substances when they are all present in the cadaveric material are developed.     

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.     

A rapid method of isolating a phenothiazine derivatives from cadaveric specimens

Proximate method for isolation of 10 psychotropic compounds of phenothiazine series from the cadaveric material was developed using acetonitrile with subsequent extraction of these derivatives by ether at pH 13.0 and reextraction by 0.5 n. solution of sulfuric acid. Method of isolation by acetonitrile shortens time for analysis by 5-6 times as compared with modified Stas-Otto method suggested previously for this purpose.     

The forensic chemical analysis of cadaveric material for the presence of drug and narcotic compounds]

The authors consider that the list of drugs and narcotics which can be reliably identified in a general forensic chemical analysis of cadaveric material (not a purposeful screening) should be changed. Isolation by acidified water, hydrochloric acid hydrolysis, and by acetonitrile should be used for isolation of drugs and narcotic compounds in forensic chemical analysis of cadaveric material.     

Estimation of postmortem interval using kinetic analysis of the third component of complement (C3) cleavage

To estimate postmortem interval (PMI), spontaneous cleavage of the third component of complement (C3) was studied in aged blood and cadaveric blood by crossed immunoelectrophoresis. Using the kinetics of C3 cleavage in vitro described as dC/dt = -kC, where C is the concentration of native C3 at time t and k is a first-order rate constant, Arrhenius' equation, and another equation which assumes a linear drop of body temperature after death, the percentages of C3 cleavage were calculated. There was a significant positive correlation between the calculated percentages and the measured percentages of up to 10% in cadaveric blood. We found that the comparison between the calculated percentage of C3 cleavage for each optional postmortem interval and the measured percentage of up to 10% in cadaveric blood leads to the estimation of PMI. This approach is one step towards the development of an accurate method for determining PMI based on C3 cleavage, that is, on a first-order reaction.