[The chemical toxicological investigation of gamma-hydroxybutyric acid in biological objects and the interpretation of the results of the analysis]. / Khimiko-toksikologicheskoe issledovanie GOMK v bioob''ektakh i interpretatsiia rezul'tatov analiza.

The authors propose a method for the quantitative determination of gamma-hydroxybutyric acid (GHBA) in biological objects including biological fluids (blood, urine) and tissues with the use of gas chromatography with mass-selective detector. The samples for the analysis were prepared by liquid-liquid extraction by butyl acetate with subsequent derivatization using a N,O-Bis(trimethylsilyl)trifluoroacetamide/Trimethylchlorosilane mixture (BSTFA + 1%TMCS). The graded graphs were linear in the range of GHBA concentrations from 26.4 to 1321.6 mg/l. Coefficients of correlation for all the graphs were higher than 0.999. The threshold of detectability for GHBA in blood, urine, and internal organs was 10 mg/l, the quantification limit concentration 26 mg/l.

[Organization of quality control of the forensic medical investigations]. / Organizatsiia kontrolia kachestva sudebno-khimicheskikh issledovanii.

The article describes the system of quality control at all stages of forensic chemical investigations (including pre-analytical, analytical, and post-analytical ones) carried out by the Saint-Petersburg Bureau of Forensic Medical Expertise It is shown that standardization and control taken together make up a solid foundation for obtaining the reliable and reproducible results of forensic chemical investigations. Responsibility for the quality control at all stages of forensic chemical investigations lies on the heads of the respective departments. Special staff members are appointed to supervise performing each concrete form of control and keeping the relevant documentation.

[The influence of the packaging on the storage qualities of the volatile substances]. / Vliianie upakovki na sokhraniaemost' letuchikh veshchestv.

The objective of the present study was to evaluate the storage qualities of the acetone and ethanol aqueous solutions kept in the polyethylene flasks, polypropylene and glass tubes that were stored under different environmental temperature. It was shown that the acetone aqueous solution better retained its properties when stored in glass vials at room temperature as well as at 0° C and 4° C. The most pronounced decrease of acetone concentrations (from 70 up to 95%) was documented after its storage in the polyethylene flasks. The ethanol concentration fell down by 40% when stored in polyethylene flasks at room temperature.

[The development of the method for the determination of the low-molecular weight alcohol content in the specimens of the biological materials]. / Razrabotka metodiki opredeleniia soderzhaniia nizkomolekuliarnykh spirtov i atsetona v obraztsakh biomaterialov.

The objective of the present study was the development and metrological attestation of the method for the determination of concentrations of low-molecular weight (C1-C4) alcohols and acetone in the biological materials, such as urine and blood including partially dehydrated blood. The method is based on the chromatographic analysis of the equilibrium vapour phase with the use of the static headspace autosampler. The calculations were carried out making use of the results obtained with the application of propanol-1 as the internal standard. In order to enhance the reliability of the identification of the analytes in the complex blood matrix, the two-channel configuration was employed that consisted of a single evaporator, passive flow division, two capillary columns of different polarity, and two flame ionization detectors. The proposed technique provided for the first time the unique possibility to perform the quantitative measurement of the internal standard in the starting specimen before the main analysis. The validated procedure for the quantitative determination of the alcohol concentration of blood samples with the reduced water content has been described. The present study made it possible to collect the total amount of relevant statistical data necessary to calculate the metrological characteristics of the method in question. The method was certified based at D.I. Mendeleev All-Russian Research Institute of Metrology under No 754/242-(01.00250)-2016.

[Thin layer chromatography for the analysis of certain anti-inflammatory medicines].

This work was devoted to the elucidation of conditions for isolation of ketorolac and diclofenac from biological fluids. A method is proposed for the extraction of these compounds from solutions with organic solvents at different pH values. Other methods permit to optimize identification of analytes by thin layer chromatography while the densitometric technique may be used for qualitative and quantitative analysis of their composition in biological fluids.

[The use of enzymatic hydrolysis for isolation of barbituric acid derivatives from blood (as exemplified by phenobarbital and barbamyl)].

Modern isolation techniques by direct extraction with organic solvents or after protein precipitation by various sedimenting or salting-out agents are characterized by low efficiency and do not permit to liberate derivatives of barbituric acid from their complexes with blood proteins. The use of enzymatic hydrolysis makes it possible to break bonds between barbiturates and protein and thereby improve the efficiency of isolation. We performed enzymatic hydrolysis of the model phenobarbital-blood and barbamyl-blood complexes with the use of trypsin, pepsin, chymotrypsin, and papain. The degree of phenobarbital extraction with trypsin and barbamyl was estimated at 62.1 +/- 1.2% and 75.1 +/- 1.6% respectively; in other words, it was 32.7 +/- 1.0% and 51.1 +/- 1.0% higher than that achieved by traditional methods. Certain validation characteristics of the new method are presented.