Terms and Concepts of Analytical Toxicology. Objectives of Toxicology. Chemical-Toxicological Analysis

Any chemical substance becomes a poison if, upon interaction
with an organism, it causes disease or death (intoxication, poisoning, etc.) (Fundamentals of Toxicology. Kutsenko S.A., 2002).

Poison (toxicant) — a toxic substance of any nature, capable of disrupting the homeostasis of a biological system and exerting a harmful effect on it upon interaction, causing damage or death.
Toxic substance – a chemical substance which, upon acting on the human (animal) organism, may cause disturbances in the state of
health or a disease of varying severity, both in the course of
contact with the substance and in the remote periods of life of the current and subsequent generations (Clinical Toxicology. Luzhnikov E.A., 1982).
Toxicant — a broad concept, used to denote substances that cause not only intoxication of the organism, but also provoke other forms of the toxic process in biological
systems: in cells – cytotoxicity, in populations – ecotoxicity (Drug Toxicology. Drogovoz S.M., 2015).
Toxins – highly toxic chemical compounds and substances of a protein nature, of bacterial, animal or plant
origin.
Toxicity – the ability of substances, by acting on biological systems (organism, cells, populations), to cause their damage
or death.
Toxic process – the formation and development of reactions of a biological system to the action of a toxicant, which leads to its damage or death.
Intoxication – a toxic process occurring as a result of the action of toxic substances on the organism.
Xenobiotic – a foreign substance (not used
in the plastic or energy metabolism of the organism with the environment) that has entered the internal environment of the organism.
Biological (sectional, cadaveric) material – organs and tissues removed during autopsy of a corpse.
Isolation – the process of separating toxicants from the biological
matrix, or the process of extracting toxicants from biological objects.
Extraction (extrahere – to remove) – the process of extracting
toxicants from biological objects with the aid of solvents
(extractants).
Extract (extractus — removed) — a concentrated extraction obtained from biological objects.
Liquid–liquid extraction — a method of separating substances between
two immiscible liquid phases.
Mineralization – the process of oxidation (combustion) of the organic
component of biological material.

Mineralizate — the extract of metals obtained as a result of mineralization of biological material.
Distillation — the process (method) of isolating volatile
substances from biological objects with the aid of water vapor.
Distillate — the extract of volatile substances obtained from biological material as a result of distillation.
Sample preparation — the totality of actions performed on the object of analysis (grinding, extraction, concentration, separation, etc.) for the purpose of converting the sample into a form convenient for further analysis.

Toxicant – a toxic chemical substance of any chemical nature, capable of disrupting the homeostasis of a biological system and exerting a harmful effect on it upon interaction, causing damage or death.

Xenobiotic – a foreign substance introduced into the organism by any route. When a poison acts on the organism, poisoning — intoxication — occurs.

Intoxication— a pathological state caused by the general action on the organism of toxic substances of endogenous or exogenous origin.

Tasks of toxicology. Toxicometry

General toxicology is based on the study of the movement of toxic substances in the organism: the routes of their intake, distribution, metabolic transformation (biotransformation) and elimination.

The first task of toxicology is the detection and characterization of the toxic properties of chemical substances that are capable of causing pathological changes in the organism of animals or humans, as well as the study of the conditions under which these properties arise, are most clearly manifested, and disappear. The interaction of a poison with the organism is studied in two aspects: how the substance affects the organism (toxicodynamics) and what happens to the substance in the

organism (toxicokinetics).

The second task of toxicology is the determination of the zone of toxic action of the chemical substance under study (toxicometry).

By the nature of the effect of the toxic substance on the organism, the following types of intoxication are distinguished:

Acute intoxication (acute intoxication) – a pathological state of the organism resulting from a single or short-term exposure; accompanied by pronounced clinical signs

Subacute intoxication (subacute intoxication) – a pathological state of the organism resulting from several repeated exposures (up to 1 month); clinical signs are less pronounced compared to acute intoxication

Over-acute intoxication (over-acute intoxication) – acute intoxication characterized by damage to the central nervous system, the signs of which are convulsions and impaired coordination; death occurs within a few hours

Chronic intoxication (chronic intoxication) – a pathological

state of the organism resulting from prolonged (chronic) 24 exposure (more than 3 months); not always accompanied by pronounced clinical signs.

Subchronic intoxication – involves repeated administration

of the toxicant over a period of 1–3 months.

Poisoning — a disease or other disorder of the vital functions of the organism arising as a result of a poison or toxin entering the organism, as well as the act that caused such a disease (for example, murder or suicide by means of poison).

CHEMICAL-TOXICOLOGICAL ANALYSIS: DEFINITION, DIRECTIONS AND METHODOLOGY

The basis of analytical toxicology is chemical-toxicological analysis.
Chemical-toxicological analysis — is a systematic analytical investigation, the purpose of which is the identification and quantitative determination of toxic substances in objects of various origin.
Components of chemical-toxicological analysis:
1) selection of objects and sampling for investigation;
2) sample preparation (isolation of toxicants from the objects of investigation, purification of extracts from impurities of various nature, concentration, derivatization, separation of toxicants, etc.);
3) detection and identification of toxicants;
4) quantitative determination of toxicants;
5) interpretation of analysis results.
The above components are applicable to many types of CTA,
since they reflect its general concept and methodology
of performance. However, depending on the direction of application, the purpose
and tasks of the analysis, the objects of investigation and other circumstances, some
of its components may not be appropriate in all cases. For example, when examining physical evidence, in most cases
isolation and quantitative determination of the substance under investigation of unknown chemical nature is not carried out, if such analysis is performed to establish its
membership among narcotic substances; in carbon monoxide poisoning, carboxyhemoglobin is determined
directly in the blood without prior isolation from the biological object, etc.
Variants or the direction
of performance of chemical-toxicological analysis
Depending on the specific circumstances of the case, clinical situations, the results of autopsy, the data of the preliminary investigation

or preliminary tests, etc., several variants of performing CTA are distinguished.
Directed CTA is carried out in the case where, based on the materials of the case, an assumption has been made or it has become known which
substance or group of substances caused the poisoning.
Undirected CTA is carried out in the case where the materials of the case lack information on the chemical nature of the toxic substance. This analysis is also defined as a general analysis
or an analysis for an unknown substance.
Depending on the circumstances of the case, the place of performance, the objects
of investigation, etc., several directions of application
CTA (Table 1.1).

Table 1.1 directions of application of chemical-toxicological analysis: