Halogens are nonmetals that are prone to reaction. Halogens are found in nature as minerals, not as elements. The chemical structures of the halogens are in the form of elemental molecules with 2 atoms.

The main halogens are HCl (hydrochloric acid), HBr (hydrobromic acid), HF (hydrofluoric acid), Br2 (bromine molecule) and Cl2 (chlorine molecule).

At room conditions, the fluorine and chlorine halogens are gaseous, the bromine halogen is in the liquid state and the iodine halogen is in the solid state. These halogens are poisonous and hazards to human health. As soon as they react with metals, ionic salts begin to form. All halogens have a high electronegativity level. These elements have the highest tendency to receive electrons.

In workplaces using these halogens, employees are exposed to the harmful effects of halogens, either because of their theme or inhalation.

Halogen determination in accredited laboratories is done by sampling method. however, the characteristics of the source from which the data are collected are crucial for the reliability and validity of the research results. Although results from the whole source are more accurate and realistic, this is not always possible. Therefore, laboratories generally work on the sample to be taken from this source instead of examining the whole source.

When determining halogen by sampling, the most important condition is that the sample taken can represent the whole source. The samples taken therein must be in sufficient quantity and the sample taken by appropriate methods.

Total halogen sampling and determination studies within the scope of emission measurements must be national and international standards and an objective approach. These laboratories must operate in accordance with the standards of TS EN ISO / IEC 17020 General Criteria for the Operation of Various Types of Inspection Organizations and have the accreditation authority in accordance with this standard.