TOF – total organic fluorine
The analysis of the sum parameter TOF (total organic fluorine) is often used for monitoring environmental samples such as water and, in particular, checking packaging materials for foodstuffs. This check is required to determine the total amount of fluorine in samples and assess the level of contamination. Precise analysis and evaluation of the level of contamination are therefore necessary.
Table of contents
What is the sum parameter TOF?
TOF is an analytical parameter that measures the total amount of organically bound fluorine in a sample. These compounds can occur in various materials and environmental samples and can be potentially harmful for the health and the environment. Along with TOF, there are other sum parameters such as TF (total fluorine), AOF (adsorbable organically bound fluorine) and EOF (extractable organically bound fluorine). TOF acquires not only specific fluorine compounds such as PFASs (per- and polyfluoroalkyl substances), but also all organic compounds that contain fluorine.
TOF, AOF and EOF: relationship and difference
The sum parameters TOF, AOF and EOF are related, however they acquire distinct portions of the organically bound fluorine in different conditions. They often complement each other during analysis to permit a more detailed understanding of the contamination situation.
TOF measures the total organically bound fluorine content in a sample and is used as a comprehensive indicator of fluorine contamination. It acquires all organic fluorine compounds, independent of their structure or composition.
AOF on the other hand relates to the part of the organic fluorine compounds in a sample that can be bound by means of adsorption on activated carbon. This parameter is focused on the easily adsorbable organic fluorine compounds and permits a more specific analysis.
EOF refers to the portion of organic fluorine compounds that can be obtained from a sample by means of extraction using a suitable solvent. This extraction is aimed at the acquisition of a broader palette of organic fluorine compounds that may not be acquired solely by adsorption.
Characteristics of organic fluorine compounds
Organic and inorganic fluorine compounds differ in their chemical structure, their characteristics and their origin. Organic fluorine compounds contain carbon and are often part of organic molecules such as hydrocarbons. These compounds may be of natural or synthetic origin and are characterised by their stability and their complex structures. A well-known example of organic fluorine compounds is per- and polyfluoroalkyl substances (PFASs).
Inorganic fluorine compounds, on the other hand, do not contain any carbon atoms and consist of simple chemical compounds that contain fluorine atoms. Inorganic fluorine compounds can occur in nature or may be synthesised by chemical processes. An example for an inorganic fluorine compound is sodium fluoride (NaF).
TOF: variability, persistence, toxicity
Organic fluorine compounds can have numerous different structures and characteristics, depending on their chemical composition and their origin. The TOF group includes PFASs (per- and polyfluoroalkyl substances), fluorosurfactants, fluorohydrocarbons and other fluorine compounds. In addition, due to their long-term chemical stability, some organic fluorine compounds can accumulate in the environment and in biological systems and have a toxic, polluting effect.
TOF analytics
at Quality Analysis
We undertake precise TOF analyses to better understand and evaluate environmental and health risks. These analyses permit the determination of the total amount of organic fluorine compounds in your sample and the identification of potential sources of fluorine contamination.
- Determination of the concentration of organically bound fluorine using the sum parameter TOF to measure even low concentrations reliably
- Analysis by means of combustion ion chromatography (CIC) for precision and the highest accuracy
- Highly specialised instruments and trained specialist personnel ensure exact, reliable results
- Laboratory with accreditation from Deutsche Akkreditierungsstelle GmbH (DAkkS) as per DIN EN ISO/IEC 17025
TOF and PFASs
As a comprehensive parameter for the determination of the total concentration of organically bound fluorine, TOF also includes PFASs (per- and polyfluoroalkyl substances), an important sub-group of fluoroorganic compounds. Due to their widespread use and their persistence in the environment, PFASs are of major interest for environmental and health experts. The analysis of TOF is a crucial instrument for the characterisation and monitoring of these compounds in different environmental media. A high TOF value is an indication that a considerable amount of organically bound fluorine is present in the sample. For this reason, a high TOF value can also signify that a large quantity of PFASs is present. However, other fluoroorganic compounds can also contribute to a high TOF value.
Applications for TOF analysis
Environmental monitoring
The sum parameter TOF is measured in environmental samples such as water, soil and sediments to determine the total concentration of fluoroorganic compounds. TOF analysis can be used to identify the causes of contamination, track the spread of pollutants and evaluate the effectiveness of remedial measures.
Waste management
TOF analysis is playing an increasingly important role in waste management, in particular during the characterisation and monitoring of waste streams. For this purpose, the sum parameter TOF in waste is measured to identify hazardous waste, prevent its incineration or dumping and find alternative disposal channels.
Research
Researchers use TOF analyses to obtain important insights into potential environmental effects as well as the spread and persistence of fluorine compounds. In environmental, material and health sciences, these analyses help with the assessment of fluorine contamination and the development of strategies for risk reduction.
Product control
TOF is measured in various products such as textiles, carpets, electronics and packaging to check the fluoroorganic compound content. TOF analysis can be used to ensure products comply with limits and consumers are protected against harmful chemicals. In Denmark, for instance, a maximum upper limit of 20 milligrams of organically bound fluorine per kilogram is specified for packaging for foodstuffs.
Which regulations and standards apply to TOF?
In Germany, there are currently no specific statutory limits for TOF. In environmental media such as water, soil or sediments, more specific parameters such as PFASs are often checked instead.
Although the German drinking water ordinance (TrinkwV) stipulates limits for various harmful substances in drinking water, there are no specific limits for TOF. Instead, limits for individual PFAS compounds in drinking water are specified, for example perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA).
Summary
Using the sum parameter TOF, the concentration of total organic fluorine compounds in a sample is determined. This includes, along with PFASs, all organic compounds that contain fluorine. Above all, environmental and industrial samples such as water and packaging materials are analysed. TOF analysis provides a holistic insight into the fluorine contamination and makes it easier to evaluate risks for the environment and consumers.
