Comparison of TF, TIF, and TOF
TF, TIF, and TOF are total fluorine parameters that can be used to measure and classify different fractions of fluorine in a sample. TF describes the total fluorine content, TIF the inorganically bound fraction, and TOF the organically bound fraction. These parameters are closely related both analytically and mathematically. Which value is relevant depends on what conclusion is to be drawn about a sample’s fluorine content.
Table of Contents
- TF, TIF, and TOF at a glance
- How are TF, TIF, and TOF related?
- When Is which total fluorine parameter appropriate?
- What role do TF, TIF, and TOF play in PFAS analysis?
- Total fluorine parameters for packaging
- Frequently asked questions about total fluorine parameters
- Total fluorine parameters: A brief summary
Contact us –
expert support is just a conversation away.
Using state-of-the-art analytical methods, we assist you with quality issues, damage claims, and development challenges – providing precise, well-founded, and solution-oriented support.
TF, TIF, and TOF at a glance
TF, TIF, and TOF are closely related in terms of analysis and calculation, but they provide different information. The following overview shows the most important differences:
| Parameter | What Is tracked? | Key question |
|---|---|---|
| TF – Total Fluorine | Organically and norganically bound fluorine | How much fluoride is there in total in the sample? |
| TIF – Total Inorganic Fluorine | Inorganic fluorine content | What percentage of total fluorine is bound in inorganic form?? |
| TOF – Total Organic Fluorine | Organically bound fluorine content | What is the percentage of organically bound fluorine in the sample? |
Considering these parameters together allows for a more nuanced assessment of the fluoride content of a sample.
A high TF value alone initially only indicates that a large total amount of fluoride has been detected. Only further analysis can provide clues as to the proportion that is inorganically or organically bound.
Example: If an elevated TF value is measured and a high TIF fraction is simultaneously detected, a corresponding portion of the total fluorine is inorganically bound. The TF value alone would therefore not be sufficient to directly infer the content of PFAS .
How are TF, TIF, and TOF related?
The starting point is the total fluorine content (TF). It includes organically and inorganically bound fluorine.
TIF describes the inorganically bound fraction. TOF represents the organically bound fluorine fraction.
In simple terms, the relationship can be illustrated as follows:
If TOF is determined mathematically, the following applies:
In Quality Analysis, TOF is calculated from the separately determined values for TF and TIF. The result must therefore always be considered in the context of the methods used, their limits of quantification, and measurement uncertainties. Other laboratories may also determine TOF using different analytical approaches.
When is each fluorometric sum parameter appropriate?
TF, TIF, and TOF examine the same sample from different perspectives. Which parameter is examined depends on the analytical question.
TF: How much total fluorine is present?
TF (Total Fluorine), also known as total fluorine , measures the total fluorine content of a sample—regardless of whether the fluorine is bound in organic or inorganic form. This makes TF a suitable overarching value for fluorine screening. However, the parameter does not indicate which fluorine compounds are present or how the fluorine content is distributed between organic and inorganic components.
TIF: How much of it is inorganic?
TIF (Total Inorganic Fluorine) describes the inorganically bound fluorine content. This parameter becomes relevant when the total fluorine content needs to be further differentiated. At Quality Analysis, the determination is performed using an in-house method. The exact sample preparation and applicability depend on the specific sample matrix. The TIF value does not indicate which specific inorganic fluorine compounds are present.
TOF: How much of it is organic?
TOF (Total Organic Fluorine) describes the organically bound fluorine content of a sample. In Quality Analysis, TOF is not measured directly, but is calculated as TF minus TIF. The value thus indicates how much fluorine is present in an organically bound form, but does not specify which specific organic fluorine compounds are responsible for it.
What roles do TF, TIF, and TOF play in PFAS analysis?
TF first provides an overview of the total fluorine content of a sample. TIF is used to determine the inorganically bound fraction. TOF describes the organically bound fluorine fraction, to which PFAS may also contribute.
The total parameters thus enable broader screening for fluorine-containing compounds than a pure analysis of selected individual PFAS substances. However, they do not provide information about which specific PFAS compounds are present in a sample. Thus, the fluorine sum parameters are an important component of PFAS analysis and help to further classify potential PFAS contamination in a sample.
Where do AOF and EOF fit in?
In addition to TF, TIF, and TOF, other total fluorine parameters are used depending on the sample and the research question. AOF measures adsorbable organic fluorine compounds and is used in particular for water samples. EOF detects extractable organic fluorine compounds and is particularly relevant for solids.
Total fluorine parameters for packaging
As of August 12, 2026, specific PFAS limits for food contact packaging will apply under the European Packaging Regulation (PPWR) . If the total fluorine content exceeds 50 mg/kg, it must be possible, upon request, to determine which portion of the measured fluorine is attributable to PFAS and which to non-PFAS.
Distinguishing between organically and inorganically bound fluorine can aid in this classification. However, TIF and TOF do not identify individual PFAS and do not replace the targeted analyses that may be required for the limit values of 25 and 250 ppb.
Which analytical strategy is right for your sample?
Which sum parameters and further analyses are appropriate in packaging analysis depends on the sample matrix and the required conclusions. Quality Analysis determines TF, TIF as well as the sum parameters TOF, AOF, and EOF using appropriate analytical methods for each. Before submitting samples, the sample material, the purpose of the analysis, and the required detection limits should be coordinated.
Frequently asked questions about Total Fluorine parameters
TF describes the total fluoride content of a sample. TIF represents the inorganically bound fluoride, while TOF represents the organically bound portion. In Quality Analysis, TOF is calculated as the difference between TF and TIF.
No. TOF encompasses all organically bound fluorine compounds and is therefore not limited to PFAS. The value can provide indications of organic fluorine, but does not identify individual PFAS compounds.
TOF, AOF, and EOF measure different fractions of organically bound fluorine. TOF describes the total organically bound fluorine content of a sample. AOF measures the adsorbable fraction, and EOF measures the extractable fraction of organically bound fluorine.
A high TF value can also be caused by a high inorganic fluoride content. Only by determining TIF is it possible to distinguish between the two and thus determine TOF.
Total parameters capture fluorine concentrations beyond those of selected individual PFAS compounds. They are therefore suitable for preliminary screening and can indicate whether further analytical clarification is needed. However, a PFAS-specific risk assessment or statement of compliance cannot be made based solely on total parameters.
TF can be used as a screening parameter for the total fluorine content of a packaging sample. TIF and TOF allow for further differentiation between inorganically and organically bound fluorine. However, they do not indicate which specific PFAS are present. Additional substance-specific methods are required for this purpose.
Total fluorine parameters: A brief summary
TF, TIF, and TOF enable a differentiated assessment of fluorine contamination: TF measures total fluorine, TIF measures the inorganically bound fraction, and TOF measures the organically bound fraction. Together with AOF and EOF, these total parameters provide a broad analytical basis for assessing potential PFAS contamination. Particularly in packaging analysis , they are gaining importance due to regulatory requirements for PFAS and help to reliably classify fluorine levels.