Study of the composition of a tattoo ink

A tattoo corresponds to an injection using a needle of colored pigments under the skin at the level of the dermis.
The pigment therefore penetrates the skin for life.

Therefore, it is important to be certain of the composition of its ink, because some compositions would be problematic and could cause allergies, or even be carcinogenic.

The POLYMEX team was also tasked with studying the proportions of the components of tattoo inks.
To carry out this study, 3 analyzes were carried out, each with a specific goal.


  • Thermogravimetry analysis: TGA
    The first analysis was a load study by thermogravimetry or TGA, the interest here was to determine the volatile organic fraction contents, the organic fraction contents as well as the residual load fraction contents.
    TGA is a thermal analysis technique for measuring the variation in mass of the sample when it is subjected to certain temperatures under a controlled atmosphere.
Analyse par TGA
This analysis then gives us the proportions in volatile organic fraction, polymeric and inorganic of the sample of tattoo ink.
For example, in this sample, 4 levels of mass loss are observed as a function of the temperatures.
Going from the lowest to the highest, there is a first level corresponding to the evaporation of VOCs of solvent type, then a second representing the evaporation of VOCs having a higher boiling point, the third level corresponding to the decomposition of the polymers and finally the last step with the highest temperature which refers to the inorganic fillers present .
If the loss of mass of the latter is very low, it means that there are no inorganic charges.

• Water content: Karl Fisher

In parallel, a check of the water content was carried out according to the Karl Fischer method.
The principle is to react the water present in the sample with iodine and sulfur dioxide in the presence of methanol and a base.

As long as there is water iodine reacts with it, and the amount of iodine formed is proportional to the electrolysis current.
Knowing that a water molecule is equivalent to a precise quantity of electricity formed, we are therefore able to deduce the quantity of water present in the sample analyzed.



  • Laser particle size analysis
    The last analysis made on this sample of tattoo ink was a particle size analysis, which will allow us to count the particles present in the ink by class .
    For this we disperse the sample in solvent by ultrasound to avoid agglomerates and the solution passes into a glass cell illuminated by a beam of laser light , and it is this interaction between the particles and the laser which will give us the distribution of molecules of equivalent sizes.
    Thus we know the maximum and minimum sizes of the particles present in our tattoo ink.

These analyzes therefore allowed us to compare different formulations and to observe differences, in particular on the water content and the presence or absence of fillers.

Analyse par TGA
The laboratory is able to go further on the study of composition, by identifying and quantifying for example the light and ultralight organic components by carrying out an analysis by qualitative GCMS or by identifying the polymer fraction by pyrolysis / GCMS .
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Study of the blue dye content

Study of the blue dye content

Pigments in a tattoo penetrate the skin and stay there for life. It is therefore important to know the composition of your ink to avoid..
Study of the composition of a tattoo ink

Study of the composition of a tattoo ink

Identifying the constituents of an ink
Identifying the constituents of an ink

Identifying the constituents of an ink

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