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Tattoo removal by laser: the BfR identifies
cleavage products
There is currently a lack of data for a risk assessment, in particular with
regard to the dispersion of substances contained in tattoo inks in the hu-
man body and to the cleavage products from these that can arise when
exposed to energy such as, for example, in UV irradiation or lasering. The
BfR is therefore currently investigating the identity of cleavage products
from tattoo inks in particular within the framework of a research project.
This involves thermal cleaving of the tattoo inks in experimental tests by
means of pyrolysis and subsequent mass spectrometry analysis (pyroly-
sis GC/MS). Thermal cleaving occurs at 800 degrees Celsius. This corre-
sponds to the temperature that can be expected in the human skin during
laser removal of tattoos.
Initial comparisons of samples treated with laser exposure or experi-
mentally with pyrolysis confirm that both scenarios lead to the same
cleavage products. Conclusive confirmation of this is not yet forthcom-
ing and is the aim of current testing. To identify the resulting fragments,
the BfR is using a so-called reference library. This details the character-
istics of certain known cleavage products. Researchers are establish-
ing whether the fragments created via pyrolysis match the substances
listed in the reference library. So far a total of 14 organic pigments have
been analysed using this technique. One result is that the pyrolysis of
the yellow azo pigment Yellow 74 releases a possibly carcinogenic sub-
stance, o-anisidine.
Besides identification of cleavage products from pigments, this method
is also suitable for determining the cleavage products from other tattoo-
ing agent ingredients like preservatives and formulation additives. The
latter are often polymers, which are hard to analyse with other tech-
niques. The application of these methods in the analysis of tattoo inks
and their cleavage products is to be further developed at the BfR, and
a spectrum library is to be compiled for the identification of substances
frequently contained in tattoo inks.
Yellow tattoo inks contain the azo pigment
Yellow 74. During lasering, it degrades into
a potentially carcinogenic substance.
Cleavage products
Health risks
o-anisidine
Toxic, possibly carcinogenic
2-methoxyphenyl isocyanate
Harmful to health, irritant
2-methoxy-4-nitroaniline
Harmful to health, irritant
Cleavage products resulting from pyrolysis of pigment
Yellow 74
Main Topics 2013 | Tattooing agents
