Perfluorinated compounds (PFCs) in
consumables- fabrics
Introduction:
Perfluorinated substances ( PFCs ) belong to persistent organic pollutants ( POPs ) and as such
are monitored by world organizations (UNECE; OECD; UNEP). Their production and use are
limited by several international conventions (Stockholm Convention on persistent organic
pollutant; CLRTAP). Directive 2006/122/EC of the European Parliament and the Council of
December 12, 2006 is binding on the European Union and thus on the Czech Republic.
PFCs are relatively new compounds. Although they have only been industrially produced since
the 1950s, their widespread use has resulted in significant environmental contamination.
Thanks to the fluorine atoms in the molecule, these substances are very stable. They are
resistant to chemical, photochemical, thermal and biochemical decomposition. They have the
potential for long-distance transport, which is why they are present even in areas where they
have never been produced or used. This aspect also enhances the ability of bioaccumulation
in animal tissues.
Perfluorinated substances are compounds containing a hydrophobic alkyl chain with
a variable number of carbons (usually C4 to C16), where all hydrogen atoms are replaced by
a fluorine atom. If the hydrophobic part is only partially fluorinated, then the molecules are
called polyfluorinated. For substances that only have a partially fluorinated hydrophobic part
of the molecule, its properties are determined by the position and number of fluorines. In
addition to the hydrophobic part, the molecule also contains a hydrophilic part, e.g.
a carboxyl, sulfone or alcohol group.
PFCs include several basic groups of compounds, the most important of which are
perfluoroalkyl carboxylic acids ( PFCAs ), perfluoroalkyl sulfonates ( PFASs ) from the point of
view of consumables . These are substances of an oleophobic and hydrophobic nature. This
property is widely used in protective coatings, surface treatment of fabrics, carpets or food
packaging materials.
Principle:
PFCs are often applied to textile materials to protect them from water and dirt. PFCs from
consumables are extracted into an organic solvent in an ultrasonic bath. After filtering, they
are analyzed using high-performance liquid chromatography with tandem mass detection
(HPLC-MS/MS).
Equipment:
• laboratory scales
• polypropylene centrifuge tubes (50 ml)
• ultrasonic bath
• Pasteur pipettes, automatic pipettes
• tweezers, scissors
• ruler
• syringe (2 ml)
• syringe nylon filter (0.45 m)
• LabEva Nitrogen Evaporation System
• vortex
Chemicals:
• methanol
• mixed standard for method recovery (M8PFOA, M8PFOS) with a concentration of 100
ng /ml
• 0.1 M hydrochloric acid
• 5 mM ammonium acetate
• mixed internal standard (MPFBA, MPFHxA , MPFOA, MPFNA, MPFDA, MPFDoDA ,
MPFHxS , MPFOS)
Notice:
• all containers and tools must be washed with methanol before use (applies to PP
tubes, Pasteur pipettes, scissors, tweezers)
Procedure:
• put about 2 g of the sample, which is cut into small pieces of about 1x1 cm, into a
50 ml polypropylene tube, write down the exact weight and the measured surface
area
• prepare a second test tube for blind determination of the blank
• add the extraction solvent - 20 ml of methanol with the addition of ammonium acetate
(1 g of ammonium acetate per 2.5 l of methanol) and 5 ml of 0.1 M HCl
• the centrifuge tubes in the ultrasonic bath and let them extract for 15 minutes
• centrifuge the samples at 4000 rpm for 10 minutes
• transfer the clear supernatant to a clean labeled tube
• repeat the extraction two more times with a new solvent of 10 ml and combine the
extracts
• concentrate the extract under a stream of nitrogen to the last drop
• dilute the residue with 1 ml mobile phase methanol: 5 mM ammonium acetate 1:1
and vortex the sample
• remove any impurities by filtering through a syringe nylon filter
• a mixed internal standard is added to the sample using an automatic autosampler
Evaluation and questions:
Calculate the concentration of individual PFCs per mass (ng/g) and surface (ng/m2) of the
material.
Write an example of materials or consumer products where you would expect higher
concentrations of PFCs.
How can PFCs get into the environment? Outline the possible life cycle of PFCs in the
environment and determine in which environmental matrices the highest concentrations
are expected.
Are there any legislative limits on the use of PFCs?