Migration from coffee filter
papers
Presentation of Diploma Thesis
Matthias Fellner
18.06.2010
Who drank coffee today?
• Should you worry?
Goals
• Characterize commercial available
Austrian coffee filter papers
• Determine the migration of
certain substances into coffee by
simulating with water or organic
solvents
• Compare the results with safety
limits and get a conclusion if the
results call for further inquiry
Samples
• 1 Melitta
Original
bleached!
2 Spar
Kaffeefilter
(Spar)
• 3 Hofer
Kaffee
(Hofer)
4 Clever
Kaffee-Filter
(Billa)
• 5 Brigitta
Kaffeefilter
(Zielpunkt)
6 Schlecker AS
Kaffeefilter
(Schlecker)
• 7 Aromata Structured Coffee
Filter Papers (Lidl)
Standards
• ISO: International Organization for
Standardization
• CEN: Comité Européen de Normalisation
• DIN: Deutsches Institut für Normung
• ÖNORM: Austrian Standards Institute (formerly
Österreichisches Normungsinstitut)
• TAPPI: Technical Association of the Pulp and
Paper Industry
• SCAN: Scandinavian Pulp, Paper & Board Testing
Committee
Used Standard Methods
(compendium)
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DIN
DIN
DIN
DIN
DIN
DIN
DIN
EN 645 Preparation of a cold water extract
EN 647 Preparation of a hot water extract
EN 920 Determination of dry matter content
EN 20287 Determination of moisture content
53124 Determination of pH aqueous extracts
EN 1541 Determination of formaldehyde
54603 Determination of glyoxal content
Cold and Hot Water
Extraction
• Simulating coffee with water
• Cold water extraction (cwe): 10g paper with
200ml water for 24h at room temperature (23°C)
• Hot water extraction (hwe): 10g paper with
200ml water for 2h at 80°C
A coffee filter paper (Size 4)
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cost: ~1-2 cents per filter
weight: ~1,60 - 1,85g
contact area: 2,875 dm²
moisture content: 0,2 - 1,2%
dry matter cwe: 1 bleached: ~5000 mg/kg
2-7 unbleached: ~1500-2300 mg/kg
• dry matter hwe: 1 bleached: ~2700 mg/kg
2-7 unbleached: ~800-2400 mg/kg
• pH cwe: ~7,2-7,5 (blank 6,9)
• pH hwe: ~7,0-7,4 (blank 6,7)
Potassium permanganate
method
Titrimetric determination of volatile
and none volatile organic substances
in an extract
1 Melitta, 2 Spar, 3 Hofer, 4 Billa, 5 Zielpunkt, 6 Schlecker, 7 Lidl
Glyoxal
• Used for paper coatings or cellulose derivatives
• Photometric measurement (405nm) of the
product of HMBT + Glyoxal
• Safety limit: 1,5 mg/dm²
-> all samples
lower than that
by a factor of
~1500-2500
Glyoxal
• Test close to detection limit
• Comparison extraction with 100ml to 200ml with
sample Nr. 6 - good result:
– Absorbance nearly doubled
– which means concentration is nearly the same
Formaldehyde
• Main source paper coatings (problem in 1960s),
monomer from Urea-Formaldehyde resins
• Photometric measurement (410nm) of the
product of Formaldehyde + Acetylacetone
• Safety limit: 1,0 mg/dm²
-> all samples
lower than
that by a
factor of
~200-300
Pentachlorphenol (PCP)
PCP has been used as a herbicide,
insecticide, fungicide, algaecide,
disinfectant -> preserving wood
Very toxic: forbidden since 1989
Safety limit: 2mg/kg
Old method: Photometric test with 4amino-antipyrin showed no reproducible
results -> gas chromatography necessary
to confirm
Fraunhofer Institute for
Process Engineering and
Packaging IVV
Freising - Germany
Scanning Electron Microscope
Bleached Filter (Nr. 1)
1mm
Unbleached Filter (Nr. 4)
1mm
Bleached Filter (Nr. 1)
80μm
Unbleached Filter (Nr. 4)
80μm
Headspace Gas Chromatography
Mass Spectrometry
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Sample in 15ml Vial + 150°C + 1bar
Gasphase analyzed with GC-MS
Identification with library and standards
Quantification tricky
Results: All filters seam to be clean,
except some small
peaks which could
not be identified
Headspace GC-MS Examples
Filter 1 gas chromatogram: except airpeak (3,98) no big peaks
Same chromatogram: the small peaks couldn’t be identified with the library
Filter Package 1: more bigger peaks, some could be identified with
the library and with measurement of standards
17,37 = benzaldehyde; 21,44 acetophenone -> printer’s ink?
X-ray fluorescence
spectroscopy
Results:
• Filter Papers: Sometimes detectable
concentrations of Na, S, Cl and Ca but always
under 0,3% -> questionable (contaminations
from hands possible and too light elements)
• Filter Packages: Same but:
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Fe, Cu, Sr 0,01-0,1%
Al 1-4%
printer’s ink?
Si 1-5%
Ca 8-24% - CaCO3 filler material
Multimethod
Extraction with Accelerated Solvent
Extraction (ASE)
GC-MS (Shimadzu QP-5000) Determination of:
• Benzophenone
• Diisopropylnaphthalene (DIPN)
• Michler's ketone
• Phthalates
• Pentachlorphenol (PCP)
ASE + Sample Preparation
• Preextraction with empty cartridge
• Dichloromethane extraction
-> 3 times for 15 minutes at 100 bar and 80°C
• Direct GC-MS analysis with standards
• Only PCP needs derivatization
Results Phthalates
Nothing found at:
Dimethylphthalat, Diethylphthalat, Diallylphthalat, Dipropylphthalat ,
Benzylbutylphthalat, Dicyclohexylphthalat, Diphenylphthalat,
Didecylphthalat, Diisooctylphthalate, Diisodecylphthalat, Dioctylphthalate
Echelle Plasma Emissions
GC Detector EPED
• P/T (Purge-and-Trap) sampling system
• EPED: GC Detector for sulfur and
halogens chlorine, bromine, fluor, iodine
– Atomization of molecules at 8000K and
atmospheric pressure in a Helium plasma
– Detection of emission lines with a
polychromator
Other results Multimethod
and EPED
• The lab work at both methods is
done and the measuring is finished
• But the reprocessing of the data is
not finalized to be presented
• So far nothing indicates any high
concentrations of any concerning
substances
Conclusion
• No safety limits are exceeded at Formaldehyde,
Glyoxal (PCP pending)
• Concentrations of Phthalates low, but concerning
• No indication of toxic metals (Hg, Cd, Pb, Chrom
VI)
• No indication of migration from
the packages
• No indication that recycled paper
was used
• Some results still open but so
far nothing to really worry
Thanks to
Research Division Food Chemistry
• Ingrid Steiner
• Kathrin Scharnhorst
• Herbert Hafner
Product Safety and Analytics
• Ludwig Gruber
• Gerd Wolz
•Nicole Weise
•Dominik Fiedler
•Michael Barwitz
Thank you for your
Attention