Development of a rapid and simple analytical method for the ...
Development of a rapid and simple analytical method for the determination of benzophenone, diphenylbutadiene and Uvitex® OB in spiked LDPE films J. Maia(1), R. Franz(2), A. Seiler(2), E. L. Bradley(3), I. Leon(3), C. Simoneau(4), G. Beldi(4), S. Pastorelli(5), J. M. Cruz(6) and P. Paseiro(1) [email protected] (1) Department of Analytical Chemistry, Nutrition and Food Science, Faculty of Pharmacy. University of Santiago de Compostela, E-15782 Spain. (2) Fraunhofer Institut fürVerfahrenstechnik und Verpackung, Giggenhauser Str. 85354 Freising, Germany. (3) The Food and Environment Research Agency, Department for Environment, Food and Rural Affairs, Sand Hutton, York, YO41 1LZ, UK. (4) European Commission, DG Joint Research Centre, Institute for Health and Consumer Protection, Unit Chemical Assessment and Testing, T.P. 260, 21020 Ispra (Va), Italy. (5) Nestlé Research Center, Q&S; PO Box 44, CH-1000 Lausanne 26 (6) Department of Chemical Engineering, E.T.S.E.I. University of Vigo, Spain
WP 4.2
Introduction Packaging is an important procedure in food manufacturing. This practice has the important task of protecting foodstuff from spoilage and degradation through storage and distribution, increasing its shelf life. In this area, plastic is one of the packaging materials most widely used by the food industry. This is not an inert material and is able to interact with the surrounding environment, allowing food-packaging interactions, such as sorption, permeation and migration1. Plastic additives, commonly used to modify their appearance and to improve polymer properties, and residual monomers and oligomers are not chemically bound to the polymer molecules and can, therefore, move freely within the polymer matrix2. In this way, substances from food packaging are able to migrate into the foodstuff. This phenomenon, known as migration, claims special attention in the aspect of food safety because the chemicals that migrate into food may be potentially harmful to human health3. The aim of this study is to develop a quick and simple method for the simultaneous analysis of three chemicals in low density polyethylene (LDPE) film. The chemicals chosen for this work were: benzophenone (one of the most commonly used photo-initiators in inks that are cured with UV light), 1,4-diphenylbutadiene (DPBD; model substance widely used in food migration studies) and Uvitex® OB (optical brightening agent). The addition of the chemicals into the LDPE film took place during the extrusion process. The three chemicals were spiked into LDPE and are to be used as model substances for subsequent work in measuring migration kinetics and developing enhanced migration models as part of the EU-FP7 project FACET.
Materials and methods
Results and discussion mAU
mAU
Standarts:
A
350
B
100
mAU 300
Three model substances were chosen:
300
50
200 100
Name
CAS no.
Formula
Use
mAU
0
250
225
275
325
140
375 nm
0
100
200
Benzophenone
119-61-9
photo-initiator 150
mAU 60
20
1,4-Diphenyl butadiene
model substance widely used in food migration studies
538-81-8 H3C
Uvitex® OB
7128-64-5
O
N
optical brightening agent
S
H3C N
CH3
0 225
275
325
375 nm
50
0
CH3 CH3
H3C
100
Benzophenone
40
60 20 225
275
325
375 nm
-50
mAU
2
4
6
8
10
12
14
16 min
C
100
Uvitex® OB
1,4-diphenylbutadiene
O
50
0
-50
-50
O
2
Table 1: Model substances used.
The addition of the chemicals into the LDPE film took place during the extrusion process.
4
6
8
10
12
14
16 min
2
4
6
8
10
12
14
16 min
Figure 1: Standard solution with a 5.0 µg.ml-1 concentration of the three model substances in ethanol and respective UV absorption spectra (A); First extraction solution of a LDPE spiked with the three model substances (B); Second extraction solution of a LDPE spiked with the three model substances (C).
Calibration line parameters: Extraction from LDPE: A sample of spiked LDPE film (area = 1x6.5 cm2; average thickness = 220 µm; average weight = 120 mg) was placed in a glass flask with 50 ml of ethanol and extracted for 6 hours at 70 ºC. An second extraction was done, using the same conditions.
Parameters of calibration line
Benzophenone
DPBD
Uvitex®OB
Slope
217.29
583.97
266.55
Intercept
-1.6069
13.811
8.9436
Correlation coeficient
0.99991
0.99974
0.99991
Range (µg·mL-1)
Cromatographic conditions
0.05 - 10 Table 3: Calibration lines parameters.
Injection volume Column temperature
Wavelength
20 µL
Limit of detection
30 ºC Substance
λ (nm)
Benzophenone
256
DPBD
330
Uvitex® OB
372
Column
Kromasil C18 25 x 0.36 cm I.D., 5 μm particle size
Mobile phase
A: Milli-Q water B: THF 30% methanolic solution (v/v)
Flow rate
Gradient
Benzophenone limit of detection (LOD) was 50 ng.ml-1. For 1,4-diphenylbutadiene and Uvitex® OB, the limit of detection was 10 ng.ml-1, for both substances.
Conclusions The first extraction proved to be enough to extract the three model migrants completely. Calibration lines, ranging 0.05-10.0 µg·ml-1, showed a good linearity (r2 > 0.9997).
0.5 mL·min-1 Time (min)
%A
%B
0.00
30.00
70.00
4.00
30.00
70.00
15.00
0.00
100.00
17.00
0.00
100.00
Table 2: Chromatographic conditions.
The resulting chromatograms showed three well resolved peaks. It is concluded that the method is fast and accurate. The method will be used extensively within FACET to provide data on the initial concentration of the model substances in the plastic (Cp,o) which is an important parameter in migration modelling. The method will also provide migration concentration data in foods and equilibrium partition coefficients, estimated as the mass fraction lost from the film after a migration experiment.
References:
Acknowledgement:
[1] Sanches Silva, A., Cruz Freire, J. M., Franz, R., Paseiro Losada, P. (2008). Time-temperature study of the kinetics of migration of
This work was co-funded by the European Union under Grant Agreement 211686 (Project FACET - Flavours, Additives and food Contact material Exposure Task) and by Xunta de Galicia (Proj. nº INCITE08PXIB203096). The findings and the conclusions in this poster are the responsibility of the authors alone and they should not be taken to represent the opinion of sponsors.
diphenylbutadiene from polyethylene films into aqueous foodstuffs. Food Research International, 41 (2) 138-144. [2] Sanches Silva, A., Cruz Freire, J. M., Sendón García, R., Franz, R., Paseiro Losada, P. (2007). Time-temperature study of the kinetics of migration of DPBD from plastics into chocolate, chocolate spread and margarine. Food Research International, 40 (6) 679-686. [3] Munro, I. C., Hlywka, J. J. and Kennepohl, E. M. (2002). Risk assessment of packaging materials. Food Additives and Contaminants, 19 (1) 3-12
The authors are also grateful to C. Casal, P. Blanco and G. Hermelo for their excellent technical assistance.
WP 4.2
Introduction Packaging is an important procedure in food manufacturing. This practice has the important task of protecting foodstuff from spoilage and degradation through storage and distribution, increasing its shelf life. In this area, plastic is one of the packaging materials most widely used by the food industry. This is not an inert material and is able to interact with the surrounding environment, allowing food-packaging interactions, such as sorption, permeation and migration1. Plastic additives, commonly used to modify their appearance and to improve polymer properties, and residual monomers and oligomers are not chemically bound to the polymer molecules and can, therefore, move freely within the polymer matrix2. In this way, substances from food packaging are able to migrate into the foodstuff. This phenomenon, known as migration, claims special attention in the aspect of food safety because the chemicals that migrate into food may be potentially harmful to human health3. The aim of this study is to develop a quick and simple method for the simultaneous analysis of three chemicals in low density polyethylene (LDPE) film. The chemicals chosen for this work were: benzophenone (one of the most commonly used photo-initiators in inks that are cured with UV light), 1,4-diphenylbutadiene (DPBD; model substance widely used in food migration studies) and Uvitex® OB (optical brightening agent). The addition of the chemicals into the LDPE film took place during the extrusion process. The three chemicals were spiked into LDPE and are to be used as model substances for subsequent work in measuring migration kinetics and developing enhanced migration models as part of the EU-FP7 project FACET.
Materials and methods
Results and discussion mAU
mAU
Standarts:
A
350
B
100
mAU 300
Three model substances were chosen:
300
50
200 100
Name
CAS no.
Formula
Use
mAU
0
250
225
275
325
140
375 nm
0
100
200
Benzophenone
119-61-9
photo-initiator 150
mAU 60
20
1,4-Diphenyl butadiene
model substance widely used in food migration studies
538-81-8 H3C
Uvitex® OB
7128-64-5
O
N
optical brightening agent
S
H3C N
CH3
0 225
275
325
375 nm
50
0
CH3 CH3
H3C
100
Benzophenone
40
60 20 225
275
325
375 nm
-50
mAU
2
4
6
8
10
12
14
16 min
C
100
Uvitex® OB
1,4-diphenylbutadiene
O
50
0
-50
-50
O
2
Table 1: Model substances used.
The addition of the chemicals into the LDPE film took place during the extrusion process.
4
6
8
10
12
14
16 min
2
4
6
8
10
12
14
16 min
Figure 1: Standard solution with a 5.0 µg.ml-1 concentration of the three model substances in ethanol and respective UV absorption spectra (A); First extraction solution of a LDPE spiked with the three model substances (B); Second extraction solution of a LDPE spiked with the three model substances (C).
Calibration line parameters: Extraction from LDPE: A sample of spiked LDPE film (area = 1x6.5 cm2; average thickness = 220 µm; average weight = 120 mg) was placed in a glass flask with 50 ml of ethanol and extracted for 6 hours at 70 ºC. An second extraction was done, using the same conditions.
Parameters of calibration line
Benzophenone
DPBD
Uvitex®OB
Slope
217.29
583.97
266.55
Intercept
-1.6069
13.811
8.9436
Correlation coeficient
0.99991
0.99974
0.99991
Range (µg·mL-1)
Cromatographic conditions
0.05 - 10 Table 3: Calibration lines parameters.
Injection volume Column temperature
Wavelength
20 µL
Limit of detection
30 ºC Substance
λ (nm)
Benzophenone
256
DPBD
330
Uvitex® OB
372
Column
Kromasil C18 25 x 0.36 cm I.D., 5 μm particle size
Mobile phase
A: Milli-Q water B: THF 30% methanolic solution (v/v)
Flow rate
Gradient
Benzophenone limit of detection (LOD) was 50 ng.ml-1. For 1,4-diphenylbutadiene and Uvitex® OB, the limit of detection was 10 ng.ml-1, for both substances.
Conclusions The first extraction proved to be enough to extract the three model migrants completely. Calibration lines, ranging 0.05-10.0 µg·ml-1, showed a good linearity (r2 > 0.9997).
0.5 mL·min-1 Time (min)
%A
%B
0.00
30.00
70.00
4.00
30.00
70.00
15.00
0.00
100.00
17.00
0.00
100.00
Table 2: Chromatographic conditions.
The resulting chromatograms showed three well resolved peaks. It is concluded that the method is fast and accurate. The method will be used extensively within FACET to provide data on the initial concentration of the model substances in the plastic (Cp,o) which is an important parameter in migration modelling. The method will also provide migration concentration data in foods and equilibrium partition coefficients, estimated as the mass fraction lost from the film after a migration experiment.
References:
Acknowledgement:
[1] Sanches Silva, A., Cruz Freire, J. M., Franz, R., Paseiro Losada, P. (2008). Time-temperature study of the kinetics of migration of
This work was co-funded by the European Union under Grant Agreement 211686 (Project FACET - Flavours, Additives and food Contact material Exposure Task) and by Xunta de Galicia (Proj. nº INCITE08PXIB203096). The findings and the conclusions in this poster are the responsibility of the authors alone and they should not be taken to represent the opinion of sponsors.
diphenylbutadiene from polyethylene films into aqueous foodstuffs. Food Research International, 41 (2) 138-144. [2] Sanches Silva, A., Cruz Freire, J. M., Sendón García, R., Franz, R., Paseiro Losada, P. (2007). Time-temperature study of the kinetics of migration of DPBD from plastics into chocolate, chocolate spread and margarine. Food Research International, 40 (6) 679-686. [3] Munro, I. C., Hlywka, J. J. and Kennepohl, E. M. (2002). Risk assessment of packaging materials. Food Additives and Contaminants, 19 (1) 3-12
The authors are also grateful to C. Casal, P. Blanco and G. Hermelo for their excellent technical assistance.
