Introduction

Materials and methods

Injection

volume20 µL

Column

temperature30 ºC

Wavelength

Substance λ (nm)

Benzophenone 256

DPBD 330

Uvitex® OB 372

ColumnKromasil C18 25 x 0.36 cm I.D.,

5 μm particle size

Mobile phaseA: Milli-Q water

B: THF 30% methanolic solution (v/v)

Flow rate 0.5 mL·min-1

Gradient

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

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)

joaquimmanuel.alves@usc.es

(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

Cromatographic conditions

Table 2: Chromatographic conditions.

Results and discussion

Development of a rapid and simple analytical method for the determination of

benzophenone, diphenylbutadiene and Uvitex® OB in spiked LDPE films

Acknowledgement:

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.

The authors are also grateful to C. Casal, P. Blanco and G. Hermelo for their excellent technical assistance.

References:

[1] Sanches Silva, A., Cruz Freire, J. M., Franz, R., Paseiro Losada, P. (2008). Time-temperature study of the kinetics of migration of

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

Name CAS no. Formula Use

Benzophenone 119-61-9 photo-initiator

1,4-Diphenyl

butadiene538-81-8

model substance widely used

in food migration studies

Uvitex® OB 7128-64-5 optical brightening agent

Three model substances were chosen:

Standarts:

O

N

O

SH3C

CH3

H3C

N

O

CH3

CH3

H3C

The addition of the chemicals into the LDPE film took place during the extrusion

process.

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.

Table 1: Model substances used.

Parameters of

calibration lineBenzophenone DPBD Uvitex®OB

Slope 217.29 583.97 266.55

Intercept -1.6069 13.811 8.9436

Correlation

coeficient0.99991 0.99974 0.99991

Range (µg·mL-1) 0.05 - 10

Calibration line parameters:

Limit of detection

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).

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.

Table 3: Calibration lines parameters.

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.

60

40

20

0

mAU

225 275 325 375 nm

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.

B

C

A

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).

Ben

zop

he

no

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Uvite

x®

OB

1,4

-dip

he

nylb

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die

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2 6 84 1210 14 16 min

2 6 84 1210 14 16 min

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2 6 84 1210 14 16 min

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mAU

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225 275 325 375 nm 140

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225 275 325 375nm

WP 4.2