Analytical methods for food-contact materials additives in olive oil simulant at sub-mg kg-1 level.

Methods of analysis for four additives (two antioxidants, IRGANOX 245 and 1035; an ultraviolet absorber, CHIMMASORB 81; and an optical brightening agent, UVITEX OB) in olive oil are reported. These additives have the potential to migrate from food-contact materials into the European Union fatty food simulant olive oil, which is the most difficult matrix for analysis. The additives were chosen because they differed in their chemically active groups, had different functions within the polymer, have low proposed specific migration limits and are commonly used in food-contact materials such as polystyrenes and polyolefins. The proposed analytical methods for the additives are simple, rapid, inexpensive and also broadly applicable to the aqueous food simulants. All methods were evaluated by constructing calibration curves, measurement of recovery and precision, and determining the limits of detection. Most of the methods involve direct injection of an olive oil solution for high-performance liquid chromatography analysis with ultraviolet-visible or fluorescence detection. The methods allowed establishment of additive stability and measurement of migration of the selected additives into olive oil at different time-temperature conditions used in migration studies into food simulants.

HPLC method for determining ethylenediamine migration from epoxy-amine food packaging coatings into EU food simulants.

A simple, rapid, sensitive and inexpensive method has been developed for the determination of ethylenediamine (EDA) in European Union food simulants. The method involves precolumn derivatization with ortho-phthaldehyde (OPA) and 2-mercaptoethanol (ME) to obtain a fluorescent derivative. Liquid chromatographic (HPLC) elution was achieved with methanol-ultrapure water (65:35) as mobile phase with a Waters Spherisorb 5 microm ODS 2 column. Fluorescence detection (FD) was performed at 330 nm (excitation wavelength) and 450 nm (emission). Total chromatographic analysis time was < 10 min. The proposed method was validated by checking linearity, detection and quantification limits, and precision. Relative recovery rates were of about 100% because samples and standard-spiked blanks were processed in the same way. Method precision (RSD < 6%) was satisfactory and the quantification limit (0.25 mg x (-1)) indicated that specific migration limit for EDA in EU food simulants (12 mg x kg(-1)) can be easily controlled. When the validated method was applied to epoxy-amine formulations used for can coatings under different curing conditions, EDA migration was < 1.4 mg x l(-1).

m-Xylylenediamine determination in the official EU aqueous food simulants.

European Union directive 90/128/EEC prescribes a specific migration limit of 0.05 mg/kg for the aliphatic diamine m-xylylenediamine (m-XDA) into food or food simultants, but there is no generally accepted method of analysis available for compliance testing with the given restriction. A method is described for the determination of m-XDA monomer in the following food simulants: distilled water, 3% (w/v) acetic acid, and 15% (v/v) ethanol. The method is appropriate for the quantitative determination of m-XDA at a minimum level of 0.020 mg/kg in these food simulants. Detection limits are in the range of 0.004 to 0.010 mg m-XDA per kilogram food simulant (depending on the type of food simulant). The method should also be applicable to other aqueous food simulants. m-XDA in aqueous simulant test samples is determined by high-performance liquid chromatography with fluorescence detection following derivatization with fluorescamine. Quantitation is relative to external standards. The identity of m-XDA may be confirmed by the presence of a second peak in the chromatograms obtained from samples derivatized with less fluorescamine or by comparison with authentic samples.

Stability of the Secondary Antioxidant Bis(2,4-di-tert-butylphenyl)pentaerythritol Diphosphite in Food Simulants.

To establish the stability of Ultranox 626 (an antioxidant added to plastics) in food simulants under migration conditions, migrations tests have been performed. A method has been developed for the determination of Ultranox 626 in the aqueous food simulants distilled water, 3% (w/v) acetic acid, and 15% (v/v) ethanol and in the fatty food simulants 95% (v/v) ethanol and isooctane. The method uses reversed-phase high-performance liquid chromatography with ultraviolet detection at 230 nm, is fast, and can be run automatically. To determine the stability of Ultranox 626, it was heated in each of the listed food simulants under the conditions stipulated in EU regulations for testing for compliance with migration limits. These experiments showed that this additive had acceptable stability in water, 15% and 95% (v/v) ethanol, and isooctane but that it decomposed completely in 3% (w/v) acetic acid. Migration testing with 3% acetic acid is of no use, since by the end of the testing regime the additive will have undergone substantial or total decomposition, and the level detected will not reflect the true level of migration. The EU Commission should replace 3% acetic acid with 15% ethanol as an appropriate test simulant for the determination of Ultranox 626 in all types of acid- and alcohol-containing foodstuffs. A number of experiments were carried out to develop a suitable method for the determination of Ultranox in fat simulants such as olive oil and HB 307. It appeared not possible, within the scope of this project, to obtain a method suitable to establish the stability of Ultranox 626 in fat simulants. Best results were obtained by freezing out the fat at -80 degrees C, but recovery was limited to 50%, which was insufficient for the intended purpose. Further experiments are required to establish the stability of Ultranox 626 in fat simulants such as olive oil and HB 307.