Migration of nanoparticles from plastic packaging materials containing carbon black into foodstuffs

Figures & data

Table 1. Properties of carbon black grades used in the study.

Property	Printex^® 85	Printex^® 80
Manufacturer	Orion Engineered Carbons GmbH	Orion Engineered Carbons GmbH
Type	Medium colour furnace	Medium colour furnace
Relative tinting strength (%); IRB 3 = 100%	120	126
Volatile matter 950°C (%)	1.2	1.2
Oil absorption number (OAN) (ml 100 g^−1)	54	105
pH	9.5	9.0
Ash content (%)	0.6	0.1
Brunauer–Emmett–Teller (BET) surface area (m^2 g^−1)	200	220
Average primary particle size (nm)	16	16

Note: IRB 3, Industry Reference Black No. 3.

Table 2. Additives used for mathematical migration modelling.

Additive	Chemical name/composition	CAS No.
Irganox 1076	Octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate	2082-79-3
Irganox 1010	Pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)proprionate)	668319-8
Tinuvin 770	1,3,5-Triazine-2,4,6-triamine,N,N´´´-[1,2-ethane-diyl-bis[[[4,6-bis-[butyl(1,2,2,6,6-pentamethyl-4-piperidinyl)amino]-1,3,5-triazine-2-yl]imino]-3,1-propanediyl]]bis[N´,N´´-dibutyl-N´,N´´-bis(1,2,2,6,6-pentamethyl-4-piperidinyl)	106990-43-6

Figure 1. TEM micrographs of carbon black in the dry state: left: Printex^® 80, right: Printex^® 85.

Figure 2. TEM micrographs of 2.5% Printex^® 80 in LDPE at two magnifications.

Figure 3. TEM micrographs of 2.5% Printex^® 85 in LDPE at two magnifications.

Figure 4. TEM micrographs of 2.5% Printex^® 80 in PS at two magnifications.

Figure 5. TEM micrographs of 2.5% Printex^® 85 in PS at two magnifications.

Figure 6. Signal of the 90° MALLS detector of Printex^® 80 (50 µg l^–1) overlaid with the solvent blank (black dots) and the calculated radii of gyration per elution time (grey dots).

Figure 7. Signal of the 90° MALLS detector of Printex^® 85 (50 µg l^–1) overlaid with the solvent blank (black dots) and the calculated radii of gyration per elution time (grey dots).

Figure 8. Fractograms of the LDPE migration samples: 5.0% Printex^® 80 in LDPE, 5.0% Printex^® 85 in LDPE and LDPE blanks of the isooctane (24 h/40°C) and 95% ethanol (10 days/60°C) migration samples.

Figure 9. Fractograms of the LDPE migration samples: 5.0% Printex^® 80 in LDPE, 5.0% Printex^® 85 in LDPE and LDPE blank of 3% acetic acid (10 days/60°C) migration samples.

Figure 10. Fractograms of the PS migration samples: 5.0% Printex^® 80 in PS, 5.0% Printex^® 85 in PS and PS blanks of the isooctane (24 h/40°C), 95% ethanol (10 days/60°C) migration samples.

Figure 11. Fractograms of the PS migration samples: 5.0% Printex^® 80 in PS, 5.0% Printex^® 85 in PS and PS blank of 3% acetic acid (10 days/60°C) migration samples.

Figure 12. 5.0% Printex^® 85 in LDPE migration sample (10 days/60°C in 95% ethanol): untreated (black) and spiked with 50 µg l^–1 of Printex^® 85 (grey).

Figure 13. 5.0% Printex^® 80 in PS migration sample (24 h/40°C in isooctane): untreated (black) and spiked to 25 µg l^–1 with Printex^® 80 (grey).

Figure 14. Sequential dilution of Printex^® 80: blank, 10, 25, 50, 100 and 250 µg l^–1; signal of the 90° MALLS detector.

Figure 15. Sequential dilution of Printex^® 85: blank, 10, 25, 50, 100 and 250 µg l^–1 signal of the 90° MALLS detector.

Figure 16. Calibration curve for Printex^® 80: total MALLS output versus concentration of standard (1000 µl injections) with relative standard deviations.

Figure 17. Calibration curve for Printex^® 85: Total MALLS output versus concentration of standard (1000 µl injections) with relative standard deviations.

Figure 18. Stability of a Printex^® 80 dispersion in 95% ethanol: signal of the 90° MALLS detector of a freshly prepared dispersion (black) and of a dispersion stored for 10 days at 60°C (grey).

Figure 19. Stability of a Printex^® 85 dispersion in 95% ethanol: signal of the 90° MALLS detector of a freshly prepared dispersion (black) and of a dispersion stored for 10 days at 60°C (grey).

Table 3. Stability of carbon black in 95% ethanol at migration conditions (1000 µl injections of 100 µg l⁻¹ dispersions).

Carbon black type	Simulant	Area		Detection limit (10 µg l^−1 standard)
		Without storage	With storage	Without storage		With storage
		(V*min)	(V*min)	(V*min)	(ng)	(ng)
Printex^® 80	95% ethanol	206.6 ± 2.5	128.4 ± 1.7	24.3 ± 7.4	10	16
Printex^® 85	95% ethanol	28.5 ± 1.5	17.4 ± 0.6	3.5 ± 1.8	10	16

Table 4. Stability of carbon black in isooctane and 3% acetic acid at migration conditions (1000 µl injections of 100 µg l⁻¹ dispersions).

		Area		Detection limit (10 µg l^−1 standard)
		Without storage	With storage	Without storage	With storage
Carbon black type	Simulant	(V*min)	(V*min)	(ng)	(ng)
Printex^® 80	Isooctane	186.3 ± 2.9	101.2 ± 2.1	11	20
Printex^® 80	3% acetic acid	204.9 ± 3.8	102.5 ± 1.9	10	20
Printex^® 85	Isooctane	23.2 ± 2.5	12.1 ± 0.3	12	24
Printex^® 85	3% acetic acid	26.9 ± 1.3	13.5 ± 0.9	11	21

Table 5. Migration modelling of three additives in relation to their molecular size (plaques 3 mm, 5% additive concentration, 10 days/40°C, K = 1, surface to volume ratio 6 dm² kg⁻¹).

Additive	Molecular weight (g mol^−1)	Molecular/particle volume (nm^3)	LDPE diffusion coefficient (AP 11.5, τ 0) (cm^2 s^−1)	LDPE migration (mg kg^−1)	PS diffusion coefficient (AP –1, τ 0) (cm^2 s^−1)	PS migration (mg kg^−1)
Irganox 1076	531	0.588	2.2 10^−9	1323	8.2 10^−15	3.12
Irganox 1010	1178	1.190	3.1 10^−11	160	1.1 10^−16	0.37
Tinuvin 770	2286	2.417	2.0 10^−13	13	7.3 10^−19	0.03

Table 6. Comparison of diffusion coefficients at 25°C obtained according to Simon et al. (2008) with that according to the modelling guideline (Simoneau 2010).

Additive	Molecular/particle volume (nm^3)	Radius (nm)	LDPE diffusion coefficient according to Simon et al. (2008) (cm^2 s^−1)	LDPE diffusion coefficient (AP 11.5, τ 0) (cm^2 s^−1)	PS diffusion coefficient according to Simon et al. (2008) (cm^2 s^−1)	PS diffusion coefficient (AP –1, τ 0) (cm^2 s^−1)
Irganox 1076	0.588	0.52	6.36 10^−14	4.09 10^−10	<2.10 10^−18	1.52 10^−15
Irganox 1010	1.190	0.66	5.03 10^−14	5.72 10^−12	<1.66 10^−18	2.13 10^−17
Tinuvin 770	2.417	0.83	3.97 10^−14	3.66 10^−14	<1.31 10^−18	1.36 10^−19
Particle
Ø 10 nm	524	5.00	6.61 10^−15		<2.18 10^−19
Ø 16 nm	2145	8.00	4.13 10^−15		<1.36 10^−19
Ø 100 nm	523599	50.00	6.61 10^−16		<2.18 10^−20

Simon P, Chaudhry Q, Bakos D. 2008. Migration of engineered nanoparticles from polymer packaging to food – a physicochemical view. J Food Nutr Res. 47:105–113.

 Web of Science ®Google Scholar

Simoneau C. 2010. Applicability of generally recognised diffusion models for the estimation of specific migration in support of EU Directive 2002/72/EC. JRC scientific and technical reports: EUR 24514 EN.

 Google Scholar