100B-10 |
The chemical changes in an amorphous nylon polymer upon irradiation |
V. KOMOLPRASERT1, T. P. McNeal2, C. Adhikari3, and T. H. Begley2. (1) Food and Drug Administration and National Center for Food Safety and Technology, 6502 South Archer Road, Summit-Argo, IL 60501, (2) Food and Drug Administration, 200 C Street SW, Washington, DC 20204, (3) National Center for Food Safety and Technology, 6502 South Archer Road, Summit-Argo, IL 60501 The chemical changes in an irradiated amorphous nylon, Selar PA 2072, were studied to determine the stability of the material intended for the packaging of foods prior to irradiation. The objective was to determine the chemical changes in the nylon after irradiation. The nylon was irradiated at 5, 25, and 50 kGy at ambient temperature with a Co60 radiator. After irradiation, volatiles were determined using HS/GC/MSD. Nonvolatiles were extracted with 10% and 50% ethanol solution maintained at 40oC for up to 10 days. The soluble solids were weighed and analyzed using HPLC with PDA and MS detection. The HS/GC/MSD results suggest that gamma irradiation generates n-butanal, acetic acid and methyl-cyclopentene-1-one. These chemicals were not quantifiable after exposure to 5 kGy. After exposure to 50 kGy, their concentrations increased to 1.7 ppm, 28.5 ppm, and 2.1 ppm respectively. Methyl ethyl ketone (MEK) and n-pentanal were detected in both non-irradiated (NIR) and irradiated (IR) test specimens. MEK concentrations increased from trace levels in the NIR specimens to 1.0 ppm after exposure to 50 kGy. n-Pentanal levels increased from 0.66 ppm in the NIR specimens to 71.6 ppm after exposure to 50 kGy. Before irradiation, the average weight-percentages of soluble solids were 0.49% and 0.97% for 10% and 50% ethanol, respectively. No significant increases in percent solids were seen after exposure to 5, 25, and 50 kGy doses. The HPLC results suggest that no new chemicals were detected in the irradiated nylon. 30 peaks were detected by PDA but only 9 of them were seen with MS detection. The m/z ratios for the base ion of the nine peaks were 138, 171, 285, 544, 719, 857, 882, 1133, and 1429. The data suggest that gamma irradiation at 5-50 kGy doses significantly increases the concentrations of volatiles but has little if any effect on the formation of non-volatiles.
Session 100B, Food Packaging
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