Survey of formaldehyde, acetaldehyde and oligomers in polyethylene terephthalate food-packaging materials.

Polyethylene terephthalate (PET) is frequently used as a packaging material for beverage bottles, fruit and vegetable trays, and egg crates in Japan. Levels of formaldehyde (FA), acetaldehyde (AA) and PET oligomers in various PET food packaging were determined. PET samples were initially dissolved in trifluoroacetic acid with 2,4-dinitrophenylhydrazine to derivatize formaldehyde and acetaldehyde to their dinitrophenylhydrazones. The stable derivatives along with the oligomers were analysed using HPLC with ultraviolet light detection at 360 and 254 nm, respectively. The PET pellets contained 3.5–12.4 µg g−1 AA and 4.0–7.2 mg g−1 oligomers, while FA was below the determination limit. FA, AA and oligomer levels in Japanese bottles were 0.6–3.0 µg g−1, 8.4–25.7 µg g−1 and 5.0–8.7 mg g−1, ND–1.6 µg g−1, 5.0–13.1 µg g−1 and 4.9–8.2 mg g−1 in French and Italian bottles, and ND–1.2 µg g−1, 9.1–18.7 µg g−1 and 5.6–8.0 mg g−1 in US and Canadian bottles, respectively. Compared with European bottles, Japanese bottles...