Determination of various constituent elements of polyethylene terephthalate bottles used for beverages in Japan

Abstract

Polyethylene terephthalate (PET) bottles are some of the most commonly used containers for beverages. During the manufacturing process of PET resin in Japan, metallic catalysts such as Sb and Ge are widely used, with other metals or metallic compounds also being employed to improve the quality of PET bottles. However, few reports into the contents of such elements exist. Thus, we herein report the concentrations of 34 elements (ie, Li, B, Na, Mg, Al, P, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Rb, Sr, Zr, Mo, Ag, Cd, Sn, Sb, Cs, Ba, W, Pb, and U) in 16 samples of unused virgin PET bottles for beverages. The measurement was performed by inductively coupled plasma optical emission spectrometry (ICP‐OES) and inductively coupled plasma mass spectrometry (ICP‐MS), and these bottles were found to contain five main elements (ie, <0.5‐ to 50‐mg/kg Ge, <1‐ to 26‐mg/kg Ti, <0.1‐ to 279‐mg/kg Sb, <10‐ to 48‐mg/kg P, and <0.5‐ to 53‐mg/kg Co) that were used as polymerisation catalysts, stabilisers, oxidation catalysts, and bluing agents. Furthermore, when these residual element concentrations in 21 commercial mineral‐water PET bottles were determined, there was no significant difference from unused bottles.

Migration of catalyst elements from polyethylene terephthalate bottles into food simulants and mineral water under short‐ and long‐term conditions

“…Eight PET bottles with different compositions were selected from the unused PET bottles for which the constituent elements were determined in our previous report. 4 These were virgin PET bottles that did not contain recycled resin. Two of the samples were heat-resistant bottles manufactured using Ge catalysts, two were heat-resistant bottles manufactured using Ti catalysts and four were non-heat-resistant bottles manufactured using Sb catalysts (Table 1).…”

“…4). 4 curves to correct for instrumental drift. The internal standard solution was mixed with the sample solution using a peristaltic pump at a fixed rate (sample solution/internal standard solution ≈ 4:1).…”

“…However, few studies have comprehensively investigated elements other than Sb in bottle materials 2,3 . Therefore, we previously determined the residual concentrations of 34 elements in 16 unused PET beverage bottles 4 . The PET bottles were found to contain five elements (Ge, Ti, Sb, Co and P) that originated from polymerization catalysts, oxidation catalysts, bluing agents and stabilizers.…”

“…2,3 Therefore, we previously determined the residual concentrations of 34 elements in 16 unused PET beverage bottles. 4 The PET bottles were found to contain five elements (Ge, Ti, Sb, Co and P) that originated from polymerization catalysts, oxidation catalysts, bluing agents and stabilizers. The contents of these elements were lower than the regulatory limits for catalysts defined by the Japan Hygienic Olefin and Styrene Plastics Association (JHOSPA) and the German Federal Institute for Risk Assessment (BfR) (i.e., 100 mg/kg Ge, unregulated or 120 mg/kg Ti, 350 mg/kg Sb, 95 or 125 mg/kg Co and unregulated or 125 mg/kg P).…”

“…In this study, we performed migration tests on unused PET beverage bottles, the elemental contents of which were determined in our previous study. 4 In particular, the migration levels of five elements (Ge, Ti, Sb, Co and P) contained in the PET bottles into food simulants were investigated under various conditions (food simulants: distilled water, 4% acetic acid and 50% ethanol; time: 10 days to 24 months; temperature: 25-60 C). To date, many studies on the migration of Sb have been published, 3,[15][16][17][18][19] but only a few have investigated the migration of other elements.…”