Determination of Residual Acetaldehyde in Polyethylene Terephthalate Bottles, Preforms, and Resins by Automated Headspace Gas Chromatography

Abstract

A rapid and sensitive method based on automated headspace gas chromatography for the determination of residual acetaldehyde in polyethylene terephthalate (PET) resins, preforms, and bottles is described. The analysis sequence entails sample grinding in a liquid nitrogen mill, storage is septum capped vials, thermal treatment to liberate acetaldehyde, and subsequent headspace analysis for acetaldehyde content. Quantification is based on comparison to acetaldehyde in a PET reference sample. The method offers significant advantages in sensitivity, precision, and sample through-put compared to solid injection gas chromatography. Acetaldehyde analysis of PET carbonated beverage bottles and resins is important because small amounts of acetaldehyde can affect beverage taste and hence consumer acceptance.