This procedure measures the amount of acetaldehyde in PET resin or a PET preform.
PET resin or preform samples are ground to a small particle size. A known weight of this ground material is sealed into a glass vial equipped with a teflon-lined rubber septum. These vials are then heated to drive the AA to the headspace of the vial. A sample of the equilibrated headspace in the vial is removed and is injected into a gas chromatograph and the software measures the acetaldehyde peak area. A suitable acetaldehyde standard is used to calibrate the gas chromatograph. This is then used to calculate the amount of acetaldehyde in the samples.