Acetaldehyde residue in polyethylene terephthalate (PET) bottles

A simple sample preparation technique was developed for rapid analysis of acetaldehyde residue in Polyethylene Terephthalate ( PET) bottles. A laboratory-built heating system was used and coupled with gas chromatography-flame ionization detector ( GC-FID) at optimized conditions. The results were a tremendous reduction of the sample preparation time from 24 hours, for the conventional method, to only one hour. The analysis took only 1.5 min with other good analytical performances i.e. a low detection limit, 0.3 ng mL(-1) and a wide linear dynamic range, 0.3 ng mL(-1) to 6.6 mu g mL(-1) with R-2 > 0.99. Acetaldehyde residue in freshly blown bottles were analyzed and found in the range of 0.4 to 1.1 ng mL(-1). The results were good agreement with the conventional 24-hour airspace method ( P < 0.01). The PET-bottle sampling technique was also developed to minimize the complication of sample transportation and pre-concentration. A purge and trap technique was found to be the most suitable. Then, it was implemented and compared, the results showed no significant difference ( P < 0.01) with and without purge and trap.