Quality Analysis of Plastics

Thirteen samples were analyzed in triplicate by placing approximately 23 mg of shaved PET pellet into a Gerstel microvial that was placed into a TDU tube and heated to 280oC for 5 minutes inside a thermal desorption unit (TDU). The TDU transfer temp was 300oC and operated in splitless mode. Volatiles generated during the melting process were swept onto a cryo-cooled (LNO2) inlet liner at -120oC (CIS4 liner in split mode 20:1). The liner contained glass beads for increased adsorption. The liner was heated to 280oC and volatiles were transferred to the analytical MACH column. Column heating conditions were: held at 40oC for 2 minutes then 20oC/ minute to 280oC and held for 16 minutes. Total ion chromatogram time was 32.5minutes. Conditions were ramped pressure with initial pressure 7.10 psi for 2 min then 1.14psi /min to 20.80psi and held for 16 minutes. MSD transfer line temperature 300oC. Scan parameters were 45-350amu. The capillary column utilized was a 0.25mm I.D., 0.25µm film thickness, 30M DB5. Components were identified by matching spectra with a Wiley 2007 library.

Data analysis was conducted by integrating total ion chromatograms with Agilent Chemstation and copying selected peak areas to an Excel spreadsheet. Compounds selected were those present in the majority of the 13 samples tested. The mean, standard deviation, standard error, and percent relative standard deviation were calculated utilizing Excel. Component retention time and characteristic identifying ions were utilized to ensure accuracy of peaks attributed to a specific component. Graphs were generated utilizing Excel and Powerpoint. Error bars denoted in graphs indicate standard error.