An evaluation of aromatic hydrocarbons in recycled PET fibers by a reliable and effective static headspace GC-FID method

Abstract

The volatile organic compounds (VOCs) released from recycled polyethylene terephthalate products has raised much concern in consideration of ecological safety. This work has established a reliable and effective headspace GC-flame ionization detection (HS-GC-FID) method for the determination of aromatic hydrocarbons (including benzene, toluene, ethylbenzene, xylene, styrene and cumene) in R-PET fibers. The optimum equilibration time and temperature, and sample weight were identified as 40 min, 110C and 1.0 g, respectively. By contrasting with 15 mL headspace bottle, the testing results of samples incubated in 120 mL headspace bottle provided a higher data repeatability. The linear equations to calculate VOCs content were obtained by linear regression analysis, and the linear regression coefficients were validated to be over 0.997. Limits of detection for benzene, toluene, ethylbenzene, p-xylene + m-xylene, o-xylene + styrene and cumene were calculated as 3.95 ng, 3.68 ng, 4.16 ng, 3.30 ng, 2.59 ng, 8.64 ng, respectively. Reproducibility tests of the method generated relative standard deviations of 6.0% or less, with recoveries in the range of 82%–109%. The availability of proposed method in application of VOCs detection in R-PET fibers was confirmed by detecting VOCs contents of virgin PET fibers, and R-PET fibers produced by physical, chemical and physical-co-chemical processes.。