2.4 Quantification of PAH using GC-MS
PAH congener quantifications were performed on an Agilent 7890A gas chromatograph (Agilent Technologies, Waldbronn, Germany) equipped with a MPS2 autosampler including an automated tube exchange device (Gerstel, Mülheim/Ruhr, Germany), a Gerstel thermal desorption unit (TDU) including a TDU tray, a Gerstel CIS4 cold injection system, and a Select PAH column (30 m x 0.25 mm 0.15 µm) from Agilent. The gas chromatograph was coupled to an Agilent 5975C inert XL mass selective detector. The TDU was run in the splitless mode and started at 30 °C (held for 1 min) and was ramped with 12 °C min-1 to 300 °C. The TDU transfer temperature was kept at 320 °C. The CIS4 was operated in the solvent vent mode at 8.77 psi and a helium (5.0) vent flow of 60 mL min-1. The GC oven program started at 70 °C (held for 1 min) and was ramped with 40 °C min-1 to 140 °C, then ramped with 20 °C min-1 to 350 °C and held for 5 min. Helium 5.0 was used as carrier gas with a constant flow of 1.0 mL min-1. The CIS injector was run in the splitless mode, the transfer line, the ion source, and the quadrupole were kept at 280 °C, 230 °C, and 150 °C, respectively. The detector was run in the single ion monitoring mode (electron impact, 70 eV) using the fragments and retention time windows listed in supplementary Table S1. For calibration of PAH determinations in extracts from PU foams, quartz filters, and PAH source material fourteen gravimetrically prepared dilutions of NIST 1647f in toluene were injected via the CIS4 injector into of the GC-MS system similar as likewise the processed extracts (section 2.3). For details on the concentrations and the calibration curves obtained by linear regression throughout with coefficients of determination > 0.995 see supplementary Table S1. For calibration of the SBSE analyses seven cleaned SBSE devices were spiked with toluene solutions of NIST 1647f and submitted to the TDU via the tube exchange device similar to the SBSE devices exposed for airborne PAH sampling (supplementary Table S1).