2.2 Sampling with stir bar sorptive extraction
SBSE devices were cleaned in a TDU C200 conditioner (Gerstel) at 300 °C
under a nitrogen flow of 100 mL min-1 for two hours
and kept in closed chromatography glass vials containing inserts with
metal springs (Gerstel) until application on the sampling spots. For
sampling, the devices were positioned on specific sites of the steel
construction and the wall. In order to avoid direct contact with the
wall or steel tubes aluminum foil were placed between the magnetic SBSE
devices and the steel part. For sampling of the cross section of the
room a tape was fixed on the ground and SBSE devices were placed on top
of it as outlined in Fig. 1. Room temperature and air humidity were
monitored using a VoltCraft DL-121 TH Multidata Logger. After the
respective exposition time, SBSE devices were collected and put into the
vials for transport to the laboratory and stored until analysis under
repeatability conditions on the last day of each sampling campaign.