2.3 Pump sampling
Indoor air was collected with a Gasprobenehmer GS312 pump sampler
(Desaga, Heidelberg, Germany) equipped with a flowmeter from Kirchner
GmbH (Hamburg, Germany). the PU foam cartridges each with a quartz
filter mounted on top were placed 1 m above ground level and connected
with a polyethylene hose to the pump sampler. Air was sucked through the
filter at a flow of 10 L min-1 until a total volume of
1 m3 was reached. Thereafter, the pump was turned off
and the filter was dismantled and stored in the original amber glass
bottles until analysis in the laboratory on the same day. Each quartz
filter was dismantled and the cartridge was spiked with 20 µL of the
surrogate standard solution in toluene (1:10) and submitted to
pressurized fluid extraction on a ASE™-350 instrument (Thermo
Scientific, Karlsruhe, Germany) using a 22 mL cell equipped with an ASE
extraction cellulose filters on the bottom (Thermo Scientific). The
cells were heated to 100 °C for 10 min (static extraction) and
cyclohexane/diethyl ether (95:5, v:v) was used as extraction solvent at
140 bar. The flush volume was 60%. Extracts were collected in 60 mL
glass vials and concentrated to 1 mL under a stream of nitrogen and
transferred to a GC vial. Each quartz filter was spiked and extracted in
the same manner.