2.4. Sample collection and microcosms tests at laboratory scale
Water samples of the final effluent of the secondary clarifier of
WWTP of Parada, localized on the North of Portugal, were collected
at July 2012 in pre-rinsed amber glass bottles (2 L) and transported
at 4 C to the laboratory. The degradation assays were performed
into 2 L pre-rinsed glass bottles covered with aluminium foil with
400 mL of wastewater sample spiked with the enantiomeric mixture
of FLX to obtain a concentration of each enantiomer of
25 ng mL1
. These assays were done in quadruplicate on a shaker
(130 rpm) at 25 C. Non spiked controls were assayed at the same
conditions. The concentration of each enantiomer was monitored during 46 days using the described SPE-HPLC-FD validated
method.