Gas chromatography triple quadrupole mass spectrometry method for monitoring multiclass organic pollutants in Spanish sewage treatment plants effluents

► Multi-residue GC-MS/MS method (MRM) developed for 57 multi-class organic contaminants in wastewater samples. ► Analysis of both liquid phase and particulate matter of wastewater samples included (as required by the European WFD). ► Evaluation of the presence of such compounds in different wastewater treatment plants effluents (33 samples). ► Hexachlorobenzene frequently detected in the studied samples (at levels below 5 μg L−1).