Cytostatic compounds in sludge and sediment: extraction and determination by a combination of microwave-assisted extraction and UHPLC-MS/MS.

Cytostatic compounds are an important group of micro-pollutants since they are used to kill cells or stop cell division. For this reason, they are also considered mutagenic. Several cytostatic compounds have been detected in hospital effluents, in the influents and effluents of wastewater treatment plants and even in river water. However, their detection in solid matrices is very scarce. In this work, we have developed a new procedure based on microwave-assisted extraction (MAE) for the extraction of cytostatic compounds from sludge and sediment before determination by ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). To develop this procedure, we have chosen a group of eight widely used cytostatic compounds and carried out a systematic experimental design to optimize the extraction conditions. Under these optimal conditions, the studied cytostatic compounds are extracted with good sensitivity, with recoveries ranging from 65 to 122% in sludge and recoveries varying between 49 and 109% in sediment, with the exception of etoposide, which has a lower recovery from these types of samples. The limits of detection were from 0.42 to 79.8 ng g-1 in sludge and from 0.10 to 87.5 ng g-1 in sediment. Intraday and interday relative standard deviations (RSDs) were below 15% and 18%, respectively, in both matrices at the tested concentrations. The total procedure was applied to samples of sludge taken from the main wastewater treatment plant (WWTP) of the island of Gran Canaria (Spain) and for sediment samples obtained close to the marine outfalls of different wastewater treatment plants for the same island. Graphical abstract.