Persistent and mobile organic chemicals in the aquatic environment: Occurrence and analytical challenges

The for screening of environmental samples routinely applied reversed-phase liquid chromatography high-resolution mass spectrometry (RPLC-HRMS) substantially supported the awareness of the partially ubiquitous occurrence of man-made chemicals in the aquatic environment.

However, RPLC does not allow sensitive screening for highly polar chemicals due to poor chromatographic retention resulting in devastating matrix effects and poor peak shape during chemical analysis, thus resulting in an anlytical gap. Hence, only a very limited number of monitoring data is available for this compound class. This is of concern, since polar and persistent compounds (PM-substances) can pass barriers like waste-water treatment, the subsurface environment during bank filtration or infiltration and finally even drinking water treatment. In consequence, PM-substances are a potential threat to the quality of water and thus not only the aquatic environment, but also human health.

This is of particular importance, if PM substances are also toxic (PMT substances). The growing awareness of the risk posed by PM(T) substances to our water resources is reflected in the European Commission's recent proposal to consider the mobility of chemicals as an important criterion for their risk assessment.

Important chromatographical methods that retain very polar compounds and thus broaden the polarity window that can be analyzed include supercritical fluid chromatography (SFC) and hydrophilic interaction liquid chromatography. Only recently, SFC was applied to narrow the knowledge gap concerning the occurrence of PM(T) substances in the water cycle and for non-target screening of treated wastewater for polar ozonation products of organic chemicals.

This presentation will focus on SFC by (i) highlighting methodical challenges and promising advantages of this technique in comparison to RPLC and (ii) will present several applications of SFC for analysis of PM(T) substances in environmental water samples.

Presenter: Matthias Muschket, Ph.D. (Research Scientist, Helmholtz Centre for Environmental Research, Department of Analytical Chemistry, Leipzig)

Research focus: Persistent and mobile organic chemicals – Occurrence and fate in the aquatic environment, molecular descriptors of mobility and challenges in the chemical analysis of (highly) polar substances.