Fast and automated monitoring of gadolinium-based contrast agents in surface waters

• Published in: Water research (Oxford) 2021-12, Vol.207, p.117836-117836, Article 117836
• Main Authors: Macke, Marcel, Quarles, C. Derrick, Sperling, Michael, Karst, Uwe
• Format: Article
• Language: English
• Subjects: Automation; Contrast Media; Gadolinium; Gadolinium DTPA; Gadolinium-based contrast agents; Humans; Inductively coupled plasma-mass spectrometry; Ion exchange chromatography; Magnetic Resonance Imaging; Organometallic Compounds; Rivers; Speciation analysis; Water monitoring
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2021.117836

•A fast and automated method to monitor Gd-based contrast agents in water samples.•Based on a rapid ion-chromatographic method for high-throughput speciation analysis.•Inductively coupled plasma-mass spectrometry for sensitive detection.•Applied for quantitative Gd monitoring in a multitude of surface water samples.•Identification of commonly used contrast agents but also of one unknown Gd species. Gadolinium-based contrast agents (GBCAs) are frequently used for magnetic resonance imaging to improve image contrast. These inert complexes are excreted unmetabolized from the human body and pass through wastewater treatment plants almost unaffected, leading to a significant release of anthropogenic Gd into the environment. However, long-term ecotoxicological effects of GBCAs are mainly unknown and thus powerful methods of speciation analysis are required to monitor their distribution and fate in aquatic systems. In this work, a rapid and efficient monitoring method was developed utilizing a fully automated single platform system for total metal analysis and syringe-driven chromatography in combination with inductively coupled plasma-mass spectrometry (ICP-MS). An anion-exchange chromatography (IC) method was developed and applied to achieve a rapid separation and sensitive detection of the five complexes Gd-HP-DO3A, Gd-BT-DO3A, Gd-DOTA, Gd-DTPA, and Gd-BOPTA that are commonly administered in the European Union. Furthermore, the use of an automated inline-dilution function allowed a fast-external calibration from single stock standards. A chromatographic run time of less than 2 min and species-specific detection limits between 11 and 19 pmol L−1 on a quadrupole ICP-MS proved to be competitive compared to previously published methods, but without the use of aerosol desolvation and/or sector field ICP-MS to enhance sensitivity. The automated IC-ICP-MS method was applied for quantitative GBCA monitoring in a multitude of surface water samples that were obtained in the German state of North Rhine-Westphalia. The complexes Gd-HP-DO3A, Gd-BT-DO3A, and Gd-DOTA, were detected and quantified. In addition, the occurrence of an unidentified Gd species was observed for one of the sampled river systems. [Display omitted]