High-Throughput Solid Phase Extraction for Targeted and Non-Targeted Exposomics

Characterizing the chemical exposome relies on advanced instrumentation including tandem mass spectrometry coupled to liquid chromatography (LC-MS/MS), and non-targeted analysis (NTA) using high-resolution MS. However, proper sample pretreatment, balancing broad analyte coverage, method robustness, and throughput remain a major bottleneck in exposomics. Here, we developed a robust and scalable solid-phase extraction (SPE) protocol in 96-well format for human urine and plasma and optimized it for a panel of 94 highly diverse environmental and food-related contaminants (LogP -0.7 ~ 6.8). Extraction recoveries (RE) and signal suppression and enhancement (SSE) were determined using targeted LC-MS/MS. Acceptable REs (60% - 140%) were achieved for >70% of all analytes, and acceptable SSE values (60% -140%) for 86% and 90% in urine and plasma, respectively. Subsequently, the method was transferred to 96-well format, significantly improving throughput to meet the capacity requirements needed for exposome-wide association studies (ExWAS). The established workflow is approximately 10× faster than routinely used metabolomics-based protein precipitation approaches when comparing the estimated total analysis time for 1000 samples. The method’s applicability for NTA and suspect screening was tested and compared to a generic protein precipitation protocol using NIST standard reference materials for urine (SRM 3672) and plasma (SRM 1950). Better performance was shown for the protein precipitation workflow while the SPE protocol demonstrated promising results. Therefore, the developed workflow is not only superior for future high-throughput targeted exposomics but also offers an option for NTA applications. The presented well-balanced approach is likely applicable to research in pharmacology, food safety, or systems toxicology.