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. How-ever, 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) proto-col in 96-well format for human urine and plasma and optimized it for a panel of 94 highly diverse environmen-tal and food-related contaminants (LogP -0.7 ~ 6.8). Extraction recoveries (RE) and signal suppression and en-hancement (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, respective-ly. 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 com-paring 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). Favorable performance was shown for the protein pre-cipitation workflow while the SPE protocol demonstrated promising results. The developed workflow is thus not only superior for future high-throughput targeted exposomics but also offers an option for NTA applications. The presented well-balanced approach is scalable and also applicable to research in the fields of pharmacology, food safety, or systems toxicology.