Blood Sample Preparation for Human Chemical Exposomics: Insights from Large-Scale Applications

Area of Science:

• Environmental Health Sciences
• Analytical Chemistry
• Biochemistry

Background:

• Liquid chromatography-high-resolution mass spectrometry (LC-HRMS) is crucial for profiling the internal chemical exposome in human biofluids.
• Scaling up exposomics research requires sensitive, robust, and high-throughput methodologies.

Purpose of the Study:

• To compare two sample preparation methods (SPMs): protein precipitation (PPT) and PPT with phospholipid removal (PLR).
• To assess the impact of these SPMs on LC-HRMS repeatability and chemical coverage in blood plasma and serum.
• To evaluate the effectiveness of additional filtration for sample concentration.

Main Methods:

• Two cohorts (plasma n=109, serum n=75) were analyzed using PPT and PLR SPMs.
• LC-HRMS was employed for chemical profiling.
• A suspect screening strategy was used to compare chemical coverage for 184 compounds.
• Additional filtration was tested for sample concentration.

Main Results:

• Both SPMs provided acceptable chemical coverage for large-scale exposomics (78-86% detection).
• A significant fraction of chemicals showed preferential (>2-fold) or exclusive detection with one SPM, indicating matrix effects or recovery differences.
• Low-abundance chemicals were more sensitive to the choice of SPM.
• Additional filtration on PLR plates allowed for doubled sample concentration without impacting repeatability.

Conclusions:

• Both PPT and PLR are viable for large-scale exposomics, but neither is universally superior.
• The compound-dependent detection rates highlight the importance of using complementary sample preparation methods for maximal chemical coverage.
• Further research may be needed to understand the physicochemical drivers of SPM performance for low-abundance chemicals.