High-Throughput Mass Spectrometry Imaging of Single Human Hair Strands

Abstract Human hair provides a stable, noninvasive matrix for longitudinal chemical analysis but remains under-utilized because of challenges in sample preparation, reproducibility, and throughput. Here, we present an automated, high-throughput platform for mass spectrometry imaging analysis of single human hair strands. This workflow integrates robotic longitudinal sectioning with custom-designed microscope slides to enable consistent sample preparation with minimal user intervention. The method achieves <5 min processing per hair strand from cleaning to sectioning, >95% success rate of sectioning, and strong interlaboratory concordance. We demonstrate spatial mapping of endogenous lipids, metabolites, environmental contaminants, and pharmaceuticals across hair substructures, including the cortex and medulla. The platform enables temporal chemical profiling along the hair shaft and supports detection of both incorporated and exogenous compounds and establishes a scalable framework for biomarker discovery and forensic applications.