Unraveling the chemical complexity of Areca catechu by combining pH-dependent SPE-2D LC-HRMS and mass spectrometry imaging

Areca nut ( Areca catechu L.) is a widely consumed food and medicinal plant with both nutritional value and documented health risks. To comprehensively characterize its chemical composition and spatial distribution, we developed an integrated analytical platform combining solid-phase extraction (SPE), offline two-dimensional liquid chromatography with high-resolution mass spectrometry (2D-LC-HRMS), and desorption electrospray ionization mass spectrometry imaging (DESI-MSI). This approach enriched trace constituents while minimizing matrix interference, enabling the identification of 323 compounds-including terpenes and triterpenoids (89), alkaloids (52), flavonoids (31), lignans (17), and steroids (12). A pH-orthogonal separation system (alkaline and acidic modes) significantly improved resolution of structurally similar, low-abundance compounds. Spatial analysis via DESI-MSI revealed three distribution patterns: seed-specific enrichment, pericarp enrichment, and uniform distribution. By integrating compositional and spatial data, this study offers new insights into the pharmacological basis, potential toxicity mechanisms, and safe applications of areca nut in food systems.