Improved Point-of-Care\nMass Spectrometry Analysis\nwith Thin-Layer Chromatography-Based Two-Dimensional Separation and\nSpray Ionization

Point-of-care\ntesting (POCT) involves administering rapid\non-site\nanalysis to provide fast biochemical testing results. POCT reduces\ndelays in clinical decision-making and eliminates the need to transport\nand prepare clinical samples for immediate diagnosis or clinical intervention\nby healthcare professionals. Herein, a novel methodology integrating\nthin-layer chromatography-based two-dimensional separation with miniature\nmass spectrometry was developed for rapid on-site clinical analysis.\nAs a proof-of-concept demonstration, γ-aminobutyric acid, 2-hydroxyglutarate,\nand <i>N</i>-acetyl-l-aspartic acid, which are\nwidely known as biomarkers for brain gliomas, were selected as model\nanalytes for method development and validation. The proposed approach\nexhibited satisfactory analytical performance, with 1 ng/mL limits\nof detection, 2 ng/mL limits of quantitation, and recoveries in the\nrange of 85.9–107.2%. Additionally, on-TLC derivatization and\nreactive spray ionization strategies were utilized to enhance the\nmass spectrometric signals compared to underivatized analysis. This\nmethod was applied to analyze clinical samples, showcasing its attractive\npotential outside the laboratory.