Highly Stable MOF-Packed Miniaturized Chromatographic Columns for High-Resolution Separation of Trace Acetylene

Online acetylene (C₂H₂) monitoring is essential for fault diagnosis in oil-deficient electrical equipment, yet spatial constraints impose stringent demands on chromatographic miniaturization. Against this backdrop, achieving baseline separation of trace C₂H₂ (∼10 ppmv) from structurally similar interferents, most notably ethylene (C₂H₄, ∼500 ppmv), within ultrashort columns represents a formidable challenge. Here, we report two novel miniaturized columns based on electronegative-site-rich metal-organic framework (MOF) stationary phases that enable unprecedented separation performance: baseline resolution (R > 1.5) with exceptional column efficiency (HETP = 0.03 cm), 2.7-5.0 fold corresponding efficiency of commercial materials. Moreover, the columns exhibited exceptional air stability and recyclability, maintaining unchanged performance following 4 months of air exposure and 80 consecutive injection cycles. Mechanistic investigations reveal that chromatographic separation is governed primarily by the pronounced thermodynamic disparity between C₂H₂ (ΔH = -50.4 to -50.7 kJ/mol) and C₂H₄ (ΔH = -35.9 to -36.8 kJ/mol). This work underscores the potential of MOF-based stationary phases as a viable platform for high-efficiency separation of trace C₂H₂, paving the way for their integration into field-deployable analytical instrumentation.