Enhanced stability and separation resolution of gas chromatographic stationary phases via nano-MIL-103 fabrication.

The development of stable and high-performance stationary phases is essential for achieving high-resolution gas chromatographic (GC) isomer separation. This study demonstrated a simple and effective method for synthesizing a stable nano metal-organic framework (MOF) as an efficient stationary phase for GC separation. The introduction of weakly basic pyridine played a key role in modulating the generation rate of small crystal particles while inhibiting the aggregation of nanoparticles. By reducing particle size from micrometers to nanometers, the surface properties and mechanical strength of the material are significantly enhanced, leading to improved stability. The nano-sized MIL-103 (MIL-103-N) stationary phase exhibited a significantly longer lifetime than the micro one, with a lifespan of up to one month. The elution order of dichlorobenzenes followed p-, m-, and o-, which was consistented with the principle that a more negative ΔH (-49.1 ± 2.19 kJ/mol, -54.6 ± 0.390 kJ/mol, -57.4 ± 0.260 kJ/mol for p-, m-, and o-, respectively) value correlated with later elution. The standard curve for m-dichlorobenzene on the MIL-103-N column was y = 3.95 × 108x-3.12 × 106 (R-squared = 0.999). The MIL-103-N column showed high-resolution separations of a series of disubstituted benzene isomers, aromatic compounds, and alkanes. Notably, the resolution of the MIL-103-N column for dichlorobenzenes, dibromobenzenes, and trichlorobenzene isomers exceeded 1.50, achieving baseline separation. The exceptional performance of MIL-103-N can be attributed to its refined interactions with analytes and reduced diffusion barriers. This research offered a promising method for producing stable, efficient columns to separate isomer analytes.