Adsorption/desorption behavior and pore size effect of ordered mesoporous carbons embedded polymer monoliths for in-tube solid-phase microextraction application

In this paper, an ordered mesoporous carbon (OMC), CMK-3, endowed with high surface area, uniform pore size and high interaction sites was incorporated into the polymer monolith and applied in solid-phase microextraction (SPME) of sulfonamide antibiotic drugs. In addition, several carbon materials, CMK-8, graphene and activated carbon (AC), were separately incorporated into the polymer monolith and compared their extraction performances with CMK-3-polymer. Although both CMK-8- and AC-polymer monoliths demonstrated high adsorption efficiencies for the analytes, difficulty in desorbing led to poor extraction recoveries for both monoliths. This was due to the analytes trapped within the pore structure of CMK-8 and blocked in the pores of AC. Under the optimized conditions, CMK-3-polymer monolith demonstrated remarkable extraction recoveries for target analytes. The precision and reproducibility based on the extraction recoveries of sulfonamide drugs based on intra-day, inter-day and column-to-column were in the range of 94.4 % to 100.8 % (< 4.7 % RSDs), 93.4 % to 99.5 % (< 3.2 % RSDs) and 96.3 % to 99.1 (< 3.6 % RSDs), respectively. Under the optimized condition, the limits of detections were in the range of 0.018 – 0.035 μg mL⁻¹ and limit of quantifications between 0.046 and 0.096 μg mL⁻¹. The CMK-3-polymer monolith was applied in SPME of environmental water sample by spiking trace-level sulfonamides at 0.100 μg mL⁻¹. The extraction recoveries obtained were in the range of 82.3 % to 99.0 % (< 4.5 % RSDs). Overall, the good extraction performance of CMK-3-polymer monolith for the analytes could be attributed to the two-dimensional (2D) hexagonal structure of CMK-3, which prevented the aggregation of analytes and thus enhances the elution of the analytes.