Determination of fenofibric acid in saliva and exhaled breath condensate samples using metal- organic frameworks based dispersive micro solid phase extraction coupled to HPLC-PDA.

This study introduces the use of an ultrathin nickel-benzene dicarboxylate metal-organic framework (Ni-BDC-MOF) for the extraction of fenofibrate. For the first time, the ultrathin Ni-BDC-MOF, known for its exceptional adsorption capacity and structural functionality was utilized as a sorbent for dispersive micro-solid phase extraction (D-μSPE) and enrichment of fenofibric acid (the main metabolite of fenofibrate). Quantification was done using high-performance liquid chromatography with photodiode array detection (HPLC-PDA). The ultrathin Ni-BDC-MOF significantly increased the surface contact area and dispersed uniformly within the sample solution, facilitating efficient fenofibric acid extraction under basic conditions. To extract the analyte, 2 mL of the sample solution was extracted using 5 mg of the prepared sorbent. The mixture was sonicated for 4 min to accelerate the contact time of the sorbent and sample solution. The sorbent particles were then collected at the bottom of the sample solution with centrifugation. After removing the supernatant, the adsorbed analyte onto the sorbent was eluted with 250 μL of methanol assisted by vortexing for 4 min. Under optimal conditions, the method showed a linear range of 4.8-500 ng/mL for fenofibric acid, with a determination coefficient (r2) of 0.990. The limits of detection (LOD) and quantitation (LOQ) were 1.6 ng/mL and 4.8 ng/mL, respectively. The method's relative standard deviations (RSDs) at 5 ng/mL, 50 ng/mL and 200 ng/mL were below 11.3%, indicating good precision. This simple, reliable, and cost-effective method was successfully applied to analyze fenofibrate in exhaled breath condensate and saliva samples.