Polyethylene glycol-modified MIL-88B(Fe) coating for headspace solid-phase microextraction of C6-C10 aldehydes in exhaled breath.

A polyethylene glycol (PEG)-modified MIL-88B(Fe) composite was synthesized by a one-pot route and evaluated as a coating for headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS) for the determination of five C6-C10 aldehydes. Among the materials prepared at PEG/Fe3+ molar ratios of 0, 5, 10, and 15%, PEG10@MIL-88B(Fe) produced the highest peak areas for all five aldehydes. Characterization by powder X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy, and N2 adsorption-desorption analysis supported PEG modification while retaining the structural characteristics of MIL-88B(Fe). Under the optimized conditions, the developed method provided enrichment factors of 2563-15,562. Calibration curves were linear over 0.1-500 ng mL-1 (R2 = 0.9911-0.9988), with LODs of 0.018-0.030 and LOQs of 0.059-0.099 ng mL-1 of calibration solution (liquid-standard-equivalent). Intra-day, inter-day, fiber-to-fiber, and batch-to-batch RSDs were 3.9-5.9%, 4.2-8.2%, 4.0-9.8%, and 5.3-10.1%, respectively. The method showed limited interference from representative breath volatile organic compounds, with relative responses of 89.30-92.02%, while matrix effects ranged from 94.7% to 104.1%. After 110 extraction/desorption cycles, the coating retained 87.9-93.9% of its initial response. The PEG10@MIL-88B(Fe)-coated SPME fiber was applied to exhaled-breath samples, with spike recoveries of 87.2-105.5%, supporting its applicability to the trace determination of C6-C10 aldehydes in exhaled breath.