Synthesis and application of MUV-10/graphene oxide composite fibers for headspace SPME-GC-MS determination of flavor compounds in Baijiu

In this study, MUV-10/graphene oxide (GO) composite solid-phase microextraction (SPME) fibers were prepared on stainless steel wire substrates by the sol-gel method. A sensitive and reliable analytical method was developed by combining the Headspace-SPME (HS-SPME) procedure with gas chromatography/mass spectrometry (GC/MS) for the determination of aroma compounds in six different aged Baijiu samples. Several experimental parameters affecting the adsorption efficiency were investigated, including fiber thickness, salt concentration of the sample solution, etc. Under optimized conditions, the self-made MUV-10/GO-1% fiber was found to have better adsorption efficiency for polar analytes (such as alcohols and esters) than the commercial 50/30 μm PDMS/DVB/CAR fiber. The linear range of the established method was 0.1–100 μg/L, with correlation coefficients (r) ranging from 0.9957 to 0.9998. The limits of detection (LODs) and quantification (LOQs) were 0.001–1.147 μg/L and 0.003–3.824 μg/L, at the signal-to-noise ratio of 3 and 10, respectively. The relative standard deviations (RSDs) of the fibers were 8.1–13.5% (between fibers) and 4.6–10.1% (for a single fiber). The established HS-SPME/GC-MS method was used to analyze six different aged Baijiu samples, revealing that the concentrations of several off-flavor compounds decreased with the extension of storage time and the levels of long-chain fatty acid ethyl esters (LCFAEEs) gradually increased.