<p>UiO-66 is a metal–organic framework with a high specific surface area, nanoporosity, and acetone adsorption and selectivity. Acetone gas, a biomarker of diabetes, is present in human breath at concentrations ranging from several hundred parts per billion (ppb) to parts per million (ppm). Detecting low concentrations of acetone among various biomarker gases requires detailed verification of UiO-66’s selectivity, which has not yet been reported and is essential for practical application. In this study, the influence of UiO-66 on the selectivity of biomarker gases with respect to their concentration is investigated using a quartz crystal microbalance. The results show that higher acetone selectivity occurs at higher gas concentrations, supporting the usefulness of parts per million -level detection for acetone biomarker gases. The selectivity aligns with density functional theory calculations, indicating it is driven by differences in the adsorption energies of biomarker gas molecules on the UiO-66 crystal. Furthermore, to leverage UiO-66’s high selectivity for gas detection in the ppm range, a prototype quartz crystal microbalance sensor system with a UiO-66-based concentrator is fabricated, enabling acetone detection at levels as low as several hundred ppb. The high selectivity and adsorption capacity of UiO-66 make it a promising material for compact, cost-effective diagnostic devices, aiding in non-invasive health monitoring and addressing the growing burden of lifestyle-related diseases.</p> Graphical abstract <p></p>