This dataset accompanies a manuscript on Potassium (K) concentration determination for feldspar luminescence dating, currently under review at the journal Geochronology. It includes sample-specific K-concentrations measured using both a β-counter and a WDXRF instrument. In addition, single-grain K-concentrations were obtained through SEM-EDX and µ-XRF analyses. The dataset also provides background-corrected Tn signals from a dose recovery test, conducted on the same individual grains used for K-concentration measurements. For further details on the analytical procedures and luminescence measurements, see: https://doi.org/10.5194/egusphere-2025-806