Turning pan-sensor contact variability into a calibration tool for Sub-1% accuracy in heat capacity measurements with disk-type DSC

• Sub-1% accuracy in cp is achieved for small samples in disk-type DSC. • Pan-sensor contact variability is repurposed from an error source to a calibration tool. • Software-only correction uses isothermal heat flow as positioning metric. • Thermal model with leakage resistance explains the observed positioning effects. • Instrument-agnostic method applies to various materials and masses The accuracy of absolute heat capacity (c p ) measurements in disk-type differential scanning calorimetry (DSC) has been perennially compromised by a fundamental yet unresolved issue: the poor reproducibility of pan-sensor thermal contact resistance (PS-TCR) upon manual repositioning. This systematic error, frequently treated as random noise, routinely introduces significant uncertainties that limit the reliability of c p data, especially for small samples. This work introduces a methodological advancement to overcome this limitation. We demonstrate that the isothermal heat flow (Q̇ iso ), a readily measurable parameter in step-scan protocols, serves as a highly sensitive and quantitative signature of pan-positioning artifacts. By establishing a robust linear correlation between Q̇ iso and the integrated enthalpy signal (Q s ), we develop a novel correction procedure that effectively isolates and subtracts the positioning-dependent error component. This strategy, validated experimentally and supported by a refined thermal model, systematically reduces c p measurement uncertainty to below 1 % for sample masses as low as 5 mg, a level of precision previously unattainable in conventional disk-type DSCs without specialized equipment. Crucially, this approach requires no hardware modifications, relying solely on software-based post-processing of existing step-scan data. Our findings provide a practical and universally applicable solution to a decades-old problem, finally enabling high-accuracy c p determination on standard DSC instruments and democratizing precision for the broader materials science community.