To monitor the degradation of bioplastics by microbes and enzymes, conventional weight-based and chromatography-based

methods have been commonly used. However, these approaches require time-consuming sample preparation and often suff er

from low reproducibility from diff erent recovery method. As an alternative, this study proposes a quantitative approach using

diff erential scanning calorimetry (DSC), a technique traditionally used to analyze the thermal properties of polymers. This

method directly applies lyophilization without washing and drying samples and uses DSC analysis to quantify the enthalpy

change (ΔH) at the melting temperature of bioplastic residues. When PHB fi lms were analyzed after optimizations, a strong

linear correlation (R 2 > 0.99) between ΔH and fi lm mass was observed across all cases. Compared to conventional, the DSC

method showed less than 3.5% deviation from the gas chromatography (GC) method, contrary to the weight-based method

showing more than 14% diff erence from the GC-based method. This method expands the ability to quantify diff erent types

of bioplastics such as poly(butylene succinate) (PBS) and polycaprolactone (PCL), simultaneously. This research highlights

DSC as a simple, reproducible, and broadly applicable approach for monitoring bioplastic degradation quantitatively, off ering

a promising alternative to labor-intensive conventional methods.