The introduction of extreme ultraviolet lithography in high-volume manufacturing has once again ensured further progress in semiconductor technology. As we journey toward future technology nodes with smaller features, the quest for photoresists that meet these stringent specifications becomes increasingly challenging. Stochastic effects, such as the compositional dispersion of molecules in photoresists, have become a limiting factor in the lithography performance of photoresists. Here, we report on chromatographic techniques to separate random copolymers within photoresist materials according to chemical composition. We present a systematic study aimed at providing a fundamental understanding of how the molecular weight distribution and chemical composition of polymers included in photoresists influence lithography performance. Compared to other conventional methods, such as size exclusion chromatography, the approach in this study offers superior accuracy and resolution. It presents a promising approach to accurately identify and quantify the organic polymers within photoresists. Improved molecular dispersion of the polymers leads to an enhancement of the resist’s performance in EUV lithography. Our approach sets a standard in photoresist analysis and offers a viable approach to reduce stochastic effects, paving the way for photoresists with better performance for future technology nodes.