In this talk I will discuss new avenues for studying complex hetero-component mixtures by analytical ultracentrifugation (AUC), involving multi-wavelength detection. With new instruments available that support multi-wavelength AUC, we can take advantage of spectral decomposition of the hydrodynamic information collected in an AUC experiment, to gain additional insights into the chemical composition of the analytes and the dynamic complexes they form in the mixture. Importantly for applications in biochemistry, we can take advantage of unique chromophores and spectral properties of different biopolymers (in particular, proteins, DNA, RNA, and lipids), as well as small organic molecules with aromatic and/or fluorescent properties. I will describe the method and illustrate the concepts by way of several systems recently studied in our lab, involving RNA loaded lipid nanoparticles (similar to the Covid-19 vaccine formulations from Pfizer/Biontech and Moderna) and other viral vector-based gene therapy formulations.