A new liquid flow cell assembly for light scattering measurements is disclosed which utilized a floating manifold system. The assembly operates with minimal stacked tolerances by aligning the cell to the windows within a manifold and independently aligning the cell to the read head directly. This configuration enables the ability to replace the flow cell or the flow cell/manifold assembly within a light scattering instrument without the need to realign the flow through elements with the light scattering illumination source while still maintaining reproducible, quality data. Some embodiments employ wide bore cells which enable the measurement of process analytic technology (PAT) including online monitoring of reactions.