The present disclosure describes a flow cell, a read head, and a skid attachment for measuring real-time molecular weight for downstream process control. In an embodiment, the flow cell comprises a hollow cylindrical tube, an inlet flange connected to an inlet of the tube, and an outlet flange connected to an outlet of the tube. In an embodiment, the read head comprises at least one push rod, at least two line contacts, where the at least one push rod is configured to push an outer side wall of a flow cell against the at least two line contacts. In an embodiment, the skid attachment comprises a plurality of arms connected to an enclosure configured to house at least a multi-angle light scattering instrument comprising a read head.