To achieve the best results and avoid peak broadening it is recommendable to work with the lowest dead volume combination of flow cell and column. KNAUER offers analytical and preparative flow cells. UHPLC flow cells with 2 µl (10 mm), analytical either 10 µl (10 mm) or 2 µl (3 mm). Preparative flow cells are available with 1.7 µl or 3 µl (0.5 mm). The flow cell with shorter pathway and smaller cell volume will achieve sharp peaks because of minimized dead volume. Using a flow cell with a greater layer thickness makes your detection more sensitive. The right flow rate depends on column dimension and of course on the application. The smaller the chosen flow rate, the more influence the dead volume will have. The following flow rates are typical guiding values for a 5 µm particle size material: ID 2 mm flow 0.15 ml/min–0.5 ml/min, ID 3 mm flow 0.6 ml/min, ID 4+4.6 mm, flow 0.8 ml/min–2.0 ml/min, ID 8 mm 2.0 ml/min–4.0 ml/min.
