Fig. 4

First set of sampled volumes (n = 6). Comparison between operators (OP 1, OP 2 and OP 3) and methods (CEM and DM) related to RC (green line) performed on 250 μL (a), 275 μL (b), 300 μL (c), 325 μL (d), 350 μL (e) and 375 μL (f). Different letters show significant statistical differences between operators compared to RC (α = 0.05)