Figure 2.

Comparison retention time reproducibility of HPLCs. The percentage RSDs of four selected peptides' (shown in Figure 1B) retention times were compared among the LCs. ANOVA demonstrates that the Eksigent nanoLC-2D/Bruker HCT combination (denoted by an asterisk) had significantly less reproducibility than other LCs. This lack of reproducibility resulted from the occasional (but repeatable) catastrophic run in which all elution times shift by ∼10 min and is not the result of the nanoLC-2D per se, but from the combination of the nanoLC-2D and Bruker Ion Trap. It was accompanied by electrical etching of the autosampler stator, and therefore, appears to involve an improper path to the ground. Small gray lines represent individual LC retention time data points around the mean RSD on the data swarm plot.