A Fully Integrated Multi-Column System for Abundant Protein Depletion from Serum/plasma

This work details the transformation of a conventional HPLC system to a low back pressure liquid chromatography set-up for automated serum/plasma depletion and fractionation. A Dionex U3000 HPLC was converted to low back pressure operation (125psi max) by replacing all narrow-bore lines to larger inner-diameter tubing. The system was configured to use two immunoaffinity columns, first for depletion of the top 14 most abundant proteins (Seppro IgY14), then for the next 200–300 proteins (Seppro SuperMix). The autosampler was dual-purposed for both injection and fraction collection. Both the flow-through and SuperMix bound proteins were collected in an automated fashion. Three samples could be depleted consecutively before the system required user intervention, and up to nine samples could be depleted within a 24h period. This study documents the validation of the instrument performance with a 90-patient sample set, demonstrating overall CVs for 86 of the 90 samples to be within the 95% confidence intervals. Additionally, there was excellent reproducibility within the same patient (biological replicates) across days.