An optical biosensor for real-time chromatography monitoring: Breakthrough determination

The use of an optical biosensor for immunorecognition of protein products during affinity chromatography is discussed to provide rapid data describing the loading and subsequent breakthrough, followed by elution and fraction collection. The optical biosensor works by following in real-time the interaction of soluble ligate with an appropriate ligand attached to the optically active surface. The initial rate of interaction between soluble ligate and immobilized ligand has been shown to correlate well with ligate concentration. This method of analysis has also been shown to agree well with ELISA, the traditionally employed technique for immunoassay of protein products lacking, for example, catalytic activity. Forward prediction, using models of the breakthrough fitted to the real-time data, has enabled the column saturation point to be determined before it has been reached, thus enabling appropriate action to ensure minimal loss of protein product while improving column utilization efficiency. The biosensor, operated within a flow injection analysis regime, has been demonstrated to provide concentration data within 10 s, with a total assay turnaround of 30 s. (C) 1998 Elsevier Science S.A. All rights reserved.