Affinity Capture

Affinity Capture – Mass Spectroscopy is a technique which combines the sensitivity of NPOI with the information richness of MS. In a single technique, both the binding parameters can be measured and identity of an unknown analyte can be determined.

AC-MS may be used during screening, where targets for a particular protein are screened in parallel against the protein immobilized on the surface. The set of targets is introduced onto a SKi Sensor™ prepared with the ligand of interest. Depending on the details of the relative affinities and concentrations of the targets, one or more targets may bind to the ligand, which is monitored using NPOI.

As NPOI switches to its dissociative phase, the eluent from the SKi Sensor™ is trapped onto a reverse phase trapping down column and the analyzed using standard LC-MS setup.

Because NPOI uses highly porous sensor chip, up to 100 ng of material may be captured within the pores (a typical run might be a small molecule ranging from 95-900 Daltons with 50 µL of sample at 100 nM concentration) and then eluted onto the trap column. There is more than enough captured material for coupling SKi Pro™ to an electrospray-based LC-MS system, which means there are not the lower limits on mass range often seen in MALDI setups.