Patent ID: 8338577

Claim:
A method for quantifying PrA leakage from a PrA based affinity chromatography resin, the method comprising the steps of: (a) labeling the PrA in the PrA based chromatography resin with one or more fluorescent tags; (b) dividing the labeled resin into equal first and second parts; (c) treating first part with suitable means to release the labeled PrA from the resin and adding an excess amount of immunoglobulin (Ig) to the second part; (d) measuring fluorescence (FL digest ) and PrA concentration ([PrA]) from the treated resin in the first part in step (c); and (e) measuring resin Ig eluate concentration ([Ig]) and fluorescence signal in an Ig eluate (FL Ig ) from the second part in step (c), wherein PrA leakage is quantified by calculating {(FL Ig )/((FL digest )/[PrA]))}[Ig].