Poor AAV recovery could be due to one or more of the following:
Incorrect pH adjustment of AAV sample for binding. A pH level of 3.5-3.8 works best for binding AAV to the resin. Ensure that the sample is adjusted to approximately this value with Binding Buffer A prior to sample loading. In phenol red-containing media, this will turn the media a bright yellow color.
Initial titer of the sample applied to the column was too low. A sufficient amount of AAV particles is required in the starting sample to ensure success in downstream applications. It may be required to increase the volume of the starting sample or increase the AAV vector titer of the starting sample by optimizing transfection conditions and/or vector constructs.
Elution Buffer O stored improperly. Ensure that the Elution Buffer O is aliquoted into 1.5 mL microfuge tubes after opening, taking care to minimize the amount of air left in the tubes (1 mL to 1.5 mL aliquots). Store tightly capped at 4°C.