Hi Stanley,
for concentration, you might use a very low cut off mw dialysis
membrane and reduce the volume by "dialysis" against high mw poly-
ethyleneglycol.
You also first might might separate monomeric Abeta with 10kD cut off
spin column concentrator and the concentrate the flow through with a
1kd concentrator. In the latter step, you also may obtain some
desalting when you dilute your sample with dd water before the
concentration.
Just some thoughts and good luck!
Wo
