Use carbonyl compounds to form acetals or hemiacetals. 

Are you sure you have a chemical like 1-ethoxyethane-1,1-diol, I supposed that it will condensate one molecule of water into ethyl acetate.

You must be saying 1-ethoxyethane-1,2-diol, it make sense. However, it is difficult to distinguish it from ethanol with a chemical reaction.

If it is 1-ethoxy-1,2-diol then I would form the acetal with acetone and then try to separate it, alternatively if you could get a polystyrene resin covered with B(OH)2 groups then maybe you could trap this diol on the resin

To separate 1-ethoxyethane-1,1-diol from ethanol see the solubility of 1-ethoxyethane-1,1-diol in  water. I it is insoluble then using separating  funnel you can separate.