The electrons released during oxidation reactions cannot be captured by:

The electrons released during oxidation reaction can not be captured by NADPH [Nicotinamide Adenine Dinucleotide Phosphate Hydrogen].
The pentose phosphate pathway is a metabolic pathway that generates NADPH and pentoses, which are five carbon sugars. The reactions in the pathway are divided into two; oxidative and non oxidative reactions.The oxidative reactions are irreversible while the oxidative reactions are reversible. The oxidative part of the pathway result in the production of NADPH and ribulose 5 phosphate. The electrons released during this process can not be captured by NADPH. 

The electrons released during oxidation reactions cannot be captured by NADPH. Reactions involving electron transfers are known as oxidation-reductions. Oxiation reactions involves the loss of electrons to an electron acceptor. NADPH is the reduced form of NADP+, therefore can not be in a position to gain electrons or in other words undergo reduction process. NADPH can only act as reducing agent, meaning it can only loose electrons and therefore can not gain electrons.