Final answer:
The size of the collection vial does not affect the concentration of the eluate obtained from a wet generator. The concentration is determined by factors such as the time since the last elution and the amount of 99Mo activity, not by the vial size or volume of saline added.
Step-by-step explanation:
In the context of a wet generator used for radiochemistry, such as the production of technetium-99m (99mTc) from molybdenum-99 (99Mo), the concentration of the resulting eluate can be influenced by various factors.
Time since last elution affects the concentration as it directly relates to the decay of 99Mo into 99mTc and the saturation of the alumina column. The volume of saline added to the charging port can also influence the concentration, as it affects the dilution of the eluate. The amount of 99Mo activity present on the alumina column is another crucial factor that can impact the concentration of eluate; more activity can yield a higher concentration of 99mTc. However, the size of the collection vial does not affect the concentration of the eluate obtained from the wet generator, as the concentration is determined before it is collected in the vial.
Therefore, the correct answer to which factors do not affect the concentration of eluate is the size of the collection vial and the volume of saline added (both b and c).