Not only was your sample insufficient in quantity, it was also impure.
What we require is more green glow. The troggs are obviously not irradiated sufficiently to fulfill our needs. You will have to go into Gnomeregan and bring back some radioactive fallout, straight from the tap. I am speaking of the irradiated slimes, lurkers and horrors. Be warned, the containment of this type of fallout is difficult. You may need to make several attempts with the phial until a suitable sampling is recovered.
Completion
<Ozzie examines you.>
Impressive, you still have all of your limbs. Now it's time to see what this stuff can do!
Rewards
25
2200 XP (2450 on level 31)
Notes
The irradiated slimes, lurkers, and horrors are located at the bottom level of the Hall of Gears inside Gnomeregan. The Hall of Gears is the first circular room inside the front entrance. The bottom level is usually accessed by going through the Clean Zone.
Unlike on the previous quest, you must harvest the glow from a living creature; and even then, it may fail. Make sure you have an empty spot in your inventory for the Fallout, as the Collection Phial will not contain it.
The High Potency Radioactive Fallout has a duration of only 2 hours; the quest must be turned in before then. If you don't get back in time, you still have the Collection Phial, so you can return to Gnomeregan and try again.
If you don't want to walk/ride all the way back to Kharanos, you can let one of the mobs kill you, and you will end up in the graveyard halfway between Gnomeregan and Kharanos, where the Spirit Healer can resurrect you.