Vial of Vitriol
Vial of Vitriol is an Imbuing ingredient needed to imbue the Elemental Slayer property onto weapons.
It can be found as loot on Acid Slugs in the Underworld.
Crafting
It can also be crafted by Alchemists with at least 90 Alchemy skill and 75 Magery.
Skill Required : 90 Alchemy 75 Magery Items required : 1 Parasitic Plant, 30 Nightshade