an alchemist's puzzle

[Quickleaf]

The next adventure I'm leading my PCs through is the Thieves' Maze of Daggerdale. A while ago I had posted the "Gate of Nine Thieves" puzzle-trap as an example of the sorts of challenges I was inventing - immersive, requiring thinking not just dice rolling, and dangerous.

I've got one more puzzle to make and then the adventure will be finished. This one is the vault door to the thieves' treasure vault (the PCs need to get in to retrieve the king's stolen will). There's been a gnomish theme to several of the traps, a gnome who was supposed to forge the king's will, and gnomes who may betray the PCs at one point. Contuining that theme I thought it would be appropriate to make this puzzle-trap an Alchemist's Vault Door...so here's what I've got so far, but I'm feeling pretty stuck...

Before you is a giant vault door with a glass tube inlay in the shape of the Thieves’ Maze. There are 3 holes at the top where one could pour a solution in; they correspond to three ways into the Thieves’ Maze – the Gate of 9 Thieves, through the rafters/control rooms, and the secret passage from the sewers. On either side of the door are a shelf of flasks with all sorts of reagents, oils, potions, and alchemical mixtures. A brass plaque at the center of the glass map of the Thieves’ Maze – where the vault before you would be – reads: “Beware the one bearing false gifts.”

Any ideas how to make this into a cool puzzle? Thanks!

 

[Mark]

At the least, make it at a comfortable height for gnomes.

 

[Herobizkit]

The problem could be twofold:
a) identify the correct reagents, then
b) identify the correct amount and type of each.

Perhaps there exists "real" potion of treasure finding and a plain, obvious potion of treasure finding that is cursed. Using the correct PoTF will identify the proper alchemical reagents (though not necessarily the order or amount necessary), while the incorrect PoTF would identify false reagents. The latter issue could perhaps be solved with some kind of math-related logic puzzle.

Using the wrong reagents and/or the incorrect amount or type would result in the trap being activated which would then summon a guardian or guardians; you might use an alchemical golem (perhaps a re-skinned water elemental) or some such.