I keep hoping that my work will get a gas chromatograph mass spectrometer that I can play with. We keep getting close, but not quite.
As Longmorn noted, the phenols are a huge class of aromatic compounds that is primarily responsible for what we describe as a peaty character in many whiskys. Although we lump them together when measuring the phenol content from different distilleries, that masks the fact that the composition of the phenols varies across those distilleries. My understanding about the sea/iodine flavors is that the peat from some of the coastal and Island distillerys has a both a decent amount of seaweed in it as well as simply having gotten a lot of seawater in the bogs over the eons. Both contribute the medicinal notes to whisky. Some of the peat bogs are quite ancient, and I don't think a direct correlation to location today vs. where the sea used to be can be made.
The composition of phenols further varies based on the way the malting is actually done; the temperature at which the malt is roasted, for how long, etc, and distilleries often order their malt from larger malting houses. I presume that would normalize the flavors from that particular malting, whereas the distillerys which have their own maltings are often quite jealous of their peat bogs and can make a more distinctive malting for their whisky. On Islay, for instance, the Port Ellen maltings supplies many of the Islay distilleries, who order their malt based on phenol content. I would imagine then, that all the malts from Port Ellen to have a similar character (changing in intensity, but not composition per se with ppm); but a distillery like Laphroaig that has its own maltings probably has a completely different character in its malt as it sources its own peat, uses its own process/temperatures, etc.
They also say that sea flavors can be imparted as the casks breathe over the 10-12 years the whiskys age. And the wharehouses come in all different styles to alter how the air flows over the casks, so that has an effect also.