Rogues who study alchemy are adventurous botanists and chemists, always searching for unusual or strange flora in exotic or distant environments. They obsess over the natural world as much as they do their laboratories. Many alchemists spend their time making potions to heal but are often the first people to turn to for an adequate poison. In the magical world, an alchemist is an ideal person to turn to for specialized knowledge. They have a tendency to be homebodies, with endless projects and experiments that can keep them busy for weeks or months. But there are occasional alchemists who take an active role in exploring the wild world around them, and these explorers are the true pioneers of alchemy.
Starting at 3rd level, if you don't already have them, you gain proficiency with Alchemist's supplies and Poisoner's kit.
When you choose this archetype at 3rd level, you gain the ability to mix alchemical formula using Alchemist's supplies at half the cost. The process by which alchemical formula is created is magical but the finished products are not always magical.
Additionally, an Alchemist can use their Alchemist's supplies to Identify (as per the ritual spell) any liquid or potion.
At 9th level, you can attempt to create a missing rare ingredient for a special formula (such as Wyvern venom for a poison) using Alchemist's supplies. Assume it takes at least eight hours and supplies worth 2d6 x 50 gold pieces to adequately create a substitute ingredient.
By 13th level, you have the ability to create your own potions using Alchemist's supplies and in half the time as described in the DMG. You can make any potion that you have ever used, Identified, or come into physical contact with, but cannot brew your own creations.
THE PERFECT SOLUTION
When you reach 17th level, you can produce Alkahest. It costs 10,000 gp and requires 200 days to craft a single vial using Alchemist's supplies. Alkahest is a powerful disintegration solvent and does not count as a poison or a magical potion. The spell purify food and drink will immediately neutralize the acid if the Alkahest is within range.
If thrown or poured onto a single object or creature, Alkahest immediately deals 4d8 points of damage, and another 4d8 points of damage each round thereafter until it is neutralized. Magical objects have damage resistance against the Alkahest, but assume they will be destroyed just like a regular object of their type once their hit points are reduced to zero (page 246, DMG). A creature which is reduced to 0 hit points by Alkahest is reduced to black residue, and cannot be raised or resurrected. Preventing damage can be done by either submerging the subject in water or wiping it off with clothing, rags, or something similar (both methods will reduce damage by 1 die each round of submersion/activity, but in the latter case the objects used to wipe it off take 1d8 damage each round they are used or until destroyed).
A creature which drinks Alkahest must make an immediate Constitution saving throw versus DC 30. If the saving throw fails, the creature dies immediately as its tongue, jaw, and esophagus melt away. If the saving throw succeeds, the creature takes 25d4 corrosive damage to their internal organs, any damage is interpreted as viscera melting out of the body. In either case, the result is not pretty.