The cartel sends several men to kidnap Gus' chemical supplier, but the operation is foiled by Mike.
These families of compounds should be available from a chemical supplier at reasonable cost and purity.
Hach Inc., a supplier of apparatus and test methods, or a chemical supplier such as Aldrich would be a good place to start.
I just looked in a catalog from a chemical supplier and they sell gold for research purposes that is 99.99% pure.
Reagent grade iodine, available from any chemical supplier, e.g. Sigma Aldrich, is very pure so it can be used as a primary standard.
N-methyl pyrrolidone was identified as a potential substitute by their chemical supplier.
These are available from most chemical suppliers, and they range in price and performance over a wide range.
F.D.A. approval is needed for a chemical supplier that makes ingredients for prescription drugs sold in the United States.
Much cheaper than similar stuff from a chemical supplier.
These are readily and inexpensively available from most chemical suppliers - otherwise you can make your own, but it just makes things a bit more time consuming.