Clandestine laboratories are being used to create designer drugs that have slight structural differences from previous versions of a drug. As soon as a drug is listed as a controlled substance in the United States, chemists in designer drug laboratories, which are located primarily in China, change an atom or two of that drug to create a new substance that is not controlled. The current project focused on the identification of designer drugs known as "bath salts," which are synthetic drugs chemically related to cathinone, a stimulant found in the khat plant. Synthetic cathinones have become a popular alternative to other illicit drugs, such as cocaine, MDMA (ecstasy), and methamphetamines. They have the appeal of being a psychostimulant with empathogenic effects. In the current project, researchers used general chemical techniques in developing methods for chemically identifying designer modifications in three distinct regions of the cathinone molecule, i.e., the aromatic ring, the alkyl side chain, and the amino group. The project developed methods that identify ring-substituted aminoketone compounds, which are cathinone derivatives. The methods increase the forensic drug chemistry knowledge base for aminoketone-type designer drugs. By developing a framework of analytical properties and their relationship to drug structure, the researchers indicate the project has produced results that will enable a forensic expert to identify new designer analogues as they emerge. The grantee report on this project is entitled "Designing Methods to Identify Evolving Designer Drugs."