New on-site color test to discriminate cocaine and cathinone derivatives.

Color tests are advantageous for the field detection of illicit drugs because of their simplicity, low cost, and rapidity. The Scott test has been widely used as a color test for cocaine; however, it has the disadvantage of reacting with cathinone derivatives. To develop a more discriminating field-testing procedure, we evaluated the Cupric Reducing Antioxidant Capacity (CUPRAC) and bicinchoninic acid (BCA) tests for cathinones, to discriminate between cocaine and cathinones. Although the BCA test has the drawback of recognizing sugars with reducing properties, this can be overcome by adding ethanol and filtering the sample before testing. Both tests successfully distinguished between cocaine and cathinone. The BCA test was superior in terms of the ease of visual discrimination, whereas the CUPRAC test had the disadvantage of a longer reaction time.