Chromogenic substrate to detect urine adulteration

The invention is directed generally to a composition and method that detects whether a urine sample submitted for drug testing contains an oxidant chemical adulterant. A device and method to detect oxidant adulterants added to a sample to prevent detection of tetrahydrocannabinol and/or tetrahydrocannabinol metabolites. The device and method detect popularly available adulterants such as chromate and nitrite through their reaction with a chromogenic substrate for a peroxidase enzyme. The substrate may be applied to a pad. A change in color in the presence of the oxidant may be detected directly or indirectly. The device and method may be used to detect the presence of any oxidant adulterant and is not specific for only one or a few adulterants added to a urine sample submitted for drug testing.