An internal standard suitable for quantification of cathinone in novel psychoactive substance (NPS) testing methods by LC/MS or GC/MS for applications in forensic analysis, urine drug testing, or clinical toxicology. Cathinone, or benzoylethanamine, is a psychoactive alkaloid found in the Khat (Catha edulis) plant. Cathinone is the keto analog of cathine and exerts strong stimulant effects.