This stable-labeled internal standard of (±)-threo-ritalinic acid is suitable for a wide variety of GC/MS and LC/MS applications from clinical toxicology and urine drug testing to forensic analysis and isotope dilution methods. Ritalinic acid is the major urinary metabolite of methylphenidate, more commonly known by the brand name Ritalin that is approved for treatment of ADHD (Attention-Deficit Hyperactivity Disorder) and narcolepsy. 

This internal standard is suitable for quantitation of methylphenidate levels in urine, serum or plasma by LC/MS or GC/MS for urine drug testing, clinical toxicology or forensic analysis. Methylphenidate is a psychostimulant that is sold under trade names Concerta and Ritalin. The drug is prescribed for the treatment of attention-deficit hyperactivity disorder (ADHD), tachycardia and narcolepsy.