An internal standard and Certified Spiking Solution® suitable for quantitation of valproic acid levels in urine or other matrices by LC/MS or GC/MS for testing applications in clinical toxicology, forensic analysis, medication monitoring, urine drug testing, or therapeutic drug monitoring. Valproic acid, sold under trade names such as Depakote, Valparin, or Stavzor, is an antiepileptic drug and mood stabilizer. The drug is prescribed for treatment of epilepsy, bipolar disorder, migraine headaches, and depression.