A stable-labeled internal standard for 11-Nor-9-carboxy-D9-THC glucuronide, a major urinary metabolite of D9-THC. This Certified Spiking Solution® is suitable for LC/MS or GC/MS applications such as forensic testing, toxicology analysis, urine drug testing, or isotope dilution methods. This internal standard provides added value in allowing for quantitation of glucuronide levels by LC-MS/MS without need of an added hydrolysis step.