In addition, poppy seed consumption does "not" serve as a defense for heroin consumption. This is because a unique metabolite (6-monoacetylmorphine) is produced from heroin use that is never produced from consuming any other substance, even other opiates like the ones present in poppy seeds. Modern tests can thus readily determine whether it was heroin or some other opiate that was ingested, should someone who had used heroin try to claim he or she merely ate poppy seeds. It is widely believed that there is no way to distinguish between poppy seeds and any other kind of opiate. However, a study published by the University of Connecticut's Department of Chemistry proposed that thebaine could be used as a marker of poppy seed consumption. They examined the urine of test subjects given 11 grams of poppy seeds, the urine of heroin users and clean urine spiked with thebaine, as a reference for GC-MS. They also tested street heroin, one morphine tablet and one codeine tablet. Urine specimens were screened by EMIT and confirmed for thebaine by GC-MS using a solid-phase extraction method. Only the subjects who had consumed the poppy seeds had thebaine in their urine, with concentrations ranging from 2 to 81 ng/mL with a limit of detection of 0.5 ng/mL. Thebaine was not detected in any of the tested powdered drugs (street heroin, morphine tablet, codeine tablet) or the urine of the heroin users.