Background: Impurities in narcotics are one of the factors that cause or exacerbate the symptoms of acute and chronic poisoning. Heavy metals as one of the impurities found in the opioids can cause toxicity to consumers. Opioids contamination and its complications are a social health problem in Middle Eastern countries such as Iran. Lead smugglers add more benefits during the drug production process in order to increase their weight.

Background: Methadone abuse in drug addiction centers and increased methadone consumption among addicts is a new cause of mortality due to substance abuse in forensic medicine. The usual method of extracting urine from corpses in most legal centers is a long and costly method of liquid-liquid extraction, which in addition to the high consumption of solvents and environmental contamination causes severe damage to the column of laboratory analysis devices. As a result, QuEChERS extraction method was proposed as an easy, fast, cheap and green way.