title: 2-Nitro-6-monoacetylmorphine: potential marker for monitoring the presence of 6-monoacetylmorphine in urine adulterated with potassium nitrite.
abstract: 6-Monoacetylmorphine (6-MAM), being a unique metabolite of heroin, is routinely tested in urine samples to monitor heroin use. However, detection of 6-MAM-related opiates such as morphine is known to be affected by in vitro urine adulteration using oxidizing adulterants such as potassium nitrite. This study aimed to investigate the fate of 6-MAM after exposure to nitrite and to identify any formed oxidation products that may potentially be used for monitoring heroin abuse despite nitrite adulteration. Potassium nitrite (0.05 M and 0.6 M) was reacted with 6-MAM (5-10,000 ng/mL) in both water and blank urine with pH adjusted to range from 3 to 8. Following reaction at room temperature for varying periods, the reaction mixtures were monitored by both the CEDIA® Heroin Metabolite (6-AM) immunoassay and liquid chromatography-mass spectrometry (LC-MS) methods. Structural elucidation of the isolated oxidation products was based on mass spectrometry and nuclear magnetic resonance spectroscopic evidence. Nitrite, under acidic environment (pH<7), was shown to be effective in masking the detection of 6-MAM by both the CEDIA® immunoassay and the LC-MS methods. 2-Nitro-6-monoacetylmorphine (2-nitro-MAM) was identified as the sole oxidation product, which remained detectable in urine for at least 11 days under the experimental conditions investigated. 2-Nitro-MAM was detectable in a urine sample of a heroin user after nitrite exposure. 2-Nitro-MAM has shown potential to serve as a marker for monitoring heroin abuse when urine is adulterated with nitrite. Certification of 2-nitro-MAM reference standard for further development of its quantitative testing methods is thus warranted.
authors.affiliation: Centre for Forensic Science, School of Chemistry and Forensic Science, University of Technology, Sydney (UTS), Ultimo, NSW 2007, Australia.
authors.forename: Susan
authors.initials: S
authors.lastname: Luong
authors.forename: Ronald
authors.initials: R
authors.lastname: Shimmon
authors.forename: James
authors.initials: J
authors.lastname: Hook
authors.forename: Shanlin
authors.initials: S
authors.lastname: Fu
mesh_terms: D015415:Biomarkers / Q000032:analysis*; D002853:Chromatography, Liquid; D006801:Humans; D007118:Immunoassay; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D009022:Morphine Derivatives / Q000032:analysis* / Q000652:urine*; D009573:Nitrites / Q000652:urine*; D009293:Opioid-Related Disorders / Q000175:diagnosis / Q000652:urine
chemical_list: C574943:2-nitro-6-monoacetylmorphine; D015415:Biomarkers; D009022:Morphine Derivatives; D009573:Nitrites; C041349:potassium nitrite; C026979:6-O-monoacetylmorphine