LC–MS–MS Method Developed to Detect Synthetic Opioid
Scientists from the Center for Drug Detection and Response, a biomedical research consortium, have developed a method using liquid chromatography coupled to tandem mass spectrometry (LC–MS–MS) for the detection of acetyl fentanyl in human urine. The study published in the journal Analytical Chemistry outlines a new confirmation procedure that can be performed by toxicology laboratories.1 Acetyl fentanyl has recently been linked to over 50 fatalities in the states of Rhode Island and Pennsylvania in the USA.1
In May 2013, the state of Rhode Island Department of Health confirmed to the Center for Disease Control and Prevention (CDC) that a synthetic opioid acetyl fentanyl was implicated in a number of illicit drug overdose cases.2 The compound has never been approved for human use and is not available on prescription. It is the one of the latest synthetic compounds to come to the forefront of toxicological testing, as a so-called “designer drugs".
Amy Patton, who is a chemist at the Arkansas Department of Health, Public Health Laboratory in the USA and lead author of the paper, told The Column that the compound “may be linked to increasing morbidity reports supposedly involving a dangerous form of heroin”. Patton said: “Recent reports from Pennsylvania and Rhode Island indicate that synthetic opiates may be gaining popularity within the designer drug markets. The method we report is the latest method toxicology laboratories may want to adopt as they work to keep pace with what seems to be a never‑ending supply of designer drugs.”
When faced with an unsuspected acetyl fentanyl death, toxicological laboratories may potentially be perplexed when enzyme‑linked immunosorbent assay (ELISA) screening positively identify fentanyl, but gas chromatography–mass spectrometry (GC–MS) confirmatory tests do not. The team of collaborating scientists and medical practitioners set out to develop a validated method to detect acetyl fentanyl and the predicted human metabolite, acetyl norfentanyl. An LC–MS–MS approach with deuterium labelled internal standards was performed to separate and detect the two compounds in spiked urine samples. As part of the sample preparation, urine samples were hydrolyzed as opoids are commonly conjugated to glucuronic acid before excretion.
The major challenge of the analysis was the development of analytical standards and authentic labelled internal standards required for analyzing trace levels of acetyl fentanyl, according to Patton. She said: “Before this work, these standards were not available and no metabolic investigations had been performed with acetyl fentanyl. Here we report both the parent drug and the predicted human metabolite acetyl norfentanyl.” She further added a caution to laboratories performing analyses to control for carry-over, commenting “the drugs seem to be ‘sticky’ and carry-over can become problematic when evaluating highly concentrated samples”.
Patton told The Column that this study is a small part of a much bigger effort to continually update regulations of synthetic drugs. She said: “I work with a large group of extremely talented scientists, and we are all committed to protecting public health and preparing our state infrastructure for meeting the scientific and legal challenges posed by designer drugs. Members of this group represent several institutions including the Colleges of Pharmacy and Medicine at the University of Arkansas for Medical Sciences (UAMS), Arkansas Children’s Hospital (ACH), Arkansas Department of Health (ADH), and Arkansas State Crime Laboratory.” — B.D.
1. A. L. Patton et al,. Analytical Chemistry 86, 1760–1766 (2014).