Opioid addiction and abuse constitute a national emergency and health crisis in the U.S. Wastewater-based epidemiology (WBE) is increasingly being applied by researchers to estimate population-scale consumption of prescription and illicit drugs. This non-invasive population health assessment tool necessitates precise and accurate measurement of trace levels of drugs in a very complex analytical matrix. The present study compares the performance of two analytical approaches: (i) liquid chromatography tandem mass spectrometry (LC-MS/MS), the customary but expensive tool for WBE analysis that has become the de facto gold standard, and (ii) enzyme-linked immunosorbent assay (ELISA), an alternative method for opioid detection that is more economical but unproven with respect to accuracy and precision for wastewater analysis. Raw wastewater samples (<i>n</i>=36) from three distinct U.S. communities collected over a period of 12 months were extracted using solid-phase extraction and analyzed for morphine, codeine, oxycodone, heroin, and fentanyl using LC-MS/MS. An aliquot of the extract was reconstituted in water and was analyzed using a commercial ELISA kit providing output as morphine equivalents (mor-eq). Results show that the use of external calibration for quantification using LC-MS/MS results in underestimates of analyte concentrations by 95% on average, when compared to the method of standard addition. Oxycodone was the most frequently detected opioid (100%), followed by morphine (97%), fentanyl (92%), and codeine (81%). Heroin was not detected (&lt;0.9 ng/L) in all samples. The relative percentage difference (RPD) and recovery for the analytes using LC-MS/MS was on average 12–46% and 68–93%, respectively. Average daily mass loads of opioids in wastewater were determined in units of grams per day (g/d) for morphine (10-34), codeine (3-17), oxycodone (0.2-3), and fentanyl (0.02-0.09), respectively. Results by ELISA ranged between 11–45 g/d mor-eq, showing positive detection in 89% of the samples. The RPD using ELISA kit was low at 6±4% for one community with high domestic sewage contribution (72%) to wastewater but was high (48–76% on average) for communities that had low domestic sewage contributions (≤55%). In summary, (i) LC-MS/MS data quality was dependent on the calibration technique, and (ii) the ELISA method was comparable to LC-MS/MS results and is applicable to determine annual average opioid levels for communities with domestic-dominated sewage sources.

Analytical challenges and alternatives for monitoring opioid consumption in communities using wastewater-based epidemiology

256th National Meeting (2018)

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