Miniaturized extraction method for analysis of synthetic opioids in urine by microextraction with packed sorbent and liquid chromatography-tandem mass spectrometry.

Synthetic opioids are responsible for numerous overdoses and fatalities worldwide. Currently, fentanyl and its analogs are also mixed with heroin, cocaine and methamphetamine, or sold as oxycodone, hydrocodone and alprazolam in counterfeit medications. Microextraction techniques became more frequent in analytical toxicology over the last decade. A method to simultaneously quantify nine synthetic opioids, fentanyl, sufentanil, alfentanil, acrylfentanyl, thiofentanyl, valerylfentanyl, furanylfentanyl, acetyl fentanyl and carfentanil, and two metabolites, norfentanyl and acetyl norfentanyl, in urine samples by microextraction with packed sorbent (MEPS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed and validated. A multivariate optimization was performed to establish the number and speed (stroke) of draw-eject sample cycles and the extraction solvent. The best extraction condition was eight draw-eject sample cycles, with a velocity of 3.6 µL/sec and acetonitrile as elution solvent. Linearity was achieved between 1 to 100 ng/mL, with a limit of detection (LOD) of 0.1 ng/mL and limit of quantification (LOQ) of 1 ng/mL. Imprecision (% relative standard deviation) and bias (%) were less than 12.8% and 5.7%, respectively. The method had good specificity and selectivity when challenged with 10 different matrix sources and 36 pharmaceuticals and drugs of abuse at concentrations of 100 or 500 ng/mL. The method was successfully applied to authentic urine samples. MEPS was an efficient semi-automatic extraction technique, requiring small volumes of organic solvents (640 µL) and sample (200 µL). The cartridges can be cleaned and reused (average of 150 sample extractions/barrel inside and needle).

Development and Clinical Validation of a Sensitive Lateral Flow Assay for Rapid Urine Fentanyl Screening in the Emergency Department.

BACKGROUND: Rapid identification of fentanyl at the point-of-care is critical. Urine fentanyl concentrations in overdose cases start at single-digit nanograms per milliliter. No fentanyl point-of-care assay with a cutoff at single-digit nanograms per milliliter is available. METHODS: A competitive lateral flow assay (LFA) was developed using gold nanoparticles and optimized for rapid screening of fentanyl in 5 minutes. Urine samples from 2 cohorts of emergency department (ED) patients were tested using the LFA and LC-MS/MS. The 2 cohorts consisted of 218 consecutive ED patients with urine drug-of-abuse screen orders and 7 ED patients with clinically suspected fentanyl overdose, respectively. RESULTS: The LFA detected fentanyl (≥1 ng/mL) and the major metabolite norfentanyl (≥10 ng/mL) with high precision. There was no cross-reactivity with amphetamine, cocaine, morphine, tetrahydrocannabinol, methadone, buprenorphine, naloxone, and acetaminophen at 1000 ng/mL and 0.03%, 0.4%, and 0.05% cross-reactivity with carfentanil, risperidone, and 9-hydroxyrisperidone, respectively. In 218 consecutive ED patients, the prevalence of cases with fentanyl ≥1 ng/mL or norfentanyl ≥10 ng/mL was 5.5%. The clinical sensitivity and specificity of the LFA were 100% (95% CI, 75.8-100%) and 99.5% (95% CI, 97.3-99.9%), respectively. The positive and negative predictive values were 92.3% (95% CI, 66.7-98.6%) and 100% (95% CI, 98.2-100%), respectively. The concordance between the LFA and LC-MS/MS was 100% in the 7 suspected fentanyl overdose cases (5 positive, 2 negative). CONCLUSIONS: The LFA can detect fentanyl and norfentanyl with high clinical sensitivity and specificity in the ED population with rapid fentanyl screening needs.