Use of Diagnostic Ions for the Detection of Fentanyl Analogs in Human Matrices by LC–QTOF

Abstract

To combat the ongoing opioid epidemic, our laboratory has developed and evaluated an approach to detect fentanyl analogs in urine and plasma by screening LC−QTOF MS/MS spectra for ions that are diagnostic of the core fentanyl structure. MS/MS data from a training set of 142 fentanyl analogs were used to select the four product ions and six neutral losses that together provided the most complete coverage (97.2%) of the training set compounds. Furthermore, using the diagnostic ion screen against a set of 49 fentanyl analogs not in the training set resulted in 95.9% coverage of those compounds. With this approach, lower reportable limits for fentanyl and a subset of fentanylrelated compounds range from 0.25 to 2.5 ng/mL in urine and 0.5 to 5.0 ng/mL in plasma. This innovative processing method was applied to evaluate simulated exposure samples of remifentanil and carfentanil in water and their metabolites remifentanil acid and norcarfentanil in urine. This flexible approach enables a way to detect emerging fentanyl analogs in clinical samples.

Review of analytical methods for screening and quantification of fentanyl analogs and novel synthetic opioids in biological specimens

“…Extraction procedures utilized for LC–MS/MS quantitative methods are more expansive due to the applicability to multiple matrix types. While LLE [21,38,39,40,41,42,43,44,45] and SPE [23,37,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70] remain the most common techniques, PP [17,71,72,73,74,75,76,77,78,79,80,81,82], simple dilution [11,14,37,83] solvent extraction [82,84,85], SLE [86,87] and QuECHeERs [16,71,88] have been described as suitable extraction techniques among their evaluated scenarios. In some studies, sample pretreatment techniques such as PP and physical preparations (grinding [89,90], pulverization [62], and digestion [37]) were employed before extraction.…”

“…Traditionally, HRMS has been used for screening purposes; however, quantification by LC‐HRMS has been utilized in recent years with high success. Studies by Fogarty et al, Maher et al, Krajewski et al, Palmquist el al., and Swanson et al, have all employed LC‐QTOF‐MS for fentanyl analog quantification [40,52,66,67,86,87] and, more recently, Zhang et al was able to perform quantification (including seven sets of fentanyl analog isomers) using LC‐Orbitrap‐MS [93]. Fentanyl analogs are particularly amenable to LC‐HRMS quantification due not only to low concentrations requiring high sensitivity, but also the abundance of similar structural analogs which may be differentiation by acquisition of more comprehensive fragmentation data.…”

“…In a study by Busardo et al, LOQs were as low as 0.002 μg/L and 0.011 ng/g in whole blood or urine and hair, respectively [37]. [11,14,37,83] solvent extraction [82,84,85], SLE [86,87] and QuECHeERs [16,71,88] have been described as suitable extraction techniques among their evaluated scenarios. In some studies, sample pretreatment techniques such as PP and physical preparations (grinding [89,90], pulverization [62],…”

Dependency of fentanyl analogue protomer ratios on solvent conditions as measured by ion mobility‐mass spectrometry

“…10 Wichitnithad et al first investigated the tandem mass spectrometry (MS/MS) pattern of fentanyl, revealing isobaric fragments that could complicate its identification. 11 Since then, numerous studies have focused on characterizing fragmentation pathways of fentanyl and its many analogues with tandem MS, [12][13][14][15][16] including by both electrospray ionization (ESI) [17][18][19][20][21] and electron ionization (EI). [22][23][24][25][26] This has also led to the development of highresolution mass spectrometry (HRMS) methods becoming more routinely implemented for identification of fentanyl analogues and other new psychoactive substances (NPS), 27,28 along with the development of software tools to aid in screening.…”

Deep Learning-Enabled MS/MS Spectrum Prediction Facilitates Automated Identification Of Novel Psychoactive Substances

“…The difficulty of acquiring analytical data for emerging NPS has led to efforts to predict MS/MS spectra from the chemical structures of known or hypothesized NPS. Several studies have investigated the collision-induced dissociation (CID) pathways for established classes of NPS in order to enable manual prediction of MS/MS spectra for structurally related compounds. − Unfortunately, this manual prediction of MS/MS spectra is limited in both throughput and accuracy. Recently, many are using a more viable solution to overcome the current dearth of experimental MS/MS spectra, which would be to use in silico MS spectral prediction models capable of accurately predicting MS/MS spectra directly from a given (known) structure.…”