Quantitation of Fentanyl Analogs in Dried Blood Spots by Flow-Through Desorption Coupled to Online Solid Phase Extraction Tandem Mass Spectrometry

[Development of an analytical system for dried blood spots for forensic toxicology: a case study of five common drugs and poisons]

Dried blood spot (DBS) technology is a simple and convenient method for collecting, transporting, and storing blood samples on filter paper, and has numerous applications in the clinical, research, and public health settings. This technique is gaining popularity in the field of forensic science because it facilitates the rapid analysis of prohibited drugs in blood samples and offers significant advantages in toxicology scenarios such as drinking-driving screening, drug abuse detection, and doping detection. However, the lack of a standardized system and the fact that its stability and reliability have not been thoroughly researched and demonstrated limit its application in judicial practice in China. DBS samples can be prepared, stored, and analyzed in various ways, all of which may significantly affect the results. In this study, we developed a method based on ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) that focuses on the preparation, pretreatment, analysis, and storage of DBS samples. A thorough investigation was conducted to examine the optimal preparation conditions, including the blood spot matrix, drying technique, and preprocessing parameters, such as the solvent and extraction method. Moreover, the analytical conditions, such as the mobile phase system and elution gradient, were established to facilitate the quantitative detection of methamphetamine, lidocaine, ketamine, fentanyl, and diazepam in both DBS and whole-blood samples. The impact of storage conditions, such as the temperature, humidity, and sealing, on the analytical results of the DBS and whole-blood samples was also examined. The results showed a strong linear relationship for lidocaine and fentanyl within the range of 0.5-100 ng/mL. Similarly, methamphetamine, ketamine, and diazepam exhibited good linearity within the range of 2-100 ng/mL. The coefficients of determination (r2) ranged from 0.9983 to 0.9997, and the limits of detection ranged from 0.2 to 0.5 ng/mL, indicating a high degree of correlation and sensitivity. Stability tests demonstrated that the five target substances remained stable in the DBS for 60 days, with the measured contents deviating from the nominal values by 15%. Moreover, the measurement results of the DBS samples were highly similar to those of the whole-blood samples, with mean percentage differences of 4.44%, 3.50%, 7.66%, 5.10%, and 5.25% for fentanyl, diazepam, ketamine, lidocaine, and methamphetamine, respectively. Throughout the 60-day storage period, the maintenance of temperatures of -20 and 4 ℃, as well as sealing and dry storage, was not necessary. Room temperature was the most practical storage environment for the DBS samples. The results for each target showed very small concentration differences between the whole-blood and DBS samples, indicating that the DBS samples were suitable for drug and poison analysis in blood. Furthermore, the DBSs exhibited high quantitative consistency with the whole-blood samples, rendering them suitable matrices for preserving blood samples. Because DBS samples are easy to handle and store, they can realize the lightweight preservation of blood samples and provide a novel solution for the analysis and preservation of blood samples in public security practice. We recommend conducting comprehensive validations before utilizing DBS for analysis, particularly in terms of quantification, to ensure the judicial reliability of the results.

Rapid Analysis of Fentanyl and Fentanyl Analogues from Whole Blood Using SPME Coupled to the Microfluidic Open Interface

Fentanyl and its analogues are potent opioids that pose a significant threat to society. Over the last several years, considerable focus has been on the concerning trend of increasing fentanyl usage among drug users. Fentanyl analogues are mainly synthesized to evade analytical detection or increase their potency; thus, very low concentrations are sufficient to achieve a therapeutic effect. In an effort to help combat the synthetic opioid epidemic, developing targeted mass spectrometric methods for quantifying fentanyl and its analogues at ultralow concentrations is incredibly important. Most methods used to analyze fentanyl and its analogues from whole blood require manual sample preparation protocols (solid-phase extraction or liquid-liquid extraction), followed by chromatographic separation and mass spectrometric detection. The main disadvantages of these methods are the tedious sample preparation workflows, resulting in lengthy analysis times. To mitigate these issues, we present a targeted method capable of analyzing 96 samples containing fentanyl, several fentanyl analogues, and a common fentanyl (analogue) precursor simultaneously in 2.4 min per sample. This is possible by using a high-throughput solid phase microextraction workflow on the Concept96 autosampler followed by manual coupling of solid-phase microextraction fibers to the microfluidic open interface for tandem mass spectrometry analysis. Our quantitative method is capable of extremely sensitive analysis, with limits of quantification ranging from 0.002 to 0.031 ng mL-1 and linearity ranging from 0.010 to 25.0 ng mL-1. The method shows very good reproducibility (1-18%), accuracy (81-100%) of calibration and validation points, and good interday reproducibility (6-15%).

Advances in fentanyl testing

Fentanyl is a synthetic opioid that was approved by the FDA in the late 1960s. In the decades since, non-prescription use of fentanyl, its analogs, and structurally unrelated novel synthetic opioids (NSO) has become a worsening public health crisis. There is a clear need for accessible testing for these substances in biological specimens and in apprehended drugs. Immunoassays for fentanyl in urine are available but their performance is restricted to facilities that hold moderate complexity laboratory licenses. Immunoassays for other matrices such as oral fluid (OF), blood, and meconium have been developed but are not widely available. Point of care tests (POCT), such as lateral flow immunoassays or fentanyl test strips (FTS), are widely available but not approved by the FDA for clinical use. All immunoassays are vulnerable to false positive and false negative results. Immunoassays may or may not be able to detect fentanyl analogs and NSOs. Mass spectrometry (MS) can accurately and reliably measure fentanyl and its major metabolite norfentanyl in urine and oral fluid. MS is available at reference laboratories and large hospitals. Liquid chromatography paired with tandem mass spectrometry (LC-MS/MS) is the most widely used method and has outstanding specificity and sensitivity for fentanyl and norfentanyl. When compared to immunoassays, MS is more expensive, requires more technical skill, and takes longer to result. Newer mass spectrometry methods can measure fentanyl analogs and NSO. Both mass spectrometry assays and immunoassays [in the form of fentanyl test strips (FTS)] have potential use in harm reduction programs.

Understanding the effect of spatial positioning of coated blade spray devices relative to the mass spectrometry inlet on different instrument platforms and its application to quantitative analysis of fentanyl and related analogs

RATIONALE

We evaluated the effect that the spatial positioning of coated-blade spray (CBS) devices with respect to the mass spectrometry (MS) inlet has when coupling to diverse MS platforms (i.e., triple quadrupole, linear ion trap and time of flight). Furthermore, as a proof of concept, we evaluated CBS-MS as a tool for quantitation of fentanyl and four analogues on said instruments.

METHODS

Custom-made MS interfaces were made to accurately position the blade in front of the MS inlet. CBS devices, coated with hydrophilic-lipophilic balanced particles, were used for both the optimization of the CBS position and the quantitation of fentanyl and analogues in urine and plasma samples on all instruments.

RESULTS

The SCIEX triple quadrupole instrument was the most sensitive to the position of the blade due to the presence of a curtain gas flowing laminarly out of the MS inlet. After optimization, the analytical capabilities of CBS on each instrument were assessed and the results obtained on both SCIEX and Waters platforms matched the performance obtained using a more advanced instrument by ThermoFisher Scientific. Furthermore, excellent figures of merit were attained for the quantitation of fentanyl and analogues on both triple quadrupole and linear ion trap platforms.

CONCLUSIONS

We demonstrated that optimization of MS parameters on different instrument vendors and front ends, such as the position of the CBS tip regarding the MS inlet, is vital to exploit the full quantitative potential of this technology. Application of the technology to screen and quantify fentanyl and analogues showed great potential when considering its coupling with portable mass spectrometers for therapeutic drug monitoring and point-of-care applications.

Dried matrix spots: an evolving trend in the toxicological field

Dried matrix spot (DMS) is a sampling technique, primarily used to analyze blood to diagnose metabolic diseases in newborns. As this technique has several advantages, DMS has started to be employed for other purposes using other biological matrices and increasingly in toxicology over the last decade. The aim of this work was to review the analytical methods using DMS which can be applied to drugs of abuse and which have been published since 2010. Three different databases were searched, using dried, spots, and drugs of abuse as the descriptors and using a snowball search. After applying the exclusion criteria, 39 papers remained. The most common publications were related to the use of blood, which corresponded to 77% of the papers, followed by urine and oral fluid, which corresponded to 13 and 10% of the papers, respectively. The selected studies covered different illicit drugs, sample sizes of 5 to 250 µL and spot sizes ranging from 3 to 18 mm in diameter. This review also examined the extraction techniques and the methods employed to analyze various biological matrices and drugs of abuse, mostly by liquid-extraction and liquid chromatography-tandem mass spectrometry. The benefits of DMS include: a simple sample pretreatment, better stability than liquid matrices, a simple extraction procedure, lower costs, and environmental benefits. DMS appears to be a promising technique in the field of toxicology and provides new perspectives for use in forensic laboratories.

Determination of synthetic opioids in oral fluid samples using fabric phase sorptive extraction and gas chromatography-mass spectrometry

New psychoactive substances (NPS) continue to emerge in the drug market every year, becoming a global threat to public health and safety. These compounds are mostly synthetic cannabinoids and designer cathinones. However, synthetic opioids have appeared on the recreational drug markets in recent years, particularly fentanyl and its derivatives ("fentanyls"). Fentanyl and its analogs are related to harmful intoxications and an increase in opioid-related mortality in many countries, such as in the United States and Europe in the last years. Taking the drug related global crisis into consideration, this work developed and validated an effective and sensitive method based on fabric phase sorptive extraction (FPSE) followed by gas chromatography-mass spectrometry (GC-MS) for the simultaneous determination of 11 fentanyl analogs in oral fluid samples. The extraction was carried out using a sol-gel Carbowax 20 M sorbent immobilized on 100% cellulose fabric substrate and using ethyl acetate as the desorption solvent. The limits of detection (LODs) and quantification (LOQs) ranged from 1 to 15 ng mL^-1 and 5 to 50 ng mL^-1, respectively. Intra-day and inter-day precision were found within 8.2% and 8.6%, respectively, while accuracy ranged from -5.5 to 9.1%, in accordance with the established criteria. The absolute recovery values were in the range of 94.5%-109.1%. The validated method demonstrated its great potential to detect and quantify fentanyl analogs in possible forensic work and off-site analysis in road traffic cases.

Thermal desorption bridged the gap between dielectric barrier discharge ionization and dried plasma spot samples for sensitive and rapid detection of fentanyl analogs in mass spectrometry

Guided by finite element simulations and 3D-printing, we constructed a semi-covered flat-TD surface for sufficient thermal desorption and ionization of fentanyl analogs from dried plasma/blood spot samples.

Qualitative Diagnosis of Solid Breast Mass by Blood Flow in Solid Breast Mass

Breast cancer is one of the most common malignant tumors that seriously endangers women’s physical and mental health and even life-threatening. With the increasing incidence of breast malignant tumors year by year, people are increasingly concerned about the health of female breasts. However, due to the lack of primary prevention methods for breast cancer, the key to improving the cure rate of breast cancer and reducing mortality is early detection, early diagnosis, and early treatment. Hemodynamics embodies the characteristics and laws of the movement of blood and its components in the body. Clinically, monitoring of hemodynamic indicators is usually used to reveal the physiological or pathological changes of the body and understand the development process of the disease. The blood flow in the tumor tissue is high-speed and high-impedance. CDFI can show the distribution of blood flow in the mass. The highest peak velocity (PSV), resistance index (RI) and pulsatility index (PI) of systolic phase can be measured by sampling. This study use contrast-enhanced ultrasound (CEUS) combined with color energy Doppler flow imaging (CDFI) to explore the hemodynamic information of the main blood supply arteries and masses of the breast, analyze the abnormal hemodynamic information of tumors and surrounding tissues, and explore the blood in the breast, the clinical value of hydrodynamics in the qualitative diagnosis of breast masses.

Quantitative analysis of 20 fentanyl analogues by modified QuEChERS-LC-MS/MS in health products and transdermal patches

The spreading of narcotics especially illicit novel psychoactive substances is a continuing problem in recent years. In response to reduce the morbidity and crime related to fentanyl analogues, the accurate measurement of fentanyl analogues concentrations is significantly important in the analytical laboratories for customs checks and clinical application. In this work, ethyl acetate was selected as extraction solvent, 50 mg of PSA, 100 mg of C18, and 10 mg of GCB were optimized for purification. A modified QuEChERS extraction method followed by high performance liquid chromatography-tandem mass spectrometry with the mode of multiple reaction monitoring has been developed for the simultaneous determination of 20 fentanyl analogues in collagen peptides, slimming capsules and fentanyl transdermal patches. The limits of detection (LODs) varied from 0.004 to 0.02 μg L^-1 with relative standard deviations of 4.89-11.4 % and showed good linearity in the range of 0.02-10 μg L^-1 and 0.01-1.00 mg L^-1, respectively. The recoveries for 20 fentanyl analogues in the low (at μg L^-1 level) and high (at mg L^-1 level) concentration spiked samples were in the range of 77.7-114 % and 83.9-116 %, which demonstrated the application potential of the proposed method for the determination of fentanyl analogues with low and high concentration in real case samples. In addition, the matrix effect and the cross-reactivity were also proved to not interfere with quantitation of targeted fentanyl analogues. Thus, the developed method showed high sensitivity and good accuracy, which makes it suitable for the rapid detection of fentanyl analogues for customs and border service as well as pharmaceuticals.

Determination of Fentanyl Analog Exposure Using Dried Blood Spots with LC-MS-MS

Fentanyl, and the numerous drugs derived from it, are contributing to the opioid overdose epidemic currently underway in the USA. To identify human exposure to these growing public health threats, an LC-MS-MS method for 5 μL dried blood spots (DBS) was developed. This method was developed to detect exposure to 3-methylfentanyl, alfentanil, α-methylfentanyl, carfentanil, fentanyl, lofentanil, sufentanil, norcarfentanil, norfentanyl, norlofentanil, norsufentanil, and using a separate LC-MS-MS injection, cyclopropylfentanyl, acrylfentanyl, 2-furanylfentanyl, isobutyrylfentanyl, ocfentanil and methoxyacetylfentanyl. Preparation of materials into groups of compounds was used to accommodate an ever increasing need to incorporate newly identified fentanyls. This protocol was validated within a linear range of 1.00-100 ng/mL, with precision ≤12% CV and accuracy ≥93%, as reported for the pooled blood QC samples, and limits of detection as low as 0.10 ng/mL. The use of DBS to assess fentanyl analog exposures can facilitate rapid sample collection, transport, and preparation for analysis that could enhance surveillance and response efforts in the ongoing opioid overdose epidemic.

Fentanyl Family at the Mu-Opioid Receptor: Uniform Assessment of Binding and Computational Analysis

Interactions of 21 fentanyl derivatives with μ-opioid receptor (μOR) were studied using experimental and theoretical methods. Their binding to μOR was assessed with radioligand competitive binding assay. A uniform set of binding affinity data contains values for two novel and one previously uncharacterized derivative. The data confirms trends known so far and thanks to their uniformity, they facilitate further comparisons. In order to provide structural hypotheses explaining the experimental affinities, the complexes of the studied derivatives with μOR were modeled and subject to molecular dynamics simulations. Five common General Features (GFs) of fentanyls' binding modes stemmed from these simulations. They include: GF1) the ionic interaction between D147 and the ligands' piperidine NH⁺ moiety; GF2) the N-chain orientation towards the μOR interior; GF3) the other pole of ligands is directed towards the receptor outlet; GF4) the aromatic anilide ring penetrates the subpocket formed by TM3, TM4, ECL1 and ECL2; GF5) the 4-axial substituent (if present) is directed towards W318. Except for the ionic interaction with D147, the majority of fentanyl-μOR contacts is hydrophobic. Interestingly, it was possible to find nonlinear relationships between the binding affinity and the volume of the N-chain and/or anilide's aromatic ring. This kind of relationships is consistent with the apolar character of interactions involved in ligand⁻receptor binding. The affinity reaches the optimum for medium size while it decreases for both large and small substituents. Additionally, a linear correlation between the volumes and the average dihedral angles of W293 and W133 was revealed by the molecular dynamics study. This seems particularly important, as the W293 residue is involved in the activation processes. Further, the Y326 (OH) and D147 (Cγ) distance found in the simulations also depends on the ligands' size. In contrast, neither RMSF measures nor D114/Y336 hydrations show significant structure-based correlations. They also do not differentiate studied fentanyl derivatives. Eventually, none of 14 popular scoring functions yielded a significant correlation between the predicted and observed affinity data (R < 0.30, n = 28).

Dried Blood and Serum Spots As A Useful Tool for Sample Storage to Evaluate Cancer Biomarkers

Blood sample quality is crucial to ensure accurate downstream analyses such as real-time PCR or ELISA. Correct storage of biological materials is the starting point to achieve reproducible and reliable results. All samples should be treated in the same way from blood collection to storage. Depending on the analyses to be performed, whole blood and serum samples should be stored at -20 °C or -80 °C until use. Blood/serum samples should also be aliquoted to avoid multiple freeze-thawing. Another important issue is the sample conditions during shipment from one laboratory to another. If dry ice is not available or the shipment takes longer than a few days, alternative approaches are needed. One option is to use filter paper for blood collection. Here, we propose a method for blood and serum sample collection that takes advantage of dried blood spots (DBS) and dried serum spots (DSS). We developed the procedure to extract DNA from DBS for the downstream evaluation of some single nucleotide polymorphisms (SNPs) by real time PCR. We also optimized an ELISA assay starting from proteins eluted from DSS. This method can be used with other ELISA assays or procedures evaluating proteins.

LC-MS/MS-Based Method for the Multiplex Detection of 24 Fentanyl Analogues and Metabolites in Whole Blood at Sub ng mL-1 Concentrations

The United States and numerous other countries worldwide are currently experiencing a public health crisis due to the abuse of illicitly manufactured fentanyl (IMF) and its analogues. This manuscript describes the development of a liquid chromatography-tandem mass spectrometry-based method for the multiplex detection of N = 24 IMF analogues and metabolites in whole blood at concentrations as low as 0.1-0.5 ng mL^-1. These available IMFs were fentanyl, norfentanyl, furanyl norfentanyl, remifentanil acid, butyryl norfentanyl, remifentanil, acetyl fentanyl, alfentanil, AH-7921, U-47700, acetyl fentanyl 4-methylphenethyl, acrylfentanyl, para-methoxyfentanyl, despropionyl fentanyl (4-ANPP), furanyl fentanyl, despropionyl para-fluorofentanyl, carfentanil, (±)-cis-3-methyl fentanyl, butyryl fentanyl, isobutyryl fentanyl, sufentanil, valeryl fentanyl, para-fluorobutyryl fentanyl, and para-fluoroisobutyryl fentanyl. Most IMF analogues (N = 22) could be easily distinguished from one another; the isomeric forms butyryl/isobutyryl fentanyl and para-fluorobutyryl/para-fluoroisobutyryl fentanyl could not be differentiated. N = 13 of these IMF analogues were quantified for illustrative purposes, and their forensic quality control standards were also validated for limit of detection (0.017-0.056 ng mL^-1), limit of quantitation (0.100-0.500 ng mL^-1), selectivity/sensitivity, ionization suppression/enhancement (87-118%), process efficiency (60-95%), recovery (64-97%), bias (<20%), and precision (>80%). This flexible, time- and cost-efficient method was successfully implemented at the Montgomery County Coroner's Office/Miami Valley Regional Crime Laboratory in Dayton, Ohio, where it aided in the analysis of N = 725 postmortem blood samples collected from February 2015 to November 2016.