Advances in drugs of abuse testing

Rational hapten design, antibody preparation, and immunoassay development for rapid screening xylazine in biological samples

Xylazine (XYL) is an illicit adulterant in opioids and an approved veterinary sedative drug, which has been abused, misused, and residued in food samples, endangering people health, causing drug-facilitated crimes and even death. Immunoassay used antibody as core biomaterial could to achieve highly sensitive and rapid detection screening purpose for XYL in situ. Here, we rationally designed four novel XYL haptens with different spacer arms to produce antibodies with high affinity and specificity. Ten monoclonal antibodies (mAbs) were obtained and mAb 7H5 showed a high affinity with IC50 of 0.23 ng mL-1 and ignorable cross-reactivity for the other eight analogs. One highly sensitive indirect competitive ELISA (icELISA) and lateral flow immunoassay (LFIA) were established based on heterologous haptens for XYL detection in a series of human urine and food samples. The limit of detections (LODs) of the icELISA were 0.10-2.24 μg L-1 with recovery of 83.5 % to 128.6 % and CV below 15.8 % in different samples, while, the visual limits of detection (vLOD) of LFIA were 0.10-1.80 μg L-1 with the cut-off value of 0.60-4.80 μg L-1. In addition, the molecular recognition mechanism of mAbs was explored. The study provides powerful tools for rapid screening of XYL in human urine and food samples for the first time.

Rapid detection of drug abuse via tear analysis using surface enhanced Raman spectroscopy and machine learning

With the growing global challenge of drug abuse, there is an urgent need for rapid, accurate, and cost-effective drug detection methods. This study introduces an innovative approach to drug abuse screening by quickly detecting ephedrine (EPH) in tears using drop coating deposition-surface enhanced Raman spectroscopy (DCD-SERS) combined with machine learning (ML). Using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), the average concentration of EPH in tear fluid of Sprague-Dawley (SD) rats, measured over 3 h post-injection, was 1235 ng/mL. DCD-SERS effectively identified EPH in tear samples, with distinct Raman peaks observed at 1001 cm-1 and 1242 cm-1. To enable rapid analysis of complex SERS data, three ML algorithms-linear discriminant analysis (LDA), partial least squares discriminant analysis (PLS-DA), and random forest (RF)-were employed. These algorithms achieved over 90% accuracy in distinguishing between EPH-injected and non-injected SD rats, with area under the ROC curve (AUC) values ranging from 0.9821 to 0.9911. This approach offers significant potential for law enforcement by being easily accessible, non-invasive and ethically appropriate for examinees, while being rapid, accurate, and affordable for examiners.

Rapid Determination of Methamphetamine, Methylenedioxymethamphetamine, Methadone, Ketamine, Cocaine, and New Psychoactive Substances in Urine Samples Using Comprehensive Two-Dimensional Gas Chromatography

Background/Objectives: This study evaluates the applicability of a comprehensive two-dimensional gas chromatography-flame ionisation detection (GC×GC-FID) approach for the simultaneous determination of 12 underivatised psychoactive drugs, including new psychoactive substances, that comprised of amphetamine, methamphetamine, mephedrone, 3,4-methylenedioxyamphetamine, 3,4-methylenedioxymethamphetamine, α-pyrrolidinovalerophenone, n-ethylpentylone (ephylone), norketamine, ketamine, 3,4-methylenedioxypyrovalerone, methadone, and cocaine. Methods: Separation was effected using a non-polar first dimension (1D) and a polar second dimension (2D) column, demonstrating an improved separation of drug compounds compared to a polar/non-polar column configuration. Interference-free baseline separation of all psychoactive compounds in a urine matrix was achieved within 8 min. The GC×GC-FID method was validated according to the guidelines defined by Standard Practices for Method Validation in Forensic Toxicology. Results: The calibration curves for the 12 psychoactive drugs were well correlated (r2 > 0.99) within the concentration ranges of 50-1500 ng mL-1. Detection limits of 10-20 ng mL-1 were obtained, and good repeatability and reproducibility (CV < 11.4%) were attained for retention times and peak areas. Method recoveries for the small-scale solvent extraction procedure ranged from 96.9 to 114.5%, and bias was between -3.1% and 14.5%. Conclusions: The validated approach was successfully applied for the determination of these illicit compounds in spiked urine samples of different concentrations, highlighting its potential for rapid forensic drug screening.

Ruthenium(II) N-heterocyclic carbene polymer based sensors for detection of predatory drugs like ketamine and scopolamine

The current demand in the field of abusive drug research is to have a highly sensitive and rapid method for detecting ketamine and scopolamine, which are frequently used in drug-facilitated sexual assaults administered via beverages and food. We report here the first electrochemical sensors of N-heterocyclic carbene (NHC) coordinated ruthenium organometallic 1-dimensional polymers and their multi-walled carbon nano tube (MWCNT)-based composite for detecting ketamine and scopolamine. The preparation of ruthenium NHC organometallics and the MWCNT composite as sensors offers significant advantages for electrochemical applications, with enhanced sensitivities of 121.979 and 3.273 μA μM-1 cm-2 for ketamine and scopolamine, respectively, and selectivity in sensing applications. The complex-carbon composite sensor has a low limit of detection i.e., 0.194 and 3.18 nM for ketamine and scopolamine identification, respectively. Alongside, the selectivity of the composite sensor was evaluated in the presence of other blood constituents, and the study evidenced remarkable discernment towards the title drugs. Furthermore, real-time analyses using the composite sensor demonstrated quantitative identification of ketamine and scopolamine. Therefore, this innovation has the potential to provide valuable tools for forensic investigations and address the urgent need for real-time detection of date rape drugs. This contribution demonstrates a robust proof-of-concept that emphasizes the importance of creating non-enzymatic, environmentally friendly, and cost-effective sensors for on-site sensing applications as point-of-care devices.

Facile fabrication of the immuno-MALDI-MS chip for the enrichment of abused drug in human urine integrated with MALDI-MS analysis

BACKGROUND

Drug abuse can result in both physical and mental health issues for individuals, and can also contribute to broader societal problems. The number of drug abuse cases rose to 296 million in 2021. The sample pretreatment methods commonly employed typically require longer processing times and occasionally necessitate derivatization. Furthermore, with the increase in sample sizes, traditional chromatography-mass spectrometry methods for analyzing abused drugs were no longer sufficient to handle such numerous samples. In this study, immuno-MALDI-MS chip were fabricated for specific enrichment of illicit drugs, integrating with the rapid and accurate capabilities of MALDI-MS for high-throughput analysis of drug abuse.

RESULTS

The immuno-MALDI-MS chip was successfully prepared by coating an aluminum chip with antibody-conjugated boronic acid-modified gold nanoparticles. Ketamine, a frequently abused illicit drug, served as the proof of concept for this study. The immuno-MALDI-MS chip was employed to selectively enrich ketamine in human urine samples, facilitating direct MALDI-MS analysis with the addition of α-CHCA matrix solution. The challenge of detecting abused drugs, exacerbated by interfering peaks in the low m/z region from salts and small molecules in human urine samples, was successfully overcome. The developed method exhibited a wide linear range of 10-5000 ng/mL with a limit of detection of 3.3 ng/mL for ketamine. Notably, the proposed method enabled high-throughput screening and accurate confirmation of ketamine concentrations in suspects' urine samples within few minutes, requiring a minimal sample volume of 1 μL. The obtained data were in complete agreement with the previous GC/MS analysis.

SIGNIFICANCE

A straightforward, cost-effective and sensitive method for the selective enrichment and absolute quantification of abused drugs was developed using a homemade immuno-MALDI-MS chip integrated with MALDI-MS analysis. This method combines the advantages of immunoassay and mass spectrometry, offering both speed and accuracy. The reported method for the quantification of ketamine in human urine offers a practical approach and has the potential to analyze emerging new psychoactive substances in the future.

High-performance liquid chromatography coupled to Orbitrap mass spectrometry for screening of common new psychoactive substances and other drugs in biological samples

The complexity of the drug market and the constant updating of drugs have been challenging issues for drug regulatory authorities. With the emergence of new psychoactive substances (NPS) and the nonmedical use of prescription drugs, forensic and toxicology laboratories have had to adopt new drug screening methods and advanced instrumentation. Using high-performance liquid chromatography coupled with Orbitrap mass spectrometry, we developed a screening method for common NPS and other drugs. Two milliliters of mixed solvent of n-hexane and ethyl acetate (1:1, v:v) were added to 500 μL of blood or urine sample for liquid-liquid extraction, and methanol extraction was used for hair samples. The developed method was applied to 3897 samples (including 332 blood samples, 885 urine samples, and 2680 hair samples) taken from drug addicts in a province of China during 2019-2021. For urine and blood samples, the limits of detection (LODs) ranged from 1.68 pg/mL to 10.7 ng/mL. For hair samples, the LODs ranged from 3.30 × 10-5 to 4.21 × 10-3 ng/mg. The matrix effects of urine, blood, and hair samples were in the range of 47.6%-121%, 39.8%-139%, and 6.35%-118%, respectively. And the intra-day precision was 3.5%-6.0% and the inter-day precision was 4.18%-9.90%. Analysis of the actual samples showed an overall positive detection rate of 58.9%, with 5.32% of the samples indicating the use of multiple drugs.

Assessment of atmospheric solids analysis probe as a tool for the rapid determination of drug purity

The ability to determine the purity (% controlled compound) of drug-of-abuse samples is necessary for public health and law enforcement. Here, we describe the assessment of atmospheric solids analysis probe (ASAP) for the rapid determination of drug purity for a set of formulated pharmaceuticals, chosen due to their availability, uncontrolled status and consistency. Paracetamol and loratadine were used as models of high and low purity compounds being ~90% and ~10% active ingredient, respectively. Individual tablets were ground up and diluted in an internal standard solution. The resulting samples were analysed by ASAP coupled to a Waters QDa mass spectrometer followed by confirmatory testing by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The inclusion of a non-matched internal standard (quinine) improved linearity and repeatability of drug analysis by ASAP-MS. Levels of drug purity using formulated pharmaceutical tablets were found to be highly comparable with results produced by the 'gold standard' LC-MS/MS technique. Rapid determination of drug purity is therefore possible with ASAP-MS for highly concentrated samples with minimal sample preparation. It may be possible to use this deployable system to determine drug purity outside of a laboratory setting.

A multicomponent LC-MS/MS method for drugs of abuse testing using volumetric DBS and a clinical evaluation by comparison with urine

BACKGROUND

Drug testing commonly use urine as a specimen and immunoassays for screening. The need for supervised urine collection has led to an interest in alternative specimens and a need for using mass spectrometry methods already for screening. In addition, mass spectrometry methods allow for broad multipanel screening which of great value because of the increased number of substances that needs to be covered has increased over time. One alternative specimen of interest for drugs of abuse testing is dried blood spots (DBS) and this work aimed at developing multipanel screening methods based on selected reaction monitoring liquid chromatography - mass spectrometry for both urine and dried finger blood as specimens.

MATERIALS AND METHODS

The urine method comprised 37 analytes and utilised salted out liquid/liquid extraction in 96-well format, respectively, and the blood method comprised 35 analytes, a 10 µL volumetric DBS device and a two-step solvent extraction procedure. In both cases stable isotope labelled internal standards were used for almost all analytes.

RESULTS

The methods were validated according to forensic standard. The lowest reporting limits were generally set at 100 ng/mL for urine and 1 ng/mL for blood and the accuracy and imprecision were within limits of 15 and 20%. The methods were applied in a clinical study on patients receiving methadone maintenance treatment for opioid dependence. Methadone was detected in all urine and DBS samples, for urine sometimes below the commonly applied screening cutoff limit of 300 ng/mL. In 20 out of 99 cases no other drug was detected in any specimen. The most commonly other detected substances were pregabalin, amphetamine, alprazolam, zopiclone and THCCOOH. Findings in urine and DBS generally agreed well but more positives were detected in DBS.

CONCLUSION

Multipanel methods using liquid chromatography - mass spectrometry suitable for clinical drug screening were successfully developed for urine and blood collected by finger-pricking and stored as DBS.

Simultaneous determination of 28 illegal drugs in sewage by high throughput online SPE-ISTD-UHPLC-MS/MS

This study developed an online solid-phase extraction ultra-high performance liquid chromatography-tandem mass spectrometry (Online-SPE-UHPLC-MS/MS) method for the analysis of 28 illegal drugs in sewage. To achieve this, 28 isotope internal standards (ISTDs) were added to 3 mL sewage samples, the pH was adjusted to 7-8 using hydrochloric acid or 20% ammonia water, followed by centrifugation, filtration, and analysis using UHPLC-MS/MS. The results indicated an excellent linearity of 1-300 ng L-1, and cotinine in the concentration range of 20-6000 ng L-1, linear correlation coefficient R2 > 0.995, with the limit of detection (LOD) of 0.01-6 ng L-1, and a limit of quantification (LOQ) of 0.1-20 ng L-1. The addition of three concentrates of low (2 ng L-1/40 ng L-1), medium (20 ng L-1/400 ng L-1), and high concentration (200 ng L-1/4000 ng L-1) demonstrated the matrix effect of the target compound between ± 22.0%. The extraction recovery was 70.0-119.4%, and a percent accuracy of 75.7-118.1%. Similarly, the intra- and inter-day precisions were 1.8-20.0% and 1.5-18.9%, respectively. The results cemented the sensitivity, accuracy, reliability, strong specificity, and reproducibility, which can be used to screen 28 illegal drugs in sewage for trace analysis.

Evaluation of biochemical assays and optimization of LC-MS-MS analysis for the detection of synthetic urine

Ensuring specimen validity is an essential aspect of toxicological laboratories. In recent years, substituting authentic urine specimens for synthetic urine (SU) has become increasingly popular. Such SU products consist of components expected in normal urine and show physiological values for specific gravity and pH. Thus, standard specimen validity testing may fail in revealing adulteration by SU. The present study investigated three methods to distinguish authentic and SU specimens: enzymatic detection of uric acid, the commercially available Axiom Test True SU and liquid chromatography coupled with (tandem) mass spectrometry (LC-MS-MS) analysis of 10 endogenous biomolecules. Additionally, novel direct markers of SU were investigated. Two specimen sets were analyzed by each method. Specimen set A consisted of eight SU products purchased from the Austrian/German market and 43 urine specimens from volunteers of known authenticity, which underwent double-blind analysis. Specimen set B consisted of 137 real urine specimens submitted for drug testing, which were selected due to initial suspicious test results in adulteration testing and reanalyzed by all three methods. Uric acid and LC-MS-MS-based endogenous biomolecule testing showed 100% sensitivity and specificity for set A. The commercial test had 87.5% sensitivity and 97.7% specificity for set A. For set B, uric acid and LC-MS-MS analysis showed almost similar results, even if uric acid was missing one presumptive authentic urine specimen according to LC-MS-MS findings. Nearly half of the SU assignments for the commercial test were presumptive false positives. New SU markers were observed for SU products from the Austrian/German market. One specimen in set B had both an endogenous biomolecule pattern and SU markers suggesting urine dilution with SU. In conclusion, several analytes or methods should be used rather than one, and the most reliable results are achieved if both indirect and direct markers of urine substitution are analyzed.

A Review of Drug Abuse, Misuse, and Related Laboratory Challenges

Various definitions can be considered for drugs and substance abuse. According to the National Institute on Abuse, the use of an over-the-counter drug in a different way than that prescribed to experience or arouse emotion is a simple form of drug abuse. The World Health Organization (WHO) also defines drug abuse as the persistent or sporadic use of drugs that are incompatible or unrelated to acceptable medical practice. With the increasing non-therapeutic use of prescription drugs, serious related consequences have also increased. Therefore, there is a need to know more precisely about the types of substances and drug abuse, which is the most important part of diagnosis and recognizing the tests that cause false positive and negative results. The purpose of this review article is to collect and summarize the most important and more common types of drugs of abuse and review the drugs that cause false results in screening tests. In addition, the most common detection methods of the drug will be reviewed and the advantages and drawbacks of each method will be discussed. In this article, we aimed to point out all the facts about the emerging problems in drug abuse, the methods of screening, and the possible false results in addition to troubleshooting strategies.

Dilute and shoot approach for toxicology testing

Toxicology testing is performed in clinical settings, forensic settings, and for controlling doping. Drug screening is a toxicology test to determine if drugs are present in biological samples. The most common specimen type for drug testing is urine, as drugs and/or their metabolites are often more concentrated in the urine, extending the detection window of drugs. The dilute-and-shoot method is a simple procedure used in toxicology testing, where a sample is diluted before being directly injected into the liquid chromatography-mass spectrometry (LC-MS) system. This method is easy, quick, and cost-saving, and can be used for protein-poor liquid specimens such as urine. Thus, it is reasonable and attractive for busy toxicology laboratories to combine the dilute-and-shoot method with high-resolution hyphenated-MS for urine drug screening. This method has several disadvantages, including a suboptimal detection capability for certain analytes, as well as interference from co-eluting matrix components called matrix effects, in which co-eluting matrix molecules alter the ionization efficiency of the analyte molecules at the ionization source in LC-MS, altering (mostly reducing) the analyte detection capability. The matrix effect testing is essential for the validation of LC-MS-based assays. A reasonable approach to addressing these undesirable effects would be to minimize these components. The most straightforward approach is to reduce the amounts of matrix components by using a higher dilution of the specimen and a lower volume for specimen injection. Optimization of the chromatographic separation is another reasonable approach for reducing co-eluting matrix components with the analyte.

Saliva Analysis Based on Microfluidics: Focusing the Wide Spectrum of Target Analyte

Saliva is one of the most critical human body fluids that can reflect the state of the human body. The detection of saliva is of great significance for disease diagnosis and health monitoring. Microfluidics, characterized by microscale size and high integration, is an ideal platform for the development of rapid and low-cost disease diagnostic techniques and devices. Microfluidic-based saliva testing methods have aroused considerable interest due to the increasing need for noninvasive testing and frequent or long-term testing. This review briefly described the significance of saliva analysis and generally classified the targets in saliva detection into pathogenic microorganisms, inorganic substances, and organic substances. By using this classification as a benchmark, the state-of-the-art research results on microfluidic detection of various substances in saliva were summarized. This work also put forward the challenges and future development directions of microfluidic detection methods for saliva.

Swab-in-Capillary Electrospray Ionization and a Miniature Mass Spectrometer for In Situ Drug Analysis

In situ analysis of drugs has been in increasing demand in many fields. As an updated version of capillary-in-capillary electrospray ionization (CC-ESI) developed previously, a disposable swab-in-capillary electrospray ionization (SC-ESI) source was designed in this study. With a micro medical swab for sampling and an integrated filter membrane for online filtration, SC-ESI was able to directly sample and MS analyze complex samples without the need for pretreatment. Coupled with a miniature mass spectrometer, SC-ESI was applied for direct analysis of effective ingredients in therapeutic drugs (in tablet, capsule, and liquid droplet) and drugs in saliva and quantitation of therapeutic drugs in blood. The limits of detection in absolute amounts were obtained as 1 ng for fentanyl and 0.5 ng for cocaine in saliva. Combining with an internal standard method, SC-ESI acquired linear quantitation ranges of 100-5000 ng/mL for imatinib in whole blood and 100-2000 ng/mL for clozapine in serum with high accuracies and precisions. The entire analysis process, from sampling to data acquisition, can be completed in less than 2 min. As demonstrated as a cheap, portable, and sampling-effective ionization source, SC-ESI has shown great potential for in situ drug analysis, especially in border drug screening and clinical therapeutic drug monitoring.

Detection of abused drugs in human exhaled breath using mass spectrometry: A review

RATIONALE

Human breath analysis has been attracting increasing interest in the detection of abused drugs in forensic and clinical applications because of its noninvasive sampling and distinctive molecular information. Mass spectrometry (MS)-based approaches have been proven to be powerful tools for accurately analyzing exhaled abused drugs. The major advantages of MS-based approaches include high sensitivity, high specificity, and versatile couplings with various breath sampling methods.

METHODS

Recent advances in the methodological development of MS analysis of exhaled abused drugs are discussed. Breath collection and sample pretreatment methods for MS analysis are also introduced.

RESULTS

Recent advances in technical aspects of breath sampling methods are summarized, highlighting active and passive sampling. MS methods for detecting different exhaled abused drugs are reviewed, emphasizing their features, advantages, and limitations. The future trends and challenges in MS-based breath analysis of exhaled abused drugs are also discussed.

CONCLUSIONS

The coupling of breath sampling methods with MS approaches has been proven to be a powerful tool for the detection of exhaled abused drugs, offering highly attractive results in forensic investigations. MS-based detection of exhaled abused drugs in exhaled breath is a relatively new field and is still in the early stages of methodological development. New MS technologies promise a substantial benefit for future forensic analysis.

Validity and reliability of in-person and remote oral fluids drug testing compared to urine drug testing

BACKGROUND

Increased telehealth use has led to greater interest in remote drug testing. The speed, acceptability, and ability to observe oral fluids testing makes it the best candidate for remote drug testing, but its validity and reliability compared to gold-standard urine drug testing have not been established.

METHODS

Veterans (N = 99) recruited from mental health clinics completed in-person and remote oral fluids testing and in-person urine drug testing. The validity of oral fluids versus urine drug testing and reliability of in-person versus remote oral fluids testing were evaluated.

RESULTS

Validity of oral fluids testing was similar for samples collected in-person and virtually. Oral fluids testing had good specificity (0.93-1.00) and negative predictive value (0.85-1.00), but lower sensitivity and positive predictive value. Sensitivity (0.21-0.93) was highest for methadone and oxycodone, followed by cocaine and then amphetamine and opiates. Positive predictive value (0.14-1.00) was highest for cocaine, opiates, and methadone, followed by oxycodone and then amphetamine. Validity for cannabis was low, likely because of differences in detection windows for oral fluids versus urine drug screens. Reliability of remote oral fluids testing was adequate for opiates, cocaine, and methadone, but not oxycodone, amphetamine, or cannabis.

CONCLUSIONS

Oral fluids testing identifies most negative, but not most positive, drug test results. While oral fluids testing is appropriate in some circumstances, its limitations should be acknowledged. Remote drug testing addresses many barriers, but also generates new barriers related to self-administration and remote interpretation. Limitations include a small sample and low base rates for some drugs.

Smart Multiplex Point-of-Care Platform for Simultaneous Drug Monitoring

Recently, illicit drug use has become more widespread and is linked to problems with crime and public health. These drugs disrupt consciousness, affecting perceptions and feelings. Combining stimulants and depressants to suppress the effect of drugs has become the most common reason for drug overdose deaths. On-site platforms for illicit-drug detection have gained an important role in dealing, without any excess equipment, long process, and training, with drug abuse and drug trafficking. Consequently, the development of rapid, sensitive, noninvasive, and reliable multiplex drug-detecting platforms has become a major necessity. In this study, a multiplex laser-scribed graphene (LSG) sensing platform with one counter, one reference, and three working electrodes was developed for rapid and sensitive electrochemical detection of amphetamine (AMP), cocaine (COC), and benzodiazepine (BZD) simultaneously in saliva samples. The multidetection sensing system was combined with a custom-made potentiostat to achieve a complete point-of-care (POC) platform. Smartphone integration was achieved by a customized application to operate, display, and send data. To the best of our knowledge, this is the first multiplex LSG-based electrochemical platform designed for illicit-drug detection with a custom-made potentiostat device to build a complete POC platform. Each working electrode was optimized with standard solutions of AMP, COC, and BZD in the concentration range of 1.0 pg/mL-500 ng/mL. The detection limit of each illicit drug was calculated as 4.3 ng/mL for AMP, 9.7 ng/mL for BZD, and 9.0 ng/mL for COC. Healthy and MET (methamphetamine) patient saliva samples were used for the clinical study. The multiplex LSG sensor was able to detect target analytes in real saliva samples successfully. This multiplex detection device serves the role of a practical and affordable alternative to conventional drug-detection methods by combining multiple drug detections in one portable platform.

Advances in testing for sample manipulation in clinical and forensic toxicology - Part A: urine samples

In many countries, adherence testing is used to monitor consumption behavior or to prove abstinence. Urine and hair are most commonly used, although other biological fluids are available. Positive test results are usually associated with serious legal or economic consequences. Therefore, various sample manipulation and adulteration strategies are used to circumvent such a positive result. In these critical review articles on sample adulteration of urine (part A) and hair samples (part B) in the context of clinical and forensic toxicology, recent trends and strategies to improve sample adulteration and manipulation testing published in the past 10 years are described and discussed. Typical manipulation and adulteration strategies include undercutting the limits of detection/cut-off by dilution, substitution, and adulteration. New or alternative strategies for detecting sample manipulation attempts can be generally divided into improved detection of established urine validity markers and direct and indirect techniques or approaches to screening for new adulteration markers. In this part A of the review article, we focused on urine samples, where the focus in recent years has been on new (in)direct substitution markers, particularly for synthetic (fake) urine. Despite various and promising advances in detecting manipulation, it remains a challenge in clinical and forensic toxicology, and simple, reliable, specific, and objective markers/techniques are still lacking, for example, for synthetic urine.

Development of a Machine Learning Algorithm for Drug Screening Analysis on High-Resolution UPLC-MSE/QTOF Mass Spectrometry

BACKGROUND

Ultra-performance liquid chromatography (UPLC)-MSE/quadrupole time-of-flight (QTOF) high-resolution mass spectrometry employs untargeted, data-independent acquisition in a dual mode that simultaneously collects precursor ions and product ions at low and ramped collision energies, respectively. However, algorithmic analysis of large-scale multivariate data of comprehensive drug screening as well as the positivity criteria of drug identification have not been systematically investigated. It is also unclear whether ion ratio (IR), the intensity ratio of a defined product ion divided by the precursor ion, is a stable parameter that can be incorporated into the MSE/QTOF data analysis algorithm.

METHODS

IR of 91 drugs were experimentally determined and variation of IR was investigated across 5 concentrations measured on 3 different days. A data-driven machine learning approach was employed to develop multivariate linear regression (MLR) models incorporating mass error, retention time, number of detected fragment ions and IR, accuracy of isotope abundance, and peak response using drug-supplemented urine samples. Performance of the models was evaluated in an independent data set of unknown clinical urine samples in comparison with the results of manual analysis.

RESULTS

IR of most compounds acquired by MSE/QTOF were low and concentration-dependent (i.e., IR increased at higher concentrations). We developed an MLR model with composite score outputs incorporating 7 parameters to predict positive drug identification. The model achieved a mean accuracy of 89.38% in the validation set and 87.92% agreement in the test set.

CONCLUSIONS

The MLR model incorporating all contributing parameters can serve as a decision-support tool to facilitate objective drug identification using UPLC-MSE/QTOF.

Drug testing in support of the diagnosis of neonatal abstinence syndrome: The current situation

Illicit drug use during pregnancy is a concern worldwide, with many international studies describing attempted strategies to mitigate this problem. Drug misuse during pregnancy is associated with significant maternal as well as perinatal complications, which include a high incidence of stillbirths, fetal distress, neonatal abstinence syndrome (NAS) and increased neonatal mortality. Unfortunately, the identification of a drug-exposed mother or neonate is challenging. Maternal disclosure of drug use is often inaccurate, principally due to psychosocial factors including behavioral denial or the fear of the consequences resulting from such admissions. Likewise, many infants who have been exposed to drugs in utero may appear normal at birth and initially show no overt manifestations of drug effects. Thus, the identification of the drug-exposed infant requires a high index of clinical suspicion. Conversely, analytical testing is an objective means of determining drug exposure when it may be necessary to document proof of the infant's exposure to illicit drugs. The review will discuss the different matrices that are most commonly used for testing (e.g., maternal urine, neonatal urine, meconium, and umbilical cord), the strengths and limitations for each matrix, which drugs and metabolites are appropriate for testing, the various testing methods, and the advantages and disadvantages of each method.

Graphene-Based Electrochemical Sensors for Psychoactive Drugs

Sensors developed from nanomaterials are increasingly used in a variety of fields, from simple wearable or medical sensors to be used at home to monitor health, to more complicated sensors being used by border customs or aviation industries. In recent times, nanoparticle-based sensors have begun to revolutionize drug-detection techniques, mainly due to their affordability, ease of use and portability, compared to conventional chromatography techniques. Thin graphene layers provide a significantly high surface to weight ratio compared to other nanomaterials, a characteristic that has led to the design of more sensitive and reliable sensors. The exceptional properties of graphene coupled with its potential to be tuned to target specific molecules have made graphene-based sensors one of the most popular and well-researched sensing materials of the past two decades with applications in environmental monitoring, medical diagnostics, and industries. Here, we present a review of developments in the applications of graphene-based sensors in sensing drugs such as cocaine, morphine, methamphetamine, ketamine, tramadol and so forth in the past decade. We compare graphene sensors with other sensors developed from ultrathin two-dimensional materials, such as transition-metal dichalcogenides, hexagonal boron nitrate, and MXenes, to measure drugs directly and indirectly, in various samples.

Determination of Prenatal Substance Exposure Using Meconium and Orbitrap Mass Spectrometry

The aim of this study was to develop and to validate a toxicological untargeted screening relying on LC-HRMS in meconium including the detection of the four main classes of drugs of abuse (DoA; amphetamines, cannabinoids, opioids and cocaine). The method was then applied to 29 real samples. Analyses were performed with a liquid chromatography system coupled to a benchtop Orbitrap operating in a data-dependent analysis. The sample amount was 300 mg of meconium extracted twice by solid phase extraction following two distinct procedures. Raw data were processed using the Compound Discoverer 3.2 software (Thermo). The method was evaluated and validated on 15 compounds (6-MAM, morphine, buprenorphine, norbuprenorphine, methadone, EDDP, amphetamine, MDA, MDMA, methamphetamine, cocaine, benzoylecgonine, THC, 11-OH-THC, THC-COOH). Limits of detection were between 0.5 and 5 pg/mg and limits of identification between 5 and 50 pg/mg. Mean matrix effect was between −79 and −19% (n = 6) and mean overall recovery between 18 and 73% (n = 6) at 100 pg/mg. The application allows the detection of 88 substances, including 47 pharmaceuticals and 15 pharmaceutical metabolites, cocaine and its metabolites, THC and its metabolites, and natural (morphine, codeine) and synthetic (methadone, buprenorphine, tramadol, norfentanyl) opioids. This method is now used routinely for toxicological screening in high-risk pregnancies

Potentiality of miniaturized techniques for the analysis of drugs of abuse

Capillary electromigration (CE) and liquid chromatographic techniques (CLC/nano-LC) are miniaturized techniques offering distinct advantages over conventional ones in the field of separation science. Among these, high efficiency, high chromatographic resolution, and use of minute volumes of both mobile phase and sample volumes are the most important. CE and CLC/nano-LC have been applied to the analysis of many compounds including peptides, proteins, drugs, enantiomers, ions, etc. Over the years, the methods described here have also been used for the analysis of compounds of clinical, forensic, and toxicological interest. In this review article, the main features of the mentioned techniques are summarized. Their potentiality for the analysis of drugs of abuse are discussed. Some selected applications in this field in the period of 2015-present are also reported.

Ion Mobility–Mass Spectrometry for Bioanalysis

This paper aims to cover the main strategies based on ion mobility spectrometry (IMS) for the analysis of biological samples. The determination of endogenous and exogenous compounds in such samples is important for the understanding of the health status of individuals. For this reason, the development of new approaches that can be complementary to the ones already established (mainly based on liquid chromatography coupled to mass spectrometry) is welcomed. In this regard, ion mobility spectrometry has appeared in the analytical scenario as a powerful technique for the separation and characterization of compounds based on their mobility. IMS has been used in several areas taking advantage of its orthogonality with other analytical separation techniques, such as liquid chromatography, gas chromatography, capillary electrophoresis, or supercritical fluid chromatography. Bioanalysis is not one of the areas where IMS has been more extensively applied. However, over the last years, the interest in using this approach for the analysis of biological samples has clearly increased. This paper introduces the reader to the principles controlling the separation in IMS and reviews recent applications using this technique in the field of bioanalysis.