Characterization of solid counterfeit drug samples by desorption electrospray ionization and direct-analysis-in-real-time coupled to time-of-flight mass spectrometry

Demonstration of an End-To-End Workflow Using Atmospheric Solids Analysis Probe-Mass Spectrometry (ASAP-MS) With Real-Time Sample Recognition Software for the Identification of Falsified and Substandard Pharmaceutical Tablets

Counterfeit pharmaceuticals are a subclass of falsified and substandard medicines. They are illicit products, purporting to be genuine medicines, that are made and sold by criminal organisations. They represent a significant risk to patient safety, as well as a financial and reputational threat to the companies who make the genuine medicines. It is essential to have analytical methods to determine if suspect samples seized by law enforcement agencies are counterfeit, with mass spectrometry (MS) being a commonly used technique in forensic cases. Speed-to-answer is vital to enable law enforcement agencies to progress investigations, as well as for pharmaceutical companies so that they can notify health authorities of the circulation of counterfeit medicines. In this work, an atmospheric solids analysis probe (ASAP)-MS was assessed as a fast and simple-to-use approach to analyse tablets on a commercially available instrument. Complementing the analytics with real-time sample recognition software demonstrated that the classification of tablets as authentic or counterfeit could be achieved quickly (< 2 min) and without the need for MS interpretation skills. Authentication of five tablets (two authentic pharmaceuticals, one placebo and two counterfeits containing the correct active pharmaceutical ingredient [API] but at lower quantities than in the genuine medicine and with different excipient contents) of unknown origin was achieved with 100% success. This creates the opportunity to deploy the end-to-end workflow as a tool for non-scientists, such as law enforcement officers and border control staff, for use in-territory to obtain fast answers and make data-led decisions to control the illegal trading of medicines.

Nondestructive Measurement Technique for Substandard Amoxicillin Based on Thermal Approach

In this study, we introduce a new nondestructive measurement technique based on a thermal approach for the determination of substandard amoxicillin. The quality control of amoxicillin is critical for patient safety, and one of the essential parameters for its evaluation is the content of the active ingredient. Traditional methods for assessing amoxicillin content are defined by their time-consuming nature, reliance on skilled personnel, and frequent necessity for specific reagents. The proposed device aims to provide a rapid and low-cost alternative that can accurately measure the amoxicillin content without damaging the sample. The method validation results indicate coefficient of determination (R2) exceeding 0.99, with percent recoveries falling within the range of 98.70-103.40%. The calculated values for limit of detection and limit of quantitation were determined to be 28.11 and 85.17 mg/L, respectively. Our experiments employed amoxicillin samples with predetermined concentrations, all of which were below the standard quality. It was observed that the proposed analytical device effectively quantifies the amoxicillin content in aqueous solutions. Each measurement took no more than 10 min, underscoring the efficiency of the analysis process. The experiments were validated through independent testing at the Government Pharmaceutical Organization in Thailand and the department of engineering science in Oxford, which provides strong evidence for the effectiveness and robustness of the technique. Overall, this study demonstrates the feasibility of using a thermal approach for the nondestructive measurement of substandard amoxicillin.

Rapid Screening of Vaping Liquids by DART-MS

BACKGROUND

E-cigarette, or vaping, product use-associated lung injury was reported in over 2800 cases from August 2019 to February 2020. Samples of vaping products were submitted for laboratory analysis in conjunction with investigation of the outbreak. A rapid screening method that was selective and sensitive for multiple analytes was required to aid in the investigation.

OBJECTIVE

To develop a multi-analyte method capable of screening vaping liquid samples that consumed small amounts of sample, required minimal sample preparation and analysis time, employed automated data processing, and provided the necessary sensitivity and selectivity.

METHODS

Vaping liquids were dissolved in acetonitrile and sampled with DIP-it® tips. The tips were analyzed by direct analysis in real-time mass spectrometry (DART-MS) and the resulting data processed with TraceFinder™ software. Laboratory-fortified samples consisting of various analytes and matrixes were evaluated prior to the analysis of submitted samples.

RESULTS

The method was successful at detecting all target analytes in all matrixes evaluated, although the method detection limits varied by analyte/matrix combination: from 0.1% nicotine in poly(propylene glycol) average Mn 1000 (the lowest level evaluated) to 5.0% poly(ethylene glycol) average Mn 400 in cannabis concentrate. Results for the analysis of submitted samples by this method compared favorably to GC-MS and FTIR results.

CONCLUSION

The DART-MS method met the objective of speed, sensitivity, and selectivity (although certain cannabinoid isomers could not be distinguished). The method may be easily adapted or expanded for additional analytes.

HIGHLIGHTS

This is a simple DART-MS method for screening vaping liquids for substances of concern in less than 2 min per sample.

The development and application of matrix assisted laser desorption electrospray ionization: The teenage years

In the past 15 years, ambient ionization techniques have witnessed a significant incursion into the field of mass spectrometry imaging, demonstrating their ability to provide complementary information to matrix-assisted laser desorption ionization. Matrix-assisted laser desorption electrospray ionization is one such technique that has evolved since its first demonstrations with ultraviolet lasers coupled to Fourier transform-ion cyclotron resonance mass spectrometers to extensive use with infrared lasers coupled to orbitrap-based mass spectrometers. Concurrently, there have been transformative developments of this imaging platform due to the high level of control the principal group has retained over the laser technology, data acquisition software (RastirX), instrument communication, and image processing software (MSiReader). This review will discuss the developments of MALDESI since its first laboratory demonstration in 2005 to the most recent advances in 2021.

A home-made sampling system coupled to hectowatt-MPT mass spectrometry in positive ion mode to confirm target ions of copper and zinc from Poyang Lake, China

A novel home-made H₂SO₄-Nafion (HN) tube sampling system coupled to a line ion trap mass spectrometer (LTQ-MS) with a versatile ambient ionization source, hectowatt microwave plasma torch (HMPT), has manifested unique advantages for picking directly metal elements in aqueous samples and acquiring the fully characteristic MPT mass spectra of copper and zinc composite ions. Here, we report the development of a novel HN-HMPT-LTQ-MS for metal elements assay based on environmental water to analyze samples of Poyang Lake, China. Detailed multi-stage tandem mass spectra show that the general structural form of target ions is [M(NO₃)_x(H₂O)_y(OH)_z]⁺ for the positive ion mode. Under the optimized conditions, the proposed method provided low limits of detection (LODs) of 0.23 μg^.L^-1 for ⁶³Cu⁺ and 1.1 μg^.L^-1 for ⁶⁶Zn⁺, with relative standard deviations (RSDs) of less than 12.7% by MPT-LTQ-MS. This new result has met the requirements of national standards (GB 5750.6-2006) and is only about one magnitude order larger than the LOD of ICP-MS method. A wide linear response range of about 4 orders of magnitude for the method with linear coefficients (R²) of 0.99709 - 0.99962 for copper and zinc tested was in accordance with that of ICP-MS. Except for the recovery of 79% for the third sample and 123.8% for the seventh sample, the present method also provided good recoveries (84 - 119.3%) in spiked 10 batches of drinking water samples. Furthermore, it is envisioned that the developed approach might build a powerful hectowatt-MPT-MS platform for food security detection, drug analysis, and origin traceability.

Application of direct analysis in real-time mass spectrometry (DART-MS) in forensic science: a comprehensive review

Background

As the rate of crime is constantly increasing, the workload on the forensic analyst also piles up. The availability of a limited number of seized samples makes it crucial to directly analyze the sample, thereby preventing wastage in the prior steps of sample preparation. Due to such needs, the forensic community is consistently working on broadening the usage of direct analysis in real-time mass spectrometry (DART-MS). DART-MS is a relatively new technique for rapid mass spectral analysis. Its use for chemical analysis credits its ability to analyze the sample at atmospheric pressure.

Main body

This article gives insight into the ionization mechanisms, data analysis tools, and the use of hyphenated techniques like thermal-desorption-DART-MS, infrared-thermal-desorption-DART-MS, Joule-heating thermal-desorption-DART-MS, etc. This review summarizes the applications of DART-MS in the field of Forensic Science reported from 2005 to 2021. The applications include analysis of drugs, warfare agents, gun-shot residues, ink differentiation, and other forensically relevant samples. The paper also presents the relation between the type of DART-MS technique and the ionization mode used for a particular class of compounds.

Conclusion

The review follows that the high-resolution mass-spectrometers or low-resolution mass-spectrometers systems in the positive or negative mode were highly dependent on the type of analyte under investigation. Drugs, inks, dyes, and paints were mainly analyzed using the positive ionization mode in the HRMS technique. The examinations of fire accelerants predominantly used the positive ionization mode in the LRMS technique. Moreover, the limit of detection values obtained from the qualitative screening of street drugs were of ppb level, indicating high sensitivity of DART-MS. Considering the work done in the past years, there are potential future research needs of this technology, especially in forensic science.

Graphical Abstract

Clinical Chemistry for Developing Countries: Mass Spectrometry

Early disease diagnosis is necessary to enable timely interventions. Implementation of this vital task in the developing world is challenging owing to limited resources. Diagnostic approaches developed for resource-limited settings have often involved colorimetric tests (based on immunoassays) due to their low cost. Unfortunately, the performance/sensitivity of such simplistic tests are often limited and significantly hinder opportunities for early disease detection. A new criterion for selecting diagnostic tests in low- and middle-income countries is proposed here that is based on performance-to-cost ratio. For example, modern mass spectrometry (MS) now involves analysis of the native sample in the open laboratory environment, enabling applications in many fields, including clinical research, forensic science, environmental analysis, and agriculture. In this critical review, we summarize recent developments in chemistry that enable MS to be applied effectively in developing countries. In particular, we argue that closed automated analytical systems may not offer the analytical flexibility needed in resource-limited settings. Alternative strategies proposed here have potential to be widely accepted in low- and middle-income countries through the utilization of the open-source ambient MS platform that enables microsampling techniques such as dried blood spot to be coupled with miniature mass spectrometers in a centralized analytical platform. Consequently, costs associated with sample handling and maintenance can be reduced by >50% of the total ownership cost, permitting analytical measurements to be operated at high performance-to-cost ratios in the developing world.

Non-contact vapor detection of illicit drugs via atmospheric flow tube-mass spectrometry

Real-time, non-contact detection of illicit drugs is a desirable goal for the interdiction of these controlled substances, but the relatively low vapor pressures of such species present a challenge for trace vapor detection technologies. The introduction of atmospheric flow tube-mass spectrometry (AFT-MS), which has previously been demonstrated to detect gas-phase analytes at low parts-per-quadrillion levels for explosives and organophosphorus compounds, also enables the potential for non-contact drug detection. With AFT-MS, direct vapor detection of cocaine and methamphetamine from ∼5 μg residues at room temperature is demonstrated herein. Furthermore, thermal desorption of low- to sub-picogram levels of cocaine, methamphetamine, fentanyl, and heroin is observed via AFT-MS using a carrier flow rate of several L min^-1 of air. These low levels can permit non-contact sampling through collection of vapor, effectively preconcentrating the analyte before desorption and analysis. Quantitative evaluation of the thermal desorption approach has yielded limits of detection (LODs) on the order of 10 fg for cocaine and fentanyl, 100 fg for methamphetamine, and 1.6 pg for heroin. The LOD for heroin was lowered to 300 fg by using tributyl phosphate as a dopant to form a proton-bound heterodimer with heroin. When used with AFT-MS, the intentional formation of specific drug-dopant adducts has the potential to enhance detection limits and selectivity of additional drug species. Species that are prone to form adducts present a challenge to analysis, but that difficulty can be overcome by the intentional addition of a dopant. Molecules unlikely to form adducts will remain essentially unimpacted, but the adduct-forming species will interact with the dopant to compress the analyte signal into a single peak. This approach would be valuable in the application of non-contact screening for illicit substances via vapor collection followed by thermal desorption for analysis.

Interpretation of Ionization Mechanism Responsible for Reagent Ion and Analyte Formation in Microwave-Induced Plasma Desorption Ionization Mass Spectrometry

Ambient desorption/ionization (ADI) sources coupled to mass spectrometer have gained increasing interest in the field of analytical chemistry for its fast and direct analysis of samples. Among many ADI sources, plasma-based ADI sources are an important branch. Despite its extensive use in mass spectrometry analysis, the ionization mechanism of these sources still remain uncertain. The study on ionization mechanism is of great significance to optimize the design of ion sources and to improve ionization efficiency. In this study, targeted research on a better understanding of afterglow distance effects on ionization process was conducted. Based on the quantified signal expression of reagent ions in mass spectrum, the concept that optimal atmospheric analysis distance of plasma ADI source is defined for the first time. From the perspective of mutual restriction effect between atmospheric components, the formation progress of reagent ions was visually revealed in detail, which involved the initial step of forming precursor reagent ions, the clusters reaction for increasing production of reagent ions, and the matrix effect results in reagent ion depletion. The formation mechanism of reagent ions further clarified the explicit reason for abundant reagent ions generated at an optimal distance. Most importantly, the analyte analysis results verified the significant impact of appropriate distance on ionization efficiency in afterglow region. It was confirmed that the quantity and type of reagent ions intimately influenced the status of analyte ions in mass spectrum.

Antibiotic analysis using Electro-Filtering Paper Spray Ionization

In this work, we analyzed the performance of the Electro-Filtering Paper Spray Ionization (EFSI) method for detecting compounds in unprocessed samples. A relatively rigid and electrically conductive copper filter was used as a substrate to insure sufficient and efficient sample-solvent extraction and to increase the conductivity for paper spraying. The method was demonstrated as applicable for indirect high-throughput analysis of large-volume unprocessed samples, which is not possible with conventional nanoESI or direct paper spray methods. The new method can generate different desired ion signals for a wide range of compounds by selecting different extraction solvents. Moreover, key parameters related to extraction efficiency were optimized in detail to obtain the most satisfactory extraction efficiency during antibiotic analysis. Finally, under optimal conditions, the EFSI method was successfully used to detect four antibiotics in animal products of egg, chicken, and chicken liver, exhibiting good reproducibility with calibration curves between 81.6% and 96.3%, and R² values above 0.99. Recoveries of 75.0%ￚ94.6% were obtained for the four antibiotics. Hence, the proposed EFSI-MS is a successful, economical, rapid, and high-throughput method that is effective for both unknown and targeted extraction of unprocessed samples by mass spectrometric analysis.

Clinical Mass Spectrometry in the Bioinformatics Era: A Hitchhiker's Guide

Mass spectrometry (MS) is a sensitive, specific and versatile analytical technique in the clinical laboratory that has recently undergone rapid development. From initial use in metabolic profiling, it has matured into applications including clinical toxicology assays, target hormone and metabolite quantitation, and more recently, rapid microbial identification and antimicrobial resistance detection by matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). In this mini-review, we first succinctly outline the basics of clinical mass spectrometry. Examples of hard ionization (electron ionization) and soft ionization (electrospray ionization, MALDI) are presented to demonstrate their clinical applications. Next, a conceptual discourse on mass selection and determination is presented: quadrupole mass filter, time-of-flight mass spectrometer and the Orbitrap; and MS/MS (tandem-in-space, tandem-in-time and data acquisition), illustrated with clinical examples. Current applications in (1) bacterial and fungal identification, antimicrobial susceptibility testing and phylogenetic classification, (2) general unknown urine toxicology screening and expanded new-born metabolic screening and (3) clinical metabolic profiling by gas chromatography are outlined. Finally, major limitations of MS-based techniques, including the technical challenges of matrix effect and isobaric interference; and novel challenges in the post-genomic era, such as protein molecular variants, are critically discussed from the perspective of service laboratories. Computer technology and structural biology have played important roles in the maturation of this field. MS-based techniques have the potential to replace current analytical techniques, and existing expertise and instrument will undergo rapid evolution. Significant automation and adaptation to regulatory requirements are underway. Mass spectrometry is unleashing its potentials in clinical laboratories.

A Mass Spectrometer in Every Fume Hood

Since their inception, mass spectrometers have played a pivotal role in the direction and application of synthetic chemical research. The ability to develop new instrumentation to solve current analytical challenges in this area has always been at the heart of mass spectrometry, although progress has been slow at times. Herein, we briefly review the history of how mass spectrometry has been used to approach challenges in organic chemistry, how new developments in portable instrumentation and ambient ionization have been used to open novel areas of research, and how current techniques have the ability to expand on our knowledge of synthetic mechanisms and kinetics. Lastly, we discuss the relative paucity of work done in recent years to embrace the concept of improving benchtop synthetic chemistry with mass spectrometry, the disconnect between applications and fundamentals within these studies, and what hurdles still need to be overcome. Graphical Abstract.

Paper-Based Enzyme Competition Assay for Detecting Falsified β-Lactam Antibiotics

Falsified and substandard antibiotics are a growing worldwide problem that leads to increased patient mortality and decreased trust in healthcare, and contributes to antimicrobial resistance. Monitoring falsified antibiotics is difficult because most falsified pharmaceuticals are most commonly found in developing countries, where detecting the active ingredient is difficult due to lack of access to complex instrumentation. Herein, we describe the development and optimization of a microfluidic paper-based analytical device (μPAD) to detect the active ingredient in the most falsified class of antibiotics, β-lactams. The assay is based on enzyme competition, making it the first demonstrated competitive enzyme assay reported in paper-based devices. The assay uses nitrocefin, a chromogenic substrate, to compete with β-lactam antibiotics in a reaction with β-lactamase. A yellow color indicates legitimate drugs, while a color change from yellow to red indicates falsified drugs. In addition to testing for the active ingredient, another section of the device was added to test the sample pH to further verify results and identify common falsified ingredients like aspirin or baking soda. Calibration curves for four different antibiotics, including cefazolin, have been generated making it the first paper-based device capable of detecting both cephalosporin and penicillin antibiotics. The μPAD has also been tested with common falsified ingredients and four antibiotics in tablet or injectable form, demonstrating its potential for in-field falsified antibiotic testing.

Recent advances in ambient mass spectrometry of trace explosives

Ambient mass spectrometry has evolved rapidly over the past decade, yielding a plethora of platforms and demonstrating scientific advancements across a range of fields from biological imaging to rapid quality control. These techniques have enabled real-time detection of target analytes in an open environment with no sample preparation and can be coupled to any mass analyzer with an atmospheric pressure interface; capabilities of clear interest to the defense, customs and border control, transportation security, and forensic science communities. This review aims to showcase and critically discuss advances in ambient mass spectrometry for the trace detection of explosives.

Direct analysis in real time-Mass spectrometry (DART-MS) in forensic and security applications

Over the last decade, direct analysis in real time (DART) has emerged as a viable method for fast, easy, and reliable "ambient ionization" for forensic analysis. The ability of DART to generate ions from chemicals that might be present at the scene of a criminal activity, whether they are in the gas, liquid, or solid phase, with limited sample preparation has made the technology a useful analytical tool in numerous forensic applications. This review paper summarizes many of those applications, ranging from the analysis of trace evidence to security applications, with a focus on providing the forensic scientist with a resource for developing their own applications. The most common uses for DART in forensics are in studying seized drugs, drugs of abuse and their metabolites, bulk and detonated explosives, toxic chemicals, chemical warfare agents, inks and dyes, and commercial plant and animal products that have been adulterated for economic gain. This review is meant to complement recent reviews that have described the fundamentals of the ionization mechanism and the general use of DART. We describe a wide range of forensic applications beyond the field of analyzing drugs of abuse, which dominates the literature, including common experimental and data analysis methods. © 2016 Wiley Periodicals, Inc. Mass Spec Rev 37:171-187, 2018.

Confirmation of Pharmaceutical Identifiers via DART-TOF-MS

A direct analysis in real time ion source coupled with a time-of-flight mass spectrometer (DART-TOF-MS) is a suitable confirmatory technique for the analysis of pharmaceutical preparations, with accompanying reference sources for preparation markings. The DART-TOF-MS instrument allows for simple sample preparation and decreased analysis time, both crucial in a forensic laboratory setting. Differentiation can be made between active drug ingredients with the same molecular weight, such as hydrocodone and codeine, as well as pharmaceutical preparation mixtures, such as oxycodone and acetaminophen, using exact masses of the protonated molecules and fragment peaks compared to a standard.

Use of DART-TOF-MS for Screening Drugs of Abuse

Screening is an integral component of an analytical scheme to identify the presence of controlled substances in submissions to the crime laboratory. Many techniques are utilized, including color tests, thin-layer chromatography, and ultraviolet spectroscopy. While these are useful techniques to guide the examiner, all will, at best, categorize the material into a broad group of compounds. Direct Analysis in Real Time (DART), coupled with a time-of-flight (TOF) mass spectrometer, is an emerging technique that yields highly definitive screening data leading to the identity of controlled substances present in a case sample. Sample preparation is quick and simple and run times are typically only a few minutes. Collected data will allow the examiner to determine appropriate standards for confirmation, making the overall analysis much more efficient. Presented here is a guide to using this technique for the screening of case submissions for controlled substances.

Fighting falsified medicines: The analytical approach

Given the harm to human health, the fight against falsified medicines has become a priority issue that involves numerous actors. Analytical laboratories contribute by performing analyses to chemically characterise falsified samples and assess their hazards for patients. A wide range of techniques can be used to obtain individual information on the organic and inorganic composition, the presence of an active substance or impurities, or the crystalline arrangement of the formulation's compound. After a presentation of these individual techniques, this review puts forward a methodology to combine them. In order to illustrate this approach, examples from the scientific literature (products used for erectile dysfunction treatment, weight loss and malaria) are placed in the centre of the proposed methodology. Combining analytical techniques allows the analyst to conclude on the falsification of a sample, on its compliance in terms of pharmaceutical quality and finally on the safety for patients.

Oxidative Ionization Under Certain Negative-Ion Mass Spectrometric Conditions

1,4-Hydroquinone and several other phenolic compounds generate (M - 2) ^-• radical-anions, rather than deprotonated molecules, under certain negative-ion mass spectrometric conditions. In fact, spectra generated under helium-plasma ionization (HePI) conditions from 1,4-hydroquinone and 1,4-benzoquinone (by electron capture) were practically indistinguishable. Because this process involves a net loss of H^• and H⁺, it can be termed oxidative ionization. The superoxide radical-anion (O₂^-•), known to be present in many atmospheric-pressure plasma ion sources operated in the negative mode, plays a critical role in the oxidative ionization process. The presence of a small peak at m/z 142 in the spectrum of 1,4-hydroquinone, but not in that of 1,4-benzoquinone, indicated that the initial step in the oxidative ionization process is the formation of an O₂^-• adduct. On the other hand, under bona fide electrospray ionization (ESI) conditions, 1,4-hydroquinone generates predominantly an (M - 1) ^- ion. It is known that at sufficiently high capillary voltages, corona discharges begin to occur even in an ESI source. At lower ESI capillary voltages, deprotonation predominates; as the capillary voltage is raised, the abundance of O₂^-• present in the plasma increases, and the source in turn increasingly behaves as a composite ESI/APCI source. While maintaining post-ionization ion activation to a minimum (to prevent fragmentation), and monitoring the relative intensities of the m/z 109 (due to deprotonation) and 108 (oxidative ionization) peaks recorded from 1,4-hydroquinone, a semiquantitative estimation of the APCI contribution to the overall ion-generation process can be obtained. Graphical Abstract ᅟ.

DART-MS analysis of inorganic explosives using high temperature thermal desorption

An ambient mass spectrometry (MS) platform coupling resistive Joule heating thermal desorption (JHTD) and direct analysis in real time (DART) was implemented for the analysis of inorganic nitrite, nitrate, chlorate, and perchlorate salts. The resistive heating component generated discrete and rapid heating ramps and elevated temperatures, up to approximately 400 °C s^-1 and 750 °C, by passing a few amperes of DC current through a nichrome wire. JHTD enhanced the utility and capabilities of traditional DART-MS for the trace detection of previously difficult to detect inorganic compounds. A partial factorial design of experiments (DOE) was implemented for the systematic evaluation of five system parameters. A base set of conditions for JHTD-DART-MS was derived from this evaluation, demonstrating sensitive detection of a range of inorganic oxidizer salts, down to single nanogram levels. DOE also identified JHTD filament current and in-source collision induced dissociation (CID) energy as inducing the greatest effect on system response. Tuning of JHTD current provided a method for controlling the relative degrees of thermal desorption and thermal decomposition. Furthermore, in-source CID provided manipulation of adduct and cluster fragmentation, optimizing the detection of molecular anion species. Finally, the differential thermal desorption nature of the JHTD-DART platform demonstrated efficient desorption and detection of organic and inorganic explosive mixtures, with each desorbing at its respective optimal temperature.

Development of a simple and specific direct competitive ELISA for the determination of artesunate using an anti-artesunate polyclonal antiserum

Background

Since artesunate (ART) became a vital component of artemisinin (ARM)-based combination therapies for the treatment for malaria, counterfeit ART drugs have spread in regions of Southeast Asia and Africa. The consumption of counterfeit ART drugs has resulted in the death of many patients. Thus, evaluating the quality of ART drugs is needed. There are several methods for quantitating the ART content in tablets, the most common being a high-performance liquid chromatography. However, that method is hampered by the need for expensive equipment and a rather time-consuming process of extraction. By contrast, enzyme-linked immunosorbent assays (ELISAs) are faster and much less expensive, and they require less sample preparation than the above method. The objective of the present study was to establish a simple and specific direct competitive ELISA for the determination of ART concentrations using an anti-ART polyclonal antibody (pAb).

Results

Anti-ART pAb was raised in mice, and ART-horseradish peroxidase (HRP) conjugate was produced. A direct competitive ELISA was performed by simultaneously incubating ART and the ART-HRP conjugate with the anti-ART pAb over a second antibody. Subsequently, the enzyme activity of the remaining ART-HRP conjugate was measured. The intra- and inter-assay coefficients of variation of the ELISA were less than 10 % in the range of 0.3 to 30 ng/ml with a detection limit of 0.1 ng/ml. The cross-reactivities of the anti-ART pAb with ARM and dihydroartemisinin were 0.12 and 0.04 %, respectively, and those with other antimalarial drugs were negligible. Furthermore, the recovery of 10 or 50 ng/ml ART added to the drug tablet solutions containing an expected amount of 10 ng/ml was estimated by the ELISA. The recovery of the ART amount ranged between 98 and 106 %, with coefficient variations of less than 7.0 %.

Conclusions

The present ELISA is a simple and specific method for the determination of ART concentrations. Thus, this ELISA can be used to identify ART counterfeits and substandard drugs and to quantify the ART drugs.

Rapid High-throughput Species Identification of Botanical Material Using Direct Analysis in Real Time High Resolution Mass Spectrometry

We demonstrate that direct analysis in real time-high resolution mass spectrometry can be used to produce mass spectral profiles of botanical material, and that these chemical fingerprints can be used for plant species identification. The mass spectral data can be acquired rapidly and in a high throughput manner without the need for sample extraction, derivatization or pH adjustment steps. The use of this technique bypasses challenges presented by more conventional techniques including lengthy chromatography analysis times and resource intensive methods. The high throughput capabilities of the direct analysis in real time-high resolution mass spectrometry protocol, coupled with multivariate statistical analysis processing of the data, provide not only class characterization of plants, but also yield species and varietal information. Here, the technique is demonstrated with two psychoactive plant products, Mitragyna speciosa (Kratom) and Datura (Jimsonweed), which were subjected to direct analysis in real time-high resolution mass spectrometry followed by statistical analysis processing of the mass spectral data. The application of these tools in tandem enabled the plant materials to be rapidly identified at the level of variety and species.

Multimodal Vacuum-Assisted Plasma Ion (VaPI) Source with Transmission Mode and Laser Ablation Sampling Capabilities

We have developed a multimodal ion source design that can be configured on the fly for various analysis modes, designed for more efficient and reproducible sampling at the mass spectrometer atmospheric pressure (AP) interface in a number of different applications. This vacuum-assisted plasma ionization (VaPI) source features interchangeable transmission mode and laser ablation sampling geometries. Operating in both AC and DC power regimes with similar results, the ion source was optimized for parameters including helium flow rate and gas temperature using transmission mode to analyze volatile standards and drug tablets. Using laser ablation, matrix effects were studied, and the source was used to monitor the products of model prebiotic synthetic reactions.

Detection of polydimethylsiloxanes transferred from silicone-coated parchment paper to baked goods using direct analysis in real time mass spectrometry

The non-stick properties of parchment papers are achieved by polydimethylsiloxane (PDMS) coatings. During baking, PDMS can thus be extracted from the silicone-coated parchment into the baked goods. Positive-ion direct analysis in real time (DART) mass spectrometry (MS) is highly efficient for the analysis of PDMS. A DART-SVP source was coupled to a quadrupole-time-of-flight mass spectrometer to detect PDMS on the contact surface of baked goods after use of silicone-coated parchment papers. DART spectra from the bottom surface of baked cookies and pizzas exhibited signals because of PDMS ions of the general formula [(C2H6SiO)n  + NH4 ](+) in the m/z 800-1900 range.

Direct Analysis of Pharmaceutical Drugs Using Nano-DESI MS

Counterfeit pharmaceutical drugs imply an increasing threat to the global public health. It is necessary to have systems to control the products that reach the market and to detect falsified medicines. In this work, molecules in several pharmaceutical tablets were directly analyzed using nanospray desorption electrospray ionization mass spectrometry (nano-DESI MS). Nano-DESI is an ambient surface sampling technique which enables sampling of molecules directly from the surface of the tablets without any sample pretreatment. Both the active pharmaceutical ingredients (APIs) and some excipients were detected in all analyzed tablets. Principal component analysis was used to analyze mass spectral features from different tablets showing strong clustering between tablets with different APIs. The obtained results suggest nano-DESI MS as future tool for forensic analysis to discern APIs present in unknown tablet samples.

Determination of Dicyandiamide in Powdered Milk Using Direct Analysis in Real Time Quadrupole Time-of-Flight Tandem Mass Spectrometry

The direct analysis in real time (DART) ionization source coupled with quadrupole time-of-flight tandem mass spectrometry (Q-TOF MS/MS) system has the capability to desorb analytes directly from samples without sample cleanup or chromatographic separation. In this work, a method based on DART/Q-TOF MS/MS has been developed for rapid identification of dicyandiamide (DCD) present in powdered milk. Simple sample extraction procedure employing acetonitrile-water (80:20, v/v) mixture was followed by direct, high-throughput determination of sample extracts spread on a steel mesh of the transmission module by mass spectrometry under ambient conditions. The method has been evaluated for both qualitative and quantitative analysis of DCD in powdered milk. Variables including experimental apparatus, DART gas heater temperature, sample presentation speed, and vacuum pressure were investigated. The quantitative method was validated with respect to linearity, sensitivity, repeatability, precision, and accuracy by using external standards. After optimization of these parameters, a limit of detection (LOD) of 100 μg kg(-1) was obtained for DCD with a linear working range from 100 to 10000 μg kg(-1) and a satisfactory correlation coefficient (R(2)) of 0.9997. Good recovery (80.08%-106.47%) and repeatability (RSD = 3.0%-5.4%) were achieved for DCD. The DART/Q-TOF MS/MS-based method provides a rapid, efficient, and powerful scheme to analyze DCD in powdered milk with limited sample preparation, thus reducing time and complexity of quality control.

Forensic Mass Spectrometry

Developments in forensic mass spectrometry tend to follow, rather than lead, the developments in other disciplines. Examples of techniques having forensic potential born independently of forensic applications include ambient ionization, imaging mass spectrometry, isotope ratio mass spectrometry, portable mass spectrometers, and hyphenated chromatography-mass spectrometry instruments, to name a few. Forensic science has the potential to benefit enormously from developments that are funded by other means, if only the infrastructure and personnel existed to adopt, validate, and implement the new technologies into casework. Perhaps one unique area in which forensic science is at the cutting edge is in the area of chemometrics and the determination of likelihood ratios for the evaluation of the weight of evidence. Such statistical techniques have been developed most extensively for ignitable-liquid residue analyses and isotope ratio analysis. This review attempts to capture the trends, motivating forces, and likely impact of developing areas of forensic mass spectrometry, with the caveat that none of this research is likely to have any real impact in the forensic community unless: (a) The instruments developed are turned into robust black boxes with red and green lights for positives and negatives, respectively, or (b) there are PhD graduates in the workforce who can help adopt these sophisticated techniques.

A Repeat Random Survey of the Prevalence of Falsified and Substandard Antimalarials in the Lao PDR: A Change for the Better

In 2003, a stratified random sample survey was conducted in the Lao People's Democratic Republic (Laos) to study the availability and quality of antimalarials in the private sector. In 2012, this survey was repeated to allow a statistically valid analysis of change through time. The counterfeit detection device 3 (CD-3) was used to assess packaging quality in the field and HPLC and mass spectroscopy analysis chemical analysis performed. The availability of oral artesunate monotherapies had significantly decreased from 22.9% (22) of 96 outlets in southern Laos in 2003 to 4.8% (7) of 144 outlets in 2012 (P < 0.0001). All the samples collected in the 2012 survey contained the correct active pharmaceutical ingredients (APIs) in contrast to the 21 (84%) falsified artesunate samples found in the 2003 survey. Although none of the medicines found in 2012 survey had evidence for falsification, 25.4% (37) of the samples were outside the 90–110% pharmacopeial limits of the label claim, suggesting that they were substandard or degraded. Results obtained from this survey show that patients are still exposed to poorly manufactured drugs or to ineffective medicines such as chloroquine. The quality of artemisinin-based combination therapies (ACTs) used in Laos needs to be monitored, since falsified ACTs would have devastating consequences in public health.

Collaborative health and enforcement operations on the quality of antimalarials and antibiotics in southeast Asia

Counterfeit (or falsified) and substandard medicines pose a major public health risk. We describe the findings of Operation Storm I and II conducted in 2008–2009 to combat counterfeit medicines through partnership between national customs, Drug Regulatory Agencies (DRAs), and police in Cambodia, Indonesia, Laos, Myanmar, Singapore, Thailand, and Vietnam. Samples were obtained from seizures and market surveillance by national DRAs. Laboratory analysis using spectroscopic and chromatographic techniques and examination of packaging were performed. Ninety-three suspect antibiotics and 95 antimalarial samples were collected. Of the 93 antibiotics, 29 (31%) had % active pharmaceutical ingredient content (%API) < 85% or > 115% (including one counterfeit). Of the 95 antimalarials, 30 (32%) had %API < 85 > 115% API (including one counterfeit). A significant minority of samples, antimalarials (13%) and antibiotics (15%), were collected in plastic bags with minimal or no labeling. Of 20 ampicillin samples, 13 (65%) contained < 85% API (with one counterfeit containing additional amoxicillin). Of 34 oral artesunate samples, 7 (21%) contained %API out of the 85–115% range. Coordinated and synergistic partnership adopted by the participating countries, International Criminal Police Organization (INTERPOL), World Health Organization (WHO), and laboratories facilitated a platform for discussions and intelligence sharing, helping to improve each participating country's capacity to combat poor-quality medicines.

Substandard/counterfeit antimicrobial drugs

Substandard/counterfeit antimicrobial drugs are a growing global problem. The most common substandard/counterfeit antimicrobials include beta-lactams (among antibiotics) and chloroquine and artemisin derivatives (among antimalarials). The most common type of substandard/counterfeit antimicrobial drugs have a reduced amount of the active drug, and the majority of them are manufactured in Southeast Asia and Africa. Counterfeit antimicrobial drugs may cause increased mortality and morbidity and pose a danger to patients. Here we review the literature with regard to the issue of substandard/counterfeit antimicrobials and describe the prevalence of this problem, the different types of substandard/counterfeit antimicrobial drugs, and the consequences for the individuals and global public health. Local, national, and international initiatives are required to combat this very important public health issue.

Mass spectral similarity for untargeted metabolomics data analysis of complex mixtures

While in nucleotide sequencing, the analysis of DNA from complex mixtures of organisms is common, this is not yet true for mass spectrometric data analysis of complex mixtures. The comparative analyses of mass spectrometry data of microbial communities at the molecular level is difficult to perform, especially in the context of a host. The challenge does not lie in generating the mass spectrometry data, rather much of the difficulty falls in the realm of how to derive relevant information from this data. The informatics based techniques to visualize and organize datasets are well established for metagenome sequencing; however, due to the scarcity of informatics strategies in mass spectrometry, it is currently difficult to cross correlate two very different mass spectrometry data sets from microbial communities and their hosts. We highlight that molecular networking can be used as an organizational tool of tandem mass spectrometry data, automated database search for rapid identification of metabolites, and as a workflow to manage and compare mass spectrometry data from complex mixtures of organisms. To demonstrate this platform, we show data analysis from hard corals and a human lung associated with cystic fibrosis.

Recent advances in forensic drug analysis by DART-MS

Mass spectrometry methods play a major role in many forensic applications. While gas chromatography-mass spectrometry methods are commonly used in crime laboratories and enforcement agencies, a variety of advanced techniques are now available that can improve upon standard methods and address emerging issues in forensic science. New mass spectrometry technologies include more versatile ionization sources, allowing the next generation of instrumentation to be more multipurpose and adaptable to the needs of the discipline. Direct analysis in real-time mass spectrometry is an ambient ionization method that allows direct testing of gas, liquid and solid samples without the need for any preparation or extraction, based on thermal desorption and ionization directly from the sample surface. This Review will provide an in-depth description of direct analysis in real-time time-of-flight mass spectrometry as applied to samples relevant to forensic science, with a focus on analysis and characterization related to forensic drug chemistry.

A comprehensive high-resolution mass spectrometry approach for characterization of metabolites by combination of ambient ionization, chromatography and imaging methods

RATIONALE

An ideal method for bioanalytical applications would deliver spatially resolved quantitative information in real time and without sample preparation. In reality these requirements can typically not be met by a single analytical technique. Therefore, we combine different mass spectrometry approaches: chromatographic separation, ambient ionization and imaging techniques, in order to obtain comprehensive information about metabolites in complex biological samples.

METHODS

Samples were analyzed by laser desorption followed by electrospray ionization (LD-ESI) as an ambient ionization technique, by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging for spatial distribution analysis and by high-performance liquid chromatography/electrospray ionization mass spectrometry (HPLC/ESI-MS) for quantitation and validation of compound identification. All MS data were acquired with high mass resolution and accurate mass (using orbital trapping and ion cyclotron resonance mass spectrometers). Grape berries were analyzed and evaluated in detail, whereas wheat seeds and mouse brain tissue were analyzed in proof-of-concept experiments.

RESULTS

In situ measurements by LD-ESI without any sample preparation allowed for fast screening of plant metabolites on the grape surface. MALDI imaging of grape cross sections at 20 µm pixel size revealed the detailed distribution of metabolites which were in accordance with their biological function. HPLC/ESI-MS was used to quantify 13 anthocyanin species as well as to separate and identify isomeric compounds. A total of 41 metabolites (amino acids, carbohydrates, anthocyanins) were identified with all three approaches. Mass accuracy for all MS measurements was better than 2 ppm (root mean square error).

CONCLUSIONS

The combined approach provides fast screening capabilities, spatial distribution information and the possibility to quantify metabolites. Accurate mass measurements proved to be critical in order to reliably combine data from different MS techniques. Initial results on the mycotoxin deoxynivalenol (DON) in wheat seed and phospholipids in mouse brain as a model for mammalian tissue indicate a broad applicability of the presented workflow.

Extraction-free in situ derivatisation of timosaponin AIII using direct analysis in real time TOF/MS

INTRODUCTION

Direct analysis in real time (DART) TOF/MS has been used for mass information of various non-polar phytochemicals in raw material with no sample preparation. However, low ionisation efficiency for polar compounds including glycosides limits its extensive use in the field of phytochemical analysis.

OBJECTIVE

In order to develop a direct analysis method for polar glycosides using in situ derivatisation, which improves ionisation efficiency of hydrophilic glycosides.

METHOD

Anemarrhena Rhizoma was used as a model plant targeting on Timosaponin AIII utilising a Dip-It module. Permethylation was applied to the powdered raw material with tetramethylammonium hydroxide in front of a DART ion source. Also, DART TOF/MS combined with permethylation was applied to timosaponin AIII standard solution to obtain the limit of detection (LOD).

RESULTS

In situ methylation of timosaponin AIII and Anemarrhena Rhizoma raw material were successfully used to ionise the glycoside. The LOD was found to be in the range of 2.4-4.8 ng for permethylated timosaponin AIII and this level is four times higher than the range of the underivatisation analysis. Direct analysis of permethylated timosaponin from Anemarrhena Rhizoma was also successfully performed.

CONCLUSION

A simple and quick derivatisation method with tetramethylammonium hydroxide was developed for the direct identification of a hydrophilic saponin from the plant tissue. Better ionisation efficiency conferred by in situ permethylation enabled ionisation of whole molecules of timosaponin AIII from the plant tissue. This simple analytical method will provide a solution to reduce tedious sample preparation steps, not only for non-polar but also hydrophilic natural products directly from the tissue.

The counterfeit anti-malarial is a crime against humanity: a systematic review of the scientific evidence

BACKGROUND

The counterfeiting of anti-malarials represents a form of attack on global public health in which fake and substandard anti-malarials serve as de facto weapons of mass destruction, particularly in resource-constrained endemic settings, where malaria causes nearly 660,000 preventable deaths and threatens millions of lives annually. It has been estimated that fake anti-malarials contribute to nearly 450,000 preventable deaths every year. This crime against humanity is often underestimated or ignored. This study attempts to describe and characterize the direct and indirect effects of counterfeit anti-malarials on public health, clinical care and socio-economic conditions.

METHODS

A search was performed using key databases, WHO documents, and English language search engines. Of 262 potential articles that were identified using a fixed set of criteria, a convenience sample of 105 appropriate articles was selected for this review.

RESULTS

Artemisinin-based combination therapy (ACT) is an important tool in the fight against malaria, but a sizable number of patients are unable to afford to this first-line treatment. Consequently, patients tend to procure cheaper anti-malarials, which may be fake or substandard. Forensic palynology reveals that counterfeits originate in Asia. Fragile drug regulations, ineffective law-enforcement agencies and corruption further burden ailing healthcare facilities. Substandard/fake anti-malarials can cause (a) economic sabotage; (b) therapeutic failure; (c) increased risk of the emergence and spread of resistant strains of Plasmodium falciparum and Plasmodium vivax; (d) an undermining of trust/confidence in healthcare stakeholders/systems; and, (e) serious side effects or death.

CONCLUSION

Combating counterfeit anti-malarials is a complex task due to limited resources and poor techniques for the detection and identification of fake anti-malarials. This situation calls for sustainable, global, scientific research and policy change. Further, responsible stakeholders in combination with the synthesis and supply of next generation malaria control tools, such as low-cost anti-malarials, must promote the development of a counterfeit-free and malaria-free future.

Mind the gaps--the epidemiology of poor-quality anti-malarials in the malarious world--analysis of the WorldWide Antimalarial Resistance Network database

BACKGROUND

Poor quality medicines threaten the lives of millions of patients and are alarmingly common in many parts of the world. Nevertheless, the global extent of the problem remains unknown. Accurate estimates of the epidemiology of poor quality medicines are sparse and are influenced by sampling methodology and diverse chemical analysis techniques. In order to understand the existing data, the Antimalarial Quality Scientific Group at WWARN built a comprehensive, open-access, global database and linked Antimalarial Quality Surveyor, an online visualization tool. Analysis of the database is described here, the limitations of the studies and data reported, and their public health implications discussed.

METHODS

The database collates customized summaries of 251 published anti-malarial quality reports in English, French and Spanish by time and location since 1946. It also includes information on assays to determine quality, sampling and medicine regulation.

RESULTS

No publicly available reports for 60.6% (63) of the 104 malaria-endemic countries were found. Out of 9,348 anti-malarials sampled, 30.1% (2,813) failed chemical/packaging quality tests with 39.3% classified as falsified, 2.3% as substandard and 58.3% as poor quality without evidence available to categorize them as either substandard or falsified. Only 32.3% of the reports explicitly described their definitions of medicine quality and just 9.1% (855) of the samples collected in 4.6% (six) surveys were conducted using random sampling techniques. Packaging analysis was only described in 21.5% of publications and up to twenty wrong active ingredients were found in falsified anti-malarials.

CONCLUSIONS

There are severe neglected problems with anti-malarial quality but there are important caveats to accurately estimate the prevalence and distribution of poor quality anti-malarials. The lack of reports in many malaria-endemic areas, inadequate sampling techniques and inadequate chemical analytical methods and instrumental procedures emphasizes the need to interpret medicine quality results with caution. The available evidence demonstrates the need for more investment to improve both sampling and analytical methodology and to achieve consensus in defining different types of poor quality medicines.