Ethyl carbamate (EC) is a process contaminant that can be formed as a by-product during fermentation and processing of foods and beverages. Elevated EC concentrations are primarily associated with distilled spirits, but this compound has also been found at lower concentrations in foods and beverages, including breads, soy sauce, and wine. Evidence from animal studies suggests that EC is a probable human carcinogen. Consequently, several governmental institutions have established allowable limits for EC in the food supply. This review includes EC formation mechanisms, occurrence of EC in the food supply, and EC dietary exposure assessments. Current analytical methods used to detect EC will be covered, in addition to emerging technologies, such as nanosensors and surface-enhanced Raman spectroscopy. Various mitigation methods have been used to maintain EC concentrations below allowable limits, including distillation, enzymatic treatments, and genetic engineering of yeast. More research in this field is needed to refine mitigation strategies and develop methods to rapidly detect EC in the food supply.

Microplastic research is a rapidly developing field, with urgent needs for high throughput and automated analysis techniques. We conducted a review covering image analysis from optical microscopy, scanning electron microscopy, fluorescence microscopy, and spectral analysis from Fourier transform infrared (FT-IR) spectroscopy, Raman spectroscopy, pyrolysis gas-chromatography mass-spectrometry, and energy dispersive X-ray spectroscopy. These techniques were commonly used to collect, process, and interpret data from microplastic samples. This review outlined and critiques current approaches for analysis steps in image processing (color, thresholding, particle quantification), spectral processing (background and baseline subtraction, smoothing and noise reduction, data transformation), image classification (reference libraries, morphology, color, and fluorescence intensity), and spectral classification (reference libraries, matching procedures, and best practices for developing in-house reference tools). We highlighted opportunities to advance microplastic data analysis and interpretation by (i) quantifying colors, shapes, sizes, and surface topologies with image analysis software, (ii) identifying threshold values of particle characteristics in images that distinguish plastic particles from other particles, (iii) advancing spectral processing and classification routines, (iv) creating and sharing robust spectral libraries, (v) conducting double blind and negative controls, (vi) sharing raw data and analysis code, and (vii) leveraging readily available data to develop machine learning classification models. We identified analytical needs that we could fill and developed supplementary information for a reference library of plastic images and spectra, a tutorial for basic image analysis, and a code to download images from peer reviewed literature. Our major findings were that research on microplastics was progressing toward the use of multiple analytical methods and increasingly incorporating chemical classification. We suggest that new and repurposed methods need to be developed for high throughput screening using a diversity of approaches and highlight machine learning as one potential avenue toward this capability.

OBJECTIVE: Illicit drug abuse has reached an epidemic level in the United States. Drug overdose has become the leading cause of injury-related deaths since 2008 due to the recent surge of opioid overdose by heroin, controlled prescription drugs, and nonmethadone synthetic opioids. Synthetic designer drugs such as synthetic cathinones (\"bath salts\") and synthetic cannabinoids (\"Spice\" and \"K2\") continue to emerge and attract recreational users.
METHODS: The emergence of new drugs of abuse poses a steep challenge for clinical toxicology laboratories. Limited information about the emerging drugs and their metabolism, \"rebranding\" of the illicit drugs, and a lack of Food and Drug Administration-approved screening methods for these drugs contribute to this difficulty. Here we review detection methods that can aid in identifying emerging drugs of abuse.
RESULTS: One promising approach is the utilization of untargeted drug screening by mass spectrometry. Historically, gas chromatography-mass spectrometry has been the gold standard.
CONCLUSIONS: Liquid chromatography-tandem mass spectrometry and liquid chromatography-high-resolution mass spectrometry offer improved detection capability of new drugs with simplified sample preparation, making it the new standard.

The continually-evolving field of fire debris analysis presents challenges to examiners on a regular basis. This article combines an overview of the scientific literature with novel samples that illustrate the current issues faced by fire debris examiners. Unusual liquids that contradict current classification schemes are discussed, as are complex matrices with noteworthy interferences. The matrix effects range from inherent interferences to the degradation of ignitable liquids. Finally, non-routine analyses are discussed, including the analysis of vegetable and lubricating oils and novel ignition methods. Through open discussion of complex samples and individual experiences, the problems in fire debris analysis can be overcome, resulting in the production of accurate and authoritative information.

Eicosanoids are potent lipid mediators of inflammation and are known to play an important role in numerous pathophysiological processes. Furthermore, inflammation has been proven to be a mediator of diseases such as hypertension, atherosclerosis, Alzheimer\'s disease, cancer and rheumatoid arthritis. Hence, these lipid mediators have gained significant attention in recent years. This review focuses on chromatographic and mass spectrometric methods that have been used to analyze arachidonic acid and its metabolites in brain tissue. Recently published analytical methods such as LC-MS/MS and GC-MS/MS are discussed and compared in terms of limit of quantitation and sample preparation procedures, including solid phase extraction and derivatization. Analytical challenges are also highlighted.

Selenium is an essential element for the normal cellular function of living organisms. However, selenium is toxic at concentrations of only three to five times higher than the essential concentration. The inorganic forms (mainly selenite and selenate) present in environmental water generally exhibit higher toxicity (up to 40 times) than organic forms. Therefore, the determination of low levels of different inorganic selenium species in water is an analytical challenge. Solid-phase extraction has been used as a separation and/or preconcentration technique prior to the determination of selenium species due to the need for accurate measurements for Se species in water at extremely low levels. The present paper provides a critical review of the published methods for inorganic selenium speciation in water samples using solid phase extraction as a preconcentration procedure. On the basis of more than 75 references, the different speciation strategies used for this task have been highlighted and classified. The solid-phase extraction sorbents and the performance and analytical characteristics of the developed methods for Se speciation are also discussed.

Persistent organic pollutants (POPs) are major environmental concern due to their persistence, long-range transportability, bio-accumulation and potentially adverse effects on living organisms. Analytical chemistry plays an essential role in the measurement of POPs and provides important information on their distribution and environmental transformations. Much effort has been devoted during the last two decades to the development of faster, safer, more reliable and more sensitive analytical techniques for these pollutants. Since the Stockholm Convention (SC) on POPs was adopted 12 years ago, analytical methods have been extensively developed. This review article introduces recent analytical techniques and applications for the determination of POPs in environmental and biota samples, and summarizes the extraction, separation and instrumental analyses of the halogenated POPs. Also, this review covers important aspects for the analyses of SC POPs (e.g. lipid determination and quality assurance/quality control (QA/QC)), and finally discusses future trends for improving the POPs analyses and for potential new POPs.

BACKGROUND: The aerial parts of Senecio scandens Buch.-Ham. (family Asteraceae) have a long history in traditional Chinese medicine as a treatment for various ailments, such as bacterial diarrhea, enteritis, conjunctivitis, and respiratory tract infections.
METHODS: A bibliographic investigation of Senecio scandens was accomplished by analyzing secondary sources, including the Chinese Medicinal plantal Classics, the Internet (Google Scholar and Baidu Scholar), and scientific databases accepted worldwide (Pubmed, Scopus, Web of Science, SciFinder, and CNKI). These sources were scrutinized for available information about the uses of Senecio scandens in traditional Chinese medicine, phytochemistry, pharmacology, and toxicology.
RESULTS: Senecio scandens is a medicinal plant with a climbing woody stem. Phytochemical studies have shown the presence of numerous valuable compounds, such as flavonoids, alkaloids, phenolic acids, terpenes, volatile oils, carotenoids, and trace elements. Among them, PAs are the characteristic constituents, adonifoline is one of the index ingredients of Senecio scandens. Studies in modern pharmacology have demonstrated that extracts and compounds isolated from Senecio scandens show a wide spectrum of pharmacological activities, including anti-inflammatory, antimicrobial, anti-leptospirosis, hepatoprotective, anti-infusorial, antioxidant, antiviral, antitumoral, analgesic, mutagenic, and toxicological activities.
CONCLUSIONS: Phytochemical and pharmacological studies have demonstrated that the extracts of the plant possess various pharmacological activities that can be attributed to the presence of various flavonoids, phenolic acids, and alkaloids. Newer technologies for qualitative and quantitative methods of PAs need to be developed to obtain better accuracy and sensitivity. Due to the toxicity of PAs present in this medicinal plant, the regulations on PAs of Senecio scandens were varied among different countries and regions. In China, the PAs toxicity of Senecio scandens ranking criteria is not well defined in the Chinese Pharmacopoeia 2010, and there is no strict uniform requirement on the PAs in western countries. We propose that the use of Senecio scandens should be reevaluated based on a set of criteria, which includes risk-benefit analysis and severity of the toxic effects, clinical and preclinical data to ensure safe use while continuing to satisfy the need for access to the medicinal plant.

Mass spectrometric approaches have been fundamental to the identification of metabolites associated with steroid hormones, yet this topic has not been reviewed in depth in recent years. To this end, and given the increasing relevance of liquid chromatography-mass spectrometry (LC-MS) studies on steroid hormones and their metabolites, the present review addresses this subject. This review provides a timely summary of the use of various mass spectrometry-based analytical techniques during the evaluation of steroidal biomarkers in a range of human disease settings. The sensitivity and specificity of these technologies are clearly providing valuable new insights into breast cancer and cardiovascular disease. We aim to contribute to an enhanced understanding of steroid metabolism and how it can be profiled by LC-MS techniques.