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Developing efficient methods to analyze inhibitors resulting from the breakdown of the lignocellulosic matrix in brewery spent grain is crucial for selecting optimal pretreatment strategies and monitoring these compounds during biodigestion processes. However, to date, these determinations have been based on separate methodologies that have not been subjected to the analytical validation stage. This study optimized QuEChERS extraction methods combined with High-Performance Liquid Chromatography (HPLC) analysis to determine 5-hydroxymethylfurfural (5-HMF), furfural, and p-cresol, simultaneously, in the semisolid and liquid fraction of the BSG hydrolysate. The analytical methods were validated by AOAC and INMETRO guidelines. All analytes showed good linearity, with correlation coefficients (R2) greater than 0.97, and low limits of quantification. Recoveries at low, medium, and high levels were 94–116 %, repeatability was 0.6–6.8 %, and intermediate precision was 0.5–7.6 %. The method proved efficient when applied to a set of seven samples. It will contribute to monitoring inhibitory compounds present in biodigestion systems even at low concentrations, which is currently a challenge. [Display omitted] • A method was developed to detect 5-HMF, furfural, and p-cresol simultaneously. • The analytical method stands out for its low LODs for all compounds. • The developed method was successfully applied in BMP tests using BSG hydrolysate. • The method provides a reference for quantifying anaerobic digestion inhibitors. • The AGREE metric has confirmed the greenness of the proposed procedure. [ABSTRACT FROM AUTHOR]

The pursuit of green analytical chemistry has led to the exploration of deep eutectic solvents (DESs) as green solvents in sample preparation processes. DESs, formed by hydrogen bond donor and acceptor components, exhibit unique properties such as low toxicity, biodegradability, and designable structures that make them ideal for extraction technologies. However, no comprehensive assessment of the utilization of DES-based magnetic nanofluid for analytical sample pretreatment has been performed. This review summarized the preparation methods of DES-based magnetic nanofluids and their application in various microextraction technologies, including vortex-assisted, ultrasonic-assisted, dispersive, and microfluidic device-based approaches, highlighting their role in enhancing the efficiency and sustainability of analytical methods. The paper underscored the importance of the stability of magnetic nanofluids in sample pretreatment and the advantages of using DESs, such as reduced organic solvent usage and compatibility with green chemistry principles. Key findings from recent research on the application of DES-based magnetic nanofluids in microextraction were presented, demonstrating their high extraction recoveries, low detection limits, and applicability to a wide range of analytes and matrices. The outlook suggests potential directions for future research, including the refinement of DES-based magnetic nanofluids for improved performance in analytical sample preparation. This review provides a valuable reference for researchers and practitioners in the field of analytical chemistry, showcasing the potential of DES-based magnetic nanofluids as a sustainable and efficient tool for sample preparation and microextraction. [Display omitted] • DES has emerged as a novel and promising alternative to traditional solvent for sample preparation. • Synthesis of DES-based magnetic nanofluid for analytical sample preparation. • Applications of DES-based magnetic nanofluid in analytical sample preparation. • The future expected trends of DESs used in magnetic nanofluid for sample pretreatment. [ABSTRACT FROM AUTHOR]

Selective homonuclear proton correlation NMR spectroscopy (COSY) provides a useful detection tool for elucidating molecular structures and identifying chemical compositions in 1D spectroscopic patterns. However, conventional 1D selective COSY experiments highly rely on the performance of selective excitation on targeted signals and their applications generally suffer from spectral congestion in complex chemical and biological samples. Herein, based on the concept of targeted excitation on coupled proton pairs and spectroscopic separation on their respective COSY responses, we propose a 1D selective NMR approach that is capable of individually recording direct coupling correlation information of targeted proton groups for analyses on complex samples, free of spectral congestion. The performance of the proposed approach is demonstrated on a medicine sample, a biological molecule, and a real metabonomics sample of human serum. This approach shows a promising analytical technique for structural studies and component analyses in chemical and biological applications. Keywords : NMR spectroscopy, Correlation spectroscopy, Targeted signal excitation, Spectral congestion, Molecular structure analysis. [Display omitted] • A 1D NMR approach is proposed for targeted probing of compositions and structures on complex samples. • This method adopts the concept of target excitation and spectroscopic separation for individual COSY responses. • It allows for component and molecular structure analyses on practical samples suffering from spectral congestion. • A modified Dixon separation scheme is introduced to separate coupling correlation of targeted proton pairs. • The method presents a useful detection tool in chemical and biological applications. [ABSTRACT FROM AUTHOR]

Linseed (Linum usitatissimum L.) and linseed oil, with a fatty acid profile rich in both macro and micro elements, are recognized as functional foods due to their valuable positive effects on health. Fatty acids composition (FAC) is a key indicator in assessing the quality of linseeds. The FAC of linseed is typically determined using chromatographic methods, yielding highly accurate results. However, chromatographic methods entail drawbacks such as requiring pre-chemical processes, generating chemical waste, and being both expensive and time-consuming, similar to chemical analyses. This study focused on the feasibility of colorimeter and FT-NIRS data to determine the FAC (%), protein (%) and neutral detergent fiber (NDF %) in linseed samples. By employing the PLSR analysis based on FT-NIRS, it was determined that the ratios of stearic (R2 val = 0.74, RMSEP = 0.09 %), oleic (R2 val = 0.75, RMSEP = 0.26 %), linoleic (R2 val = 0.85, RMSEP = 0.58 %), linolenic (R2 val = 0.71, RMSEP = 1.07 %), 8,11,14 eicosatrienoic (R2 val = 0.77, RMSEP = 0.02 %), margaric (R2 val = 0.71, RMSEP = 0.01 %), myristic (R2 val = 0.75, RMSEP = 0.02 %), and behenic (R2 val = 0.74, RMSEP = 1.12 %) in linseed could be successfully predicted. Furthermore, results demonstrated that the protein (R2 val = 0.87, RMSEP = 0.9 %) and NDF (R2 val = 0.90, RMSEP = 0.6 %) content in linseeds can be successfully predicted. PLSR demonstrated that FT-NIRS had relatively higher predictive capability compared to color models. [Display omitted] • Non-destructive analytical methods give promising results for determining the composition of fatty acids in linseeds. • The FT-NIRS system is successful in identifying fatty acid composition of linseed genotypes. • The FT-NIRS system is more successful in determining fatty acids compared to colorimeter. • The Sarı-85 has higher oil ratio (%), as well as higher L* and b* parameters compared to other genotypes. • FT-NIRS demonstrated that promising results in the rapid prediction of protein and NDF (%) in linseed genotypes. [ABSTRACT FROM AUTHOR]

The conceptual expansion, fast development, and general acceptance of flow analysis are consequence of its adherence to the principles of green and white analytical chemistry, and chemical derivatization plays an essential role in this context. Through the flow analysis development, however, some of its potentialities and limitations have been overlooked. This is more evident when the involved modifications in flow rates, timing and/or manifold architecture deteriorate the analytical signals. These aspects have not always been systematically investigated, and are addressed here in relation to flow analyzers with UV–Vis spectrophotometric detection. Novel strategies for solution handling, guidance for dealing with the aforementioned analytical signal deterioration, and an alternative possibility for exploiting differential aspiration are presented. The concept of blank reagent carrier stream is proposed. [Display omitted] • Overlooked aspects relevant for chemical derivatization in flow analysis. • Guidance for modifying figures of merit in spectrophotometric flow analysis. • Relevance of nature and amounts of the color-forming, buffer and masking agents. • Differential pumping for modifying sensitivity. • The concept of blank reagent carrier stream. [ABSTRACT FROM AUTHOR]

In contemporary society, developing dependable point-of-care (POC) biosensors for the timely detection of cancer markers is crucial. Among various sensor types, screen-printed electrode (SPE)-based sensors, particularly electrochemical ones, stand out as promising candidates for POC applications. Despite ongoing efforts to create numerous SPE-based sensors, there is a continuous pursuit to enhance their sensitivity and analytical capabilities. This study presents an advanced electrochemical sensor designed to sensitively detect the hepatocellular carcinoma (HCC) marker Alpha-fetoprotein (AFP) in saliva. The sensor employs a gold SPE modified with hydroxyapatite, TiO 2 nanoparticles, 1-butyl-3-methylimidazolium bis(trifluoromethyl sulfonyl)imide ionic liquid (IL), and AFP monoclonal antibodies. After thorough characterization and optimization using cyclic voltammetry (CV) and differential pulse voltammetry (DPV), the biosensor exhibited a broad detection range (0.01–400 ng/mL), a low limit of detection (LOD) at 0.058 ng/mL, and demonstrated high selectivity, repeatability, reproducibility, and stability. Furthermore, when tested with spiked human saliva samples, the biosensor displayed excellent recovery and robustness, showcasing its potential for noninvasive and POC diagnosis of HCC. In an environmentally conscious evaluation, the biosensor's greenness was assessed using the AGREE metric, yielding a high score of 0.85. This score indicates the biosensor's alignment with the principles of green analytical chemistry, underlining its eco-friendly attributes. This innovative electrochemical sensor contributes to the ongoing efforts for efficient and reliable POC diagnostic tools and aligns with a broader commitment to developing environmentally friendly solutions. [Display omitted] • Sensor surface modification with hydroxyapatite, TiO 2 , and ionic liquid composite. • The sensor demonstrates good potential for AFP detection in saliva. • Sensor achieves a wide detection range (0.01–800 ng/mL) and low LOD (58 pg/mL). • The system adheres to the AGREE metric showing a high greenness score. [ABSTRACT FROM AUTHOR]

Oxidative stress is a pathological condition that contributes to the onset of various diseases. In this way, studying oxidative stress could lead to significant discoveries in the field of therapeutic and preventive medicine. Lipid peroxidation is the most significant event in the oxidative stress process and the gold standard biomarkers for endogenous oxidative damage to lipids are isoprostanes (IsoPs). This project aims to develop a reliable analytical method for the liquid-liquid microextraction technique, parallel artificial liquid membrane extraction (PALME) and LC–MS/MS analysis. PALME allowed to obtain a significant enrichment factor and, at the same time, a good sample purification by removing compounds that cause signal suppression, thereby reducing matrix effect. The chromatographic and mass spectrometric conditions have been fine tuned to improve the sensitivity of the method and therefore obtaining very low LOD and LOQ values. The recovery values obtained for the analytes are slightly above 50 %, except for 6-keto Prostaglandin F1A (24 %). Matrix effects were ≤ −10 %, with LODs ranging between 1 and 5 pg mL−1. The developed method is characterized by high sensitivity and low consumption of organic solvents, according to the principles of Green Analytical Chemistry and enables the determination of basal levels of IsoPs in oral fluid by processing 96 samples simultaneously. [Display omitted] • Determination of four isoprostanes in oral fluid by UHPLC-MS/MS. • PALME provided a high enrichment factor with low matrix effect. • A green method with minimal consumption of organic solvents was developed. • Processing of up to 96 samples simultaneously with detection down to few pg mL−1. [ABSTRACT FROM AUTHOR]

The presented study focused on developing and optimizing a modern electroanalytical platform for the direct quantitative determination of galantamine. This work used different voltammetric methods to use a screen-printed sensor with a working boron-doped diamond electrode (SP/BDDE). Beneficial analytical performance for detecting galantamine was achieved in a Britton-Robinson buffer with pH 3.0. The oxidation peaks at 0.92 V and 1.20 V were followed for electrochemical quantification of galantamine. High-resolution mass spectrometry was used for the first time to analyze the products of preparative electrolysis, and a mechanism for the electrochemical oxidation of galantamine was proposed, which describes the demethylation of galantamine and the further oxidation of the hydroxyl group to a ketone group in the galantamine molecule. Coupled with the optimized parameters of differential pulse voltammetry and square-wave voltammetry on the SP/BDDE detected galantamine in two linear ranges (the first range was from 1.22 μM to 10 μM; the second range was from 10 μM to 200 μM), providing the limit of detection and limit of quantification on a micromolar level (0.50 μM and 1.48 μM, respectively). Amperometry and chronoamperometry were employed to develop a rapid detection method for galantamine. In this approach, galantamine can be detected at a level of 1.08 μM (amperometry at the second peak). The selectivity of the optimized amperometric methods was found to be excellent in the presence of ten times higher concentrations of certain interferences. The practical applicability of the SP/BDDE for detecting galantamine was demonstrated through the analysis of pharmaceutical products and human urine samples. The proposed procedure fully complies with the latest requirements of green analytical chemistry. [Display omitted] • The first report on a novel SP/BDDE sensor for galantamine quantification. • The BDDE as an electrochemical sensor detected galantamine in the pharmaceutical samples. • High selectivity and reproducibility determination of galantamine by amperometry and chronoamperometry. [ABSTRACT FROM AUTHOR]

Exposomics aims to measure human exposures throughout the lifespan and the changes they produce in the human body. Exposome-scale studies have significant potential to understand the interplay of environmental factors with complex multifactorial diseases widespread in our society and whose origin remain unclear. In this framework, the study of the chemical exposome aims to cover all chemical exposures and their effects in human health but, today, this goal still seems unfeasible or at least very challenging, which makes the exposome for now only a concept. Furthermore, the study of the chemical exposome faces several methodological challenges such as moving from specific targeted methodologies towards high-throughput multitargeted and non-targeted approaches, guaranteeing the availability and quality of biological samples to obtain quality analytical data, standardization of applied analytical methodologies, as well as the statistical assignment of increasingly complex datasets, or the identification of (un)known analytes. This review discusses the various steps involved in applying the exposome concept from an analytical perspective. It provides an overview of the wide variety of existing analytical methods and instruments, highlighting their complementarity to develop combined analytical strategies to advance towards the chemical exposome characterization. In addition, this review focuses on endocrine disrupting chemicals (EDCs) to show how studying even a minor part of the chemical exposome represents a great challenge. Analytical strategies applied in an exposomics context have shown great potential to elucidate the role of EDCs in health outcomes. However, translating innovative methods into etiological research and chemical risk assessment will require a multidisciplinary effort. Unlike other review articles focused on exposomics, this review offers a holistic view from the perspective of analytical chemistry and discuss the entire analytical workflow to finally obtain valuable results. [Display omitted] • Adequate analytical workflows are crucial for quality results in exposomics. • Blood and urine are predominately selected for studying the exposure to EDCs. • Alternative matrices (saliva, breast milk or DBS) seem promising for EDC studies. • The combination of LC-MS and GC-MS allows a greater coverage of biomarkers. • Data analysis and annotation are one of the analytical bottlenecks of exposomics. [ABSTRACT FROM AUTHOR]

Cation exchange membranes (CEMs) are widely used in many applications. The fixed anionic groups e.g., COO−, –SO 3 -, etc. in the polymer matrix ideally allows the passage only of oppositely charged cations, driven by a potential or a concentration gradient. Anions, charged negative, the same as the membrane matrix, cannot pass through the membrane due to electrostatic repulsion. Such "Donnan-forbidden" passage can, however, occur to some degree, if the electrical or concentration gradient is high enough to overcome the "Donnan barrier". Except for salt uptake/transport in concentrated salt solutions, the factors that govern such Forbidden Ion Transport (FIT) have rarely been studied. In most applications of transmembrane ion transport, whether electrically driven as in electrodialysis, or concentration-driven, it is the transport of the counterion to the fixed charged groups, such as that of the proton through a CEM, that is usually of interest. Nevertheless, CEMs are also of interest in analytical chemistry, specifically in suppressed ion chromatography. As used in membrane suppressors, both transport of permitted ions and rejection of forbidden ions are important. If the latter is indeed governed by electrostatic factors, other things being equal, the primary governing factor should be the charge density of the membrane, tantamount to its ion exchange capacity (IEC). In fabricating microscale suppressors, we found useful to synthesize a new ion exchange polymer that can be easily molded to make tubular microconduits. Despite a high IEC of this material, FIT was also found to be surprisingly high. We measured several relevant properties for thirteen commercial and four custom-made membranes to discover that while FIT is indeed linearly related to 1/IEC for a significant number of these membranes, for very high water-content membranes, FIT may be overwhelmingly governed by the water content of the membrane. In addition, FIT through all CEMs differ greatly among strong acids, they may still be transported as the molecular acids and the extent is in the same order as the expected activity of the molecular acid in the CEM. These results are discussed with the perspective that even for strong acids, the transport does take place as un-ionized molecular acids. [Display omitted] • Reports water sorption Ion exchange capacity and dilute acid penetration for many cation exchange membranes (CEMs). • Activated CEMs (in the form they are used) always absorb less water than as received membranes. • Water sorption cannot be accounted for by proton hydration alone; the matrix plays a role. • Strong acid transport through a perfluorinated CEM most likely takes place in the molecular acid form. • Donnan-forbidden transport of acids through a CEM is also strongly influenced by the water content of a CEM. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic compounds (PACs) encompass a wide variety of organic analytes that have mutagenic and carcinogenic potentials for human health and are recalcitrant in the environment. Evaluating PACs levels in fuel (e.g., gasoline and diesel), food (e.g., grilled meat, fish, powdered milk, fruits, honey, and coffee) and environmental (e.g., industrial effluents, water, wastewater and marine organisms) samples are critical to determine the risk that these chemicals pose. Deep eutectic solvents (DES) have garnered significant attention in recent years as a green alternative to traditional organic solvents employed in sample preparation. DES are biodegradable, have low toxicities, ease of synthesis, low cost, and a remarkable ability to extract PACs. However, no comprehensive assessment of the use of DESs for extracting PACs from fuel, food and environmental samples has been performed. This review focused on research involving the utilization of DESs to extract PACs in matrices such as PAHs in environmental samples, NSO-HET in fuels, and bisphenols in foods. Chromatographic methods, such as gas chromatography (GC) and high-performance liquid chromatography (HPLC), were also revised, considering the sensibility to quantify these compound types. In addition, the characteristics of DES and advantages and limitations for PACs in the context of green analytical chemistry principles (GAC) and green profile based on metrics provide perspective and directions for future development. [Display omitted] • DESs are introduced as a novel and promising alternative to conventional solvents for PACs extraction. • DESs benefits over traditional solvents: efficacy, cost, sustainability. • DES variables in PACs extraction: viscosity, density, pH, polarity, hydrogen bonding. [ABSTRACT FROM AUTHOR]

This paper presents an innovative application of chitosan material to be used as pH-responsive valves for the precise control of lateral flow in microfluidic paper-based analytical devices (μPADs). The fabrication of μPADs involved wax printing, while pH-responsive valves were created using a solution of chitosan in acetic acid. The valve-forming solution was applied, and ready when dry; by exposure to acidic solutions, the valve opens. Remarkably, the valves exhibited excellent compatibility with alkaline, neutral, and acidic solutions with a pH higher than 4. The valve opening process had no impact on the flow rate and colorimetric analysis. The potential of chitosan valves used for flow control was demonstrated for μPADs employed for nitrate determination. Valves were used to increase the conversion time of nitrate to nitrite, which was further analyzed using the Griess reaction. The μPAD showed a linear response in the concentration range of 10–100 μmol L−1, with a detection limit of 5.4 μmol L−1. As a proof of concept, the assay was successfully applied to detect nitrate levels in water samples from artificial lakes of recreational parks. For analyses that require controlled kinetics and involve multiple sequential steps, the use of chitosan pH-responsive valves in μPADs is extremely valuable. This breakthrough holds great potential for the development of simple and high-impact microfluidic platforms that can cater to a wide range of analytical chemistry applications. [Display omitted] • The development of pH-responsive valves offers a simple fabrication method and operational advantage in paper-based devices. • Control over the chitosan valve is achieved by adjusting the proton concentration using acid solutions • Chitosan is a biocompatible material for constructing valves, enabling precise control over nitrate reduction • A proof-of-concept study using urban park water analysis demonstrates the effectiveness of chitosan valves. [ABSTRACT FROM AUTHOR]

Needle Trap Device (NTD) as a novel, versatile, and eco-friendly technique has played an important role in analytical and environmental chemistry. The distinctive role of this interdisciplinary technique can be defended through the sampling and analysis of biological samples and industrial pollutants in gaseous and liquid environments. In recent years, significant efforts have been made to enhance the performance of the needle trap device resulting in the development of novel extraction routes by various packing materials with improved selectivity and enhanced adsorption characteristics. These achievements can lead to the facilitated pre-concentration of desired analytes. This review tries to have a comparative and comprehensive survey of the three important areas of NTD technique: I) Fabrication and preparation procedures of NTDs; II) Sampling techniques of pollutants using NTDs; and III) Employed materials as adsorbents in NTDs. In the packing-material section, the commercial and synthetic adsorbents such as carbon materials, metal-organic frameworks, aerogel, and polymers are considered. Furthermore, the limitations and potential areas for future development of the NTD technique are presented. [Display omitted] • Needle trap device is considered as a microextraction method. • NTDs have been used in various studies for sampling and analysis of pollutants in air and biological monitoring. • Different synthetic and commercial adsorbents are packed in NTD. [ABSTRACT FROM AUTHOR]

A cheap and easy to use Arduino self-assembled automatic system was employed to continuously monitor the hydrogen peroxide consumption during the photo-Fenton degradation of caffeine, selected as model target compound. The automatic system made it possible to measure the H 2 O 2 concentration in the reaction cell via a colorimetric reaction and to take samples for HPLC analysis minimising the operator manual intervention and exposure to UV radiation. The obtained results were compared in terms of LOD and LOQ with H 2 O 2 measurements manually performed using UV–Vis spectrophotometry, evidencing better analytical performance when using the automatic system; LOD and LOQ were respectively 0.032 mM and 0.106 mM for the automatic system against 0.064 mM and 0.213 mM for UV–Vis spectrophotometry. Furthermore, the photo-Fenton treatment was optimised by means of a Design of Experiments (DoE) investigating the effect of added H 2 O 2 concentration, iron concentration and caffeine initial concentration on system performances. The use of the automatic device for such monitoring provided several advantages: automation (with consequent reduction of the workload), measurement increased precision, reduced reagents consumption and waste production in agreement with the principles of Green Analytical Chemistry. [Display omitted] • An automatic system enabled H 2 O 2 quantification & minimized manual intervention. • The automatic measurement showed lower LOD & LOQ than the traditional method. • DoE combined with automatic device allows photo-Fenton treatment optimization. • New device offers automation, precision, reduced workload & operator exposure. • Study showcases automatic devices potential in laboratory analyses. [ABSTRACT FROM AUTHOR]

β-cyclodextrin (β-CD), as an important pseudo-stationary phase (PSP) in capillary electrophoresis (CE), frequently confronts challenges stemming from its limited water solubility, particularly when high concentrations are required for resolving complex analytes. Traditionally, researchers often resort to the use of (toxic) organic solvents to enhance the solubility of β-CD, establishing non-aqueous capillary electrophoresis (NACE) for specific separations. However, such practices are hazardous to health and run counter to the principles of green analytical chemistry. In this study, we demonstrate a deep eutectic solvent (DES), Proline:Urea (PU), as a promising alternative to conventional organic solvents for β-CD-based CE separations. The DES exhibits a solubility of up to 30% for β-CD, a significant improvement compared to the 1.8% solubility in the aqueous phase. Utilizing this DES-type separation medium, we achieved simultaneous baseline separation of a complex analyte composed of eight structurally similar naphthoic acid derivatives. Furthermore, we conducted a systematic comparison of β-CD's performance in aqueous CE buffers, organic solvents, and DESs, highlighting the superiority of this novel and environmentally friendly CE separation medium. [Display omitted] • β-CD's solubility increased from 1.8% in water to over 30% in the DES. • β-CD's hydrophobic effect was well-preserved in the DES. • Simultaneous baseline separation of 8 naphthoic acids in the DES-type CE media. • A systematic comparison of aqueous, organic, and DES media for β-CD PSP. [ABSTRACT FROM AUTHOR]

The essential utilization of rare earth elements (REEs) for the production of several electronic devices is making the demand for them being increased all the time. This extensive use of these elements has also increased concern about human and environmental health. Previous studies have shown that REE levels are higher in environmental samples near mining sites, and they are highly possible to be transferred to biota. In this study, REE levels were determined in environmental samples collected from three abandoned mining sites of bauxite (Gargano, Otranto, and Spinazzola) in the region of Puglia, Southern Italy. The samples were digested and analyzed by two different techniques, Total X-Ray Fluorescence (TXRF) and Inductively Coupled Plasma – Mass Spectroscopy (ICP-MS) to investigate which technique is the most suitable for analysis of the REE content in samples from abandoned mining sites of bauxite. Only 6 REEs could be detected by TXRF, while all REEs were detected in all the samples by ICP-MS. Spinazzola is the richest site and Ce the most abundant REE in all three regions. REE levels are correlated between the soil and biota samples in many cases, although the calculation of the bioconcentration factor showed that REEs are not bioaccumulative. ICP-MS seems to be a more suitable technique for analysis of the whole REE content in environmental samples from abandoned mining sites of bauxite. [Display omitted] • The abandoned mining sites of bauxite in Puglia contain significant amounts of REEs. • The mining site of Spinazzola has a high content of REEs. • Ce is the most abundant REE. • ICP-MS is more ideal than TXRF for determining REEs in environmental samples from abandoned mining sites of bauxite. [ABSTRACT FROM AUTHOR]

Analytical chemistry on archaeological material is an essential part of modern archaeological investigations and from year to year, instrumental improvement has made it possible to generate data at a high spatial and temporal frequency. In particular, Raman spectral imaging can be successfully applied in archaeological research by its simplicity of implementation to study past human societies through the analysis of their material remains. This technique makes it possible to simultaneously obtain spatial and spectral information by preserving sample integrity. However, because of the inherent complexity of the samples in Archaeology (e.g. seniority, fragility, lack or full absence of any information about its composition), chemical interpretation can be difficult at first glance. Indeed, specific problems of spectral selectivity related to unexpected chemical compounds could appear due to their state of conservation. Furthermore, detecting minor compounds becomes challenging as major components impose their contributions in the acquired spectra. Therefore, a relevant chemometric approach has been introduced in this context to characterize distinct spectral sources in a Raman imaging dataset of an archaeological specimen – a mosaic fragment. The fragment was unearthed during the Ruscino archaeological dig on the outskirts of Perpignan, France. It dates back to the oppidum period. The aim is to extract selective spectral information from pixel clustering analysis in order to enhance the initial optimisation step within the Multivariate Curve Resolution and Alternating Least-Squares (MCR-ALS) algorithm, a well-known signal unmixing technique. The underlying principle of the MCR-ALS is that the acquired spectra can be expressed as linear combinations of pure spectra of all individual components present in the chemical system under study. Sometimes it can be difficult to obtain the desired results through the algorithm, particularly if initial estimates of spectral or concentration profiles are inaccurate due to complex signals, noise or lack of selectivity, resulting in rank deficiency (i.e. a poor estimation of the total number of pure signals). For this reason, an innovative threshold-based clustering algorithm, combined with multiple Orthogonal Projection Approaches (OPA), has been developed to improve matrix rank investigation and thus the initialisation step of the MCR-ALS approach before optimisation. The effective analysis of Raman imaging data for an archaeological mosaic played a crucial role in uncovering significant chemical information about a particular biogenic material. This insight sheds light on the origins of mortar manufacture during the oppidum period. Presentation of an original chemometric strategy in Raman imaging in order to improve the matrix rank search stage and thus obtain better spectral initialisation matrix before optimising by ALS the pre-processed data matrix. The aim is to obtain the most exhaustive characterization possible to explain the origin of the manufacture of mortar in the oppidum period with regards to a piece of mosaic found in the archaeological excavation at Ruscino. [Display omitted] • Chemometric strategy for characterising specific spectral sources in Raman imaging on an archaeological mosaic piece with mortar of unknown content. • Generation of best initial guesses prior to MCR-ALS optimisation using a threshold-based clustering algorithm followed by multiple orthogonal projection approaches. • The remarkable archaeological finding of this research is the detection of biogenic substances (such as magnesium calcites or amino acids) of animal origin, specifically from fish or shellfish, in curved mortar. [ABSTRACT FROM AUTHOR]

This article explores the influence and applications of Artificial Intelligence (AI) in analytical chemistry, highlighting its potential to revolutionize the analysis of complex data sets and the development of innovative analytical methods. Additionally, it discusses the role of AI in interpreting large-scale data and optimizing experimental processes. AI has been fundamental in managing heterogeneous data and in advanced analysis of complex spectra in areas such as spectroscopy and chromatography. The article also examines the historical development of AI in chemistry, its current challenges, including the interpretation of AI models and the integration of large volumes of data. Finally, it forecasts future trends and the potential impact of AI on analytical chemistry, emphasizing the need for ethical and secure approaches in the use of AI. [Display omitted] • AI revolutionizes data analysis in analytical chemistry. • Advanced AI aids complex spectroscopy and chromatography interpretation. • AI in chromatography enhances compound identification and quantification. • Machine learning predicts properties, enhancing drug and material discovery. • Explainable AI models improve interpretability in analytical chemistry. [ABSTRACT FROM AUTHOR]

Ceramic passive samplers or toximeters (packed with active carbon 1%, w/w, on celite), in combination with the CALUX bioassay have been used as a time-integrated monitoring technique for dissolved dioxin-like PCBs in urban and industrial wastewaters. The technique showed to be reliable during laboratory experiments: (1) PCB-126 amounts extracted from the passive samplers increased linearly with the time of exposure and (2) PCB-126 concentrations calculated from the amounts accumulated by the passive samplers were in agreement with their concentrations in the testing solution. Afterwards the toximeters were applied in the field. Two sampling sites located in Egypt were chosen: the Belbeis drainage canal, and the EMAK paper mill. A total of 18 ceramic toximeters were exposed to the wastewater in both sampling sites for a maximum period of 4 weeks. Two samplers were collected weekly from each site to monitor the increase in target analytes over time. Extracts were analyzed using the CALUX bioassay and the total dioxin-like PCB toxicity was reported for the aqueous phase (water column), as well as the solid phase (sediment and sludge) in both sampling sites. The time-weighted average concentration (TWA) of dl-PCBs in wastewater of the paper mill during the sampling period ranged between 7.1 and 9.1 pg-BEQL(-1), while that of the drainage canal ranged between 9.5 and 12.2 pg-BEQL(-1). The dl-PCBs in the fibrous sludge (paper mill) and bottom sediment (drainage canal) were 0.5 and 0.4 pg-BEQg(-1) dry-weight, respectively. The organic-carbon normalized partition coefficients between sediment and water (logKoc) for the paper mill and the canal were 2.4 and 4.3, respectively.

Deep eutectic solvents (DES), regarded as promising green solvents, have gained attention due to their distinctive properties, particularly in analytical chemistry. While the use of DES in solvent extraction and separation has been extensively studied, its application in the synthesis of adsorbents has just begun. Phenolic resin, with its polyhydroxy structure and stable spherical morphology, could serve as an effective as adsorbents for enrichment of active ingredients in herbal medicine. Designing adsorbents with high selectivity and adsorption capacity presents a critical challenge in the enrichment of active ingredients in herbal medicine. In this study, alcohol-based DESs were employed as regulators of morphology and structure instead of organic solvents, facilitating the creation of polyhydroxy structure, adjustable pores and high specific surface areas. The resulting DES-regulated porous phenolic resin demonstrated enhanced extraction and separation capacity for active ingredients compared to conventional spherical phenolic resin owing to the alcohol-based DES offering more interaction modes with the analytes. [Display omitted] • New porous resin regulated by deep eutectic solvent is synthesized. • DES-Rsein presents special recognition to tanshinones from Salvia miltiorrhiza. • The newly proposed porous structure resin avoids the defect of low permeability caused by spherical structure. [ABSTRACT FROM AUTHOR]

This paper reports a method for the differential analysis of volatile chemical components in five novel types of mosquito-repellent products based on chemometrics combined with headspace gas chromatography-Orbitrap high-resolution mass spectrometry (HS-GC-Orbitrap HRMS) nontargeted screening. A total of 358 unknown substances were detected in 30 samples under specific headspace conditions. Through principal component analysis and orthogonal partial least-squares discriminant analysis, 36 significantly different substances with variable importance in the projection values greater than 1 were further screened, and these substances were accurately identified by GC-Orbitrap HRMS. Most substances were found for the first time in mosquito-repellent products. The clustered heat map, Venn diagram and peak area histogram showed that the mosquito-repellent products had similar volatile composition, and the volatile species and content of different types of mosquito-repellent products significantly varied. Substances, such as eucalyptol, d -limonene, α -pinene, β -pinene, dl -menthol and methyl salicylate, may be the main sources of odour in mosquito-repellent products. This work explored the characteristic volatile components in mosquito-repellent products and comparatively analysed the chemical composition of different types of products. It can be generalised to consumer products as a case study and has positive implications for promoting product quality and safety and improving production processes. [Display omitted] • Volatile species and content varied significantly among mosquito-repellent products. • The 36 differential substances screened were identified by GC-Orbitrap HRMS. • Eucalyptol, d -limonene, α-pinene et al., may be the main sources of odour in products. • The method can be used to identify characteristic substances that cause differences in products. [ABSTRACT FROM AUTHOR]

A review is presented of recent multi-way calibration protocols involving three-, four- and five-way data. A brief description of the various data structures and processing models is shown, with emphasis on model selection based on the matching between the data structure and the physicochemical model assumptions. Calibration research works are then discussed, classified according to the type of measured instrumental data and model/algorithm selection. Image 1 • Recent multi-way calibration protocols are reviewed. • The relationship between data structures and chemometric models is detailed. • Second-, third- and fourth-order data generation is discussed. • Implications to green analytical chemistry are underlined. [ABSTRACT FROM AUTHOR]

In this study, differences in the chemical compositions of rebated excise duty diesel oil samples that were caused by fuel laundering were investigated. Two possible laundering pathways were simulated using either reduction or adsorption agents in model samples that were spiked with Solvent Yellow 124 and Solvent Red 19. The samples were characterized by their chromatographic fingerprints, which were recorded using gas chromatography coupled with a nitrogen chemiluminescence detector. The collections of fingerprints were further analyzed by discriminant partial least squares and the models with the optimal complexities presented the correct discrimination rates in the range of 69.1%–99.6%, respectively. The most informative fingerprint sections that were associated with the investigated differences were identified using the variable importance in projection, selectivity ratio and uninformative variable elimination methods. The reduced multivariate discriminant models presented a relatively high performance with the correct classification rates in the range of 74.9%–99.8%, respectively. O -toluidine and 2,5-diaminotoluene were identified as potential markers of diesel oil counterfeiting by laundering through a reduction agent. Image 1 • Chemical analysis of counterfeited rebated excise duty diesel oil was conducted. • Discoloration treatments based on the absorption and reduction were simulated. • Nitrogen chemiluminescence detector was used for chemical fingerprints registration. • PLS-DA models were constructed based on chromatographic signals. • Potential marker of rebated excise diesel oil 'laundering' was determined. [ABSTRACT FROM AUTHOR]

Paper microzone plates and thermal infrared enthalpimetry (TIE) were combined with potato juice as natural reagent extract to perform the determination of hydrogen peroxide in pharmaceutical, bleaching, and toiletry products. A multichannel pipette was used for reagent addition simultaneously in multiple zones of paper devices, and the temperature rise was determined using an infrared camera. In order to provide suitable measurements, some parameters were optimized such as pH, volume of reagents, and stability of the extract. Results for the hydrogen peroxide were compared with those obtained using methods from official compendia (United States Pharmacopeia and ASTM D2180 –17), with agreements ranging from 96 to 103%. The green analytical procedure index was used to compare the greenness of the proposed method with official ones, with clear advantages for TIE. Only microliters of samples and natural reagent extracts were required for analysis, and it was found that waste generation could be greatly reduced. After analysis, the paper device could be directly disposed since the final products of the reaction were O 2 and water. According to these features, the proposed method could be considered a promising alternative to routine analysis in agreement with green analytical chemistry principles. Image 1 • New sensing approach for paper devices is proposed using infrared thermal imaging. • Paper microzone plates were used to perform green enthalpimetric analysis. • Potato juice was used directly as a natural reagent extract. • Drastic reduction of waste generation, energy and time consumption was reached. • Green analytical chemistry metrics was used for comparison with official methods. [ABSTRACT FROM AUTHOR]

This review is a broad survey of ion exchange membranes (IEMs) in chosen areas of analytical chemistry. The coverage is comprehensive in ion chromatography (IC) applications, this includes in-line water purification for IC use, chemical and electrodialytic eluent suppression, eluent generation, eluent purification, pH modification, buffer generation, use in ion exclusion chromatography, charge-based detection, as well as suppressor-detector combinations. The use of IEMs in sample treatment using ion transfer devices and Donnan dialysis preconcentration are discussed. Introduction of reagents through an IEM, whether through a concentration gradient large enough to overcome the Donnan barrier or active electrodialysis, does not involve volumetric dilution. Reagent introduction in this fashion, enabling conductometric detection of otherwise non-ionized weak electrolytes, is discussed. Several important applications of IEMs, in which ion exchange plays little or no role, are discussed; these include (a) diffusion-based gas collection and analysis, (b) evaporative concentration in a flow system, (c) drying of gas streams and (d) sensing of moisture in gases and liquids. An important area that is not covered is ion-sensing with IEMs and/or ionophores. Image 1 • Use of Ion Exchange membranes in all areas of Ion chromatography, including sample pretreatment, eluent generation, purification, pH adjustment, suppression, and detection are discussed. • The review covers water transport across ion exchange membranes for water removal or evaporation. • Water sensors based on the affinity of H+-form cation exchange membranes for water are explored. • Utility of ion exchange membranes in diffusion based gas collection is described. [ABSTRACT FROM AUTHOR]

Chemical attribution signatures (CAS) can be used to obtain useful forensic information and evidence from illicit drug seizures. A CAS is typically generated using hyphenated chemical analysis techniques and consists of a fingerprint of the by-products and additives present in a sample. Among other things, it can provide information on the sample's origin, its method of production, and the sources of its precursors. This work investigates the possibility of using multivariate CAS analysis to identify the synthetic methods used to prepare seized fentanyl analogues, independently of the analogues' acyl derivatization. Three chemists working in two labs synthesized three different fentanyl analogues, preparing each one in duplicate by six different routes. The final collection of analogues (96 samples) and two intermediates (16 + 32 samples) were analysed by GC-MS and UHPLC-HRMS, and the resulting analytical data were used for multivariate modelling. Independently of analogue structure, the tested fentanyls could be classified based on the method used in the first step of their synthesis. The multivariate model's ability to classify unknown samples was then evaluated by applying it to six new fentanyl analogues. Additionally, seized fentanyl samples was analysed and classified by the model. Image 1 • Fentanyl analogues and its precursor, NPP and ANPP were analysed. • A model that could reliably predict the method of fentanyl synthesis were developed. • Seized fentanyl analogues were analysed and its synthetic method determined. [ABSTRACT FROM AUTHOR]

A simple cost-effective device for downscaling chemical analysis with microliter-scale dropwise handing and smartphone detection is proposed. The platform was made from easily available materials. Drops of constant volume of analyte and reagent were placed onto a channel then moved by gravity force to mix and react with each other. The color change due to reaction was monitored with a smartphone. Assays of iron, copper and phosphate employing the platform were demonstrated with 1,10-phenanthroline, bicinchoninic acid and molybdate reagents, respectively. Kinetic study was also demonstrated for this simple device. Image 1 • A platform with moving micro drops is proposed for green chemical analysis. • This simple platform is an alternative cost-effective downscaling portable device. • The platform is made from easily available materials. • The platform was able to apply for kinetics study of both fast and slow reactions. • Assays were demonstrated for Fe2+, Cu2+ and phosphate using 1,10-phenanthroline, BCA and molybdate. [ABSTRACT FROM AUTHOR]

Abstract The practice of drug counterfeiting is an important challenge due to the extremely rapid growth rate of this disturbing trend and its immense potential harmfulness. According to WHO even 10% of counterfeit medicines can be exact copies of genuine medicines: they have exactly the same quantitative and qualitative composition in terms of both API and excipients. Thus, the identification of such drugs using chemical analysis methods can be very difficult or even impossible. The aim of this study was to verify the effectiveness of using computed microtomography in the identification of counterfeit medicines. The General Electric v|tome|x s microtomography system was used in the study. The recorded microtomographic scans were subjected to analysis and image processing. The following parameters of image analysis and processing were identified: mean brightness, homogeneity, contrast, quadratic tree decomposition. The original and falsified 100-mg Viagra® tablets (Pfizer) were compared. 8 original Viagra® tablets (hereinafter referred to as T) and 8 falsified tablets (hereinafter referred to as F1-F8) were tested. The range of variation for the genuine medicines against fake products was: brightness: 90.9–117.1 vs 33.8, 50.1, homogeneity: 0.84–0.92 vs 0.94–1.01 and quadratic tree decomposition for the 1 × 1 mask: 55768–58792 vs 0–439. The proposed method of microtomographic image analysis and processing enables to identify solid dosage forms, including those that are an accurate chemical copy, with high sensitivity and specificity, 94.5% and 97%, respectively. The advantage of the μCT method is its high efficiency and speed, whereas the disadvantages include the possibility of using only solid dosage forms and high equipment costs. Graphical abstract fx1 Highlights • μCT enables to identify counterfeit medicines with high sensitivity and specificity. • Brightness, homogeneity and QTDECOMP differentiate fake/original medicines. • μCT enables to identify chemical copies of original medicines. • Disadvantage of μCT: costs of μCT scanner; only for solid dosage forms. [ABSTRACT FROM AUTHOR]

Abstract Black Powder (BP) is one of the most common improvised explosives, due to broad access in precursors and simple home-made preparation. Deflagration of black powder results in residues the chemical analysis of which presents limitations and has been performed with several techniques until today; nevertheless, Gas Chromatography–Mass Spectrometry (GC–MS) has never been used. In this study, a simple experimental protocol has been developed towards black powder residues identification, using GC–MS. The sample preparation does not require specialized equipment. Derivatization of thiocyanates coming from BP deflagration and identification of the relative derivative (PBF-SCN) was achieved by monitoring ions m/z 239, 181 and 161. This characteristic derivative was used as a marker to indicate BP usage. The protocol was optimized by investigating individually all experimental parameters and it was evaluated for false positives and negatives. Repeatability and limit of detection were calculated to be %RSD 7.67 and < 1 mg, respectively. No interference coming from other ingredients that might co-exist in BP residues was observed. This protocol may be applied directly and without previous preparation to evidence coming from cases of explosions, thus practically contributing in BP residues identification. Graphical abstract fx1 Highlights • A new method for black powder residues identification. • A simple, inexpensive and repeatable experimental protocol. • Immediate application for forensic laboratories in evidence coming from real cases. • Exploitation of GC-MS, a credible, trustful and universal technique. [ABSTRACT FROM AUTHOR]

Abstract This manuscript covers the application of the main techniques for simultaneous optimization of multiple responses generated by the application of multivariate designs (two-factor factorial, Central Composite, Doehlert, etc.) or by chromatographic runs in the development of analytical methods. Special attention will be given to the graphical method, desirability function, multiple response function and chromatographic response functions, since they are more frequently used in the analytical area. The advantages, disadvantages, limitations, and potentialities of these methods will also be addressed, as well as some of their applications, commenting on real examples from the literature. Some less usual methods in multiple response optimization in Analytical Chemistry will also be commented. Graphical abstract fx1 Highlights • Most usual techniques for simultaneous multiple response optimization. • Didactic approach and applied to analytical methods optimization. • Critical discussion of advantages, disadvantages, limitations and potentialities. • Comments about some real examples from the literature. [ABSTRACT FROM AUTHOR]

Abstract Multivariate analyses are increasingly popular to explore the underlying structure of multivariate datasets, which are more and more prevalent in analytical chemistry. However, difficulties can be associated with estimating the number of components for the data with considerable coherence and noise. The method of Angle Distribution of Loading Subspace (ADLS) has been proposed to estimate the number of components for Principal Component Analysis (PCA) and PARAllel FACtor analysis (PARAFAC), which showed some advantages, in particular in the case of datasets with high coherence, over the commonly used methods (scree plot and cross-validation in PCA, and core consistency diagnostics (CORCONDIA) in PARAFAC). In this paper, we systematically improved and applied ADLS to estimate the number of components in different multivariate methods including, Multivariate Curve Resolution (MCR), PARAFAC and four-way PARAFAC. Firstly, we showed that ADLS performed better when estimating the chemical rank for MCR analysis, compared with scree plots. As well as this, we improved ADLS in multi-way analysis (three- and four-way PARAFAC) by calculating the loading subspace in advance using the Khatri-Rao product. The improved ADLS in multi-way analysis provided the correct result for the simulated three-way fluorescence datasets with unevenly distributed coherence at different dimensions, while the previous version of ADLS showed biased results and CORCONDIA / split-half analysis provided relatively unstable results. Moreover, ADLS was used to estimate the chemical rank for a four-way real-life fluorescence dataset analyzed by four-way PARAFAC. In this case the result of chemical rank results from ADLS was more precise and informative compared with CORCONDIA /split-half analysis in four-way analysis. Graphical abstract fx1 Highlights • Angle Distribution of Loading Subspace (ADLS) is applied in different multivariate methods for a chemical rank estimation. • ADLS outperforms scree plot in MCR analysis. • Loading subspace is calculated using the Khatri-Rao product to improve ADLS in multi-way analysis. • ADLS shows advantage compared with core consistency diagnose in four-way analysis. [ABSTRACT FROM AUTHOR]

The determination of endocrine-disrupting chemicals (EDCs) has become one of the biggest challenges in Analytical Chemistry. Due to the low concentration of these compounds in different kinds of samples, it becomes necessary to employ efficient sample preparation methods and sensitive measurement techniques to achieve low limits of detection. This issue becomes even more struggling when the principles of the Green Analytical Chemistry are added to the equation, since finding an efficient sample preparation method with low damaging properties for health and environment may become laborious. Recently, deep eutectic solvents (DESs) have been proposed as the most promising green kind of solvents, but also with excellent analytical properties due to the possibility of custom preparation with different components to modify their polarity, viscosity or aromaticity among others. However, conventional extraction techniques using DESs as extraction solvents may not be enough to overcome challenges in analysing trace levels of EDCs. In this sense, combination of DESs with solid supports could be seen as a potential solution to this issue allowing, in different ways, to determine lower concentrations of EDCs. In that aim, the main purpose of this review is the study of the different strategies with solid supports used along with DESs to perform the determination of EDCs, comparing their advantages and drawbacks against conventional DES-based extraction methods. [Display omitted] • The use of DES in the microextraction field is increasing. • DES-based solid supports have some advantages over conventional DES methods. • Different strategies with static and dispersive techniques has been proposed. • Combination of DESs and supports offers several benefits for the extraction of EDCs. • Future perspective should be focused on reducing the impact of the methods. [ABSTRACT FROM AUTHOR]

Dual ionization sources combining an ultraviolet (UV) lamp source and a corona discharge (CD) source were first used as ionization sources for high-field asymmetric waveform ion mobility spectrometry (FAIMS) to switch ionization modes without changing hardware. The CD source was manufactured using a tungsten needle and a copper ring and its usability was verified. The UV source and the CD source were combined into the FAIMS sensor and multiple ionization modes were attempted by controlling their on-off status. The optimal flow rate, quantitative and qualitative capabilities of the system were investigated, and the experiments on the impact of humidity and interferent on the system were conducted. The experimental results indicated that the flow rate of 3–4 L/min could ensure sufficient sensitivity and resolution of the system. The dual ionization sources configuration provided richer qualitative and quantitative information for FAIMS. This platform could operate in three ionization modes and had the potential to expand the analyzable compounds of UV-FAIMS. In summary, the research demonstrates that the dual ionization sources could be used as ionization sources for FAIMS, and the combined system provided convenience for chemical analysis. Multiple ionization sources were combined into high-field asymmetric waveform ion mobility spectrometry for obtaining more ion information. [Display omitted] • A novel dual ionization sources FAIMS with different ionization modes was developed. • Two ionization sources provided richer qualitative and quantitative information for FAIMS. • Multiple ionization modes were achieved by controlling the on-off status of the combined ionization source. • Switching the ionization modes without changing the hardware has the potential to expand the analyzable compounds of FAIMS. [ABSTRACT FROM AUTHOR]

Apple ring rot caused by Botryosphaeria dothidea can cause fruit decay during the growth and storage stages of apple fruit. Understanding the infection process and cellular defense response at the cellular micro-level holds immense importance in the field of prevention and control. Consequently, there is a pressing need to develop suitable chemical imaging analysis methods. Here we proposed a label-free, high-throughput imaging method for cellular investigation of apple fruit ring rot infected by Botryosphaeria dothidea , based on confocal Raman microspectroscopic imaging technology combined with multivariate curve resolution-alternating least squares algorithm (MCR-ALS). We conducted Raman measurements on every apple fruit and obtain an image cube. This cube was then unfolded into an augmented matrix in a column-wise manner. We proceeded with simultaneous MCR-ALS analysis, resolving the single-substance spectrum and concentration profile from the mixed signals. Lastly, the accurate and pure molecular imaging of low methoxyl pectin, high methoxyl pectin, cellulose, lignin, and phenols were realized by refolding the resolved concentration data to construct the composition image. Thereafter, we realized the study of the spatial-temporal changes distribution of the above substances in the cuticle and cell wall of green and red apples at different stages of infection. The imaging method proposed in this paper is expected to provide a chemical imaging strategy for studying pathogen infection process and fruit defense response at the cellular level. In addition, by utilizing a fiber-optic probe near-infrared reflection spectrometer in conjunction with machine learning, we developed a rapid and non-destructive classification method. This method allows for the timely identification of apples exhibiting early infection by Botryosphaeria dothidea. Notably, both principal component analysis-quadratic discriminant analysis and support vector machine achieved a classification accuracy of 100%. [Display omitted] • A label-free and high-throughput cell imaging method is proposed for apple ring rot. • The method is based on confocal Raman imaging microscopy and chemometrics. • The spatial-temporal changes of five substances in cellular level are investigated. • A rapid near-infrared based machine learning method is proposed for apple ring rot. • Identification of apples with early infection by Botryosphaeria dothidea is achieved. [ABSTRACT FROM AUTHOR]

Deep eutectic solvents (DESs) have recently sparked considerable attention in a variety of scientific and technological fields. The unique properties of DESs include biodegradability, easy preparation, low cost, and tuneability, rendering them a new and prospective alternative to hazardous solvents. Analytical chemistry is one of the most appealing fields where DESs proved to be applicable in either sample preparation or chromatographic separation. This review summarizes the new horizons dedicated to the application of DESs in microextraction and chromatographic separation. The utilization of DESs in microextraction, in chromatography as mobile phase additives, and in chromatographic material preparation processes is outlined. The enhancements in chromatographic performance achieved using DESs and any potential explanations deduced from the experimental findings were primarily discussed. An additional brief discussion on DESs preparation, characterization, and properties is addressed in this work. Finally, current challenges and future trends are also presented, supplying evidence for distinct possibilities regarding new research approaches involving DESs. This review can represent a guide and stimulate further research in this field. [Display omitted] • The latest applications of DES in microextraction are reviewed. • The applications of DESs in chromatographic mobile and stationary phases are discussed. • The underlying mechanisms of DES in chromatography are investigated. • Challenges and prospects of DESs in analytical chemistry are debated. [ABSTRACT FROM AUTHOR]

The assessment of the risks of mycotoxins to humans through consuming contaminated foods resulted in specific legislation that evaluates the presence, quantities, and type of mycotoxins in agricultural commodities and foodstuffs. Thus, to ensure compliance with legislation, food safety and consumer health, the development of suitable analytical procedures for identifying and quantifying mycotoxins in the free or modified form, in low-concentration and in complex samples is necessary. This review reports the application of the modern chemical methods of analysis employed in mycotoxin detection in agricultural commodities and foodstuffs. It is reported extraction methods with reasonable accuracy and those present characteristics according to guidelines of Green Analytical Chemistry. Recent trends in mycotoxins detection using analytical techniques are presented and discussed, evaluating the robustness, precision, accuracy, sensitivity, and selectivity in the detection of different classes of mycotoxins. Sensitivity coming from modern chromatographic techniques allows the detection of very low concentrations of mycotoxins in complex samples. However, it is essential the development of more green, fast and more suitable accuracy extraction methods for mycotoxins, which agricultural commodities producers could use. Despite the high number of research reporting the use of chemically modified voltammetric sensors, mycotoxins detection still has limitations due to the low selectivity from similar chemical structures of mycotoxins. Furthermore, spectroscopic techniques are rarely employed due to the limited number of reference standards for calibration procedures. [Display omitted] • Identification and quantification of mycotoxins using modern chemistry techniques. • Extraction methods used in mycotoxins from agricultural commodities and foodstuffs. • Mycotoxins detection using modern chromatographic and spectroscopic techniques. • Mycotoxins detection by electroanalysis allied to chemically modified electrodes. • Advances and perspectives in mycotoxin detection in agricultural commodities. [ABSTRACT FROM AUTHOR]

Abstract Although arsenic (As) toxicity in soil vary depending on its chemical forms and oxidation states, regulatory limits for this compartment rely on total As content. Conventional methods of total As determination are expensive and time-consuming. The development of predictive techniques might enable a speditive assessment of As contamination in those scenarios, such as thermal spring sites, where exposure to the metalloid poses a threat to human health. The objective of this study was to assess the suitability of Visible Near Infrared spectrophotometry for predicting the total As content in highly calcareous thermal spring soils and the same aim was pursued for those elements (i.e. Al, Fe and Mn) the chemistry of which is tightly connected with that of As. A Partial Least Square approach, including cross-validation and external independent test, was used to relate the concentrations of the target elements to spectral data. The most accurate prediction was found for As with Pearson's coefficient, RMSE, RPD and SEP being equal to 0.94, 69.65, 2.9 and 66.99, respectively. Less accurate predictions were found for Al (r = 0.88; RMSE = 11014; RPD = 1.96; SEP = 11014) , Fe (r = 0.93; RMSE = 6921.1; RPD = 2.45; SEP = 6462.4), and Mn (r = 0.92; RMSE = 542.01; RPD = 2.43; SEP = 529.79). Graphical abstract fx1 Highlights • Arsenic contamination is a common scenario in thermal spring sites (TSS). • Soils in TSS of volcanic origin are generally highly calcareous. • Hyperspectral spectrophotometry enabled an accurate As prediction in TSS soils. • Other As-connected elements were predicted with good accuracy by the same technique. [ABSTRACT FROM AUTHOR]

Abstract Sheep cheese whey (SCW) is a by-product from the dairy industry, and due to its composition, it is very hazardous for natural bodies of water. However, illegal discharges of this product have been commonly reported in watercourses and reservoirs. To prevent this type of actions, a simple and affordable sensor has been designed and validated using diverse water samples from different sources containing SCW, such as water from two Spanish reservoirs and two Spanish rivers located in the province of Madrid. Using these waters, different SCW solutions (lower than 20% in weight) have been prepared and measured. The equipment used to sense the samples is based on combining fluorescence measurements, obtained with light emitting diodes (LEDs), and algorithms which rely on chaotic parameters. Every sample was measured by six different types of LEDs possessing distinct emission wavelengths (blue, orange, green, pink, white, and UV), leading to 1786 fluorescence spectra that were employed during the modeling phase. After the mathematical analysis, the dataset that generates the best statistical results was from the blue LED. This approach was dually validated via leave-one-out cross-validation as well as externally validation, and the results were very promising (error around 6.5% and 8% quantification error, respectively). Additionally, it is important to note that the sensor used has been designed and developed by a 3D printer and has the potential of being applied in situ for real-time and cost-effective analysis of natural bodies of water. Graphical abstract fx1 Highlights • LEDs to record sheep cheese whey concentration in natural bodies of water. • Meticulous data collection and processing for real-time implementation. • Chaotic parameters lead to chemometric tools for environmental control. • Inexpensive approach to assess pollution originated at dairy industries. • Ability to operate in situ and free of technical personnel. [ABSTRACT FROM AUTHOR]

Abstract In this contribution a highly cost-effective flow analysis system for determination of alkaline phosphatase (ALP) activity is presented. This fully-mechanized bioanalytical system is based on economic solenoid micropumps and microvalves (powered and actuated by Arduino microcontroller) and extremely cheap dedicated optoelectronic flow-through detectors allowing absorbance and fluorescence measurements. The detection schemes for ALP assaying realized in this system are based on orthophosphate determination. For the detection of these ions formed in the course of enzymatic conversion a molybdate method requiring only common and inexpensive chemicals is utilized. Thus, for the enzymatic assays the simplest not-chromogenic/not-fluorogenic ALP substrates can be applied. Such approach results in the use of low-cost reagents for ALP assays, whereas the mechanization of assay causes low consumption of reagents as well as samples. In the course of reported investigations six ALP substrates were examined and the most promising results have been obtained for the inorganic compound – monofluorophosphate (MFP). The obtained linear ranges of absorbance and fluorescence measurements are 100–600 U L−1 and 30-30/30-100 U L−1, with sensitivities of 0.7 mV L−1 U−1 and 2.3/1.0 mV L−1 U−1, respectively. The calculated limits of detection are 5.1 U L−1 (photometry) and 0.9 U L−1 (fluorometry). The throughputs of the developed system are 13 and 12 samples/h for photometric and fluorometric detections, respectively. To demonstrate the practical utility of the developed bioanalytical system the ALP assays in complex matrix samples have been carried out. The results of ALP activity determination in serum samples are well-correlated with those obtained using reference method recommended for routine clinical analysis. Graphical abstract fx1 Highlights • Analytical system for determination of alkaline phosphatase activity has been developed. • Utility of several enzyme substrates for activity assays have been tested. • Developed system could be applied for serum analysis. [ABSTRACT FROM AUTHOR]

Linear models for calibration curves are overwhelmingly created based on minimization of least squares error, with their goodness-of-fit (GOF) quantified using the square of the correlation coefficient (R 2 ). Yet, R 2 has well-known disadvantages when used to quantify GOF of calibration curves stemming from its calculation based on the absolute error of the signal (i.e., calculated vs. experimental). These disadvantages are exacerbated when using a geometric series of concentrations for calibration standards (e.g., 1, 2, 5, 10, etc.) and when calibration curves span 2–3 orders of magnitude, which is typical for modern analytical techniques. While there are multiple alternative GOF measures, R 2 overwhelmingly persists in the field of Analytical Chemistry as the most reported measure of GOF. We evaluated R 2 , alternative GOF measures, and multiple quantitative bias parameters, along with residual analysis, for over 60 experimental calibration curves. R 2 did a poor job of consistently and accurately quantifying the GOF over the entire calibration curve. This was especially true for situations where the low concentration calibrators were not accurately described by the calibration equation. While other GOF parameters, including the sum of the absolute percent error, mean absolute percent error, and quality coefficient, did a better job of describing GOF of calibration curves, each had significant theoretical and/or practical disadvantages. Therefore, we introduce a descriptive GOF parameter called Percent Residual Accuracy (%RA or PRA) which equally weights the accuracy of all calibrators into a single value, generally falling between 0% and 100%, with 100% representing a perfect fit and a “good” fit for calibration data producing a %RA of 90–100%. The %RA much more effectively described the GOF for the entire calibration range than R 2 , and it similarly quantified GOF as compared to the other GOF parameters tested. With the performance and practical advantages of %RA, we conclude that it is the most advantageous GOF parameter and that it should be reported as a standard GOF measure for calibration curves. [ABSTRACT FROM AUTHOR]

A new colorimetric and fluorescent chemosensor for visual determination of carbonate ions was developed by the microwave assisted solvent free synthesis of 7,8-dihydroxy-3-(4-methylphenyl) coumarin ( DHMC ). The structural characterization of DHMC was confirmed by microanalysis and spectroscopy methods (MALDI-TOF, FT-IR, 1 H NMR, 13 C NMR, and 2D HETCOR). The binding behaviors of DHMC were investigated towards various anions by UV–vis and fluorescence spectroscopy. DHMC showed a selective and sensitive fluorometric and colorimetric responses towards carbonate ion over other anions. The detection limit of CO 3 2- was found to be 1.03 µM. Moreover, the fluorescence imaging in living cells suggests that DHMC has a great potential in the biological imaging application. It has been demonstrated that DHMC can be used as a rapid and reliable sensor for the determination of carbonate anion in a variety of practical applications. [ABSTRACT FROM AUTHOR]

High performance liquid chromatography (HPLC) with a solvent gradient and absorbance detection is one of the most widely used methods in analytical chemistry. The observed absorbance baseline is affected by the changes in the refractive index (RI) of the mobile phase. Near the limited of detection, this complicates peak quantitation. The general aspects of these RI-induced apparent absorbance effects are discussed. Two different detectors with fundamentally different optics and flow cell concepts, a variable-wavelength detector equipped with a conventional flow cell and a diode-array detector equipped with a liquid core waveguide flow cell, are compared with respect to their RI behavior. A simple method to separate static – partly unavoidable – RI effects from dynamic RI effects is presented. It is shown that the dynamic RI behavior of an absorbance detector can be well described using a single, relatively easy-to-determine metric called the G-index. The G-index is typically in the order of a few seconds and its sign depends on the optical flow cell concept. [ABSTRACT FROM AUTHOR]

A sensitive and artful colorimetric immunosensor based on horseradish peroxidase (HRP) was designed by labelling metal–organic frameworks (Cu-MOFs) on the second antibody (Cu-MOFs@Ab 2 ) as signal amplification for the detection of trace dibutyl phthalate (DBP). In this system, when Cu-MOFs@Ab 2 was captured by antigen- primary antibody (Ab 1 ) complex, tremendous Cu(II) will be released from Cu-MOFs in the presence of nitric acid (HNO 3 ), and Cu(II) will be further reduced to Cu(I) after the addition of sodium ascorbate (SA), consequently, inhibiting the HRP to catalyse the colorless 3,3′,5,5′-tetramethylbenzidine (TMB) into blue oxidized TMB (ox TMB). Under the optimized conditions, the limit of detection (LOD) was 1 μg L −1 , which was almost 60 times lower than that using a conventional ELISA with the same antibody. In addition, our method showed good accuracy and reproducibility (recoveries of 87.73–103.4%; CV values of 1.46–5.95%) through a spike-recovery analysis. The proposed immunosensor indicated great potential for trace DBP determination from environmental and food samples. [ABSTRACT FROM AUTHOR]

A new gradient ratio approach to Chemical H-point Standard Addition Method (C-HPSAM) was developed in flow injection analysis with spectrophotometric detection. C-HPSAM is based on an idea to use SAM for calibration in several different chemical conditions in order to correct unspecific (additive) interferences in samples with unknown matrix. The approach proposed in this paper employs the gradient ratio flow-injection technique to generate a continuous change of chemical conditions. By doing so a set of two-point SAM calibration curves with different slopes are possible of registering that are intersected in a common point indicating the values of both unspecific interferences and analyte concentration in a sample. The applicability of the approach was verified on the examples of spectrophotometric determinations of ascorbic acid and paracetamol. Ascorbic acid was determined in soft drinks and juices basing on reduction of Fe(III) to Fe(II) and reaction of the latter ion with o-phenantroline to form the ferroin complex absorbing at 512 nm. Paracetamol determined in pharmaceuticals was nitrificated in reaction with sodium nitrite in acidic medium and then the formed derivative species was converted into a more stable compound in reaction with sodium hydroxide, for which absorbance was recorded at 430 nm. All analytical results were obtained within the confidence interval of the values obtained by capillary electrophoresis and the relative errors were below 6%. It was proved that the developed method is readily applicable to analysis of real samples of complex unknown matrices. As it is additionally effective, low-cost and green, it can be considered as a helpful analytical tool. [ABSTRACT FROM AUTHOR]

Isotope ratio analysis has been shown to discriminate samples of forensic interest and to link many synthesized and natural materials to their precursors when traditional chemical and physical analyses cannot. Successful application of stable isotope analysis to chemicals of interest requires a background of likely variations in stable isotope ratios; often, this background population can be generated from analysis of possible precursors and the relationships of stable isotopes of precursor(s) to product(s), which may depend on synthesis techniques. Here we measured the carbon ( 13 C/ 12 C) and hydrogen ( 2 H/ 1 H) isotope ratios of the oft-illicitly manufactured explosive triacetone triperoxide, TATP, and one of its precursors, acetone. As acetone is the sole source of carbon and hydrogen to TATP, a survey of acetone from 12 countries was conducted to explore the breadth of 13 C/ 12 C and 2 H/ 1 H variation in the precursor, and therefore, its product. Carbon and hydrogen isotope ratios were measured using continuous flow isotope ratio mass spectrometry (IRMS) techniques. We observed greater ranges in both C and H isotope ratios of acetone than previously published; we also found that country-of-purchase was a large contributing factor to the observed variation, larger than acetone grade and brand. Following clandestine production methods, we observed that the stable isotope ratios of TATP retained the stable isotope signatures of acetone used in synthesis. We confirmed the robustness of TATP carbon isotope ratios to both recrystallization and time-dependent sublimation, important considerations when faced with the task of practical sampling of potential unexploded TATP from a crime scene. [ABSTRACT FROM AUTHOR]

A new means for assessing analytical protocols relating to green analytical chemistry attributes has been developed. The new tool, called GAPI (Green Analytical Procedure Index), evaluates the green character of an entire analytical methodology, from sample collection to final determination, and was created using such tools as the National Environmental Methods Index (NEMI) or Analytical Eco-Scale to provide not only general but also qualitative information. In GAPI, a specific symbol with five pentagrams can be used to evaluate and quantify the environmental impact involved in each step of an analytical methodology, mainly from green through yellow to red depicting low, medium to high impact, respectively. The proposed tool was used to evaluate analytical procedures applied in the determination of biogenic amines in wine samples, and polycyclic aromatic hydrocarbon determination by EPA methods. GAPI tool not only provides an immediately perceptible perspective to the user/reader but also offers exhaustive information on evaluated procedures. [ABSTRACT FROM AUTHOR]

In this work, computational and experimental methods were used to study the adsorption of estrogens and glucocorticoids on metal–organic frameworks (MOFs). Computer-aided molecular simulation was applied to predict the adsorption of eight analytes on four MOFs (MIL-101(Cr), MIL-100(Fe), MIL-53(Al), and UiO-66(Zr)) by examining molecular interactions and calculating free binding energies. Subsequently, the four water-stable MOFs were synthesized and evaluated as adsorbents for the target hormones in aqueous solution. As the MOF exhibiting the highest adsorption capacity in both computations and experiments, MIL-53(Al) was chosen as a sorbent to develop a dispersive micro-solid-phase extraction procedure coupled to ultra-performance liquid chromatography tandem mass spectrometry for simultaneous determination of the target analytes in water and human urine samples. Experimental parameters affecting the extraction recoveries, including pH, ionic strength, MIL-53(Al) amount, extraction time, desorption time, and desorption solvent, were optimized. The optimized method provided a linear range of 0.005025–368.6 μg/L with good correlation coefficients (0.9982 ≤ r 2 ≤ 0.9992), and limits of detection (S/N = 3) and quantification (S/N = 10) of 0.0015–1.0 μg/L and 0.005–1.8 μg/L, respectively. The analyte recoveries were in the range of 80.6–98.4% in water samples and 88.4–93.2% in urine samples. Furthermore, MIL-53(Al) showed good stability over 10 extraction cycles (RSD < 10.0%). Good agreement between experimental measurements and computational results showed the potential of this approach for elucidating adsorption mechanisms and predicating extraction efficiencies for MOFs and targets, providing new directions for the development and utilization of MOFs. [ABSTRACT FROM AUTHOR]

In this work, polypropylene hollow fiber was replaced by agarose gel in conventional electro membrane extraction (EME) to develop a novel approach. The proposed EME method was then employed to extract two amino acids (tyrosine and phenylalanine) as model polar analytes, followed by HPLC-UV. The method showed acceptable results under optimized conditions. This green methodology outperformed conventional EME, and required neither organic solvents nor carriers. The effective parameters such as the pH values of the acceptor and the donor solutions, the thickness and pH of the gel, the extraction voltage, the stirring rate, and the extraction time were optimized. Under the optimized conditions (acceptor solution pH: 1.5; donor solution pH: 2.5; agarose gel thickness: 7 mm; agarose gel pH: 1.5; stirring rate of the sample solution: 1000 rpm; extraction potential: 40 V; and extraction time: 15 min), the limits of detection and quantification were 7.5 ng mL −1 and 25 ng mL −1 , respectively. The extraction recoveries were between 56.6% and 85.0%, and the calibration curves were linear with correlation coefficients above 0.996 over a concentration range of 25.0–1000.0 ng mL −1 for both amino acids. The intra- and inter-day precisions were in the range of 5.5–12.5%, and relative errors were smaller than 12.0%. Finally, the optimized method was successfully applied to preconcentrate, clean up, and quantify amino acids in watermelon and grapefruit juices as well as a plasma sample, and acceptable relative recoveries in the range of 53.9–84.0% were obtained. [ABSTRACT FROM AUTHOR]