Chemistry and Materials Science

Abstract: Accurate quantification of nitrate (NO_3-) in tropical drinking water sources is routinely compromised by significant interference from natural organic matter. This study evaluated three regulatory standard methods (APHA 4500-NO_3- B, E, and J) against an optimised homogeneous vanadium (III) chloride (VCl₃) reduction assay. Optimal VCl3 operational parameters were established at 1.0 M HCl, 60°C incubation, and a 45 min reaction time. Results revealed major disparities in matrix tolerance across evaluated pathways. Direct UV Spectrophotometry (Method B) failed in samples with dissolved organic carbon levels exceeding 3.0 mg C/L due to non-linear spectral overlap. Enzymatic reduction (Method J) suffered severe humic acid inhibition, dropping recoveries to 54.1±4.2 % at 20.0 mg C/L DOC. Conversely, chemical reduction pathways (Cd and VCl3) maintained high selectivity and matrix tolerance (98.5%-101.2% recovery) by shifting spectral detection to = 540 nm. The optimised VCl3 method achieved a limit of quantification (LOQ of 0.010 mg N-NO3-/L, intra-day repeatability of 1.0%-2.2% RSD, and superior multi-analyst reproducibility (2.2%-3.8% RSD) compared to cadmium column reduction (4.5-6.2% RSD). Operating as a single-phase liquid system, the VCl₃ protocol eliminates packed-bed column maintenance, flow-rate dependence, and toxic cadmium waste generation, providing a robust, cost-effective, high-throughput solution for tropical water testing laboratories.

Abstract: This study describes the synthesis, characterization, and evaluation of enantiomeric recognition properties of two fluorescent chiral ionic liquids (FCILs), L-aspartyl-L-phenylalanine methyl ester bis-(trifluoromethanesulfonyl) amide [ASP] [NTf₂] and L-aspartyl-L-phenylalanine methyl ester bis-(perfluoroethylsulfonyl) imide [ASP] [BETI]. The two FCILs were synthesized by means of ion-exchange between L-aspartyl-L-phenylalanine methyl ester hydrochloride [ASP] [HCl] and the lithium salts of bis-(trifluoromethanesulfonyl) amide (LiNTf₂) and bis-(perfluoroethylsulfonyl) imide (LiBETI). The products FCILs, [ASP] [NTf₂] and [ASP] [BETI], were viscous liquids at room temperature and were stable up to 366 oC. UV and fluorescence studies indicated the FCILs were highly UV absorptive and had strong fluorescence backgrounds. Fluorescence studies demonstrated the FCILs ability to discriminate between the enantiomers of naproxen and propranolol indicating ability serving as effective fluorescent recognition agents for chiral pharmaceutical analytes.

Abstract: This quantification methodology eliminates the need for complex and time-consuming pretreatments, like digestion or extraction, by leveraging digital-image colorimetry. It relies on a chromogenic complexation reaction within the emulsion, between the target metal and a suitable reagent: quercetin for aluminum and ferrozine for iron. For aluminum, the method demonstrated linearity with R² ≥ 0.971, acceptable accuracy (relative bias ≤ ±8.5 %) and intermediate precision (CV ≤ 9.4 %) upon Quality Controls (above the LLOQ) analysis and was successfully applied to commercial antiperspirants with satisfactory accuracy (relative bias ≤ ± 15.2 %). The assay was also adapted to a paper-based format. For iron, the method showed a linear correlation (R² ≥ 0.981) acceptable accuracy (relative bias ≤ ± 13.7 %) and intermediate precision (CV ≤ 12.6 %) upon Quality Controls analysis; it was further validated against X-ray fluorescence, revealing a consistent small positive bias of 14%. Investigations showed that both assays are susceptible to interference from common chelators and certain metals. We have demonstrated that the effect of such common interferences in commercially relevant concentration was, however, minimal (relative bias of ≤ ± 15.2  for Al and ≤ ± 4.5  for Fe), when the matrix of samples and standards was matched (e.g. upon sample dilution). For routine industrial quality control of emulsions, the proposed method is a cost-effective and greener alternative that, although mostly inferior in terms of technical characteristics when compared to instrumental analysis methods, is sufficiently accurate, precise and selective under the defined conditions.

Abstract: Breast-cancer management depends on reproducible molecular classification, yet tissue-based assays provide only spatially and temporally restricted views of a heterogeneous disease. Aptamers are programmable single-stranded DNA or RNA ligands that can integrate molecular recognition with biosensing, liquid-biopsy capture and targeted delivery. This Review follows the translational chain from aptamer selection and molecular recognition to subtype resolution, signal or cargo conversion, biological validation and clinical translation. We compare HER2-directed aptamers, ERα- and PHB2-associated tools for hormone-receptor-positive disease, and phenotype-oriented ligands for triple-negative breast cancer. We further organize aptasensors by signal-conversion mechanism, distinguish analytical performance in buffer from that in clinical matrices, and clarify the complementary role of aptamers in liquid-biopsy workflows, including enrichment rather than direct sequence-variant detection of circulating tumour DNA. For theranostic systems, affinity alone is insufficient; pharmacokinetics, receptor trafficking, endosomal escape and comparator-controlled efficacy ultimately determine functional benefit. Aptamers are therefore most compelling as modular recognition elements for multiplexing, reversible engineering and targeted delivery. Progress will depend on transparent selection reporting, orthogonal target validation and prospective multicenter studies.

Abstract:

The ongoing climate crisis, caused by the annual release of 37 billion metric tons of CO₂ emissions, is putting pressure on the advancement of Carbon Capture and Storage (CCS) and Direct Air Capture (DAC) technologies. Metal–Organic Frameworks (MOFs), with their high surface areas and modular pore topologies, present a very attractive class of sorbents for CO₂ capture; however, it currently remains computationally prohibitive to explore their extensive chemical design space. Herein, we provide a thorough evaluation of how machine learning (ML) (as an emerging technology) has played an increasing role in furthering our understanding of CO₂ capture from MOFs. Through an organized investigation, we provide evaluations of the latest generation of models across four key areas: application at a process level, mechanistic interpretable modelling; physically relevant descriptors, and predictive performance metrics. Recent work with Machine Learning Interatomic Potentials (MLPs) shows that traditional assumptions about rigid frameworks are being challenged by the fact that diffusion properties and adsorption thermodynamics are heavily influenced by the flexibility of the framework. The use of physics-informed descriptor engineering yields R² values of 0.81-0.97 across gas species and pressure regimes, while the generative nature of Deep Reinforcement Learning and transformer-based architectures has been shown to allow for the inverse design of frameworks with high affinities for gas species. The trend in this sector is moving towards optimization of multiple scales simultaneously and integrating processes to achieve an optimized property prediction. Current work with machine learning is focusing on using a combination of material properties and operational indicators (such as how much gas is recovered through pressure swing adsorption) to make predictions. As these techniques improve, there will be a similar need for a design that is both physically informed and understandable, thus allowing for a link between molecular discoveries and water-stable materials that have been experimentally verified and are suitable for use in commercial applications.

Abstract: Paralytic shellfish toxins (PSTs), potent neurotoxic alkaloids produced by marine dinoflagellates and cyanobacteria, pose severe risks to human health via contaminated seafoods and waters. Current detection methods suffer from low specificity, matrix interference, or ethical concerns. Here we report a novel screening approach using vanadium pentoxide as an oxidant to convert PSTs into characteristic oxidation products, followed by high-performance liquid chromatography-tandem mass spectrometry (HPLC‒MS/MS) analysis. Under optimized conditions, vanadium pentoxide oxidizes both hydroxylated and non-hydroxylated toxins into distinct major products (P1‒P7), identified by high-performance liquid chromatography‒tandem high-resolution mass spectrometry (HPLC‒MS/HRMS). Vanadium pentoxide oxidation affords excellent product selectivity and, for most PSTs, superior signal intensities, enabling unambiguous differentiation of toxin subgroups. HPLC‒MS/MS on MRM mode was developed and yielded detection limits of 0.3‒1.5 ng/mL for a broad-spectrum of 14 PSTs in spiked plasma, recovery percentages of 81.8‒102.2%, and excellent repeatability with intra- and inter-day relative standard deviation (RSDs) ranged from 0.3% to 10.4%. Application to the First Trial OPCW (the Organisation for the Prohibition of Chemical Weapons) Biotoxin Proficiency Test samples successfully identified STX/neoSTX, confirming its practical utility for trace PSTs detection in complex biological matrices.

Abstract: Continuous, real-time monitoring of volatile organic compounds (VOCs) in surface water is critical for environmental protection, yet conventional laboratory Gas Chro-matography-Mass Spectrometry (GC-MS) suffers from analyte loss during sample transport. This study field-validates a portable Membrane Inlet Mass Spectrometry (MIMS) system for direct, on-site monitoring of seven target VOCs (benzene, toluene, xylenes, chlorobenzene, 1,2-dichloroethane, trichloroethylene, and tetrachloroeth-ylene). Laboratory validation established limits of detection between 4 and 8 µg/L, strong linearity (R2 > 0.98), and acceptable precision and accuracy per AOAC guide-lines, benchmarked against headspace GC-MS. In-field testing at 36 locations across the Danube-Tisa-Danube (DTD) irrigation canal demonstrated system robustness. Baseline canal samples remained below detection limits, but real-time MIMS success-fully identified localized benzene and toluene contamination near a gasoline station. On-site MIMS detected significantly higher volatile concentrations than delayed la-boratory GC-MS, demonstrating its key advantage in preventing sampling volatiliza-tion losses. Portable MIMS proves to be a powerful, rapid screening tool for continuous aquatic environmental monitoring.

Abstract:

Organochlorine pesticides (OCPs) residues act as critical drivers of environmental impacts and pose significant risks to human and animal health. This scenario is further exacerbated by their high environmental persistence, marked bioaccumulative potential, and chronic toxicity. The International Agency for Research on Cancer (IARC) classifies dieldrin as well as aldrin, when metabolized into this substance, as probably carcinogenic to humans (Group 2A). OCPs can accumulate in the fatty tissue of fish. Therefore, when consumed, fish can become a route of human exposure to OCPs, such as dieldrin. A novel method for determining dieldrin in Fillets of Nile tilapia (Oreochromis niloticus) using GC/MS and the original QuEChERS was developed and validated. The optimization of chromatographic parameters resulted in an appropriate retention time (R_t) for dieldrin. Matrix-matched calibration was established to correct the matrix effect (ME) in the quantitative analysis of the pesticide. Dieldrin showed matrix-induced signal suppression of -21.17%. The pesticide studied showed good linearity with a coefficient of determination (R²) of 0.9918. According to the analytical validation standards established by ANVISA, concentrations above the LOQ (50 μg L^-1) can be used as a linear working range with high reliability.

Abstract: T-2 toxin and deoxynivalenol (DON) are major trichothecene mycotoxins that frequently contaminate agricultural products and pose substantial risks to human and animal health. Here, a highly sensitive and specific surface-enhanced Raman scattering lateral flow immunochromatographic assay (SERS-LFIA) was developed for simultaneous determination of T-2 toxin and DON on a single test line. Silver-coated petal-like gap-enhanced Raman tags encoded with 4-aminothiophenol or 4-nitrobenzenethiol were conjugated with antibodies against T-2 toxin or DON, respectively. A mixture of T-2 toxin-ovalbumin and DON-ovalbumin coating antigens was immobilized on the test line. After a 15 min assay, Raman signals at 1136 cm⁻¹ and 1333 cm⁻¹ were measured for quantitative detection. The assay produced IC₅₀ values of 0.35 ng mL⁻¹ for T-2 toxin and 0.29 ng mL⁻¹ for DON, with limits of detection of 0.0033 and 0.0067 pg mL⁻¹, respectively. No mutual interference or significant cross-reactivity with aflatoxin B1, ochratoxin A, zearalenone, patulin, or fumonisin B1 was observed. Recoveries from spiked corn and wheat samples ranged from 89.7% to 114.6%, with relative standard deviations below 9.09%. This rapid platform therefore enables sensitive and specific multiplex mycotoxin analysis on a single test line.

Abstract: Sweat testing is central to cystic fibrosis diagnosis, but conventional analysis depends on clinical instrumentation, creating a need for portable point-of-care alternatives. As Part 1 of this two-part study, we systematically optimized Na⁺- and Cl^–-selective colorimetric optodes and their measurement protocols for potential integration into a wearable device for in situ sweat analysis. Fifteen chromoionophore-based sensor compositions were screened over the physiologically relevant range of 5–100 mmol/L. Candidate optodes were selected based on stability in NaCl solutions and artificial sweat, hysteresis below 0.1 log units, and equilibration times under 15 min. Their analytical performance was evaluated by spectrophotometry and digital color analysis using smartphones and research-grade cameras, with a robustness parameter used to quantify signal reliability under different imaging conditions. A simple smartphone setup provided more robust performance than the tested laboratory imaging configurations. Incorporating light-scattering TiO₂ particles into the PVC matrix produced opaque films that significantly reduced interference from colored samples without compromising sensitivity or response kinetics. Validation in artificial sweat yielded recoveries above 93% across pH 5.5–8.0. These results establish optimized sensor compositions and measurement conditions for colorimetric Na⁺ and Cl^– determination in sweat and provide the analytical basis for wearable-device development in Part 2.

Abstract: Elution chromatography was used to analyze the content of SARA fractions in simulated raffinate and extract phases containing furfural, and the influence mechanism of furfural on the content analysis of SARA in the two phases was explored by molecular simulation. The experimental results showed that the content analysis of SARA fractions was more affected by the furfural with a higher content of furfural in the sample. During the process of sample loading, some chromatographic bands of R and A significantly shifted down, some A being eluted down earlier while eluting S with n-heptane, and some R being eluted out earlier while eluting A with toluene. In addition, the molecular simulation results showed that the order of adsorption capacity of model molecules and FUL on the FCP-Al2O3 surface was S<A<FUL<R, and the order of interaction between S, A, R model molecules and FUL was S<A<R. The molecular simulation results revealed the mechanism of the influence of furfural on the analysis of SARA fractions, that was, the unadsorbed furfural would promote the desorption of some A and R, resulting in the downward movement of chromatographic bands and affecting the elution effect, thereby affecting the accuracy of the SARA fractions analysis data. Furthermore, the improved vacuum distillation method, namely the vacuum-oven method could be used to accurately determine the content of furfural in the sample.

Abstract: Helichrysum italicum is a Mediterranean medicinal plant whose phloroglucinol (PG) α-pyrones constitute a structurally distinctive and pharmacologically relevant metabolite class, yet no systematic high-resolution mass spectrometric (HRMS) study has comprehensively characterized them. In this study, the acetone extract of inflorescences from Helichrysum italicum (Roth) G. Don was profiled by UHPLC–Orbitrap–MS in negative ion mode using full-scan and data-dependent MS/MS acquisition; exact-mass elemental composition assignment and HCD fragmentation analysis were combined with unsupervised clustering of fragment-ion and neutral-loss intensity matrices, validated against a manually curated annotation table using the adjusted Rand index (ARI) and cluster purity. From a total of 59 annotated compounds, 23 corresponded to known PG-α-pyrones previously reported from Helichrysum and 36 represented structures not previously described from the genus. Diagnostic fragment ions (FIs) and neutral losses (NLs) were established for identifying specific substituents of the α-pyrone and PG moieties. Semi-quantification gave a total PG-α-pyrone content of 0.019% dry weight, dominated by arzanol. This study establishes a UHPLC–HRMS framework for profiling phloroglucinol α-pyrone derivatives and confirms H. italicum as a rich source of this class.

Abstract: The increasing occurrence of antibiotic residues in aquatic environments poses significant risks to ecosystem integrity and public health, necessitating the development of rapid, sensitive, and portable analytical technologies. Herein, a MXene-supported dual single-atom Fe–Co nanozyme nanocomposite (FeCo-SA/MXene) is proposed as a high-performance electrocatalytic platform for the ultrasensitive electrochemical detection of antibiotic contaminants in water. The nanocomposite integrates the exceptional electrical conductivity and abundant surface functionalities of Ti₃C₂Tₓ MXene with atomically dispersed Fe–N₄ and Co–N₄ catalytic sites, enabling accelerated electron transfer and enhanced electrocatalytic activity. The structural characterization confirmed successful formation of isolated Fe–Co active sites without detectable metal nanoparticles, while electrochemical impedance spectroscopy indicated a substantial reduction in charge-transfer resistance from 185 Ω for the bare glassy carbon electrode to 26 Ω after FeCo-SA/MXene modification, accompanied by a 3.5-fold increase in electrochemically active surface area. The proposed sensor exhibited wide linear detection ranges of 0.5 nM–100 μM for tetracycline, 1 nM–80 μM for ciprofloxacin, 2 nM–100 μM for sulfamethoxazole, and 5 nM–120 μM for chloramphenicol, with corresponding detection limits of 0.12, 0.28, 0.45, and 0.83 nM, respectively. The sensor further demonstrated excellent selectivity against common interfering species, retained 96% of its initial response after 30 consecutive measurements and 94% after 4 weeks of storage, and achieved recoveries of 95.9–103.1% with relative standard deviations below 3.5% in environmental water samples. These findings demonstrate the potential of FeCo-SA/MXene nanozyme nanocomposites as a promising platform for developing next-generation electrochemical sensors for rapid, ultrasensitive, and reliable monitoring of emerging antibiotic contaminants in aquatic environments.

Abstract: Plants of the genus Crataegus have been used in traditional medicine to treat different health conditions, mainly cardiovascular diseases. Standardized extracts from this genus are marketed in Europe and Asia for the treatment of heart failure. In recent years, our research group has demonstrated that Crataegus gracilior, C. rosei, and C. mexicana exert significant vasorelaxing effects and that their most abundant and vasorelaxant constituents are the triterpenic acids they contain. Therefore, an HPLC-DAD analytical method was developed to simultaneously identify and quantify euscaphic, maslinic, corosolic, oleanolic, and ursolic acids, the main chemical constituents of the leaves of these three Mexican Crataegus species. Euscaphic acid was found to be the main compound in both C. rosei and C. mexicana while ursolic acid in C. gracilior. Therefore, these two acids were selected as their most suitable chemical and pharmacological markers. Accordingly, the developed method was validated for the two acids following the ICH Q2(R1) and USP guidelines. This method can be used for quality control of any crude commercial drugs produced from these species in the future.

Abstract: Existing reviews on MNP removal from water rarely link adsorbent structural features to the molecular interactions governing removal performance. This review addresses this gap by examining MNP adsorption from a mechanism-oriented perspective, mapping six canonical interaction pathways across five adsorbent classes. Adsorption emerges as a system-dependent process governed by the interplay between polymer properties and surface chemistry rather than by the material alone. Interactions such as π–π stacking and hydrophobic affinity dominate for non-functionalised polymers on carbon-rich surfaces, while electrostatic forces and hydrogen bonding become more relevant for oxidised particles. Pore structure becomes significant when particle size and porosity match, whereas chemisorption provides a stronger and faster pathway in systems containing reactive metal sites. Across material classes, differences relate more closely to scalability and sustainability than to intrinsic adsorption capacity. Bio-based materials offer a favourable balance between performance and practical implementation, while more advanced systems provide greater control but remain limited by synthesis complexity. Importantly, laboratory capacities often overestimate real performance, and removal efficiency in complex matrices is a more reliable metric. Future progress will depend on improved standardisation, better integration with modelling, and validation under realistic conditions to support the transition from laboratory studies to practical applications.

Abstract: Quantitative fluorescence analysis of aromatic pollutants in aquatic environments is frequently compromised by the primary inner filter effect (PIFE) induced by coexisting chromophoric species. In order to address this challenge, we propose a multi-component concentration quantification correction model that integrates transmittance absorbance and lateral (90°) fluorescence intensity. By establishing a coupled model of the excitation light decay dynamics and fluorescence emission, where styrene was used as the target analyte and anthracene/phenanthrene played the role of representative interferents, the inherently nonlinear PIFE was transformed into a tractable linear regression problem. The experiment shows that: under the coexistence of anthracene and phenanthrene, the model reduces the detection deviation of styrene from 40-63% to within 10%, and the correction accuracy of the three-component mixed system is increased by 3-5 times.The model in this work provides a theoretical framework for fluorescence quantitative analysis in complex systems, and also offers a new method for high-precision online monitoring of aromatic organic pollutants.

Abstract: A ratiometric electrochemical sensor based on poly(neutral red)-silver nanorods-carbon nanotubes (PNR-AgNRs/CNTs) composite was constructed for rapid, sensitive, and an-ti-interference detection of histamine in crayfish (Procambarus clarkii). Silver nanorods (AgNRs) were synthesized via a liquid-phase reduction method using 2-mercaptobenzoic acid (2-MBA) as both reducing and stabilizing agent, and subse-quently composited with carbon nanotubes (CNTs) through ultrasonic dispersion to form a three-dimensional conductive network. Poly(neutral red) (PNR) was electro-chemically polymerized onto the AgNRs-CNTs modified glassy carbon electrode (GCE) surface via cyclic voltammetry, serving as an electrochemical signal probe. The resulting PNR-AgNRs-CNTs/GCE exhibited significantly enhanced electrochemical performance with approximately 5-fold increase in electrochemically active surface area compared to bare GCE. Histamine competitively inhibited the electrochemical signal of PNR without affecting the AgNRs signal, enabling ratiometric detection based on the current signal ratio (IPNR/IAgNRs). Under optimized conditions (pH 6.0, adsorption time 6 min, material loading 0.08 mg/cm²), the IPNR/IAgNRs ratio exhibited a good linear relationship with the logarithm of histamine concentration in the range of 1–150 μmol/L, with a linear equa-tion of I/I = −0.3152 ln(C) + 5.0613, correlation coefficient R² = 0.995, and detection limit of 0.16 μmol/L (S/N = 3). The sensor demonstrated excellent anti-interference ability against common interfering substances such as Na⁺, Ca²⁺, K⁺, PO₄³⁻, and NO₃⁻. The relative standard deviations (RSD) for continuous 8-day detection and 8 parallel electrodes were 2.56% and 1.28%, respectively, indicating superior stability and reproducibility. The spiked recoveries in crayfish samples ranged from 95.9% to 102.3% with RSD < 3%, showing no significant difference from the national standard method (GB 5009.208-2016). The developed sensor effectively eliminated interference from complex biological ma-trices through the dual-signal ratio strategy and solved the detection problem of hista-mine lacking direct electrochemical response, providing a new approach for rapid on-site detection of histamine in aquatic products.

Abstract: Levofloxacin (LVX) is a broad-spectrum antibiotic whose systemic administration can be limited by adverse effects and suboptimal drug levels at infection sites. Implantable drug-loaded meshes offer a promising strategy for localized, prolonged delivery. This study developed and validated a simple, rapid, and reliable high-performance liquid chromatography with ultraviolet detection (HPLC-UV) method for quantifying LVX in rat blood to support the preclinical evaluation of a prolonged-release LVX-loaded polypropylene mesh. The method utilized a Zorbax SB-C18 column with an isocratic mobile phase of acetonitrile:0.1% orthophosphoric acid (80:20, v/v) at a flow rate of 1.4 mL/min, with detection at 296 nm. Validation according to ICH Q2(R2) guidelines demonstrated excellent linearity (R² = 0.999) over 1–8 µg/mL, accuracy (mean recovery 99.68%), and precision (intra- and inter-day CV < 0.3%). The limits of detection and quantification were 0.3 µg/mL and 1.0 µg/mL, respectively. The validated method was successfully applied to quantify LVX in rat plasma samples collected over 10 days post-implantation, confirming its suitability for pharmacokinetic studies of implant-based antibiotic delivery systems. This method provides a practical and robust analytical tool for routine preclinical assessment of LVX release and systemic exposure from localized delivery devices.

Abstract: Conductive carbon materials have attracted significant scientific and technological interest due to their exceptional electrical, mechanical, and chemical properties. Among them, graphitized carbon fibers and glassy carbon are widely used in electrochemical applications because of their high conductivity, large active surface area, chemical stability, and environmental compatibility. Their graphitic structure enables efficient electron transfer, while surface functionalization enhances adsorption capacity, catalytic activity, and electrochemical sensitivity. Graphitized carbon fibers, particularly polyacrylonitrile-based (PAN) fibers, exhibit excellent mechanical strength, thermal stability, and resistance in aggressive chemical environments, making them suitable for microelectrodes, sensors, fuel cells, and energy storage systems. This work also examines the modification of graphitized carbon fibers through oxidation processes and the attachment of functional molecules or metal layers in order to improve electrocatalytic performance. Special emphasis is placed on thin bismuth-film electrodes, which have emerged as environmentally friendly alternatives to mercury electrodes in electroanalysis. Bismuth-coated carbon substrates combine low toxicity, favorable stripping behavior, and high analytical sensitivity with the advantageous properties of carbon materials. Different fabrication methods, including ex-situ and in-situ electrodeposition, as well as the influence of coating morphology on electrochemical performance, are discussed. Furthermore, the applications of bismuth-modified electrodes in anodic and adsorptive stripping voltammetry for the determination of heavy metals in environmental, biological, and food samples are presented. The combination of graphitized carbon materials with bismuth films provides enhanced sensitivity, selectivity, conductivity, and stability, making these systems highly promising for advanced electrochemical sensing, catalysis, environmental monitoring, and sustainable energy technologies.

Abstract: Gas chromatography–mass spectrometry (GC–MS) is widely used to separate, identify, and semi-quantify volatile and derivatizable semi-volatile constituents (mono-/sesqui-terpenoids, phenylpropanoids, fatty-acid derivatives) that carry the discriminatory chemical information needed for authentication and quality control of traditional Chinese medicinal materials (TCMMs). To frame the methodological landscape rather than merely list components, this synthesis draws on peer-reviewed GC–MS / HS‑SPME works mainly indexed in PubMed, Web of Science, and Scopus (focusing on the last decade), using searches built around keyword clusters (GC–MS, volatile oil, TCM authentication/QC, processing) and prioritizing studies that report separation conditions, pretreatment rationale, identification confidence (spectral match + retention index), and chemometric discrimination. The covered evidence shows GC–MS reliability depends less on instrument prestige than on upstream choices: pretreatment selectivity and thermal bias govern which labile markers survive; co-elution and matrix effects require explicit deconvolution/alignment; and identification confidence needs RI anchoring and, where possible, standard cross-checks, while inconsistent validation reporting and GC's intrinsic inaccessibility of strongly polar non-volatiles remain the main bottlenecks. When framed as a separation-first workflow—integrating optimized pretreatment (distillation/SPME/SFE), derivatization strategies, and multivariate modelling—GC–MS delivers verifiable chemical fingerprints to track geographical, batch, and processing-induced changes, supporting more comparable, regulation-ready QC protocols for TCMMs.