Melamine

RSC Adv. 2026 Oct 12. doi: 10.1039/d6ra07035c. Online ahead of print.

ABSTRACT

Benzoic acid is an important preservative-related marker in dairy products, and its rapid on-site detection remains challenging because conventional analytical methods generally require laboratory-based instrumentation and time-consuming procedures. In this study, a sustainable and portable colorimetric sensing platform was developed for benzoic acid detection in milk by integrating molecularly imprinted SiO₂ nanostructures with anthocyanin extracted from purple sweet potato peel. SiO₂ nanoparticles were synthesized using a modified Stöber sol-gel method and subsequently functionalized through a surface molecular imprinting polymer (MIP) strategy using benzoic acid as the template molecule and a tetraethyl orthosilicate-(3-aminopropyl)triethoxysilane (TEOS-APTES) silane system to form MIP@SiO₂ recognition sites. Anthocyanin served as a natural pH-responsive chromogenic probe, converting the selective rebinding of benzoic acid into measurable optical signals. The sensing mechanism was attributed to the synergistic effect of benzoic acid recognition within the imprinted cavities and the microenvironment-induced structural transformation of anthocyanin. The developed MIP@SiO₂/anthocyanin system exhibited a concentration-dependent colorimetric response toward benzoic acid, with a limit of detection of 27.2 mg L^-1. The sensor showed good selectivity against common milk-related interferents, including urea, melamine, sodium chloride, and calcium chloride dihydrate. Practical applicability was demonstrated in spiked milk samples, achieving satisfactory recoveries of 96.0-99.0% using smartphone red green blue (RGB) analysis and 96.32-97.20% using the portable device, with low relative standard deviations. Furthermore, a compact detection device integrating a white LED, AS7341 multispectral sensor, Arduino microcontroller, and bluetooth transmission enabled portable optical readout without requiring a conventional spectrophotometer. These results demonstrate that the proposed MIP@SiO₂/anthocyanin sensing platform provides a low-cost, sustainable, and field-deployable strategy for rapid benzoic acid screening in milk.

PMID:42866254 | PMC:PMC13656018 | DOI:10.1039/d6ra07035c

Anal Methods. 2026 Oct 12. doi: 10.1039/d6ay02047j. Online ahead of print.

ABSTRACT

Milk is an indispensable component of the human diet and is therefore an important target matrix for rapid food safety screening. Melamine adulteration of dairy products poses a potential health risk, highlighting the need for simple and reliable analytical methods for rapid screening. Herein, a thymine-derivative-functionalized silver nanoparticle-based colorimetric sensing platform was developed for the rapid detection of melamine in milk. The thymine moieties provide complementary hydrogen-bonding recognition sites for melamine, while the silver nanoparticles serve as plasmonic signal transducers. Melamine-induced interparticle association produces concentration-dependent nanoparticle aggregation and changes in localized surface plasmon resonance, resulting in a readily visible color transition from yellow to purplish red. The sensing response was interrogated through two complementary readout formats: image-based colorimetric screening using visual observation/RGB analysis and ratiometric UV-vis spectroscopy for quantitative determination. Under optimized conditions, the method exhibited excellent linearity over the concentration range of 0.16-0.28 µM (R² = 0.996) and achieved a calculated detection limit of 3.52 nM. A visible response was obtained within 90 s, and common milk-associated interferents at more than 1000-fold molar excess relative to melamine caused negligible changes in the analytical response. For independent validation using three representative commercial milk products, satisfactory recoveries of 98.6-102.9% were obtained, with relative standard deviations of 1.1-3.2%. The proposed platform integrates molecular recognition with a simple optical readout, providing a rapid approach to the screening and quantitative determination of melamine in dairy matrices.

PMID:42861739 | DOI:10.1039/d6ay02047j

J Chromatogr A. 2026 Oct 5;1789:467517. doi: 10.1016/j.chroma.2026.467517. Online ahead of print.

ABSTRACT

Estrogens are used to increase milk production but can accumulate in the human body, eventually causing adverse effects. To extract estrogens from milk, a melamine sponge stir bar adsorbent was fabricated in a dual-polymer functionalization process, using polydopamine (PDA), and polyvinyl alcohol (PVA) combined with MIL-125 (MS-PDA@PVA-MIL-125). PDA introduced additional hydroxyl and amino groups to the adsorbent surface, increasing the number of active sites available to the target analytes. PVA acted as a binder to anchor MIL-125 into the composite structure. MIL-125 was employed as the active adsorption material, significantly enhancing the extraction efficiency of estrogens through hydrogen bonding, hydrophobic interaction, and π-π interaction. The composite adsorbent extracted estradiol, ethinyl estradiol, estrone, and hexestrol from milk samples in a stir bar sorptive extraction (SBSE) procedure. The extracted estrogens were determined by high-performance liquid chromatography coupled with diode-array detector. The developed method demonstrated good linearity from 1.50 to 100 μg L⁻¹ with a limit of detection of 0.50 μg L⁻¹. Recoveries from spiked milk samples were in the range of 80 to 104%, with RSDs less than 6%. This innovative design provides high extraction efficiency, simple preparation, self-stirring capability, cost-effectiveness, and good environmental friendliness.

PMID:42843018 | DOI:10.1016/j.chroma.2026.467517

Environ Pollut. 2026 Sep 24;410:129158. doi: 10.1016/j.envpol.2026.129158. Online ahead of print.

ABSTRACT

The environmental occurrence of melamine deamination series and triazine herbicides represents a significant challenge for aquatic monitoring due to their high mobility and persistence. This study investigated cyromazine, melamine, its deamination products, and selected triazine herbicides in an urban tributary using two passive samplers, the Polar Organic Chemical Integrative Sampler (POCIS) and the Chemcatcher. Four 14-day monitoring campaigns were conducted, and passive sampler-derived time-weighted average concentrations were used to evaluate contaminant occurrence, environmental transformation, sampler comparability, and screening-level ecological risk. Melamine and cyromazine were frequently detected, indicating recurrent inputs of parent melamine-series compounds. Ammeline, ammelide, and cyanuric acid were also detected across several site-periods, demonstrating that transformation products can contribute substantially to the total triazine-related burden. Atrazine and cyanazine occurred only during the spring campaign, suggesting episodic herbicide inputs, whereas simazine was detected more persistently at lower concentrations. Molar diagnostic indices indicated that melamine-series dominated the triazine-related burden. POCIS and Chemcatcher yielded comparable detection patterns, although POCIS generally showed higher responses for the highly polar melamine-series compounds. The screening-level mixture risk was governed by atrazine during spring; When atrazine was excluded, the mixture risk quotients remained below 1. Overall, this study supports passive sampler-based pathway monitoring as a useful approach for persistent, mobile, toxic (PMT)-relevant melamine-series contaminants and highlights the need to include intermediate transformation products in water-quality surveillance and screening-level risk assessment.

PMID:42785620 | DOI:10.1016/j.envpol.2026.129158

Environ Pollut. 2026 Sep 24;410:129158. doi: 10.1016/j.envpol.2026.129158. Online ahead of print.

ABSTRACT

The environmental occurrence of melamine deamination series and triazine herbicides represents a significant challenge for aquatic monitoring due to their high mobility and persistence. This study investigated cyromazine, melamine, its deamination products, and selected triazine herbicides in an urban tributary using two passive samplers, the Polar Organic Chemical Integrative Sampler (POCIS) and the Chemcatcher. Four 14-day monitoring campaigns were conducted, and passive sampler-derived time-weighted average concentrations were used to evaluate contaminant occurrence, environmental transformation, sampler comparability, and screening-level ecological risk. Melamine and cyromazine were frequently detected, indicating recurrent inputs of parent melamine-series compounds. Ammeline, ammelide, and cyanuric acid were also detected across several site-periods, demonstrating that transformation products can contribute substantially to the total triazine-related burden. Atrazine and cyanazine occurred only during the spring campaign, suggesting episodic herbicide inputs, whereas simazine was detected more persistently at lower concentrations. Molar diagnostic indices indicated that melamine-series dominated the triazine-related burden. POCIS and Chemcatcher yielded comparable detection patterns, although POCIS generally showed higher responses for the highly polar melamine-series compounds. The screening-level mixture risk was governed by atrazine during spring; When atrazine was excluded, the mixture risk quotients remained below 1. Overall, this study supports passive sampler-based pathway monitoring as a useful approach for persistent, mobile, toxic (PMT)-relevant melamine-series contaminants and highlights the need to include intermediate transformation products in water-quality surveillance and screening-level risk assessment.

PMID:42785620 | DOI:10.1016/j.envpol.2026.129158

Toxicol Lett. 2026 Sep 22;425:113204. doi: 10.1016/j.toxlet.2026.113204. Online ahead of print.

ABSTRACT

Melamine (MEL) gained global attention years ago following hospitalizaiton of hundreds of thousands of infants due to contamination of baby formula, which had been adulterated to falsely elevate protein content. This study aimed to investigate the effects of MEL e exposure on heart tissue starting from the weaning period. Eighteen female rats in the weaning period (21 days) were divided into 3 groups. The control group received 0.1 ml of saline orally for 3 weeks. The other two groups received 50 and 75 mg/kg MEL e in 0.1 ml saline for 3 weeks, respectively. On 45th day, the rats were euthanized under anesthesia, and their heart tissue was removed and placed in neutral formalin. Histopathological analysis of hematoxylin & eosin (H&E), Masson's trichrome, periodic acid schiff (PAS), reticulin stained cardiac tissue, anti-connexin 43 (Cx43) and anti-cardiac troponin I (cTnI) positivity were evaluated. The findings showed that 50 mg/kg MEL e increased myocardial damage, congestion, and inflammatory cell infiltration, while exposure to 75 mg/kg MEL e increased myocardial damage, inflammatory cell infiltration, congestion, and fibrosis in the perivascular area, as well as decreasing cTnI and Cx43. In conclusion, MEL exposure from the weaning period or early postnatal period may cause structural and functional impairments in the heart tissue, including histological changes, as well as impairments in cTnI associated with contraction units and Cx43 units responsible for impuls transmission.

PMID:42772391 | DOI:10.1016/j.toxlet.2026.113204

Foods. 2026 Aug 28;15(17):3041. doi: 10.3390/foods15173041.

ABSTRACT

Food adulteration is a critical global threat to public health, economic stability, and social welfare. It primarily occurs in two forms: intentional and incidental. Intentional adulteration, or economically motivated adulteration, involves deliberately adding fraudulent or toxic substances such as hazardous ripening agents and harmful coloring to increase profitability. Substitution of food species is also a widely practiced form. Such adulteration can cause severe acute and chronic health issues, ranging from gastrointestinal distress to cancer and organ failure. Incidental adulteration happens through accidental contamination during processing, storage, or distribution, involving hazards such as heavy metals, mycotoxins, and pesticides. Such contaminants also lead to severe chronic diseases and dangerous allergic reactions. Food adulteration also triggers massive socio-economic consequences. Food safety incidents such as the melamine milk crisis and the horsemeat scandal caused billions of dollars in losses due to healthcare costs, product recalls, damaged brand reputation, and disrupted international trade. Global entities such as the WHO, WTO, and Codex Alimentarius have established robust legislative frameworks. However, effective enforcement remains a significant challenge in many countries. To mitigate such harmful impacts, it is essential to strengthen global surveillance systems, enhance rapid analytical detection methods, and strictly enforce compliance with existing food safety regulations.

PMID:42737286 | PMC:PMC13565193 | DOI:10.3390/foods15173041

J R Soc Interface. 2026 Sep 9;23(242):20260105. doi: 10.1098/rsif.2026.0105.

ABSTRACT

Electrophoretic ink (e-ink) holds significant potential for energy-efficient displays and sustainable alternatives to print media. However, their use in wearables is hindered by hazardous materials which are cytotoxic and sensitizing to human tissue. While commercial e-inks encapsulate these fluids in rigid, synthetic microplastics, such as melamine-formaldehyde, they lack the mechanical conformability and environmental safety required for epidermal contact. We thus present a novel approach for producing e-ink microcapsules (EIMCs) for integration into biocompatible and free-form digital devices. Spherical, core-shell EIMCs were fabricated via complex coacervation (pH 4.1), using user-friendly biopolymers (gum acacia and gelatin). A core of white electrophoretic TiO2 particles (diameter approx. 30 nm) was marked with a darker violet dye, while being homodispersed in hexylsalicylate-tetrachloroethylene (HS-PCE), as the liquid medium. Characterization of the physico-chemical and performance properties of EIMCs showed remarkable nominal compression stress at rupture (3.9 ± 0.9 MPa). When subjected to a DC voltage of 20 V, the microcapsules created a writable display, potentially enabling users to write and rewrite. The response time was approximately 0.5 seconds (2 Hz refresh rate), comparable to commercial products. In vitro cytotoxicity and CD54 expression (h-CLAT) assays demonstrated that the microcapsule shell successfully mitigated solvent-induced immunotoxicity, maintaining high cellular viability (approx. 70%) and minimal sensitization (approx. 1.7%).

PMID:42710890 | PMC:PMC13561038 | DOI:10.1098/rsif.2026.0105

J R Soc Interface. 2026 Sep 9;23(242):20260105. doi: 10.1098/rsif.2026.0105.

ABSTRACT

Electrophoretic ink (e-ink) holds significant potential for energy-efficient displays and sustainable alternatives to print media. However, their use in wearables is hindered by hazardous materials which are cytotoxic and sensitizing to human tissue. While commercial e-inks encapsulate these fluids in rigid, synthetic microplastics, such as melamine-formaldehyde, they lack the mechanical conformability and environmental safety required for epidermal contact. We thus present a novel approach for producing e-ink microcapsules (EIMCs) for integration into biocompatible and free-form digital devices. Spherical, core-shell EIMCs were fabricated via complex coacervation (pH 4.1), using user-friendly biopolymers (gum acacia and gelatin). A core of white electrophoretic TiO2 particles (diameter approx. 30 nm) was marked with a darker violet dye, while being homodispersed in hexylsalicylate-tetrachloroethylene (HS-PCE), as the liquid medium. Characterization of the physico-chemical and performance properties of EIMCs showed remarkable nominal compression stress at rupture (3.9 ± 0.9 MPa). When subjected to a DC voltage of 20 V, the microcapsules created a writable display, potentially enabling users to write and rewrite. The response time was approximately 0.5 seconds (2 Hz refresh rate), comparable to commercial products. In vitro cytotoxicity and CD54 expression (h-CLAT) assays demonstrated that the microcapsule shell successfully mitigated solvent-induced immunotoxicity, maintaining high cellular viability (approx. 70%) and minimal sensitization (approx. 1.7%).

PMID:42710890 | PMC:PMC13561038 | DOI:10.1098/rsif.2026.0105

Anal Chim Acta. 2026 Oct 22;1420:345958. doi: 10.1016/j.aca.2026.345958. Epub 2026 Jul 10.

ABSTRACT

BACKGROUND: Sensitive and specific detection of target analytes remains challenging but significant in the practical applications of hazardous chemical detection, biomarkers tracing, and environmental monitoring, etc. RESULTS: Here, a general strategy for boosting the sensitivity and specificity of the sensing system is proposed, which involves modulating the electrophilicity of the pyrimidine-based probes with different substituents (-Br, -H, -OMe), the nucleophilicity of the target analyte N₂H₄ , and the fluorescent properties of the product by adjusting the pH value. Remarkably, the bromine-substituted probe exhibited superior performance in a specific alkaline environment (pH = 7.5), achieving a theoretical limit of detection (LOD) of 5.77 nM (0.18 ppb) in solution, which is far below the 10 ppb occupational exposure limit reported by the U.S. Environmental Protection Agency. By embedding the BrPMtBu probe into a porous sponge substrate, specific recognition of trace hydrazine vapor was achieved, even in the presence of an 86-fold higher concentration of ethylenediamine (EDA) - a structural and property analog of hydrazine. Further validation of this strategy was performed using an optical sensing chip equipped with the BrPMtBu-loaded melamine sponge, which could precisely discriminate trace hydrazine in both liquid and gaseous phases at extremely low concentrations.

SIGNIFICANCE: This work provides a different viewpoint for the rational design of fluorescent probes by modulating the nature of the target, the probe and the product, as well as a versatile and reliable approach for ultra-sensitive detection of trace hazardous analytes.

PMID:42648835 | DOI:10.1016/j.aca.2026.345958

Environ Sci Technol. 2026 Sep 1;60(34):24377-24392. doi: 10.1021/acs.est.6c05884.

ABSTRACT

Inflatable rubber dams are used globally within water infrastructure, yet their potential as chemical contaminant sources remains overlooked. We investigated the occurrence of rubber additives and their transformation products within rubber dam materials (RDMs), including their organic extracts, aqueous leachates, and adjacent receiving waters, by employing targeted quantitative analysis combined with high-resolution mass spectrometry-based suspect and nontargeted screening. Targeted analysis revealed that substituted para-phenylenediamines (PPDs), their quinone/nonquinone products, and other rubber additives were abundant in RDM extracts and leachates. The antiozonant product N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine quinone (6PPDQ) was detected in laboratory leachates and receiving water adjacent to an in-service dam at toxic concentrations. Suspect and nontargeted screening of the RDM extracts and leachates identified 83 potential RDM-derived contaminants, with 75 structurally annotated (confidence level ≥3), including various hexa-(methoxymethyl)melamine analogues and 4-hydroxydiphenylamine homologues. To assess environmental health impacts, in silico toxicity predictions on unmonitored compounds prioritized from suspect and nontarget screening indicated high ecotoxicity potential, including aquatic neurotoxicity, revealing critical toxicological data deficits for rubber-derived contaminants. These findings demonstrate that water infrastructure materials can act as point sources of 6PPDQ and other contaminants, highlighting critical gaps in infrastructure risk assessment and emphasizing the need for environmentally benign rubber materials.

PMID:42599835 | DOI:10.1021/acs.est.6c05884

Anal Chim Acta. 2026 Oct 1;1417:345828. doi: 10.1016/j.aca.2026.345828. Epub 2026 Jun 10.

ABSTRACT

Tire rubber contains many chemicals that can enter aquatic ecosystems through tire wear particles or leachates from crumb rubber surfaces. The antiozonant N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD) and its transformation product, 6PPD-quinone, are of particular concern due to their toxicity associated with aquatic species mortality. Other relevant compounds from the PPD family are DPPD and IPPD. Vulcanizing and crosslinking agents, including benzothiazole, 2-mercaptobenzothiazole, N-cyclohexylbenzothiazole-2-sulfenamide (CBS) and hexamethoxymethylmelamine (HMMM), together with alkyl organophosphate esters and alkyldimethylamines are also of great interest. This work aimed to develop an analytical method for detecting and quantifying 11 emerging tire rubber contaminants in urban waters. The method is based on solid-phase microextraction (SPME) using commercial fibers followed by gas chromatography coupled to tandem mass spectrometry (GC-MS/MS). SPME parameters were optimized via multivariate design to efficiently extract all analytes. The method was successfully validated for linearity, precision, and accuracy, with mean recoveries of 84-105%. In all the urban water samples analyzed, 6PPD and 6PPDQ were detected. To our knowledge, this is the first time that GC-MS/MS has been applied to the analysis of most of these compounds, including PPDs, as well as the first proposal of SPME for the extraction and analysis of many of these compounds. This is also the first investigation of these substances in real water samples originating from recycled tire rubber surfaces as a potential source of contamination. Due to its simplicity, this multiresidue method, which includes antiozonants, vulcanizing, and crosslinking agents, can be easily implemented in any routine laboratory.

PMID:42508920 | DOI:10.1016/j.aca.2026.345828

Pestic Biochem Physiol. 2026 Aug;222:107234. doi: 10.1016/j.pestbp.2026.107234. Epub 2026 Jun 29.

ABSTRACT

Cyromazine (CYR) is a widely used insect growth regulator. Its metabolite, melamine, is classified as a Group 2B carcinogen and has been associated with urinary tract lesions and tumors. While previous toxicological studies have largely focused on high-concentration exposures, the mechanisms of toxicity at environmentally relevant concentrations remain poorly understood. In this study, using Caenorhabditis elegans as a model, we demonstrated that CYR induces dose-dependent neurotoxicity, developmental impairment, reproductive toxicity, and oxidative stress. Transcriptomic analysis revealed disruptions in glutamate, dopamine, GABA, and glutathione metabolic pathways. CYR exposure caused damage to dopaminergic and glutamatergic neurons, decreased levels of several neurotransmitters, and downregulated key genes including dop-3, tph-1, and eat-4, resulting in behavioral deficits such as impaired pharyngeal pumping, body bending, and head thrashing. Parental exposure to CYR significantly elevated reactive oxygen species (ROS) and lipofuscin accumulation, activated the glutathione-mediated antioxidant pathway, and disturbed enzymatic balance, indicating a central role for oxidative stress in CYR-induced neurotoxicity. By systematically elucidating the mechanism of ROS-mediated oxidative stress in neurobehavioral toxicity, this study provides a mechanistic foundation for understanding the broader toxicological profile of CYR, thereby offering critical insights for assessing its comprehensive health risks at environmental levels.

PMID:42493045 | DOI:10.1016/j.pestbp.2026.107234

Biomed Mater. 2026 Jul 22;21(4). doi: 10.1088/1748-605X/ae859a.

ABSTRACT

Enterococcus faecalis(E. faecalis), a leading pathogen associated with severe nosocomial infections, poses a major control challenge owing to its widespread multidrug resistance. Current first-line therapies forE. faecalisinfections combine ampicillin (Amp) with gentamicin or ceftriaxone, yet this approach is plagued by inherent toxicity and a tendency to promote drug-resistant strain colonization. To explore novel strategies againstE. faecalisinfections, we devised a combined treatment regimen consisting of methimazole (MMI) -melamine (Mel) co-functionalized gold nanoparticles (Au NPs, Mel-MMI@Au NPs) and Amp. Experiments demonstrated that Mel-MMI@Au NPs outperformed their single-ligand counterparts (Mel@Au NPs or MMI@Au NPs) in both stability and antibacterial activity. By disrupting bacterial cell membranes, Mel-MMI@Au NPs enhance Amp penetration across bacterial barriers for targeted inhibition, reducing Amp's minimum inhibitory concentration (MIC) by eightfold. The fractional inhibitory concentration index of the combination was determined to be 0.375 (below the synergism threshold of 0.5), confirming a robust synergistic antibacterial effect. This dual-modified Au NPs-antibiotic strategy achieves low-dose synergistic bactericidal activity, delays resistance evolution, and ensures favorable biosafety, thereby overcoming the limitations of single antibiotics and representing a promising approach against multidrug-resistantE. faecalis.

PMID:42392159 | DOI:10.1088/1748-605X/ae859a

Polymers (Basel). 2026 Jun 8;18(12):1432. doi: 10.3390/polym18121432.

ABSTRACT

In this study, a new approach to improving the fire resistance of flexible polyurethane (PUR) foams is presented, based on the incorporation of cotton chemically modified with boron compounds into the polyurethane matrix. The developed system was additionally modified with melamine polyphosphate (MPP). The effects of the applied modifications on the morphology and chemical structure of the PUR composites were investigated using scanning electron microscopy and infrared spectroscopy. Thermal stability was evaluated by thermogravimetric analysis, whereas fire hazard was assessed using cone calorimetry and a smoke optical density chamber. The toxicometric index (WLC_50SM) was determined using a coupled TG-Omega 5 gas analyzer system. The results provide insight into the mechanism responsible for reducing flammability and limiting the emission of toxic combustion and thermal decomposition products through the modification of PUR foams with chemically modified cotton in combination with MPP. It was observed that, during the combustion of the developed PUR composites, the addition of cotton promotes the formation of a three-dimensional spatial network, which substantially limits heat release and the emission of toxic combustion products. Consequently, the composites exhibited a reduction in heat release of up to 67% in terms of HRR_MAX, together with decreased production of HCN and CO. Nevertheless, the formation of a protective carbon layer contributed to an increase in smoke optical density, which was associated with increased CO₂ emission. Overall, this work demonstrates the development of a new synergistic system capable of reducing both the flammability and toxicity of flexible PUR foams.

PMID:42356958 | PMC:PMC13306684 | DOI:10.3390/polym18121432

Sci Rep. 2026 Jun 16;16(1):18667. doi: 10.1038/s41598-026-53511-6.

ABSTRACT

The present study demonstrated europium-decorated carbon quantum dots (Eu-CQDs), which were synthesized through a one-pot hydrothermal process using sucrose and melamine as the carbon and nitrogen sources and EuCl₃ as the rare earth metal ion of Eu. The resulting blue-emissive Eu-CQDs were confirmed using spectroscopic and microscopic techniques, including UV-Vis absorption, fluorescence (FL), FT-IR, XRD, TEM, and XPS. The Eu-CQDs showed significant UV-Vis and FL emission at wavelengths of 320 and 424 nm, respectively, with a quantum yield (QY) of 33.6%. TEM analysis revealed well-dispersed spherical Eu-CQDs with an average size of 3.19 ± 0.21 nm. Remarkably, the Eu-CQDs served as an outstanding FL probe for the selective sensing of ferric ions (Fe³⁺) and copper ions (Cu²⁺) through FL dynamic quenching, especially photo-induced electron transfer (PET), while other metal ions produced minimal intensity changes. The detection limits were 65.6 nM for Cu²⁺ and 72.1 nM for Fe³⁺, with a linear relationship observed in the range of 0-20 µM. However, the dynamic quenched FL of Eu-CQDs/Cu²⁺ and Eu-CQDs/Fe³⁺ was swiftly enhanced by EDTA via a turn-on response. The practical use of the Eu-CQDs probe for quantifying the Cu²⁺ and Fe³⁺ ion concentrations was conducted with real water samples, and the findings indicated satisfactory recoveries (101.1% for Cu²⁺ and 104.8% for Fe³⁺) and good reproducibility, which aligned with the results obtained from UV-Vis spectroscopy. Additionally, the WST assay was assess the cytotoxic effects of Eu-CQDs, and their capability to image live HCT-116 (human colon cancer cell line) cells was assessed. These results indicate that the Eu-CQDs used for the nanoscale sensing of Fe³⁺ and Cu²⁺ metal ions are both selective and sensitive, and they can be successfully used for live cell imaging of cancer cell lines when used with this probe.

PMID:42303663 | PMC:PMC13272591 | DOI:10.1038/s41598-026-53511-6

Molecules. 2026 Jun 2;31(11):1912. doi: 10.3390/molecules31111912.

ABSTRACT

Food adulteration with melamine represents a serious threat to food safety due to its toxic effects and its ability to falsely elevate protein values measured by nitrogen-based methods. Visual inspection and visible reflectance spectroscopy are unsuitable for identifying low-level adulteration. This study evaluates Fourier Transform Infrared (FTIR) spectroscopy combined with chemometric tools for the identification of melamine in brown rice flour adulterated at 0-2.00% (w/w). Under the tested conditions, no clear FTIR-detectable interactions between melamine and starch or proteins were observed, suggesting that melamine primarily acts as a physical admixture. Characteristic melamine absorption bands were identified at 3466, 3415, 1431, and 810 cm^-1. Spectral normalization and second-order derivative processing improved sensitivity and enabled quantitative calibration models. The method achieved a limit of detection of 1408 mg/kg. Although this value is above the regulatory threshold of 2.5 mg/kg, the approach provides a rapid, non-destructive screening tool for identifying highly adulterated samples and prioritizing them for confirmatory chromatographic or mass spectrometric analysis. Overall, FTIR spectroscopy combined with chemometric analysis offers an efficient first-line approach for identification of melamine adulteration in brown rice flour.

PMID:42280214 | PMC:PMC13258603 | DOI:10.3390/molecules31111912

Anal Chem. 2026 Jun 23;98(24):18031-18041. doi: 10.1021/acs.analchem.6c01553. Epub 2026 Jun 9.

ABSTRACT

The adulteration of dairy products with melamine has created an urgent need for reliable, sensitive, and convenient detection methods. Since melamine can form extensive hydrogen bonding and stacking interactions with DNA bases, aptamers represent an attractive platform for melamine sensing. In this work, capture-SELEX was employed using two DNA libraries containing either 30 or 36 randomized nucleotides. The longer library generated a greater diversity of sequence families, including a dominant family featuring more than 30 conserved nucleotides, a structural motif unattainable with the shorter library. Comparison was made with previous length-dependent SELEX experiments. The highest affinity aptamers exhibited a dissociation constant (K_d) of ∼60 nM, as determined by isothermal titration calorimetry. Screening aptamer responses using a thioflavin T fluorescence assay revealed a pair of aptamers with opposite signal readouts, enabling melamine detection with limits of detection of 61 nM and 208 nM, respectively. In 5% (v/v) milk samples, limits of detection of 89 and 315 nM were achieved, respectively. Overall, this study advances understanding of the impact of library length on aptamer selection and provides a set of high affinity aptamers along with a robust, label-free strategy for melamine detection.

PMID:42261635 | DOI:10.1021/acs.analchem.6c01553

RSC Adv. 2026 May 19;16(29):26948-26958. doi: 10.1039/d5ra05664k. eCollection 2026 May 18.

ABSTRACT

Adulteration in cattle milk is a pervasive issue, where melamine is added to milk due to its high nitrogen content, which ultimately falsely elevates the perceived protein levels of milk. However, its consumption possesses a significant threat, because it can cause severe health hazards. Conventional detection methods are often very expensive and also lack selectivity, and sensitivity towards detection of toxic adulterants. This study addresses these limitations by fabricating a highly selective maleic acid-functionalized silver nanoparticles (MA-AgNPs) based plasmonic nanofilm for highly accurate detection of milk adulterant melamine. At first, chemical reduction method was used to synthesize the AgNP swhich was later functionalized with maleic acid. The functionalized NPs were uniformly coated onto a glass slide to create localized surface plasmon resonance (LSPR) chip. The plasmonic activity of the NPs along with its selective interaction towards melamine resulted in significant shift in plasmonic peak position, enabling melamine detection below the permissible limit. To determine the optical and physical properties of the synthesized AgNPs, UV-vis spectrophotometer, X-ray diffractometer (XRD), Field Emission Scanning Electron Microscope (FESEM), Atomic Force Microscope (AFM), and Transmission Electron Microscope (TEM) studies were conducted. Validation of the milk samples spiked with melamine was performed utilizing the High-Performance Liquid Chromatography (HPLC) method. The developed LSPR-based platform offered a sustainable and inexpensive solution for detecting milk adulterant melamine, with high sensitivity, selectivity and lower detection limit.

PMID:42170095 | PMC:PMC13187901 | DOI:10.1039/d5ra05664k

Regul Toxicol Pharmacol. 2026 Sep;170:106131. doi: 10.1016/j.yrtph.2026.106131. Epub 2026 May 18.

ABSTRACT

Co-exposure to melamine (MEL) and cyanuric acid (CYA) exhibits synergistic toxicity, yet existing toxicological studies have several limitations, including suboptimal doses, short exposure durations, and lack of synergistic effect data in current TDIs and environmental guidelines. To address these gaps, this study conducted a three-stage experiment in male Sprague-Dawley rats to explore nephrotoxicity and dose-response relationships under co-exposure conditions. In Stage 1 (CYA at 10× MEL), the toxicity threshold for MEL was assessed, with trace crystal formation and mild tubular injury first observed at 2 mg/kg bw/day. In Stage 2 (MEL fixed at 4 mg/kg bw/day and CYA ranging from 0.5 to 10× MEL), the toxicity threshold for CYA was evaluated, revealing that a 1:1 ratio of MEL to CYA exhibited the highest nephrotoxic potential. In Stage 3, with exposure duration extended to 12 weeks, the no-observed-adverse-effect levels (NOAELs) were established as 0.5 mg/kg bw/day (based on tubular injury) and 2 mg/kg bw/day (based on crystal deposition). Applying an uncertainty factor of 200, the derived TDIs for combined exposure were calculated as 2.5 μg/kg bw/day (tubular injury-based) and 10 μg/kg bw/day (crystal deposition-based). These findings represent a critical advancement toward updating the current risk assessment framework for MEL and CYA co-exposure.

PMID:42155661 | DOI:10.1016/j.yrtph.2026.106131

Aquat Toxicol. 2026 Aug;297:107852. doi: 10.1016/j.aquatox.2026.107852. Epub 2026 May 14.

ABSTRACT

This study investigates how the plastic additive composition influences the toxicity of UV-aged polypropylene (PP) microplastics (MPs), nanoplastics (NPs) and leachates toward the green alga Raphidocelis subcapitata. Three materials were compared: an antioxidant-deprived additive-free PP (PPd), a base-stabilized PP containing Irgafos 168 (PPc), and a compounded melamine-polypropylene with Irgafos 168 (PPf). UV-irradiation induced surface oxidation and fragmentation across all samples, releasing NPs (< 1 µm) and ultrafiltrates (< 50 kDa), representing the dissolved and colloidal fraction. Characterization by ATR-FTIR, SEM, and GC/MS confirmed that the material deprived of the antioxidant (PPd) underwent more intense oxidation, displaying a higher abundance of oxygenated functional groups and smaller particle sizes compared to stabilized forms. Toxicity assays with R. subcapitata demonstrated a clear size-dependent trend, with ultrafiltrates > NPs > small MPs (1-50 µm) > large MPs (50-500 µm), yet the magnitude of this toxicity was strongly driven by the additive composition. Growth inhibition, reactive oxygen species (ROS) generation, and membrane depolarization were significantly increased in the absence of antioxidant additives across all size fractions, indicating higher bioavailability and reactivity of UV-generated particle surfaces or leached low-molecular-weight oligomers. But still, stabilized melamine-PP released additional leaching products and its ultrafiltrates enriched in oxidized additives and low-molecular-weight oligomers, caused high cytotoxic and oxidative responses. Overall, these results demonstrate that the additive composition not only modulates polymer stability during UV ageing but also governed the toxicity of plastics particles and leaching products toward aquatic primary producers, underscoring the ecological relevance of plastic ageing processes in aquatic ecosystems.

PMID:42134112 | DOI:10.1016/j.aquatox.2026.107852

Food Chem. 2026 Jul 30;518:149595. doi: 10.1016/j.foodchem.2026.149595. Epub 2026 May 12.

ABSTRACT

Protein corona formation on nanoparticles severely limits the reliability of surface-enhanced Raman spectroscopy (SERS) for analyte detection in protein-rich food matrices. This study aimed to mitigate protein corona induced signal suppression and improve SERS detection performance. An inorganic salt regulation strategy was developed by introducing salts into gold nanoparticles prior to sample addition, inducing nanoparticle pre-aggregation and avoiding the stabilizing effect of the subsequently formed protein corona. The results showed that weakly adsorbing anions (Cl^-) enhanced melamine detection more effectively than strongly adsorbing anions (I^-) by promoting competitive adsorption between proteins and target molecules. Meanwhile, monovalent Na⁺ ions produced more favorable nanoparticle aggregation than divalent cations (Ca²⁺, Mg²⁺, Ba²⁺). When applied to milk samples, NaCl reduced the detection limit for melamine from 2 mg/L to 0.1 mg/L. These findings provide a simple and cost-effective strategy to improve SERS detection in protein-rich food matrices.

PMID:42134126 | DOI:10.1016/j.foodchem.2026.149595

Aquat Toxicol. 2026 May 14;297:107852. doi: 10.1016/j.aquatox.2026.107852. Online ahead of print.

ABSTRACT

This study investigates how the plastic additive composition influences the toxicity of UV-aged polypropylene (PP) microplastics (MPs), nanoplastics (NPs) and leachates toward the green alga Raphidocelis subcapitata. Three materials were compared: an antioxidant-deprived additive-free PP (PPd), a base-stabilized PP containing Irgafos 168 (PPc), and a compounded melamine-polypropylene with Irgafos 168 (PPf). UV-irradiation induced surface oxidation and fragmentation across all samples, releasing NPs (< 1 µm) and ultrafiltrates (< 50 kDa), representing the dissolved and colloidal fraction. Characterization by ATR-FTIR, SEM, and GC/MS confirmed that the material deprived of the antioxidant (PPd) underwent more intense oxidation, displaying a higher abundance of oxygenated functional groups and smaller particle sizes compared to stabilized forms. Toxicity assays with R. subcapitata demonstrated a clear size-dependent trend, with ultrafiltrates > NPs > small MPs (1-50 µm) > large MPs (50-500 µm), yet the magnitude of this toxicity was strongly driven by the additive composition. Growth inhibition, reactive oxygen species (ROS) generation, and membrane depolarization were significantly increased in the absence of antioxidant additives across all size fractions, indicating higher bioavailability and reactivity of UV-generated particle surfaces or leached low-molecular-weight oligomers. But still, stabilized melamine-PP released additional leaching products and its ultrafiltrates enriched in oxidized additives and low-molecular-weight oligomers, caused high cytotoxic and oxidative responses. Overall, these results demonstrate that the additive composition not only modulates polymer stability during UV ageing but also governed the toxicity of plastics particles and leaching products toward aquatic primary producers, underscoring the ecological relevance of plastic ageing processes in aquatic ecosystems.

PMID:42134112 | DOI:10.1016/j.aquatox.2026.107852

Spectrochim Acta A Mol Biomol Spectrosc. 2026 Nov 5;360:128008. doi: 10.1016/j.saa.2026.128008. Epub 2026 Apr 28.

ABSTRACT

Due to its importance and being widely traded food commodities, milk powder is considered the target for adulteration. In the present study, a practical, reagent-free and rapid method to identify any variation in the standard composition of milk powder, and extract useful information with respect to adulteration is proposed. Fourier Transform Infrared spectroscopy (FTIR) combined with two-trace two-dimensional correlation spectroscopy (2T2D-COS) was explored not only as a high sensitive method but also as a quantitative routine. With the help of 2T2D-COS-FTIR spectroscopy, melamine was determined in milk powder with superior detection level over conventional second derivative FTIR method. It was interesting to observe that the asynchronous correlation intensities of the cross peak at (814, 1741) cm^-1 increased linearly with the difference in concentration of melamine in the two analysed spectra. A calibration curve was established and the concentration of melamine was determined with a limit of detection (LOD) value of 0.46 ppm. The present study represents one method to improve the robustness of the models to make FTIR a more reliable tool for practical applications in the food industry.

PMID:42085820 | DOI:10.1016/j.saa.2026.128008

J Expo Sci Environ Epidemiol. 2026 May;36(3):550-558. doi: 10.1038/s41370-026-00844-z. Epub 2026 Apr 27.

ABSTRACT

BACKGROUND: Breastfeeding can be a source of exposure to endocrine-disrupting chemicals (EDCs) for infants, but limited information exists on exposure to commonly used chemicals such as melamine and bisphenols in nursing infants in the US.

OBJECTIVE: We aimed to measure a suite of EDCs in breast milk and evaluate exposure of nursing infants to these chemicals.

METHODS: We analyzed EDCs in breast milk samples collected from 50 women in Seattle, Washington during 2019, including melamine, cyanuric acid, ammeline, ammelide, bisphenol A (BPA), 4-hydroxyphenyl sulfone (BPS), 4,4'-methylenediphenol, (4,4'-hexafluoroisopropylidene) diphenol, fluorene-9-bisphenol, and triclosan. We examined associations of infant age at sample collection and maternal characteristics with log10-transformed chemical concentrations using linear regression. Estimated daily intake (EDI) of each chemical through breast milk was calculated for infants 0-12 months old using our sample median chemical concentrations.

RESULTS: We frequently detected (62-92%) melamine, cyanuric acid, BPA, BPS, and triclosan in breast milk. Median concentrations were 0.48 ng/mL melamine, 0.59 ng/mL cyanuric acid, 0.311 ng/mL BPA, 0.012 ng/mL BPS, and 0.072 ng/mL triclosan. Older infant age (>6 versus <6 months) was associated with lower melamine concentrations (-0.41, 95% CI: -0.80, -0.01). Maternal obesity was associated with higher BPA (0.68, 95% CI: 0.14, 1.23) and maternal overweight with higher triclosan (0.43, 95% CI: 0.06, 0.80). Other associations with participant characteristics were suggestive but not statistically significant. EDIs for infants in the average exposure scenario ranged by infant age from 40.3 to 72.8 ng/kg-bodyweight/day for melamine and 86.5-156 ng/kg-bodyweight/day for BPA.

SIGNIFICANCE: We frequently detected melamine, cyanuric acid, BPA, BPS, and triclosan in breast milk. EDIs through breastfeeding were generally higher than for other exposure pathways (e.g., dermal uptake, dust ingestion or inhalation), and more work is needed to understand potential health effects of chronic infant exposures to even low levels of these ubiquitous chemicals through breast milk.

IMPACT: This study adds to the limited research to date on endocrine-disrupting chemicals in breast milk, exposure among nursing infants in the US, and differences by infant and maternal characteristics, to further inform cumulative exposure assessment in infants and regulatory thresholds. Melamine, cyanuric acid, BPA, BPS, and triclosan were detected with high frequency in breast milk samples in our study, and our study suggests that breast milk is an important exposure pathway for these chemicals among nursing infants. Given the importance of breastfeeding for infant health, our study highlights the need to investigate potential health effects of these chronic exposures.

PMID:42045583 | DOI:10.1038/s41370-026-00844-z

J Expo Sci Environ Epidemiol. 2026 May;36(3):550-558. doi: 10.1038/s41370-026-00844-z. Epub 2026 Apr 27.

ABSTRACT

BACKGROUND: Breastfeeding can be a source of exposure to endocrine-disrupting chemicals (EDCs) for infants, but limited information exists on exposure to commonly used chemicals such as melamine and bisphenols in nursing infants in the US.

OBJECTIVE: We aimed to measure a suite of EDCs in breast milk and evaluate exposure of nursing infants to these chemicals.

METHODS: We analyzed EDCs in breast milk samples collected from 50 women in Seattle, Washington during 2019, including melamine, cyanuric acid, ammeline, ammelide, bisphenol A (BPA), 4-hydroxyphenyl sulfone (BPS), 4,4'-methylenediphenol, (4,4'-hexafluoroisopropylidene) diphenol, fluorene-9-bisphenol, and triclosan. We examined associations of infant age at sample collection and maternal characteristics with log10-transformed chemical concentrations using linear regression. Estimated daily intake (EDI) of each chemical through breast milk was calculated for infants 0-12 months old using our sample median chemical concentrations.

RESULTS: We frequently detected (62-92%) melamine, cyanuric acid, BPA, BPS, and triclosan in breast milk. Median concentrations were 0.48 ng/mL melamine, 0.59 ng/mL cyanuric acid, 0.311 ng/mL BPA, 0.012 ng/mL BPS, and 0.072 ng/mL triclosan. Older infant age (>6 versus <6 months) was associated with lower melamine concentrations (-0.41, 95% CI: -0.80, -0.01). Maternal obesity was associated with higher BPA (0.68, 95% CI: 0.14, 1.23) and maternal overweight with higher triclosan (0.43, 95% CI: 0.06, 0.80). Other associations with participant characteristics were suggestive but not statistically significant. EDIs for infants in the average exposure scenario ranged by infant age from 40.3 to 72.8 ng/kg-bodyweight/day for melamine and 86.5-156 ng/kg-bodyweight/day for BPA.

SIGNIFICANCE: We frequently detected melamine, cyanuric acid, BPA, BPS, and triclosan in breast milk. EDIs through breastfeeding were generally higher than for other exposure pathways (e.g., dermal uptake, dust ingestion or inhalation), and more work is needed to understand potential health effects of chronic infant exposures to even low levels of these ubiquitous chemicals through breast milk.

IMPACT: This study adds to the limited research to date on endocrine-disrupting chemicals in breast milk, exposure among nursing infants in the US, and differences by infant and maternal characteristics, to further inform cumulative exposure assessment in infants and regulatory thresholds. Melamine, cyanuric acid, BPA, BPS, and triclosan were detected with high frequency in breast milk samples in our study, and our study suggests that breast milk is an important exposure pathway for these chemicals among nursing infants. Given the importance of breastfeeding for infant health, our study highlights the need to investigate potential health effects of these chronic exposures.

PMID:42045583 | DOI:10.1038/s41370-026-00844-z

Am J Kidney Dis. 2026 Mar 30:S0272-6386(26)00823-1. doi: 10.1053/j.ajkd.2025.11.017. Online ahead of print.

ABSTRACT

Individuals are increasingly exposed to a diverse array of chemicals through the environment, consumer products, and occupational settings. These exposures, often involving substances with unknown or emerging implications for human health, may pose significant kidney health risks because many are processed by the kidneys and excreted in the urine. Kidneys are particularly vulnerable to injury from inorganic chemicals such as lead, cadmium, and mercury. These originate from geogenic sources, but their exposures are multiplied by anthropogenic activities. Emerging data detail possible kidney risks from chemicals derived entirely from anthropogenic activities as well such as from per- and polyfluoroalkyl substances (PFAS), melamine, and agrochemicals. Chronic kidney disease resulting from these environmental exposures is likely underdiagnosed in clinical practice. This review describes the sources of exposure, systemic effects, and potential nephrotoxicity of implicated chemicals, aiming to increase the recognition of environmental exposures as contributors to unexplained new kidney disease. A thorough exposure history and specialized laboratory evaluation may be used for diagnosis in high-risk individuals. Increased clinical awareness and dedicated research efforts are essential to understand and mitigate environmental nephrotoxic exposures and protect kidney health.

PMID:41921740 | DOI:10.1053/j.ajkd.2025.11.017

Anal Methods. 2026 Apr 2;18(13):2622-2631. doi: 10.1039/d6ay00268d.

ABSTRACT

Zearalenone (ZEA) is a toxic compound produced by fungal metabolism, which possesses mutagenicity, teratogenicity, carcinogenicity, nephrotoxicity, immunotoxicity, and genotoxicity, posing a serious potential threat to human and animal health. Therefore, establishing a rapid and accurate detection method for ZEA residues in food is of great significance for ensuring food safety. In this work, a hydrogen-bonded organic framework (HOF) was synthesized via self-assembly using melamine and trimesic acid as building units, followed by doping with rare earth metal europium ions (Eu³⁺) to successfully prepare a europium-functionalized HOF fluorescent sensor (Eu@HOF-TMA) with excellent stability. Eu@HOF-TMA exhibited a specific ratiometric fluorescent response to ZEA. As the ZEA concentration increased, the fluorescent color of the sensor gradually changed from red to blue. Eu@HOF-TMA exhibited a limit of detection as low as 0.57 µM for ZEA, with a response time of less than 30 s, which represents the fastest-response sensor for ZEA reported to date. Moreover, Eu@HOF-TMA could realize quantitative detection of ZEA in corn flour and drinking water with good recovery rates, indicating its excellent potential for practical application. Furthermore, relying on the significant change in fluorescent color of Eu@HOF-TMA after interaction with ZEA, a portable and instrument-free visual detection method for ZEA was constructed using a smartphone RGB color recognition software. Consequently, this work successfully prepared an Eu-HOF ratiometric fluorescent sensor, which provides a new strategy for the sensitive, rapid, and portable detection of ZEA and can be effectively applied to the analysis of ZEA residues in real food samples.

PMID:41847983 | DOI:10.1039/d6ay00268d

Anal Chim Acta. 2026 May 1;1397:345281. doi: 10.1016/j.aca.2026.345281. Epub 2026 Feb 20.

ABSTRACT

BACKGROUND: Ensuring the safety of dairy products requires rapid, sensitive, and cost-effective detection of chemical contaminants.

RESULTS: We developed a green and versatile plasmonic aerogel SERS substrate via covalent cross-linking of κ-carrageenan and dialdehyde cellulose (DAC), decorated with in situ-synthesized silver nanoparticles (Ag NPs). The aerogel exhibits a hydrothermal-responsive structural transition: its 3D porous network enables efficient adsorption of contaminants in aqueous phase, while thermal drying induces a controlled collapse into a 2D layered configuration, uniformly aggregating Ag NPs and generating high-density electromagnetic hotspots. This enables ultrasensitive SERS detection with excellent reproducibility and stability. Detection limits for melamine (Mel) and thiram (TH) in milk are 53 μg/L and 75 μg/L, respectively, and 87 μg/L for Mel in milk powder.

SIGNIFICANCE: These detection limits meet regulatory requirements (EFSA: Mel/TH ≤ 1 mg/kg; Chinese Standard: Mel ≤1 mg/kg, TH ≤ 2 mg/kg). Real milk samples achieved recoveries of 97.6-107.1% (Mel) and 96.3-105.6% (TH), demonstrating high accuracy and reliability. The entire process is completed within 30 min, offering operational simplicity, low cost, environmental friendliness, and a promising platform for on-site monitoring of chemical contaminants in dairy products.

PMID:41796500 | DOI:10.1016/j.aca.2026.345281

ACS Omega. 2026 Feb 11;11(7):12697-12712. doi: 10.1021/acsomega.5c13107. eCollection 2026 Feb 24.

ABSTRACT

In this work, an analytical approach combining voltammetric detection with chemometric analysis was developed to discriminate melamine and urea adulterants in milk products. The electrochemical measurement was performed using a glassy carbon electrode (GCE) modified with acid-functionalized multiwalled carbon nanotubes (f-MWCNTs), which served as the working electrode to obtain the voltammetric fingerprint. This electrode was used to measure the voltammetric response of fresh cow milk adulterated with melamine and urea in 0.1 M KCl as the electrolyte by employing cyclic voltammetry (CV). Based on this result, milk adulterated with melamine and urea displayed broad peaks in the potential range of 0.6-0.8 V versus Ag/AgCl, attributable to the electroactive components in the adulterants and the milk. Additionally, it was found that milk adulterated with melamine exhibited several reduction peaks in the potential range from -0.4 to 0 V versus Ag/AgCl, corresponding to the reduction reaction of components present in melamine. Further chemometric analysis, i.e., principal component analysis, effectively distinguishes cow milk adulterated with melamine and urea. Moreover, the discrimination between cow's milk and its adulterants was successfully achieved using hierarchical cluster analysis, with the lowest melamine concentration detected at 0.24%. Quantitative estimates of milk adulterants were predicted using partial least-squares regression, as determined by root-mean-square error cross-validation (RMSECV), with melamine at 0.0755% and urea at 0.0064%. Therefore, this result demonstrates a promising, cost-effective analytical technique that can be further developed into a novel approach for detecting adulterants in dairy products for practical applications.

PMID:41768680 | PMC:PMC12947226 | DOI:10.1021/acsomega.5c13107

Biosensors (Basel). 2026 Feb 2;16(2):92. doi: 10.3390/bios16020092.

ABSTRACT

The precise and reliable detection of milk adulterants has garnered increased scientific interest owing to the rising incidence of food fraud. Recent years have witnessed substantial advancements in optical and electrochemical biosensors for the quick, sensitive, and on-site determination of adulterants. This review thoroughly emphasizes recent developments in electrochemical biosensors, encompassing amperometric, voltammetric, impedimetric, and photoelectrochemical sensors, alongside optical biosensors such as colorimetric, fluorometric, and plasmonic systems. Significant focus is directed towards determination of critical milk adulterants, including variations in pH, urea, formaldehyde (FA), melamine (MEL), nitrates (NO₃^-), nitrites (NO₂^-), and sulfites (SO₃^2-). The sensing mechanisms, functional nanomaterials, analytical efficacy, and sample-handling techniques of the described biosensors are critically examined. Moreover, key challenges regarding matrix interference, sensor stability, reproducibility, regulatory validation, and large-scalability are addressed. Ultimately, future directions towards economical, portable, wearable, and Internet of Things (IoT)-integrated biosensors for continuous dairy monitoring are discussed, highlighting the necessity for standardized validation protocols and next-generation technologies in food safety.

PMID:41744710 | PMC:PMC12937801 | DOI:10.3390/bios16020092

Antioxidants (Basel). 2026 Jan 17;15(1):122. doi: 10.3390/antiox15010122.

ABSTRACT

Melamine, a nitrogen-rich industrial chemical, has raised increasing concern as an emerging environmental contaminant with potential reproductive toxicity. While its nephrotoxic effects are well established, the direct impact of melamine on human sperm remains poorly defined. In this study, we investigated the in vitro effects of melamine on human sperm, under both capacitating and non-capacitating conditions. Functional analyses revealed that the exposure to 0.8 mM melamine, the highest non-cytotoxic concentration in vitro, significantly compromised sperm motility and disrupted key capacitation processes, including tyrosine phosphorylation patterns, cholesterol efflux, and the acrosome reaction. Molecular assessments demonstrated melamine-induced mitochondrial dysfunction, characterized by COX4I1 downregulation, reduced mitochondrial membrane potential, and altered reactive oxygen species production. In parallel, gene expression analyses revealed the activation of apoptotic pathways, with the upregulation of BAX and downregulation of BCL2, changes that were more pronounced during capacitation. Furthermore, melamine exposure significantly increased sperm DNA fragmentation and denaturation, indicating genotoxic stress. Collectively, these findings demonstrate that even low, non-cytotoxic concentrations of melamine compromise sperm function by disrupting capacitation, mitochondrial activity, and genomic integrity. This study identifies capacitation as a critical window of vulnerability and underscores the need to consider melamine as a potential environmental risk factor for male reproductive health.

PMID:41596180 | PMC:PMC12837316 | DOI:10.3390/antiox15010122

Materials (Basel). 2026 Jan 8;19(2):267. doi: 10.3390/ma19020267.

ABSTRACT

In the article we investigated the effectiveness of a synergistic system designed to reduce the fire hazard of flexible polyurethane (PUR) foams. The examined system consisted of a carbon-based filler graphene (G), carbon nanotubes (CNTs), or expanded graphite (EG) combined with melamine polyphosphate (MPP). The investigated polyurethane foams (PUR) were synthesized at room temperature via a polycondensation reaction between a polyol and an isocyanate, with an OH: NCO molar ratio of 2:1. Both the carbon fillers and melamine polyphosphate were homogeneously dispersed within the polyol component. Thermogravimetric analysis (TGA), cone calorimetry, and microcalorimetry were used to evaluate the influence of the fillers on the thermal stability and flammability of the PUR foams. The toxicity of the gaseous products was assessed using a coupled TG-gas analysis system, while the optical density of the evolved gases was determined using a Smoke Density Chamber (SDC). The obtained results demonstrated that the applied synergistic carbon-phosphorus filler system significantly reduced the fire hazard of the tested PUR foams. In particular, the EG5-MPP system enabled the formation of self-extinguishing materials.

PMID:41597978 | PMC:PMC12843171 | DOI:10.3390/ma19020267

Compr Rev Food Sci Food Saf. 2026 Jan;25(1):e70403. doi: 10.1111/1541-4337.70403.

ABSTRACT

Milk and milk powder are central to global nutrition, yet remain vulnerable to adulteration and contamination. Adulteration using water, urea, ammonium sulfate, thiocyanates, detergents, melamine, or compositional changes with whey and carbohydrate fillers undermines nutritional quality, reduces consumer confidence, and challenges regulatory control, particularly in infant formula products. A field-ready analytical platform that is rapid, nondestructive, and capable of multi-adulterant surveillance is urgently needed across diverse dairy matrices. This review consolidates advances in Raman spectroscopy for milk and milk powder authentication reported from 2015 to early 2025, covering conventional Raman, surface-enhanced Raman spectroscopy (SERS), Fourier-transform Raman, hyperspectral Raman imaging, confocal/mapping approaches, and portable systems. We critically evaluate preprocessing and chemometrics such as principal component analysis, partial least squares regression, and partial least squares discriminant analysis, as well as machine-learning and deep-learning pipelines for classification and quantification. Species-specific applications including cow, buffalo, goat, camel, donkey, human breast milk (macronutrients, sex-linked profiles, microplastics, antibiotics), and milk powder workflows are compared with attention to matrix effects, fluorescence interference, and validation practices. Raman enables chemically specific fingerprints of proteins, lipids, and carbohydrates, whereas common adulterants present diagnostic bands. SERS substrates routinely extend sensitivity to ppm-ppb levels and suppress fluorescence, supporting rapid detection of melamine, urea, ammonium sulfate, thiocyanates, benzoate, and selected antibiotics. Hyperspectral imaging provides spatially resolved maps, differentiating multi-adulterant mixtures and thermo-structural behavior in powders. Chemometric models achieve high accuracy for classification and concentration prediction, whereas deep-learning architectures improve robustness under nonlinear matrix variation and instrument drift. Challenges persist in substrate reproducibility, calibration transfer, fluorescence in lipid-rich systems, and detection of emerging adulterants and trace preservatives under field conditions. Future progress will hinge on multi-excitation instruments with adaptive laser power control, universal SERS substrates integrating plasmonic metals, dielectric shells, and molecular recognition, and standard operating procedure grade preprocessing. Industrial reliability requires calibration-transfer strategies, rigorous validation, and explainable artificial intelligence to link decisions to chemically meaningful features, supporting regulatory acceptance and auditability. Portable Raman and SERS systems can aid nutritional profiling and contaminant surveillance in breast milk, whereas Fourier-transform Raman and hyperspectral imaging mitigate fluorescence and map heterogeneity in powders. Raman spectroscopy, augmented by SERS, hyperspectral imaging, and intelligent analytics, offers a rapid, nondestructive, label-free, and scalable platform for dairy authentication. Continued innovation will enable real-time, on-site detection of single and multiple adulterants, strengthening consumer confidence, industrial quality assurance, and regulatory compliance while advancing global food safety.

PMID:41578976 | PMC:PMC12831472 | DOI:10.1111/1541-4337.70403

Arch Toxicol. 2026 Apr;100(4):1551-1564. doi: 10.1007/s00204-025-04289-5. Epub 2026 Jan 17.

ABSTRACT

Either melamine or cyanuric acid alone has low toxicity, but melamine-cyanuric acid crystals co-crystals melamine cyanurate (MC) is reported to cause renal toxicity and has latent effects on central nervous system. This study investigated the neurotoxic effects and mechanism of MC on hippocampus-dependent cognitive and synaptic function using a rat model administered MC during early postnatal stage. We tested the spatial learning and memory ability in Morris water maze (MWM) test and recorded hippocampal long-term potential (LTP) at CA1 synapses. Furthermore, we examined whether autophagy was involved in MC-induced cognitive, synaptic and oxidative damages. We found that MC given at a dose of 30 mg/kg/day for 28 consecutive days significantly impaired spatial performance without affecting locomotion or short-term memory ability. Hippocampal LTP at Shaffer-collateral-CA1 synapses was dramatically depressed while the presynaptic form of synaptic plasticity paired-pulse facilitation (PPF) and basal neurotransmission were not changed. Meanwhile, MC declined the expression postsynaptic GluN2A but not GluN2B subunits of N-methyl-D-aspartate (NMDA) receptors and the postsynaptic density protein 95 (PSD-95) level was also reduced. Autophagy in the hippocampus was down-regulated by MC, as indicated by reduction in the levels of Beclin-1and LC3-II, and the ratio of LC3II/LC3I. However, up-regulation of autophagy by rapamycin could effectively alleviate cognitive deficits and synaptic dysfunction. Meanwhile, retrieval of autophagic activity restored oxidation-antioxidation homeostasis, by elevating MC-declined superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) and suppressing MC-enhanced superoxide anion radical, hydroxyl free radical and malondialdehyde (MDA). Additionally, MC elevated the caspase-3 activity and caused the apoptotic cell death, which was mitigated by rapamycin treatment. However, inhibition of autophagy further deteriorated MC-induced these impairments. Therefore, we demonstrate that MC induces cognitive impairments at least due to oxidative damage and synaptic dysfunction through postsynaptic actions, which can be further attributed to the down-regulation autophagy.

PMID:41545533 | DOI:10.1007/s00204-025-04289-5