In this study, we investigate the metabolic profile of strychnine in human urine following controlled administration using liquid chromatography-quadrupole-Orbitrap mass spectrometry. A total of 25 metabolites were characterized and identified. These included 21 previously unreported and 4 previously reported metabolites. Four unreported metabolic pathways were discovered, namely, reduction, methylation, glycosylation, and glucuronidation. Among these, hydroxylation was identified as the major metabolic pathway. The detection windows in the urine for all 25 metabolites were compared with that of the parent drug. Metabolite S10 (2,3-dimethoxy-strychnine) was proposed as a novel potential biomarker for strychnine misuse, rather than strychnine itself, due to its longer detection time and higher number of strychnine-positive time points (exceeding 50 ng/mL in human urine) compared to the parent compound after oral administration. The identification of S10 extends the detection window and offers critical insights for doping control applications.

Ligand-engineered hollow Fe-NC nanozymes with enhanced peroxidase activity for smartphone-based point-of-care testing of isoniazid.

1H-qNMR analysis of human urine: Validation of an external standard approach for absolute metabolite quantitation.

Pharmaceutical residues, particularly urinary analgesics and their metabolites, are emerging contaminants that pose potential environmental and health risks. This study reports the synthesis of a novel nanocomposite (GOHD) obtained by citric acid crosslinking of H. dulcis with PCT, and its application for adsorbing PhP and PCT from fresh synthetic and real human urine. The material was characterized using various characterization techniques, indicating the formation of a heterogeneous, mesoporous structure with the presence of different functional groups. Adsorption studies revealed that GOHD reached a maximum capacity of 204.82 mg g −1 at the lowest dosage (0.125 g L −1 ). PhP uptake was favored at pH 5.0, and the general-order model well described the kinetic data. Equilibrium analysis revealed that the Freundlich isotherm effectively described the data. At the same time, the M5 statistical physics model provided a deeper interpretation, indicating the presence of two to three adsorption layers with a parallel molecular arrangement ( n < 0.5). Thermodynamic parameters confirmed that the process was spontaneous, exothermic, and governed by weak interactions ( Δ G < 0, Δ H = −12.74 kJ mol −1 ). This is corroborated by the adsorption energy values, which confirm the occurrence of physisorption. In the binary system, GOHD showed high selectivity for PhP, increasing its removal to 80.98% ( q e = 100.73 mg g −1 ), while PCT removal decreased to 11.86% ( q e = 3.75 mg g −1 ), evidencing competitive adsorption. In human urine, PhP removal reached 14.29% ( q e = 29.39 mg g −1 ), whereas PCT adsorption was not observed. The adsorption energy obtained by DFT ( E ads = 49.3 kJ mol −1 ) corroborates the statistical physics energies for the first adsorption layer Δε₁ = 8.27–13.73 kJ mol −1 ), confirming stable, surface-confined adsorption dominated by strong physical interactions. DFT calculations revealed that PhP exhibits higher chemical softness (η = 1.64 eV), electrophilicity (ω = 4.36 eV), and a lower HOMO–LUMO gap (3.27 eV) than PCT, explaining its stronger affinity and preferential adsorption on GOHD. These findings demonstrate that GOHD is a promising, sustainable adsorbent for the adsorption of PhP. • Hovenia dulcis croslinked graphene oxide for drug adsorption in synthetic urine; • A maximum adsorption capacity of 204.82 mg g −1 for phenazopyridine (PhP); • The nanocomposite (GOHD) was selective for phenazopyridine.

Leveraging micro-disk array device for sensitive duloxetine detection in human urine.

An eco-friendly method is proposed to quantify lamotrigine (LTG) across multiple matrices using novel nitrogen-doped carbon dots (N-CDs) derived from Brassica rapa greens via microwave synthesis. These N-CDs exhibit intense fluorescence and excellent water solubility. Their properties were characterized using transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), zeta potential analysis (ζ), Fourier-transform infrared (FTIR), ultraviolet (UV)-visible, and fluorescence spectroscopy. The sensor's stability was evaluated across different conditions. LTG quenched the fluorescence of N-CDs via an inner filter effect. The method demonstrated linearity over the LTG concentration range of 2.0-100.0 μM. The limit of detection (LOD) and limit of quantification (LOQ) were 0.23 and 0.70 μM, respectively. The technique was utilized to quantify LTG in urine and pharmaceutical tablets, with average recovery percentages of 99.62% ± 1.94% and 100.38% ± 1.3%, respectively. The approach was validated with International Council for Harmonization (ICH) guidelines and evaluated for greenness, blueness, redness, and sustainability. The method demonstrates excellent greenness and blueness scores. The good Red Analytical Procedure Index (RAPI) score indicates the method's high precision. The Sustainability of Analytical Methods Index (SAMI) diagram indicates favorable sustainability performance across the Sustainable Development Goals (SDGs).

A versatile colorimetric array sensor based on FeCu-based prussian blue analogue heterostructures for efficient discrimination of tetracycline antibiotics and rapid identification of urinary tract infection pathogens.

Metabolite patterns in human urine after oral administration of highly purified Δ8-THCV.

Sake, a fermented alcoholic beverage made from rice and Aspergillus oryzae through microbial fermentation, contains thiol compounds that are the primary source of its distinctive sweet aroma. However, to date, there has been no report on the detection of chiral thiol compounds in sake. This study introduces a novel UHPLC-HRMS method utilizing the (R)-(5-(3-isothiocyanatopyrrolidin-1-yl)-5-oxopentyl) triphenylphosphonium (NCS-OTPP) chiral mass spectrometry probe for the simultaneous detection of five DL-thiol compounds in sake. Separation was achieved using a YMC Triart C18 column (2.0 × 150 mm, 1.9 μm), employing an isocratic elution method to isolate DD/LL-GSH, γ-L-Glu-L-Cys, DL-Cys, DL-Hcy, and DL-Ac-Cys. The method demonstrated excellent linearity (R2 ≥ 0.9992), intraday precision (0.43%-13.18%), and an average recovery rate of 91.62%-110.40%. A comparative analysis of DL-thiol compound content in seven different types of sake from various countries and manufacturers revealed the presence of five chiral thiol compounds-LL-GSH, γ-L-Glu-L-Cys, DL-Cys, DL-Hcy, and L-Ac-Cys-across Japanese and Korean sake, with L-Cys being the most abundant and D-Ac-Cys the least. Notably, γ-L-Glu-L-Cys was detected only in two types of Korean sake and absent in Japanese sake. Additionally, the study investigated the metabolic kinetics of chiral thiol compounds in human urinary specimens after alcohol ingestion, constructing a metabolic fitting curve. The peak concentrations of DL-Cys, DL-Hcy, and LL-GSH were attained 15 min following consumption, with slow clearance, returning to baseline at 60 min. The metabolic fitting curve effectively captures the dynamic changes in urinary metabolism. This research presents a new method for detecting chiral thiol compounds in sake and monitoring urinary metabolism after alcohol consumption.

Nemonoxacin, a novel non-fluorinated quinolone, is approved for community-acquired pneumonia, but its efficacy against uncomplicated urinary tract infections (uUTIs) caused by Escherichia coli (E. coli) is uncertain. We aimed to establish an in vitro uUTIs model simulating urinary concentrations to evaluate dosing regimens. An in vitro model was developed using cation-adjusted Mueller-Hinton broth (CAMHB) and synthetic human urine (SHU) to reproduce urinary exposure. The model was applied to 12 E. coli clinical isolates and ATCC 25922 (MICs <0.03 to >512 mg/L) over 24 h. The effects of medium type on MICs and bacterial growth were assessed. Pharmacokinetics/pharmacodynamics (PK/PD) relationships were described using a sigmoid Emax model, with change in bacterial density (Δlog10 CFU/mL) and the area under the bacterial kill curve (AUBKC) as efficacy endpoints. Monte Carlo simulation (MCS) estimated the probability of target attainment (PTA) and cumulative fraction of response (CFR) for 500 mg and 750 mg once-daily regimens. Nemonoxacin MICs were higher in SHU, and bacterial growth showed early inhibition. The AUC0-24/MIC ratio best correlated with antibacterial effect (R² = 0.951 in CAMHB; 0.982 in SHU). For a 1-log CFU reduction, AUC0-24/MIC targets were 46.5 in CAMHB and 199 in SHU. The 500 mg regimen achieved ≥90% PTA for isolates with MIC ≤ 16 mg/L (CFR 92.1%) using CAMHB-derived targets but only ≤8 mg/L (CFR 59.4%) in SHU. A 500 mg once-daily regimen of nemonoxacin appears to be a promising therapeutic option for the treatment of uUTIs, although further clinical studies are necessary to validate these findings.

Urinary tract infections (UTIs) impose a large healthcare burden, with escalating antimicrobial resistance (AMR), and treatment failure. Proteus mirabilis is an undercharacterized and challenging UTI pathogen due to intrinsic resistance and biofilm formation. To understand P. mirabilis population genomics, we combined pangenome analysis, in silico AMR prediction, and phenotypic antimicrobial susceptibility testing (AST) across 1,027 P. mirabilis genomes derived from human urine specimens. This revealed a mosaic pangenome driven by extensive accessory genome plasticity. Multilocus sequence typing (MLST) identified 213 MLSTs, with only 7% having ≥10 genomes, highlighting strain diversity. AMR gene profiles were largely lineage-specific, with 25% of genomes harboring resistances for >6 antimicrobial subclasses. ST135 was identified as a highly MDR lineage, with 95% of genomes carrying ≥16 resistance genes. Mobile genetic element (MGE) analysis of 22 clinical isolates with complete, reference-level genomes revealed that Tn7 transposons, IS26-mediated genomic islands, and class 1 integrons act as vehicles for high AMR gene dissemination, including IS26-mediated gene stacking within a P. mirabilis Genomic Resistance Island 1 (PmGRI1) in ST135 isolates. While the presence of genes like aph(3')-la reliably predicted kanamycin resistance, discordance for antibiotics such as trimethoprim-sulfamethoxazole and chloramphenicol revealed that AMR gene stacking, regulatory context, and intrinsic mechanisms, like efflux pumps, modulate phenotypic outcomes. In summary, our study provides a comprehensive and phenotypic resolution of P. mirabilis AMR, establishing that resistance architecture is lineage-structured, MGE-driven, and phenotypically non-deterministic. We emphasize the need to shift toward a standardized, genome-informed surveillance framework to translate into diagnostic and therapeutic strategies.

N-Nitrosamines (NAms) are potent carcinogenic and mutagenic contaminants that may originate from both exogenous exposure and endogenous nitrosation. Human urine is an important non-invasive matrix for biomonitoring NAms exposure; however, the trace concentrations of these compounds and the complexity of the urinary matrix require highly sensitive and selective analytical methods. In this study, a highly automated method based on solid-phase extraction (SPE) coupled with gas chromatography-triple quadrupole tandem mass spectrometry (GC-MS/MS) was developed for the simultaneous determination of eight NAms in urine. By optimizing the SPE sorbent, sample loading strategy, and elution conditions, efficient enrichment and cleanup of the target compounds were achieved using only 4 mL of urine. The automated SPE procedure reduces manual handling, improves sample-preparation reproducibility, and enhances operational efficiency. Method validation showed the recoveries of 80.68% to 111.33%, with intra-day and inter-day precisions (RSDs) below 5.59% and 7.72%, respectively. The limits of detection (LOD) ranged from 0.00335 to 0.01 µg L-1. The method was applied to 60 urine samples from a community-based population, in which NDMA and NPYR showed the highest detection frequencies. These results indicate that the method is sensitive, repeatable, and analytically stable, and is suitable for biomonitoring trace-level human exposure to NAms.

The increasing demand for portable, low-cost, and sustainable analytical methodologies has motivated the development of miniaturized electrochemical systems for pharmaceutical and clinical monitoring. In this work, an electrochemical method based on screen-printed carbon electrodes and nickel oxide-modified SPCE was optimized for the voltammetric determination of acetaminophen in pharmaceutical formulations and human urine using the DropSens configuration. Square-wave voltammetry, selected for its sensitivity and suitability for on-site analysis, enabled reliable quantification under alkaline conditions (pH 9.5). Both electrode types provided detection limits in the low-ppm range and broad linearity. Precision values varied depending on the matrix and electrode type, with RSDs generally below 20%. Accuracy ranged from 87 to 108% in drug formulations and exceeded 90% in urine samples. The DropSens platform produced analytical results comparable to those obtained with a conventional electrochemical cell while reducing sample and reagent consumption. Method validation for urine analysis was performed using in-tube solid-phase microextraction coupled to nano liquid chromatography with diode-array detection, which confirmed the reliability of the voltammetric method. Excretion profiles obtained by the proposed electrodes closely matched chromatographic data, with differences below 1% at the main excretion maxima (2 and 6 h after administration). Overall, the proposed miniaturized electrochemical approach provides a rapid, accurate, and sustainable alternative for the determination of acetaminophen in complex biological matrices, offering significant advantages in terms of portability, operational simplicity, and alignment with green analytical chemistry principles. The HEXAGON tool was used to support this last statement.

Reactive carbonyl species (RCS) are highly reactive molecules linked to chronic diseases. Dihydromyricetin (DMY), a high-activity RCS scavenger, exhibited MGO- and ACR-scavenging rates of 70.1% (0.5 h) and 70.3% (2 h) at 37 °C, respectively. Multiple RCS-DMY adducts were characterized using UPLC-MS/MS, and DMY-2MGO-1 and DMY-2ACR-1 were synthesized. RCS adducts formed by DMY and its six degradation products were semiquantified in a DMY-Δ + RCS model system and in human urine and fecal samples after consuming hot-brewed (3 g) and cold-brewed (3 and 6 g) vine tea as DMY carriers. A dose-dependent increase in RCS-adduct excretion was observed in the cold-brewed tea groups, while hot-brewed tea contributed to RCS-scavenging via DMY degradation products (13.5%). No significant difference in RCS-adduct levels was found between the cold-brewed (6 g) and hot-brewed (3 g) tea groups. Overall, these findings suggest that DMY and vine tea are effective RCS scavengers.

Herein, we report for the first time the exploration of PVP-modulated copper sulfide for a high-performance electrochemical nonenzymatic sensor for noninvasive creatinine sensing. A controlled coprecipitation route in the presence of polyvinylpyrrolidone (PVP) yields phase-pure Cu7S4, while synthesis without PVP results in a heterogeneous mixture of Cu6S6, Cu7S4, and secondary phases (CuxS). Electrochemical evaluation by cyclic voltammetry demonstrates that the phase-engineered PVP-modulated Cu7S4 sensor exhibits a stable, well-defined cathodic complexation response, in contrast to CuxS-based sensor. Mechanistic understanding was further advanced through high-resolution XPS at potentials associated with redox transitions and Copper-Creatinine complexation, confirming the role of surface Cu2+ species and the C═N group of creatinine in facilitating electron transfer. The sensor demonstrated exceptional analytical figures of merit, including a wide linear range of 0-300 μM, encompassing the entire physiological and pathological range, a low detection limit of 1.196 μM, and a high sensitivity of 541.83 μA mM-1 cm-2. Furthermore, the sensor exhibited splendid specificity, effectively mitigating uric acid interference through simple 100-fold dilution, and maintained remarkable stability with a 96.68% signal retention over 26 days. Crucially, validation using clinical human urine samples showed excellent agreement with the gold standard test (P > 0.05). The PXRD, FTIR, Raman spectroscopy, UV-visible, FESEM, HR-TEM, Zeta potential, and XPS were performed for comprehensive material characterization, which revealed crucial phase engineering and functionalization influencing electrocatalytic activity. This study establishes phase-engineered PVP-modulated Cu7S4 as a robust and reproducible nonenzymatic sensing material offering mechanistic insights that can guide the design of next-generation point-of-care creatinine sensors.

High-resolution mass spectrometry (HRMS) is the gold-standard technique for comprehensively profiling chemical exposures in complex human matrices, making it a powerful analytical tool for advancing human exposome research. Yet the scarcity of HRMS reference data, including collision cross-section (CCS) measurements from ion mobility-mass spectrometry (IM-MS) and MS/MS fragmentation spectra, hinders confident structural annotation of chemical exposure agents across laboratories. We therefore developed ToxBase, a multidimensional (m/z, retention time, CCS, MS/MS) reference database for over 2,000 chemicals sourced from the U.S. Environmental Protection Agency's ToxCast chemical library. Built via high-throughput liquid chromatography-ion mobility-tandem mass spectrometry (LC-IM-MS/MS), the ToxBase database comprises 3,598 precursor ions spanning 2,075 unique compounds with excellent precision (98.5% of compounds display interday CCS RSDs < 1%) and strong cross-platform agreement. A high-quality MS/MS reference library of the fragmented precursors was assembled using targeted data-dependent acquisition and DDARawProcessor, a novel data extraction algorithm. When applied to LC-IM-MS/MS data obtained from human plasma, urine, and fecal samples (n = 20 per matrix), ToxBase rapidly enabled 42 high-confidence (Level 1) identifications. The ToxBase database is freely available and compatible with the open-source MS data processing platform Skyline for vendor-agnostic suspect screening workflows, providing a valuable resource for standardized, large-scale exposome analysis.

Tofacitinib is a potent Janus kinase inhibitor widely used in the treatment of various autoimmune diseases, including rheumatoid arthritis and psoriasis. Monitoring its concentration is vital for therapeutic efficacy and safety. In this study, a novel, rapid, and highly sensitive electrochemical sensing platform was developed for tofacitinib determination using pencil graphite electrodes (PGEs) modified with polypyrrole (PPy) and calix-[n]-arene derivatives. The modified electrodes were prepared via cyclic voltammetry (CV) by incorporating three different macrocycles: calix[4]-arene, calix[6]-arene, and calix[8]-arene. Surface characterization was performed using Scanning Electron Microscopy (SEM) and SEM-EDS. Under optimized conditions (Britton-Robinson buffer at pH 4.0, 5 polymerization cycles, and 0.005 M modifier concentration), tofacitinib was quantified using differential pulse voltammetry (DPV). The linear calibration ranges were established as 0.10-0.80 ppm for calix[4]-arene and calix[6]-arene, and 0.10-0.60 ppm for calix[8]-arene. The limits of detection (LOD) were found to be 0.0275, 0.0212, and 0.0184 ppm for calix[4], [6], and [8] derivatives, respectively, demonstrating a clear correlation between macrocyclic cavity size and analytical sensitivity. The proposed sensor exhibited excellent selectivity in the presence of common interferents like ascorbic acid, caffeine, and glucose. Furthermore, the practical applicability of the method was validated in pharmaceutical formulations and human urine samples, yielding satisfactory recovery values between 98.0% and 101.5%. This study provides a cost-effective and disposable alternative to sophisticated chromatographic methods for routine clinical analysis.

Schistosomiasis remains a major public health concern in Nigeria. We molecularly characterized Schistosoma eggs obtained from human urine to identify species and assess the presence of hybrid schistosomes in Abuja, Nigeria. Urine samples were collected from 1887 participants aged five years and above. Samples were examined for Schistosoma eggs using light microscopy. A total of 507 (26.9%) were positive for any form of Schistosoma while 91 (4.8%) had atypical Schistosoma eggs. DNA extracted from pooled ova was analyzed using metagenomic sequencing, read mapping, phylogenetic analysis, and BLASTn confirmation. Molecular analyses identified genetic signatures associated with both S. haematobium and S. bovis within pooled human urine samples, indicating the co-circulation of multiple schistosome species in the study area. Phylogenetic analyses based on trans-ITS and mitochondrial COX1 markers supported the presence of distinct nuclear and mitochondrial schistosome lineages. However, because sequencing was performed on pooled egg samples, the findings cannot distinguish between true recombinants and mixed infections involving co-circulating parental species. These findings highlight the potential complexity of schistosome transmission dynamics in endemic communities and underscore the need for enhanced molecular surveillance, especially single-parasite genomic approaches, and integrated One Health investigations to better understand schistosome transmission and its implications for control and elimination efforts in Nigeria.

Quaternary ammonium compounds in paired indoor dust and human urine: suspect screening and exposure associations.

Rapid and selective detection of Gram-negative bacteria is important for clinical diagnosis and for monitoring environmental and food-related samples. In this study, we developed a label-free ISFET sensor based on a p-type silicon/SiO2 platform modified with ZnO and colistin for the detection of Gram-negative bacteria. The sensor was evaluated against several Gram-negative species, including Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii, Salmonella enterica serovar Enteritidis, Klebsiella oxytoca, and Klebsiella pneumoniae, with the Gram-positive species Staphylococcus aureus and Enterococcus faecium used as negative controls. The device showed measurable changes in drain-source current upon bacterial binding, and the standard curves indicated a low detection limit and a linear response within the tested concentration range. The calculated limits of detection were approximately 137 CFU/mL for E. coli, 169 CFU/mL for A. baumannii, 188 CFU/mL for S. enterica, 218 CFU/mL for K. oxytoca, 235 CFU/mL for K. pneumoniae, and 289 CFU/mL for P. aeruginosa. The sensor stability was also assessed over 14 days in the E. coli assay. In addition, real-sample experiments in commercial bottled drinking water and human urine spiked with E. coli showed good agreement with PBS measurements, with a recovery of 101.13% ± 3.08% and an RSD of 3.05% in bottled water. These results indicate that the proposed platform has potential for selective detection of Gram-negative bacteria under controlled laboratory conditions and in tested real matrices.