Organochlorine pesticide (OCP) 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 (Rt) 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.
Palatability has an impact on pediatric medication adherence, yet the influence of water dilution, PBS volume fraction, and salivary pH on the sensory performance of formulations is poorly characterized. This study provides the first systematic, biorelevant evaluation of how water dilution factor, PBS volume fraction, associated ionic strength change, and physiologically relevant pH affect the palatability of three commercially available hyoscine butylbromide (HBB) syrup brands (X, Y, and Z), extending earlier characterization of undiluted formulations. Samples were evaluated using an Alpha Astree II electronic tongue (ChemFET array. Water dilution (Batch B) and PBS volume fractions of 2 mL or 5 mL at pH 6.2, 6.8, and 7.4 within a fixed total measurement volume of 25 mL simulated salivary pH and ionic composition across the physiological range relevant to pediatric and adult populations. Pure HBB API solutions were tested in parallel. Principal component analysis (>85% cumulative variance) confirmed robust discrimination across all conditions. The water dilution factor increased bitterness for all brands by disrupting excipient matrix integrity, with cellulosic polymer-containing Brands X (HEC) and Y (HPMC) retaining superior taste masking over polymer-free Brand Z. The PBS volume fraction revealed pH-dependent, brand-specific palatability responses, at pH 6.2, 6.8, and 7.4, and the hierarchy was consistently Y > X > Z, confirming the superiority of the Brand Y formulation, combining HPMC with sodium cyclamate and saccharin sodium, across the full physiological salivary pH range, noting that this superiority reflects the broader excipient composition of Brand Y, rather than polymer choice alone. Notably, Brand X exhibited substantially higher ANS sweetness scores than Brand Y at 2 mL pH 7.4 PBS, reflecting differential sweetener system sensitivity to near-neutral PBS ionic conditions. Increasing the PBS volume fraction from 2 mL to 5 mL within a fixed total measurement volume of 25 mL, increased the ionic strength and pH contribution of the simulated salivary component, amplified bitterness and attenuated sourness across all brands, reflecting changes in the ionic environment at the ChemFET sensor membrane, rather than any increase in the intrinsic bitterness of HBB itself. Taste-masking strategies that rely solely on sweeteners, without viscosity-building polymers, are inadequate under biorelevant oral conditions. pH-stratified assessment is essential for comprehensive characterization of palatability in pediatric oral liquid formulations.
Semiconductors are regarded as promising alternatives to traditional noble metals for constructing surface-enhanced Raman scattering (SERS) substrates. Nevertheless, their sensitivity is insufficient for widespread practical applications. In this work, urchin-like tungsten oxide (WO3) nanostructures with different oxygen-vacancy contents are fabricated by tuning the solvothermal reaction temperature. Oxygen-vacancy-rich WO3 nanostructures display a broad localized surface plasmon resonance band, whose resonance maximum is centered at ~585 nm. Owing to the synergistic coupling of electromagnetic enhancement and interfacial charge transfer enhancement, the as-synthesized urchin-like WO3 nanostructures exhibit outstanding SERS sensing capability toward Rhodamine 6G molecules. The lowest detectable concentration of 1 × 10−7 M and a remarkable enhancement factor of 5.1 × 105 are achieved. The relative standard deviations below 6.5% are obtained, indicating outstanding signal uniformity of the WO3 SERS substrates. In addition, these urchin-like WO3 nanostructures can serve as SERS substrates for the detection of prohibited fishery drugs. This work offers a feasible strategy for fabricating high-performance semiconductor-based SERS platforms, and the plasmonic urchin-like WO3 nanostructures show great prospects for practical chemical sensing applications.
1-Aminopyrene, as a transformation product of the priority pollutant 1-nitropyrene, has raised increasing concerns due to its carcinogenic, mutagenic, and bioaccumulative properties in marine environments. A rapid and sensitive method for trace 1-aminopyrene detection in seawater is essential for marine environmental monitoring and public health protection. In this paper, a novel electrochemical immunosensor was fabricated based on an NH2-functionalized multi-walled carbon nanotubes-chitosan (NH2-MWCNTs/CS) nanocomposite film loaded with anti-1-aminopyrene antibody on a glassy carbon electrode. The NH2-MWCNTs/CS composite served as a conductive and biocompatible matrix that facilitated interfacial electron transfer and provided a suitable surface for adsorption-based antibody immobilization. Potassium ferricyanide was employed as an electrochemical probe to generate voltammetric signals, and the immune response was investigated by differential pulse voltammetry. Under optimized experimental conditions, the peak current change was inversely proportional to the 1-aminopyrene concentration in the range of 0.5 ng·mL−1 to 110 ng·mL−1, with a detection limit of 0.36 ng·mL−1. The immunosensor demonstrated good selectivity, stability, and anti-interference capability in complex sample matrices. It was successfully applied to the determination of 1-aminopyrene in real seawater samples, with recovery rates ranging from 97.53% to 99.30% and relative standard deviations below 0.92%. The results indicate that the proposed immunosensor offers a simple, cost-effective, and environmentally friendly alternative to conventional chromatographic methods, and holds great potential for on-site monitoring of trace PAH metabolites in marine environments.
In this paper, we report a flow injection electrochemical sensor for bisphenol F based on a hierarchical multimodal nanoporous gold (hm-NPG)/multi-walled carbon nanotube (MWCNT) nanocomposite deposited onto a screen-printed carbon electrode (SPCE). The hierarchical pore structure of hm-NPG provides an enhanced electroactive surface area arising from the smaller mesopores and efficient mass transport pathways due to larger macropores, while MWCNTs enhance electrical conductivity and electron transfer. Integration of the sensor with flow injection analysis (FIA) substantially reduced the loss of electrode response associated with electrode fouling arising from the electropolymerization of BPF during oxidation. Cyclic voltammetry and electrochemical impedance spectroscopy (EIS) were employed to characterize the electrochemical behavior of the modified electrode, and chronoamperometry was used for quantitative detection. Under optimized conditions, the sensor exhibited a calculated limit of detection of 6.00 nM, with two linear concentration ranges of 0.5–10 μM and 10–100 μM. The sensor also demonstrated good repeatability (RSD = 5.64%), reproducibility (RSD = 5.78%), and limited response to some common environmental and commercial interferents. Application to spiked tap and bottled water samples demonstrated the potential of the hm-NPG/MWCNT-modified SPCE for BPF detection. The combination of hierarchical porosity of hm-NPG, MWCNTs, and FIA provides an effective strategy to improve the electrochemical detection of BPF while minimizing signal loss due to electrode fouling.
