Rhodium is one of the most challenging platinum-group metals to recover by conventional solvent extraction owing to its kinetically inert coordination chemistry. In this study, the extraction of rhodium(III) from hydrochloric acid solutions into neat ionic liquids (ILs) was investigated, focusing on trioctylammonium chloride ([HTOA]Cl), a protic IL designed for anion extraction. To overcome the slow ligand substitution of rhodium(III), the effect of thermal pretreatment of the aqueous phase was examined. Heating a rhodium(III) solution in 8.0 mol dm− 3 HCl at 100 °C for at least 2 h promoted chloro-complex formation. Subsequent dilution to 1.0 mol dm− 3 HCl immediately before extraction minimized competitive inhibition by excess chloride ions, enabling efficient anion-exchange extraction. Under optimized conditions, a distribution ratio of 31.6 and an extraction percentage of 97
Rapid identification of male-derived biological evidence enhances forensic casework efficiency, particularly in sexual assault investigations that require prioritization of male DNA for downstream short tandem repeat (STR) analysis. Here, we present an extraction-free direct loop-mediated isothermal amplification (LAMP) workflow targeting the Y-chromosomal sex-determining region Y (SRY) gene for male-specific DNA detection, with the autosomal human leukocyte antigen DRA (HLA-DRA) gene incorporated as a human-specific internal control. Three detection formats were systematically evaluated within a single extraction-free framework: colorimetric LAMP enabled visual SRY detection within 30 min at 65 °C; multiplex real-time LAMP simultaneously detected both SRY and HLA-DRA within 15 min, achieving limits of detection of 100 pg per reaction for male DNA and 10 pg per reaction for total human DNA; and an immunochromatographic strip (ICS)-based format provided instrument-free visual discrimination between male, female, and non-human samples through simultaneous dual-target readout on a single strip. To assess field applicability, five direct lysis reagents were evaluated for compatibility with each detection modality. Nuclease-free water preserved the pH conditions required for colorimetric detection, enabling reliable male DNA identification from whole blood diluted up to 1:25 and saliva diluted up to 1:5. NaOH-based lysis improved DNA release and amplification kinetics in real-time LAMP, enabling detection from blood diluted up to 1:125 and saliva diluted up to 1:625. A UDG/dUTP anti-contamination system was optimized for the ICS format to suppress carry-over–derived false-positive signals while maintaining robust visual band intensity—an essential requirement for reliable point-of-care interpretation. The optimized workflow was validated across multiple forensically relevant matrices including whole blood, saliva, swab-collected samples, and cigarette butt mock evidence, consistently discriminating male- from female-derived biological material. These results demonstrate that direct LAMP, when paired with appropriate lysis chemistry and detection modality, provides a rapid, sensitive, and operationally practical strategy for on-site male DNA screening and forensic evidence triage.
Wearable sweat analysis can extend health monitoring from clinics to daily life. However, sweat is produced slowly and at changing rates, which makes sweat handling difficult. During collection and transport, sweat may remain in the device, flow backward, mix with older sweat, or become contaminated. The liquid that reaches the sensor may therefore differ from freshly secreted sweat. Microfluidic valves can control when sweat moves, where it flows, and how it reaches the sensing region. This review compares five valve classes relevant to wearable sweat systems. They are capillary, Tesla, mechanical, stimuli-responsive, and electro-actuated valves. Each class is assessed in terms of its working principle, flow-control function, power requirement, reusability, suitable task, and practical limit. The comparison covers sweat retention, backflow control, time-separated collection, reagent isolation, and replacement of older sweat at the sensor. The reviewed studies are grouped by tested medium and setting, covering laboratory liquids, artificial sweat, collected human sweat, and direct on-body transport. The main unresolved problems are changing sweat rate, deformation during wear, limited reusability, and unstable materials or interfaces. Solving these problems is important for reliable valve operation during long-term wear.
A simplified diffuse reflectance infrared Fourier transform (DRIFT) system using commercial silver powder was investigated as an alternative to previously reported silver colloid/filter-paper systems for infrared signal enhancement. Isonicotinamide, nicotinamide, and nicotinic acid were employed as model compounds to evaluate the spectral behaviour obtained using this simplified DRIFT system. Significant band-dependent enhancement was observed for isonicotinamide and nicotinamide when the samples were subjected to solvent-assisted mixing with silver powder followed by drying. In contrast, simple dry mixing with silver powder produced little or no enhancement, and the control compound nicotinic acid showed no comparable spectral changes. The enhanced spectra exhibited non-uniform increases in band intensity together with peak shifts, band splitting, and changes in spectral shape, suggesting that the observed spectral changes cannot be explained by simple physical mixing with silver powder. The simplified powder DRIFT system enabled observation over a broad spectral region without support-derived absorption and revealed band-dependent infrared enhancement together with peak shifts, band splitting, and spectral shape changes.
Coated-type composite chiral stationary phases (CSPs) based on homosubstituted (same substituents introduced onto the glucose unit) and heterosubstituted (different substituents grafted onto the glucose unit) amylose derivatives were prepared and their enantioseparation capabilities in high-performance liquid chromatography were evaluated. Investigations demonstrated that the enantioseparation capabilities of the composite CSPs generally fell in between those of the two single-component CSPs. Notably, several chiral analytes that failed to achieve resolution on the single-component CSPs were successfully discriminated on the composite ones, thereby extending the application scope of an individual amylose derivative-based CSP. Some anomalous retention and selectivity behaviors were also observed on the composite CSPs, which may be due to some interactions between the two polymers during cocoating. Additionally, the impact of mobile phase composition on enantioseparation was examined. In the hexane/2-propanol (80/20, 90/10, and 95/5, v/v) mobile phase system, a lower 2-propanol content in the mobile phase always results in higher retention factor k1, whereas the separation factor α does not change significantly, with the maximum variation of racemate 2 being approximatley 16%.
A sensitive electrochemical sensor for the detection of methotrexate (MTX), a widely used anticancer and anti‑autoimmune drug, was constructed. MTX monitoring is of great significance for reducing toxic side effects and guaranteeing clinical medication safety. The sensor was based on a glassy carbon electrode (GCE) modified with a nanocomposite of molybdenum disulfide (MoS2) nanosheets loaded with gold gold nanoflowers (AuNFs), followed by the electrochemical polymerization of alizarin red (AR) to form a stable polymeric film (PAR) on its surface. The MoS2 nanosheets were prepared via liquid-phase exfoliation, and the AuNPs were deposited onto them via electrodeposition. The morphology of the modified electrode (PAR/Au@MoS2/GCE) was characterized by scanning electron microscopy (SEM), and its electrochemical properties were investigated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The synergistic effect of the nanocomposite and the conductive polymer significantly enhanced the electrocatalytic activity towards MTX oxidation. Under optimized conditions, the oxidation peak current of MTX at the modified electrode was nearly six times higher than that at a bare GCE. The sensor exhibited a linear response to MTX concentrations ranging from 0.4 to 38.6 µM, with a low detection limit of 0.027µM (S/N = 3). The sensor demonstrated excellent reproducibility, stability, and selectivity. Its practical applicability was successfully validated by determining MTX content in commercial tablet formulations with satisfactory recoveries. A PAR/Au@MoS2/GCE electrochemical sensor was fabricated via sonication, electrodeposition, and electropolymerization for the sensitive detection of methotrexate.
Accurate quantification of pesticide residues is critical to ensure the quality and safety of Rhizoma Polygonati, a well-recognized medicine-food homologous herb widely applied in functional food development. Strong matrix interference in gas chromatography-tandem mass spectrometry (GC-MS) detection and notable quantitative bias are frequently induced by the abundant pigments, polysaccharides, saponins and endogenous components in the herbal matrix. Conventional PSA and C18 adsorbents in standard QuEChERS protocols exhibit restricted purification capacity for this complex matrix, while most documented magnetic carbon-based adsorbents demand tedious pre-synthesis procedures that may block the active adsorption sites of nanomaterials. A modified QuEChERS-GC-MS method coupled with dynamic in-situ assembly strategy was established for 12 pesticide residues in Rhizoma Polygonati. Without pre-synthesis of any composites, in-situ functional synergy between NH2-SWCNTs and magnetic Fe3O4 nanoparticles was achieved during the dispersive solid-phase extraction (d-SPE) step. Superior purification performance to conventional adsorbents was obtained by this system, with the matrix effect range of target pesticides narrowed from -31.4
DNA adducts analysis is crucial for elucidating the mechanism of mutagenesis and carcinogenesis induced by various chemical compounds. Liquid chromatography-electrospray ionization-tandem mass spectrometry (LC–MS/MS) is commonly employed to determine DNA adduct. Pretreatment is essential in DNA adduct analysis due to a significant concentration disparity between normal 2’-deoxynucleosides (dNs) and DNA adducts. The level of DNA adducts is typically assessed by the ratio of DNA adducts to normal 2’-deoxyguanosine (dG) when the DNA adducts originate from dG. Consequently, the determination of dG and DNA adducts is necessary for accurate evaluation. Reversed-phase (RP)-solid-phase extraction (SPE) is the first choice for pretreatment of DNA adducts analysis. This pretreatment using RP-SPE effectively enriches DNA adducts while removing a substantial amount of dNs, particularly thymidine (T) and 2’-deoxyadenosine (dA), which may suppress the ionization of DNA adducts in the electrospray ionization (ESI) process. However, two separate measurements are required to determine the concentrations of dG and DNA adducts, as dG is removed during the SPE process. Therefore, an SPE method that simultaneously extracts dG and DNA adducts is desirable. In this study, we investigated the applicability of hydrophilic interaction chromatography (HILIC)-type SPE sorbents developed by our team, for the pretreatment of DNA adduct analysis. N2-ethyl-2’-deoxyguanosine (EtdG), an acetaldehyde-derived DNA adduct, was selected as a model DNA adduct. By optimizing the washing and eluting solutions, dG and EtdG were simultaneously extracted from the sample solution while eliminating T and dA. This pretreatment method enables the simultaneous measurements of dG and DNA adducts concentration, thereby enhancing the accuracy and rapidity of the DNA adducts analysis.
Osteosarcoma is a highly aggressive bone malignancy requiring precise tools for early diagnosis and effective evaluation of chemotherapy efficacy. Here, we report an “off–on” fluorescent nanosensor based on nitrogen-doped carbon nanodots (N-CNDs) for the sensitive and selective detection of caspase-3 activity, a key apoptosis executor. The sensor is constructed by conjugating carboxyl-functionalized N-CNDs with a BHQ1-labeled peptide substrate containing the caspase-3-specific DEVD cleavage motif. In the absence of caspase-3, fluorescence is quenched via FRET. Upon caspase-3 activation, the peptide is cleaved, releasing BHQ1 and restoring fluorescence. The nanosensor exhibits high sensitivity (detection limit of 0.0106 U/mL), excellent selectivity, and robust performance in complex biological media. As a proof-of-concept application, it detects elevated caspase-3 activity in osteosarcoma cell lysates (MG-63) compared to normal osteoblast lysates (hFOB1.19) and enables quantitative, dose-dependent assessment of apoptosis induced by cisplatin and doxorubicin directly in cancer cell lysates. With its current format, this cell-lysate-based platform provides a practical and sensitive tool for preclinical drug screening and rapid comparison of chemotherapeutic potency, while laying a foundation for future adaptation toward live-cell and in vivo imaging applications.
This study reports the first development of gas chromatographic columns packed with activated carbon (AC)-coated adsorbent particles. The AC-coated adsorbent particles were prepared by coating an AC layer on solid support particles using a vacuum carbon coater. Glass beads, diatomite, a porous polymer, and activated alumina particles were investigated as the support materials. The AC layer was uniformly coated on the surface of each support material, achieving a thickness of approximately 300–400 nm after 500 coating cycles. The AC-coated particles were packed in a stainless steel tube with an inner diameter of 1.0 mm and a length of 1.0 m to prepare a packed capillary column. The retention performance of the AC-coated particle-packed columns was evaluated using a capillary gas chromatograph coupled with a flame ionization detector. Strong retention for typical low-molecular-weight organic compounds, including methane, ethane, and propane, was observed. The retention power increased with increasing number of AC-coating cycles and support surface area. The theoretical plate numbers were lower for adsorbents coated on nonporous and low-porous supports, and higher for supports with a large specific surface area. The results demonstrated that the present AC-coating method readily affords AC adsorbents with high retention for typical volatile compounds.
Condensed micelle solutions are ubiquitously seen and utilized in foods, medicine, oil recovery, and so on. It is well-known that micelles formed from ionic surfactants drastically change their aggregate morphologies from spherical to short, rigid rod-like, and occasionally to long, winding worm-like structures as the concentration of the co-existing salts is varied. In general, these large-scale morphological changes induced by additive salt have been directly assessed by X-ray or neutron scattering spectroscopies. However, industrial processes are often carried out under open-system and atmospheric conditions, thus they show transient and dynamic changes of their structures and resultant viscoelastic properties according to the environmental changes. Here we examined whether Raman scattering spectroscopy is applicable for detecting such large-scale morphological changes in micelles by monitoring the corresponding changes occurring in the local packing environment of neighboring surfactant alkyl chains. As a representative micelle-salt system, cetyltrimethylammonium bromide (CTAB) and sodium p-toluene sulfonate (NapTS) were studied by varying their concentration ratio. As a result, it was proposed that the CH2 twisting and scissoring modes were useful indices to discriminate the morphological changes in micelles. These results provide a useful index for monitoring the transient structural changes of micelle solutions and elucidating the mechanism of the resultant changes in viscoelastic properties in situ and on-site monitoring.
The development of new analytical tools remains a powerful approach in analytical chemistry, and three-dimensional (3D) printing has gained increasing popularity as a manufacturing technique in recent years. The fabrication of experimental tools using 3D printers has attracted attention in many fields. However, objects fabricated by fused filament fabrication (FFF) may contain gaps between printed paths, and which can cause leakage when liquid is introduced. In this study, solvent-based post-processing was performed in order to fill layer gaps in FFF-printed polypropylene fluidic chips. As methods, a compression process and solvent-based post-processing were applied. In the compression process, a polypropylene fluidic chip was compressed using a compression tool while being heated. After this compression process, solvent-based post-processing was conducted. The post-processed chip was used to measure peak profile during flow-injection measurement. As a result, peak profiles were obtained, and no leakage from the chip was observed during the measurements.
A novel and highly sensitive electrochemical sensor based on an electropolymerized bromocresol green (BCG) film-modified pencil graphite electrode (poly(BCG)@PGE) was developed for the determination of tinidazole (TNDZ). The electropolymerization of BCG on the electrode surface significantly enhanced the electrochemical response toward TNDZ by improving electron-transfer kinetics and increasing the effective surface area. The fabrication and surface characteristics of the modified electrode were systematically investigated using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and Fourier-transform infrared spectroscopy (FT-IR). The electrochemical behavior of TNDZ was studied using CV and differential pulse voltammetry (DPV). Key experimental parameters affecting sensor performance, including the pH of the electrolyte solution, monomer concentration, and number of electropolymerization cycles, were optimized. Under the optimized conditions, the proposed sensor exhibited a wide linear dynamic range (LDR) from 0.4 to 500 µM for TNDZ determination, with a high sensitivity of 1402 µA·mM−1·cm−2 and a low limit of detection (LOD) of 0.11 µM. The practical applicability of the developed voltammetric sensor was successfully demonstrated by the determination of TNDZ in artificial blood, pharmaceutical formulation, and spring water samples. The obtained results showed satisfactory recoveries with high precision and accuracy, confirming the reliability and potential applicability of the poly(BCG)@PGE sensor for sensitive electrochemical monitoring of TNDZ in complex matrices.
As a representative member of neonicotinoid insecticides, imidacloprid (IMI) has seen growing application in agricultural seed coating treatments, raising widespread concerns over its associated environmental accumulation and food chain contamination. Graphdiyne (GDY), an emerging star carbon nanomaterial following graphene, has demonstrated exceptional versatility in analytical sensing; however, its application for electrochemical detection of IMI remains unexplored. Herein, we reported the fabrication and systematic characterization of a novel electrochemical sensing platform based on graphdiyne-coated carbon nanotube (GDY/CNTs) nanohybrids, synthesized via a facile in-situ growth strategy, for sensitive IMI detection. Key operational parameters including PBS buffer pH and GDY/CNTs modification loading were systematically optimized to enhance sensing performance. Under optimal conditions, the GDY/CNTs sensor exhibited a wide linearity of 0.01–10 µM, with a low limit of detection of 3.2 nM and a high sensitivity of 1.4656 µA·µM−1. Importantly, the developed sensor achieved satisfactory recovery rates (≥ 95
Seawater pH measurement is essential for monitoring ocean acidification and its biogeochemical impacts. Glass electrode pH sensors are widely used for in situ applications due to their ease of operation, low power consumption, and no reagent requirements. However, their accuracy can be affected by temperature-dependent effects, particularly those associated with the internal reference solution. Conventional calibration methods based on the Nernst response do not explicitly account for temperature-induced variations in the internal solution, which may lead to systematic bias under conditions with large temperature gradients. In this study, a correction method is proposed to address temperature-dependent errors by modeling the internal pH (pHin). The model incorporates two primary temperature-dependent contributions: the intrinsic temperature dependence of the phosphate buffer and potential shifts caused by activity changes in saturated KCl. These effects are combined through the electrode response factor (fR), defined as the ratio of the observed electrode slope to the theoretical Nernst slope, to estimate pHin as a function of temperature and correct measured pH values to a reference temperature of 25 °C. Application of the method to vertical seawater profiles demonstrated a reduction in deviation from colorimetric reference measurements. The corrected results showed reduced temperature-dependent bias across depth. This approach provides a practical framework for improving the reliability of in situ glass electrode pH measurements under varying thermal conditions. The proposed method addresses equilibrium temperature-dependent effects of the internal solution but does not explicitly account for transient hysteresis, pressure effects, or long-term sensor drift.
Iodine is an essential element widely used in medicine, electronics, and emerging energy technologies, and its efficient separation and speciation are increasingly important for resource recovery and environmental monitoring. In aqueous environments, iodine exists in numerous chemical species, and their interconversion strongly influences its extractability and separation behavior. Among available techniques, solvent extraction is considered one of the most versatile methods for iodine separation due to its operational simplicity, high selectivity, and scalability. This review presents a comprehensive overview of recent advances in the solvent extraction of iodide and related iodine species. First, we briefly outline the speciation of iodine in aqueous systems to clarify how its chemical species controls its extraction behavior. Then, we discuss the principal extraction mechanisms, including the redox-driven extraction of molecular iodine, metal–iodide complex formation, ion-pair extraction with cationic reagents, amine-based extraction, and anion-exchange processes using ionic liquids and related extractants. We also discuss strategies for stripping and recovering iodine species from loaded organic phases. Moreover, recent developments in emerging extraction technologies, such as dispersive liquid–liquid microextraction, liquid membrane systems, and aqueous biphasic systems, are highlighted because they enable enhanced extraction efficiency and analytical sensitivity. Industrial and environmental applications, particularly iodine recovery from natural brines and the separation and analysis of radioiodine, are also discussed. These advances provide a comprehensive framework for understanding and designing selective, efficient, and sustainable iodine separation processes.
Osteoarthritis (OA) is a leading cause of chronic pain and disability in the elderly. The lack of sensitive diagnostic methods for early OA remains a major clinical challenge. Synovial fluid contains exosomes (SF-exosomes) that carry disease-specific biomolecules, making them promising targets for early diagnosis. However, efficient isolation of SF-exosomes with high purity is technically demanding. This study aimed to develop phosphatidylserine-based molecularly imprinted polymers (P-MIPs) for the efficient enrichment of SF-exosomes and to discover potential protein biomarkers for early OA diagnosis using proteomic analysis. P-MIPs can specifically recognize phosphatidylserine on the extracellular vesicle membrane, thereby achieving highly selective enrichment of extracellular vesicles. P-MIPs were synthesized via a reverse microemulsion system. The binding capacity, specificity, and enrichment efficiency of P-MIPs were characterized. SF-exosomes from 6 OA patients and 6 healthy controls were enriched using P-MIPs and analyzed by LC–MS/MS proteomics. Differentially expressed proteins (DEPs) were subjected to bioinformatics analysis. The diagnostic value of hub genes was validated by ROC analysis in an independent cohort. The results showed that the binding capacity (Qmax) of P-MIPs was 129.71 µmol/g, and the cross-reactivity with sphingomyelin (SM), phenylphosphonic acid (PYP), and tyrosine phosphopeptides was less than 3.5
Matrix-assisted laser desorption/ionization mass spectrometry (MALDI/MS) imaging enables spatially resolved molecular analysis; however, its sensitivity depends strongly on matrix uniformity and ionization efficiency, which pose challenges for low-abundance compounds such as steroid hormones. In this study, we developed a platinum (Pt) thin film-based surface-assisted laser desorption/ionization mass spectrometry (SALDI/MS) and matrix-enhanced SALDI/MS (ME-SALDI/MS) method to increase ion yields and improve steroid imaging with minimal sample pretreatment. Using sputter-deposited Pt films, 20 endogenous steroids were comprehensively detected without chemical derivatization. Furthermore, derivatized steroids analyzed by ME-SALDI/MS exhibited significantly higher ion yields than those obtained by conventional MALDI/MS or SALDI/MS, demonstrating a synergistic enhancement of desorption and ionization efficiency. ME-SALDI/MS imaging of porcine adrenal gland tissue enabled visualization of multiple derivatized steroids with high ion yields-including progesterone, corticosterone, and cortisol-reflecting their biosynthetic localization across cortical zones. Collectively, these results highlight the potential of Pt thin film-based SALDI and ME-SALDI/MS as robust tools that provide high ion yields for imaging of steroids and other biomolecules with inherently low desorption and ionization efficiency.
