Analytical and Bioanalytical Chemistry最新文献

Upconversion nanoparticles (UCNPs)-based fluorescence lateral flow immunoassay (FLFIA) has significant application prospects in clinical diagnosis, but it still suffers from relatively low sensitivity in detecting trace amounts of biomarkers. Here, we report for the first time a strong fluorescence-emitting core-shell-shell NaLuF₄@NaLuF₄:Yb,Er@NaLuF₄ UCNP as the FLFIA probe. The UCNPs-based FLFIA platform enables point-of-care detection of cardiac troponin I (cTnI) with high sensitivity, accuracy, and resistance to autofluorescence interference. NaLuF₄:Yb,Er encapsulated in the intermediate shell layer can effectively reduce the cross-relaxation and surface quenching of the luminescence center, resulting in a higher quantum yield. Compared with the conventional core-shell NaLuF₄:Yb,Er@NaLuF₄ UCNPs, the fluorescence intensity increases by 2.4 times. The UCNPs-based FLFIA was further integrated with a portable smartphone platform for rapid, on-site detection. The UCNPs probe enabled sensitive cTnI detection, with a detection limit of 0.035 ng/mL in buffer and 0.059 ng/mL in serum, and a detection range of 0.05-100 ng/mL. In testing clinical samples, the results from the platform showed excellent correlation with hospital results. We anticipate that the NaLuF₄@NaLuF₄:Yb,Er@NaLuF₄ UCNPs can serve as a promising immunolabeling nanoprobe for highly sensitive and accurate FLFIA detection.

Solid-contact ion-selective electrodes (SC-ISEs) have gained prominence as versatile tools for monitoring ionic species in complex agricultural and food matrices, offering low-cost, miniaturizable, and field-deployable alternatives to conventional laboratory assays. This review critically examines electrochemical transduction techniques for SC-ISEs, including potentiometry, coulometry, amperometry, voltammetry, and electrochemical impedance spectroscopy. By evaluating these techniques based on their detection mechanisms, sensitivity ranges, selectivity characteristics, and application potential, we highlight how dynamic electrochemical modes can overcome potentiometry limitations. Emphasis is placed on the role of solid-contact design, nanostructured materials (e.g., conducting polymers, carbon nanomaterials, and laser-induced graphene), and integrated readout strategies that enhance sensor performance in real-world applications. We also analyze state-of-the-art configurations for ion detection in soil, water, and food products. Finally, we discuss current challenges and offer perspectives on SC-ISEs integration into cyber-physical systems, where real-time, connected, and autonomous sensing will be central for sustainable agriculture and food systems, while also addressing regulatory considerations.

Human blood plasma is the matrix of choice for clinical diagnostic applications. However, matrix effects associated with its complex composition interfere with the accurate detection of biomarkers that are often present at extremely low concentrations. This study investigates such matrix effects, particularly the nonspecific adsorption of blood plasma to the sensor surface and the interaction of endogenous antibodies with the used receptors, and shows how they can be discriminated using a surface plasmon resonance biosensor. Moreover, we describe a strategy to tackle matrix effects by combining sequential blood plasma/buffer injections, single-surface referencing, and the addition of an antibody against endogenous immunoglobulins to blood plasma. Finally, we apply this strategy to the detection of the cancer biomarker carcinoembryonic antigen in undiluted blood plasma, achieving detection limits of 12 ng/mL using direct detection, and 225 pg/mL using a sandwich assay with functional gold nanoparticles.

A method was established and verified for identifying 315 toxic organic compounds-such as chlorophenols, dyes, pesticides, perfluoroalkyl acids, and fungicides-in waste textile materials and finished products through ultrasound-assisted extraction coupled with high-performance liquid chromatography-tandem mass spectrometry. Acetonitrile was utilized as the extraction solvent in two sequential ultrasonic extraction steps to isolate the analytes from the samples. For liquid chromatography, a C₁₈ column was used for separation. In electrospray ionization positive mode, mobile phase gradient elution was performed with a mixture of acetonitrile and a 0.1% formic acid solution (containing 2 mmol/L ammonium acetate) in water. A mobile phase gradient elution using acetonitrile and a 2 mmol/L aqueous ammonium acetate solution was applied under electrospray ionization in negative mode, with detection conducted via multiple reaction monitoring (MRM). The analysis revealed that all 315 target compounds maintained strong linearity across their calibration ranges, with correlation coefficients (R²) consistently above 0.9901. The detection limits (LOD) were between 0.01 and 3.8 µg/kg, whereas the quantification limits (LOQ) ranged from 0.03 to 10.90 µg/kg. Method validation through spiking at concentrations of 10, 20, and 100 µg/kg was performed on three sample types: waste cotton lint, waste wool yarn, and waste hemp yarn. The recoveries ranged from 61.3 to 119.9%, with relative standard deviations (RSDs) between 1.1 and 15.9%. Overall, the method offers high sensitivity, accuracy, and reproducibility, rendering it effective for the routine detection of residual organic contaminants in recycled textile materials.

This study presents the development of a HiSorb microextraction method coupled with thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) for analyzing cannabidiol (CBD) in commercial hemp oils. Two HiSorb sorptive coatings were evaluated, triple-phase polydimethylsiloxane (PDMS)/carbon wide-range (CWR)/divinylbenzene (DVB) and double-phase PDMS/CWR, for their extraction efficiencies. The triple-phase HiSorb, combined with water-bath incubation for 2 h at 80 °C, delivered the highest CBD recovery. The developed HiSorb-TD-GC-MS method showed excellent linearity (R² = 0.9951), with a method limit of detection (LOD) of 30 µg/mL and a limit of quantification (LOQ) of 100 µg/mL. The total chromatographic runtime was 11.2 min. Precision was satisfactory, with intra-day RSD % ranging from 6.8 to 7.3% and inter-day RSD % ranging from 6.5 to 7.7%. Recoveries at three concentration levels for diluted sample (low 100 μg/mL, medium 300 μg/mL, high 500 μg/mL) ranged from 77.2 to 86.4%. No detectable formation of Δ⁹-THC was observed, confirming that the method does not induce isomerization of CBD during GC analysis. Greenness assessment yielded AGREE = 0.75 (analytical method) and AGREEprep = 0.54 (sample preparation). The developed method was applied to commercial hemp oil samples and revealed no significant statistical difference (p > 0.05) between the label claim and measured CBD concentration in all tested samples. The application of green analytical methods contributes to sustainability by minimizing environmental impact and enhancing resource efficiency.

Chlorogenic acid (CGA) is a significant natural antioxidant substance with considerable application prospects in the fields of medicine, health food, and chemical engineering. This study developed magnetic molecularly imprinted nanoparticles (Fe₃O₄@MIPs) through surface imprinting technology with large-particle-sized iron oxide nanoparticles (200 nm) as the core support material, utilizing CGA as the imprinting molecule and methacrylic acid (MAA) as the monomer. The synthesized material was thoroughly analyzed using a combination of SEM, FT-IR, XRD, and VSM. Adsorption equilibrium studies show that the Langmuir isotherm model better fits the binding situation of CGA on Fe₃O₄@MIPs, while kinetic analysis indicates that the pseudo-second-order model can more accurately describe the adsorption process. The maximum adsorption capacity of Fe₃O₄@MIPs for CGA is 103.09 mg/g, and it also has good selectivity and reusability. The resulting Fe₃O₄@MIPs prove particularly effective for selective enrichment and quantitative analysis of CGA in Eucommia ulmoides leaves. Recovery experiments conducted at three different concentration levels showed consistent results ranging between 84 and 88% with relative standard deviations (RSD) below 5%. The Fe₃O₄@MIPs approach demonstrates a simple and efficient methodology characterized by exceptional selectivity, swift separation efficiency, and reliable recovery outcomes.

Acute myocardial infarction (AMI) poses a severe threat to human health, making its rapid and sensitive diagnosis crucial. Cardiac troponin I (cTnI) has been established as the gold standard biomarker for AMI diagnosis. Herein, a dual-mode immunosensor was constructed by integrating manganese dioxide (MnO₂) nanozyme and fluorescence carbon dot (B-CDs) in silica (SiO₂), termed B-CDs@SiO₂@MnO₂, for the colorimetric and fluorescent detection of cTnI. The sensing signal mainly included two parts: B-CDs@SiO₂@MnO₂-based catalytic color reaction and B-CDs@SiO₂ fluorescence recovery after etching MnO₂. The MnO₂ nanozyme catalyzes the oxidation of TMB to generate blue-colored TMBox, which turns yellow upon acid addition, enabling colorimetric detection. Concurrently, the MnO₂ nanosheets quench the fluorescence of B-CDs@SiO₂. In the presence of ascorbic acid (AA), MnO₂ is reduced to Mn²⁺, leading to fluorescence recovery and thus enabling fluorescent detection. Profiting from the superior self-correction features of B-CDs@SiO₂@MnO₂ dual-mode sensor, this method exhibits good linearity and sensitivity toward cTnI among 0.05-50 ng/mL, with detection limits of 0.0074 ng/mL for the colorimetric mode and 0.0063 ng/mL for the fluorescent mode. In addition, the human serum samples' recoveries show good agreement between the colorimetric mode (90.0-117.8%) and the fluorescent mode (90.2-115.8%). Furthermore, we employ this platform to monitor cTnI levels in both cellular and blood samples from AMI patients, indicating the promising clinical application potential of this platform.

Early and rapid diagnosis of non-puerperal mastitis (NPM), as well as elucidation of its specific pathological features, is of important clinical and scientific value. Peripheral blood mononuclear cells (PBMCs), which are key mediators in the inflammatory response, contribute substantially to disease onset, progression, and therapeutic effect, making them promising biomarkers for the early identification and management of inflammatory processes. Nevertheless, novel approaches for the detection and analysis of PBMCs remain urgently needed to facilitate the development of liquid biopsy strategies. In this study, we employed Raman spectroscopy to characterize molecular alterations in PBMCs derived from two distinct groups of NPM patients and healthy controls. Additionally, several machine learning algorithms, including principal component analysis (PCA), linear discriminant analysis (LDA), partial least squares discriminant analysis (PLSDA), and support vector machine (SVM), were applied to establish diagnostic prediction models for NPM, yielding area under the curve (AUC) values exceeding 0.93. Our findings indicate that PBMC-based liquid biopsy coupled with Raman spectroscopy and machine learning provides novel opportunities for the diagnosis of NPM.

Fatty acids (FAs) are essential components of lipid metabolism and play crucial roles in biological systems. However, due to their low abundance and poor ionization efficiency, the detection of FAs in matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) poses significant challenges, making the spatial distribution of these molecules in tissues difficult to analyze. We present a novel on-tissue derivatization strategy for FAs using N,N-diethylethylenediamine (DEEA) as the derivatization reagent, which converts the carboxyl group of FAs into a positively charged moiety via amidation, thereby improving their ionization efficiency in positive ion mode. By systematically optimizing experimental parameters including catalyst type, reaction time, and matrix concentration, combined with α-cyano-4-hydroxycinnamic acid (CHCA) matrix, in situ imaging of nine key FAs (palmitic acid, linoleic acid, eicosapentaenoic acid and docosahexaenoic acid, etc.) was successfully achieved in rat kidney tissues. The derivatization products were verified by ESI-Q-TOF-MS, confirming the reliability of the method. Furthermore, comparative analysis with the conventional derivatization reagent 2-picolylamine (PA) demonstrated that DEEA markedly enhanced the derivatization efficiency of FAs. This study employs DEEA as a derivatization reagent for MALDI imaging of FAs. This derivatization method effectively enhances the ionization efficiency of FAs in the positive ion mode of MALDI-TOF-MS, thereby providing a new and referable approach for the imaging of FAs in biological tissues.

Herein, we report a non-enzymatic paper-based device for selective electrochemical detection of creatinine. This work demonstrates three modification strategies adopted for the paper-based electrochemical sensing device (PESD) for the detection of creatinine. Copper, a non-enzymatic metal electrode, was fabricated on the Whatman paper without sophisticated instrumentation. The fabricated pristine non-enzymatic PESD could detect creatinine in the linear range 10 µM to 90 µM with a detection limit of 6.6 µM. Further, the electrode and Whatman paper were modified with silver to improve the sensitivity of PESD towards creatinine. Firstly, the working electrodes were modified by the Scotch tape strategy via galvanic displacement of Ag on Cu. The Ag-modified Cu electrodes were stuck on the Whatman paper, which sensitized the creatinine in the linear range 10 nM to 240 nM with a detection limit of 0.089 nM. Secondly, the Whatman paper was modified by mussel-inspired soak, polymerize, and then reduction of silver on the paper. The modified paper works similarly to the modified electrode with Ag in the linear range 10 nM to 90 nM with a detection limit of 2.5 nM. Further, the fabricated pristine PESD was tested for Jaffe's inspired indirect electrochemical detection of creatinine in the linear range 10 µM to 100 µM with a detection limit of 6.4 µM. The sensitivity of the fabricated pristine PESD was improved from µM to nM by adopting modification strategies. The reported PESD with the least interference from the co-existing biomolecules has the potential applicability of monitoring creatinine in urine sample analysis.