Analytical Methods最新文献

Nowadays, many people are turning to medications that can help them stay calm during surgeries and their daily lives. As an anesthetic that reduces the excitability of nerve cells, propofol can achieve sedation with the advantages of fast onset and short half-life. The development of propofol sensors has tremendous application potential because they can help healthcare professionals dynamically regulate the concentration of propofol in the blood, not only to achieve the painless surgeries that patients want, to maintain the sedation that surgeons desire, but also to prevent the respiratory failure that may occur with a patient's daily sleep aids. In this paper, we prepared Fe₃O₄/C/CB nanocomposites by doping carbon black on the surface of the pyrolyzed product of MIL-88B. The nanocomposites-modified glassy carbon electrodes were used to detect propofol in phosphate buffer solution. The porous nanocomposites with high electrical conductivity promoted the charge transfer on the electrode surface, improving the performance of the modified electrodes. After optimization, the linear range, the detection limit, and the sensitivity for propofol were 5.0-205 μM, 0.102 μM, and 2.850 μA cm^-2 μM^-1, respectively. The electrochemical sensing of propofol in a medical propofol emulsion injection and in normal human serum showed that the method was rapid and repeatable.

Selected ion flow tube mass spectrometry (SIFT-MS) is a recent addition to the routine analysis and research laboratory toolkit, primarily as a quantitative tool. SIFT-MS employs ultra-soft chemical ionisation to directly analyse volatile organic compounds (VOCs) in air and headspace in real-time with high specificity and sensitivity. Coupling SIFT-MS with conventional laboratory automation equipment (i.e., that used with chromatography systems) has proved straightforward and enables unattended operation, processing up to 230 samples per day per SIFT-MS instrument. Automated SIFT-MS systems have been applied to analysis of headspace (static, continuous, multiple headspace extraction, and standard additions), sample bags, and thermal desorption tubes. Applications using these approaches include consumer and drug product testing for volatile impurities (such as benzene, formaldehyde, and nitrosamines), environmental samples, clinical research, and materials testing. The stability of the SIFT-MS technique, coupled with its ability to analyse diverse VOCs in a single run, removes the need for system configuration changes and hence reduces calibration demand and streamlines workflows, reducing the time to report the first results in a sequence schedule and increasing sample throughput compared to chromatographic systems. This article reviews the development of the automated-SIFT-MS approach using a variety of application examples and recommends hardware and software improvements that could further enhance its adoption.

Long-term consumption of foods with excessive enrofloxacin (ENRO) residues may cause the accumulation of ENRO in the human body, thus damaging human health. In this study, quantum dot-based biomimetic fluorescence immunoassays were used for enrofloxacin detection in food of animal origin. Under the most suitable conditions, the detection limit (IC₁₅) of the method in standard solution was 0.13 ± 0.02 ng L^-1 and the sensitivity (IC₅₀) was 0.13 ± 0.18 μg L^-1. The recoveries for ENRO from four fortified food samples, including chicken, eggs, shrimp, and milk, ranged from 85.74% to 114.19% and the coefficients of variation were 0.01-18.09%. The established method shows good agreement with the results obtained using commercial ELISA kits, with a correlation coefficient of 0.997. The proposed method shows the advantages of high sensitivity, specificity and wide detection range. It can be used as an alternative method for the rapid and sensitive detection of ENRO in food of animal origin.

Agriculture has a substantial demand for classification, and each agricultural product exhibits a unique ion signal. This paper summarizes the classification techniques of ion-selective electrode arrays in agriculture. Initially, data sample collection methods based on ion-selective electrode arrays are summarized. The paper then discusses the current state of classification algorithms from the perspectives of machine learning, artificial neural networks, extreme learning machines, and deep learning, along with their existing research in ion-selective electrodes and related fields. Then, the potential applications in crop and livestock growth status classification, soil classification, agricultural product quality classification, and agricultural product type classification are discussed. Ultimately, the future challenges of ion-selective electrode research are discussed from the perspectives of the sensor itself and algorithms combined with sensor arrays, which also positively impact the promotion of their application in agriculture. This work will advance the application of classification techniques combined with ion-selective electrode arrays in agriculture.

In this study, zinc ions were employed as the central metal, while 4,4',4''-nitrilotribenzoic acid (H₃NTB) served as the fluorescent organic ligand. Through a single-step solvothermal approach, a novel Zn-based metal-organic framework (Zn-MOF) fluorescent material was successfully synthesized. The Zn-MOFs exhibit a cubic morphology, outstanding fluorescence properties, excellent water dispersibility, and robust resistance to high temperature and strong alkaline conditions. Additionally, MnO₂ nanosheets (NSs) were effectively exfoliated from MnO₂ particles using ultrasonic treatment. These MnO₂ NSs possess a broad UV-Vis absorption band that overlaps with the fluorescence spectra of Zn-MOFs. Leveraging the inner filter effect (IFE) between MnO₂ and Zn-MOFs, a Zn-MOF-based fluorescence bioassay technique was developed for the detection of biothiols. The results demonstrate that this Zn-MOF-based fluorescence detection platform exhibits a remarkable sensitivity towards biothiols, achieving a detection limit of 0.067 μM, surpassing that of other reported MnO₂-based detection methods. Furthermore, this detection platform has been successfully applied to the quantitation of glutathione (GSH) in human serum, highlighting its potential for highly sensitive and specific detection of biothiols.

The concentration of formaldehyde in the environment must be precisely monitored, as it is closely linked to human health. In this paper, a decaboryl derivative formaldehyde fluorescent probe (M1) was synthesized for the first time by introducing a 5-amino-isoquinoline group into a decaborane parent. Using theoretical calculations, ¹H-NMR, ¹¹B-NMR, HR-MS, and FT-IR, the molecular structure of the probe was determined and its response mechanism to formaldehyde was examined. The fluorescence response of the probe to formaldehyde was then tested, revealing an augmented response to formaldehyde in a solution of 0-600 μM, with a detection limit of 4.18 × 10^-6 M. The results show that the formaldehyde fluorescence probe has the advantages of good linearity, strong anti-interference and high sensitivity. On this basis, a fiber optic formaldehyde fluorescence sensor based on an M1/PMMA thin film was constructed in this paper. This fiber optic fluorescence sensor, with its high selectivity, low detection limit, online and remote monitoring, and other advantages, was successfully applied to the detection of formaldehyde in both food and aqueous solutions, with results that were reliable compared to those of acetone. The detection limit of formaldehyde increased to 6.9 × 10^-8 M. The potential for its utilization in the chemical, biological, environmental, and other formaldehyde detection fields is quite promising.

The emergence of antibacterial resistance impacts healthcare networks globally, with mortality rates and linked burdens of infection disproportionately affecting the developing world. Rapid alternatives to antibiotic susceptibility testing (AST) allow for swifter, more effective treatment, though they are limited in use in low-resource settings due to significant cost barriers. Herein we demonstrate a simple, cost-effective diffraction sensing-based approach for rapidly detecting bacterial growth (a precursor to AST). Diffraction gratings (1D, lined) directly comprised of our test bacteria (Escherichia coli DH5α) were produced using soft agar-based gel templates designed to direct bacterial attachment and produce a near-zero background signal. The diffraction spot intensities from the live bacterial gratings were monitored in growth and no growth (ampicillin) conditions at room temperature, using a simple fixed laser and photodetector setup. Growth-induced differences in signal were observed within 10-20 minutes, highlighting the sensitivity of this approach and its potential to be adapted as a rapid and accessible AST alternative.

Zn²⁺ and ClO^- may be associated with a variety of pathologies, and their simultaneous measurement is crucial for disease diagnosis and environmental protection. In this work, we synthesized an independent AIE probe, HNTE, through a one step reaction. The probe HNTE displayed a distinctive fluorescence color change from deep yellow to blue for ClO^- and to green for Zn²⁺. More importantly, the probe HNTE could simultaneously detect endogenous and exogenous ClO^- and Zn²⁺ in living cells colorimetrically via the blue and green channels.

In this study, a sensitive sandwich electrochemical immunosensor for the detection of the cancer marker cancer antigen 125 (CA125) was developed using polypyrrole (PPy) microspheres for amplifying the sensing signal. The PPy microspheres provided a larger surface area for gold nanoparticle (Au NP), CA125 antibody and signal molecule adriamycin immobilization. In 0.10 M PBS of pH 7.4, a well-shaped oxidation peak for adriamycin at -0.83 V (vs. SCE) was obtained in a differential pulse voltammogram. Signal intensity was related to the level of CA125. Under optimal conditions, the immunosensor showed a wide linear response range of 10-100 U mL^-1 with a detection limit of 2.4 μU mL^-1 (at 3σ/N), and recovery was 98.1-101.2%, as evaluated using human serum samples. Furthermore, the immunosensor was applied to measure real serum samples, and the results obtained were in accordance with those of enzyme-linked immunosorbent assay (ELISA), indicating that the proposed immunosensor is an ideal platform for clinical diagnosis application.

The ability to quantify albuminuria and glucose is important in identifying conditions such as cardiovascular disease (CVD), chronic kidney disease (CKD), and diabetes. This study utilized Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy to analyze aqueous urine samples spiked with bovine serum albumin (BSA) and glucose at different concentrations. The aim was to determine the limit of detection of the technology using aqueous samples for the future development of a pathological prediction model. The ATR-FTIR spectra of the co-spiked samples exhibited pronounced amide I (1662 cm^-1) and amide II (1545 cm^-1) bands indicative of elevated protein along with glucose-associated bands at 1155, 1107, 1079 and 1036 cm^-1. Partial Least Squares (PLS) yielded promising R² values of more than 0.9 for BSA, glucose, and co-spiked glucose/protein. The limit of detection of the technique was 40.28 mg L^-1 for protein and 291.65 mg L^-1 for glucose, demonstrating the potential of the technique as a tool to identify analytes associated with pathological conditions including cardiovascular disease (CVD), chronic kidney disease (CKD), and diabetes.