基质辅助激光解析/电离飞行时间质谱(MALDI-TOF MS)在微生物鉴定中的应用*

基质辅助激光解析/电离飞行时间质谱(MALDI-TOF MS)是一种新型软电离生物质谱,具有检测速度快、操作简便、结果准确等优点,目前已成为可靠的微生物快速鉴定技术。就工作流程而言,与常规生化方法相比,MALDI-TOF MS可以将微生物鉴定的时间缩短为一天甚至更短。对于具有抗生素耐药性的微生物,使用MALDI-TOF MS鉴定也有很好的准确性。在病毒鉴定中,MALDI-TOF MS也可以发挥作用,已有报道将MALDI-TOF MS和机器学习(ML)分析方法结合来检测鼻拭子中SARS-CoV-2。此外,MALDI-TOF MS还可用于细菌的无光谱库鉴定。目前,MALDI-TOF MS正通过与其他技术(例如傅里叶红外光谱FTIR)相结合进一步扩大微生物鉴定范围。     

Rational Design of Ratiometric Fe3+ Fluorescent Probes Based on FRET Mechanism

As the most abundant transition metal element in mammals, iron(Fe) plays a vital role in life activities. It is of great significance to study the variation of Fe³⁺ level in living organisms. In virtue of the advantages of high sensitivity, good selectivity and low damage to living systems, the fluorescence detection of Fe³⁺ has attracted much attention. Compared with the intensity-based fluorescent probe, the ratiometric fluorescent probe has less interference of environmental and can realize quantitative detection. In this study, four ratiometric Fe³⁺ fluorescent probes, R1, R2, R3 and R4_, were designed and synthesized using fluorescence resonance energy transfer(FRET) mechanism to achieve quantitative detection of Fe³⁺. In the FRET systems, 1,8-naphthalimide fluorophore derivatives were adopted as donors while rhodamine B derivatives were selected as receptors. The connection sites of the donor and acceptor in R3 and R4 are different from those in R1 and R2. All the four probes showed good response and selectivity to Fe³⁺. The energy transfer efficiencies of R3 and R4 were obviously higher than those of R1 and R2. This work provided a promising strategy for the development of fluorescent ratiometic Fe³⁺sensors.     

Bipolar Electrode-based Electrochromic Devices for Analytical Applications – A Review

Bipolar electrode-based (BPE-based) electrochromic devices have garnered increasing attention in the past decade. These BPE-based electrochromic devices have been used for analytical health monitoring, point-of-care (POC) diagnostics, and chemical sensing. In this review, we highlight recent progress made regarding BPE-based electrochromic devices constructed for these analytical applications. Various, available electrochromic materials are summarized in the first section, after which the different device types (e. g., paper-based and self-powered) are discussed. Biological- and chemical-based analytical demonstrations of these devices are then reviewed. Finally, we conclude this review with a perspective on the future developments of BPE-based electrochromic devices in analytical applications.     

Synthesis,characterization and applications of schiff base chemosensor for determination of Cu2+ ions

A novel thiazole-based Schiffbase chemosensor SB1 with N- and O- donor atoms was synthesized and characterized by different techniques (UV–vis, ¹³C NMR, ¹H NMR, and FT-IR analysis). The chemosensor SB1 was used for the determination of Cu²⁺ ions in various samples. The significant spectral changes in absorption spectra of chemosensor SB1 at 220 and 416 nm and the color change from light yellow to yellowish-brown indicate high selectivity and sensitivity towards Cu²⁺ ions as compared to other cations (Na⁺, K⁺, Ag⁺, Zn²⁺, Ni²⁺, Pb²⁺, Mn²⁺, Mg²⁺, Co²⁺, Cd²⁺, Sn²⁺, Hg²⁺, Cr³⁺, Fe^3+, and Al³⁺). The sensing mechanism of SB1 was investigated through various techniques such as FT-IR, UV–vis and ¹H NMR titration experiment and further confirmed by DFT computational studies. The 2:1 binding mode between SB1 and Cu²⁺ ions was confirmed by Job‘s plot using UV–vis spectrophotometry. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 0.015 and 0.0471 µg mL^?1, respectively. The percent recovery of Cu²⁺ from various environmental samples was found to be 95.00–103.33% at various levels. These obtained results demonstrate that chemosensor SB1 is a cost-effective, facile, selective, sensitive, and colorimetric sensing platform to detect trace amounts of Cu²⁺ ions in variousenvironmental and agricultural samples.     

Ion chromatograph with three-dimensional printed absorbance detector for indirect ultraviolet absorbance detection of phosphate in effluent and natural waters

An ion chromatography system employing a low-cost three-dimensional printed absorbance detector for indirect ultraviolet detection towards portable phosphate analysis of environmental and industrial waters has been developed. The optical detection cell was fabricated using stereolithography three-dimensional printing of nanocomposite material. Chromatographic analysis and detection of phosphate were carried out using a CS5A 4 × 250 mm analytical column with indirect ultraviolet detection using a 255 nm light-emitting diode. Isocratic elution using a 0.6 mM potassium phthalate eluent combined with 1.44 mM sodium bicarbonate was employed at a flow rate of 0.75 mL/min. A linear calibration range of 0.5 to 30 mg/L PO₄³⁻ applicable to environmental and wastewater analysis was achieved. For retention time and peak area repeatability, relative standard deviation values were 0.68 and 4.09%, respectively. Environmental and wastewater samples were analyzed with the optimized ion chromatography platform and the results were compared to values obtained by an accredited ion chromatograph. For the analysis of environmental samples, relative errors of <14 % were achieved. Recovery analysis was also carried out on both freshwater and wastewater samples and recovery results were within the acceptable range for water analysis using standard ion chromatography methods.     

Cysteine combined with carbon black as support for electrodeposition of poly (1,8-Diaminonaphthalene): Application as sensing material for efficient determination of nitrite ions

Poly 1,8-Diaminonaphtahlene/cysteine (poly 1,8-DAN/Cys) combined with carbon black (CB) nanoparticles are proposed as an excellent sensor for the detection of nitrite ions. To design the electrocatalyst, a simple approach consisting on drop-casting method was applied to disperse carbon black on the surface of glassy carbon electrode, followed by the immobilization of cysteine on the surface of CB nanoparticles. The electrochemical polymerization of 1,8-Diaminonaphthalene was conducted in acidic medium by using cyclic voltammetry. The prepared hybrid material was denoted poly 1,8-DAN /Cys/CB. Several methods were used to characterize the structural and electrochemical behavior of the reported hybrid material including Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), amperometry and differential pulse voltammetry (DPV). The prepared electrode displayed an outstanding electroactivity towards nitrite ions reflected by an enhancement in the intensity of the current and a decrease of the charge transfer resistance. Poly 1,8-DAN/Cys/CB displayed an excellent sensing performance towards the detection of nitrite with a very low detection limit of 0.25 µM. Two linear ranges of 1–40 µM and 20–210 µM when using amperometry and differential pulse voltammetry (DPV) were obtained respectively. This work highlights the simple preparation of a polymeric film rich in amine and thiol groups for nitrite detection.     

Preparation and fabrication of porous-Fe2O3/carbon black nanocomposite: a portable electrochemical sensor for psychotropic drug detection in environmental samples

Herein, we reported the fabrication of porous iron oxide/carbon black (P–Fe₂O₃/CB) composite through a two-step engineering method. At first, Prussian blue microcubes were used as a precursor and further calcined to form P–Fe₂O₃ microcubes. The intercalation of CB nanoparticles with P–Fe₂O₃ nanocubes was processed through the ultrasonication method. The obtained P–Fe₂O₃/CB were successfully scrutinized through various physiochemical characterization methods. The proposed P–Fe₂O₃/CB-modified glassy carbon electrode sensor was successfully implemented in the electrochemical sensing of chlorpromazine hydrochloride due to its very low charge transfer resistance (R_ct) compared to the other electrode modifiers. The sensitive detection of CPMH through differential pulse voltammetry exemplifies an excellent electroanalytical performance such as a wide linear range of 0.5–1472 μM, a lower detection limit (0.001 μM), and an appraisable sensitivity of 1.99 μA/μM cm^?2 due to its availability of a high number of active sites and its large surface area, respectively. It also expresses excellent selectivity, repeatability, reproducibility, and stability results. Moreover, the practical feasibility of the as-fabricated P–Fe₂O₃/CB/glassy carbon electrode sensor shows exquisite recovery (98.1–100.8%) results with an appraisable current response in various biological, pharmaceutical, and environmental samples.     

Artificial intelligence-based microfluidic platforms for the sensitive detection of environmental pollutants: Recent advances and prospects

Environmental pollution and its drastic effects on human and animal health have urged governments to implement strict policies to minimize damage. The first step in applying such policies is to find reliable methods to detect pollution in various media, including water, food, soil, and air. In this regard, various approaches such as spectrophotometric, chromatographic, and electrochemical techniques have been proposed. To overcome the limitations associated with conventional analytical methods, microfluidic devices have emerged as sensitive technologies capable of generating high content information during the past few years. The passage of contaminant samples through the microfluidic channels provides essential details about the whole environment after detection by the detector. In the meantime, artificial intelligence is an ideal means to identify, classify, characterize, and even predict the data obtained from microfluidic systems. The development of microfluidic devices with integrated machine learning and artificial intelligence is promising for the development of next-generation monitoring systems. Combination of the two systems ensures time efficient setups with easy operation. This review article is dedicated to the recent developments in microfluidic chips coupled with artificial intelligence technology for the evolution of more convenient pollution monitoring systems.     

微流控芯片液滴生成与检测技术研究进展

微流控芯片液滴技术是一种操控微小体积液体的新技术,既可实现高通量微观样本的生成及控制,也可进行独立液滴的操作。分散的微液滴单元可作为理想的微反应器,在生物医药中的药物筛选、材料筛选和高附加值微颗粒材料合成领域展现出巨大的应用潜力。液滴微流控芯片是利用流体剪切力的改变,使互不相溶的两相流体在其界面处生成稳定、有序的液滴,目前微液滴的生成方法主要有水动力法、气动法、光控法和电动法等。基于液滴的微流控系统越来越多地被应用于执行复杂的多重反应、测量和分析,可以进行超小体积和超高吞吐量的化学和生物实验。对液滴微流控系统而言,液滴的速度、大小和内容物含量会影响最终的检验结果,因此对液滴形成速率和液滴的内容物含量的实时检测至关重要,目前最常用的液滴检测方法有光学检测技术与电学传感检测技术。对两相流液滴生成机理以及现有液滴生成技术开展了讨论分析,同时对液滴检测技术进行了评述。     

氮掺杂鸡毛碳点荧光关开探针用于测定百草枯

以鸡毛和乙二胺为碳源和氮源,通过一步水热法合成强荧光性能的氮掺杂碳量子点(N-CQDs),并优化其制备和掺杂条件。该碳量子点具有良好的光学、结构性质和稳定性,平均粒径7.89 nm,荧光量子产率为14%。最大激发波长为320 nm,最大发射波长为386 nm。Hg²⁺存在条件下N-CQDs溶液的荧光被猝灭(关),添加百草枯后猝灭的荧光被恢复(开)。通过N-CQDs/Hg²⁺体系设计了荧光"关-开"方法,在最佳条件下,百草枯在0.05~1.0μg/mL范围内具有良好的线性,线性方程为ΔF=92.41X+123.31(R²=0.9989),检出限为16μg/L,加标回收率为95.3%~104.4%,RSD<3.8%。以鸡毛为原料制备的高选择性和灵敏性的荧光"关-开"探针方法可有效检测实际样品中的百草枯。