Analytical Chemistry最新文献

GlycosylatedRNAs (glycoRNAs) are involved in immune response,cellular function, gene regulation, and disease development. We reporta liquid chromatography–mass spectrometry (LC-MS) method toanalyze glycans released from glycoRNAs. The developed method includesextracting RNA from mouse liver using TRIzol, digesting proteins withproteinase K under denaturing conditions, re-extracting RNA usingTRIzol, releasing N-glycans by enzymatic digestion,enriching glycans by solid-phase extraction, and analyzing glycansby LC-MS. The method was optimized to detect low-abundance N-glycans from a purchased mixture of N-glycan standards, and 65 glycans were identified. We then appliedthe method to analyze the glycans released from the glycoRNAs in mouseliver and identified 244 N-glycans from triplicateanalyses. We also detected 40 significantly changed N-glycans in the livers of 32-week-old female and male KvB2 mice.This study establishes a simple and efficient technique for characterizing N-glycans in glycoRNAs and paves the way for future studiesto understand the function of glycoRNAs.

Increasing concerns over perfluorooctanoicacid (PFOA),a representativeper- and polyfluoroalkyl substance (PFAS) often referred to as “foreverchemicals”, underscore the urgent need for simple, rapid, andsensitive detection strategies for water monitoring. Herein, we reportan ultrasensitive colorimetric sensing platform for monitoring tracelevels of PFOA in environmental water using a highly efficient hybridnanozyme, Fe₃O₄@MWCNTs. UV–vis absorbanceanalysis confirmed that the nanozyme composite effectively catalyzesthe oxidation of chromogenic substrates, such as 3,3′,5,5′-tetramethylbenzidine(TMB), exhibiting a characteristic blue color in the presence of hydrogenperoxide (H₂O₂). Upon exposure to PFOA, theactive sites on the nanozyme interface were blocked by PFOA, suppressingTMB oxidation and resulting in a clear “Turn-off” opticalresponse. This sensing platform enabled quantitative detection ofultralow concentrations of PFOA, ranging from 10 to 1,000 ng/L, witha limit of detection (LOD) of 3.12 ng/L. This work provides a cost-effective,rapid, and practical approach for monitoring environmentally relevantPFOA concentrations in water.

Pseudomonas aeruginosa is a Gram-negativeopportunisticbacterial pathogen posing severe threat to environmental safety andhuman health. To achieve rapid and accurate detection, we developeda nanobody-based colorimetric-fluorescent dual-mode sandwich immunosensorusing natural fluorescent probe and further integrated machine learningto enhance the signal readout and improve detection sensitivity. Here,specific nanobodies toward P. aeruginosa were successfullydeveloped for the first time by biopanning against an immune phage-displayednanobody library. Natural fluorescent quinine, which possesses intrinsicfluorescence and undergoes fluorescence quenching via an internalquenching effect, was employed as the fluorescent probe. With thebaseline LODs obtained by direct fitting of the raw optical signals(9.005 × 10⁵ CFU/mL for colorimetry and 3.02 ×10³ CFU/mL for fluorescence), an XGBoost model was introducedand further reduces the LOD to 3.269 × 10³ CFU/mLand 3.96 × 10² CFU/mL, achieving a 275-fold and 7.6-foldimprovement in sensitivity, respectively. Furthermore, following abrief pre-enrichment, this method enables detection of P. aeruginosa at concentrations as low as 10 CFU/mL. Recoveriesin water samples ranged from 81.47% to 119.47%, with a coefficientof variation below 8.44%, showing good agreement with machine learningpredictions (R² = 0.957). No cross-reactivitywas observed with closely related or heterologous bacteria. This methodprovides a technical approach for the precise quantitative monitoringof P. aeruginosa in complex environments.

Theburgeoning demand for efficient multienzyme cascades necessitatesadvanced scaffolds capable of precise spatial organization; however,constructing heterostructured multilayer frameworks (HMFs) remainsa formidable challenge due to harsh solvothermal conditions and impreciseenzyme localization. Herein, a biocompatible, interface-directed strategyis reported to engineer a cell-mimetic metal–organic framework@covalentorganic framework (MOF@COF) heterostructure as a versatile colorimetricbiosensing platform. Specifically, glucose oxidase immobilizationwithin defect-rich (COOH)₂-UiO-66 via competitive coordinationgenerated robust sensing elements. Subsequently, ionic liquid-catalyzedinterfacial nucleation orchestrated the in situ growthof a horseradish peroxidase-encapsulated COF shell, yielding a compartmentalizedarchitecture with hierarchical channels. Mechanistic investigationsand density functional theory (DFT) calculations reveal that the support’sdefect density and interfacial adsorption energy, rather than long-rangecrystallinity, dictate the directional assembly of the COF layer.This heterostructure exhibits enhanced cascade activity and analyticalreliability through spatial proximity and reduced mass transfer resistanceover conventional one-pot or stepwise assemblies, while control studieswith zeolitic imidazolate framework-8 and hydrogen-bonded organicframework counterparts underscore its superiority in proximity-inducedintermediate transfer. Integrating monomer reactivity with topologicalsymmetry offers a predictive blueprint for customizing structurallydiverse HMF libraries. Ultimately, flexible replacement of the coreenzyme enables the functional validation of this platform throughthe colorimetric quantification of glucose and hypoxanthine, offeringa rational blueprint for engineering biointerfaced heterostructuresin cascade biocatalysis.

Highly fluorescent 2D MoS_2–x nanosheetsexhibitingintense blue emission were synthesized using a green chemistry approach,utilizing DES as both the reaction medium and a surface passivatingagent. The material was synthesized via a hydrothermal method, followedby ultrasonication-assisted exfoliation to yield ultrathin nanosheetswith enhanced photoluminescence properties. The 2D MoS_2–x nanosheets demonstrated strong fluorescence at λ_em = 420 nm when excited at λ_ex = 330 nm. These nanosheetswere employed as a fluorescence probe for the detection of the calciumchannel blocker drug nifedipine (NIF) via a fluorescence quenchingmechanism. Upon addition of NIF, the fluorescence of the 2D MoS_2–x nanosheets was quenched due to electron transferfrom the nanosheets to the electron-deficient NIF molecules, combinedwith the inner filter effect (IFE). The nanosheets enabled highlysensitive and selective detection of NIF, with photoluminescence spectroscopyrevealing a broad linear detection range of 0.6–360 nM (R² = 0.993) and an exceptionally low limit of detection (LOD)of 0.40 nM. The system showed high selectivity toward NIF over structurallysimilar compounds, drugs, and common metal ions. The sensor was effectivelyapplied for the detection of NIF in urine and Lotus Pond water samples,highlighting its potential for practical pharmacological monitoring.This study presents a sustainable and effective approach for fabricatingDES-assisted 2D nanosheets for trace-level analyte detection.

Mass spectral MS/MSlibraries are essential in nontargeted metabolomicsas they facilitate metabolite annotation and provide the basis forin silico annotation tools and fragmentation rules. While significantprogress has been made toward more comprehensive MS/MS libraries,those efforts have focused mainly on collision-induced dissociation(CID)- and higher-energy collisional dissociation (HCD)-based approaches.In this work, we introduce a flow injection-high-resolution targetedMS/MS-based acquisition strategy that acquires electron-activateddissociation (EAD) and CID across a wide range of fragmentation energieswithin a single injection. The workflow supports both nontargetedand targeted analysis, through efficient library generation and MS/MSparameter optimization, respectively. We apply the workflow via aset of 45 steroid standards, known for their important role in humanhealth, disease, and doping, expanding the coverage of public librariesfor both CID and EAD. Finally, we utilize public MS/MS libraries andraw data to reveal that EAD MS/MS spectra can, to some extent, beannotated via existing MS/MS libraries, governed by CID and HCD, andshow that the acquired CID library enables novel annotations in publiclyavailable clinical data, demonstrating its utility for biologicalstudies.

A novel gas sensing method based on heterodyne Mach–Zehnderinterferometric phase-dispersion spectroscopy (HMIPDS) was proposedfor the first time in this work. The proposed method employed a heterodyneMach–Zehnder interferometric configuration to realize gas sensingthrough cumulative optical phase shifts induced by refractive-indexvariations during laser-gas interaction. Specifically, the laser beamwas divided into a signal arm interacting with the gas medium anda reference arm frequency-shifted by an acousto-optic modulator (AOM)to generate heterodyne interference. The gas-induced optical phasevariation was then accurately extracted via quadrature demodulationof the interference signal, thereby enabling quantitative retrievalof gas concentration. Acetylene (C₂H₂) was usedfor experimental validation. Experimental results demonstrate theHMIPDS method achieved a detection limit of 708 ppb with an integrationtime of 500 s, corresponding to an approximately 11-fold improvementin detection sensitivity compared with the conventional WMS-2f detection system (8 ppm at 500 s). Furthermore, the lineardynamic detection range was extended from 0 to 2% for conventionalWMS-2f to 0–5%, corresponding to an approximately2.5-fold enhancement. The proposed HMIPDS method provides a high sensitivity,high stability, and wide dynamic range solution for gas sensing, showingstrong potential for high-concentration and ultrasensitive trace gasdetection applications.