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Topic Review Peer Reviewed

Matrix certified reference materials (mCRMs) are materials characterized by suitable homogeneity, stability, and traceability, with certified values, including uncertainties, and a specific matrix. mCRMs constitute a reference for instrumental analytical methods and ensure their metrological consistency. Matrix certified reference materials (mCRMs) are essential tools for ensuring the accuracy and traceability of analytical measurements, particularly for samples with complex matrices. These mCRMs are carefully manufactured materials that closely mimic the composition and properties of real samples, allowing laboratories to validate their analytical methods, calibrate analytical instruments, or check the classical methods. This article highlights the challenges associated with the production and characterization of these complex mCRMs, including obtaining homogeneous materials, establishing accurate target values, and ensuring stability for different types of materials, such as gases, liquids, and metal alloys. Additionally, the process of statistical evaluation through the use of advanced statistical methods is discussed, as is the systems approach associated with the implementation of the ISO 17034 standard, which specifies the requirements for manufacturers of reference materials. This paper also includes a summary of the current status in trends of normalization as well as mCRM production.

362
06 Jun 2025

Topic Review

Transduction Mechanisms in Nanostructured Electrochemical Sensors

Transduction mechanisms in nanostructured electrochemical sensors dictate how molecular recognition events and physical interactions at an electrode interface are converted into measurable electrical, optical, or photo-driven signals. By engineering sensor architectures across structural scales—from sub-nanometer single-atom catalysts (SACs) and quantum-confined nanoclusters to two-dimensional (2D) materials (MXenes, MOFs, COFs) and three-dimensional (3D) hierarchical porous networks—the governing signal conversion pathways shift fundamentally. These modes encompass direct inner-sphere faradaic charge transfer, electrochemiluminescence (ECL) coreactant pathways, photoelectrochemical (PEC) exciton separation, and field-effect interfacial gating. Understanding and tailoring these cross-scale transduction principles is essential for designing high-sensitivity, selective, and robust bio- and chemical sensors. The key focus herein is the physical chemistry, transport physics, and quantum mechanics underlying these distinct transduction modalities.

104
07 Aug 2026

Topic Review

Carbon Nanotubes in Electrochemical Biosensing Composites

Carbon nanotubes have been extensively used as electrochemical sensing composites due to their interesting chemical, electronic, and mechanical properties giving rise to increased performance. Due to these materials' unknown long-term ecological fate, care must be given to make their use tractable.

79
27 May 2026

Topic Review

Degradation Mechanisms in Electrochemical Biosensors

Electrochemical biosensors offer unprecedented capabilities for the rapid, highly sensitive detection of physiological biomarkers, environmental toxins, and pathogens. However, the translation of these devices from controlled in vitro laboratory settings to continuous in vivo or real-time environmental monitoring is severely bottlenecked by their operational instability over time. This topic review comprehensively details the mechanistic degradation of electrochemical biosensors. It explores the physicochemical origins of failure across the recognition and transducer interfaces, emphasizing non-specific biofouling, receptor denaturation, electrode corrosion, and the exponential decay of electron transfer kinetics. Furthermore, it mathematically quantifies how interfacial degradation manifests analytically as signal drift, noise amplification, and sensitivity loss. Finally, the entry evaluates rational engineering strategies, including zwitterionic antifouling layers and permselective polymeric membranes, establishing the fundamental parameters required to decouple sensor sensitivity from long-term interfacial degradation.

33
28 Jul 2026

Topic Review

Biomass Conversion Technologies

Biomass conversion technologies encompass a suite of thermochemical processes that transform organic matter—primarily lignocellulosic biomass—into energy carriers, chemical feedstocks, or solid residues through heat-induced chemical and physical transformations [1]. These processes operate at elevated temperatures and are fundamentally distinguished by the reaction environment, particularly the presence or absence of oxygen and the extent of oxidative conversion. The three principal thermochemical pathways are combustion, gasification, and pyrolysis, each characterized by distinct operating conditions and product distributions. Combustion involves the complete oxidation of biomass in excess oxygen, yielding carbon dioxide, water, and thermal energy [2]. Gasification subjects biomass to controlled amounts of oxygen or steam at high temperatures (typically 700–1,500°C), producing a combustible synthesis gas (syngas) composed primarily of carbon monoxide and hydrogen [3]. Pyrolysis, in contrast, entails the thermal decomposition of biomass in the complete absence of oxygen at moderate temperatures (typically 300–700°C), yielding bio-oil, syngas, and solid char [2]. The fundamental mechanisms underlying these processes involve the thermal degradation of the three principal biomass constituents—cellulose, hemicellulose, and lignin—through complex reaction networks that include depolymerization, dehydration, decarboxylation, and cross-linking reactions [4]. The product distribution and chemical composition of the conversion outputs are governed by key process parameters, including temperature, heating rate, residence time, and feedstock characteristics such as moisture content, particle size, and elemental composition [1]. Thermochemical conversion is distinguished from alternative biomass valorization routes, such as biochemical and physicochemical processes, by its reliance on thermal energy rather than biological catalysts or solvent-based extraction to drive molecular restructuring [2].

10
22 Sep 2026

Topic Review

Asymmetric Supercapacitors

An asymmetric supercapacitor is a device in which the two electrodes store charge by different mechanisms, one capacitive and one faradaic, so that their potential windows add rather than overlap. Pairing them widens the cell voltage beyond the stability limit that a symmetrical device would be restricted to, and hence raises the energy density, which scales with the square of that voltage [1]. Metal-organic frameworks and their calcination products have been examined as faradaic partners, and a device built from an unmodified cobalt zeolitic imidazolate framework delivers both high energy and power [2]. Prototype cells assembled from a nickel-cobalt oxide and a carbon negative electrode show how far the laboratory figures can be pushed [3]. Pairing an iron oxide negative electrode with an iron phosphide positive one is another route to the same voltage gain [4], and combining a perovskite-type molybdate with reduced graphene oxide extends the range of chemistries examined [5]. Cycle life at the widest voltage remains the quantity that limits what the wider window is worth.

4
23 Sep 2026

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