Impurity Localization
Impurity Localization - Related Videos
09:14
Glovebox and Impurity Sensors
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2023
Source: Tamara M. Powers, Department of Chemistry, Texas A&M University The glovebox provides a straightforward means to handle air- and moisture-sensitive solids and liquids. The glovebox is what it sounds like: a box with gloves attached to one or more sides, which allows the user to perform manipulations within the glovebox under an inert atmosphere. For manipulations under inert atmospheres, chemists can choose between Schlenk or high-vacuum techniques and a glovebox. Schlenk and...
11:42
Fabrication of Gate-tunable Graphene Devices for Scanning Tunneling Microscopy Studies with Coulomb Impurities
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Cited by 14 •
2015
This paper details the fabrication process of a gate-tunable graphene device, decorated with Coulomb impurities for scanning tunneling microscopy studies. Mapping the spatially dependent electronic structure of graphene in the presence of charged impurities unveils the unique behavior of its relativistic charge carriers in response to a local Coulomb potential.
01:19
Pharmaceutical Alternatives: Excipients and Impurities-Related Therapeutic Nonequivalence
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2025
Pharmaceutical products contain more than just the active drug; they also contain various excipients such as binders, solubilizers, stabilizers, preservatives, and other elements. In some cases, impurities or contaminants might be present. Traditionally, quality control in pharmaceuticals has primarily focused on the analysis of the active drug, often overlooking the impact of these additional components. The recent issue with heparin contamination by over-sulfated chondroitin sulfate, a...
11:23
Purifying the Impure: Sequencing Metagenomes and Metatranscriptomes from Complex Animal-associated Samples
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Cited by 30 •
2014
Using the cystic fibrosis airway as an example, the manuscript presents a comprehensive workflow comprising a combination of metagenomic and metatranscriptomic approaches to characterize the microbial and viral communities in animal-associated samples.
13:13
Nano-fEM: Protein Localization Using Photo-activated Localization Microscopy and Electron Microscopy
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Cited by 14 •
2012
We describe a method to localize fluorescently tagged proteins in electron micrographs. Fluorescence is first localized using photo-activated localization microscopy on ultrathin sections. These images are then aligned to electron micrographs of the same section.
FAQs
Impurity localization becomes reliable when spatially resolved measurements are compared across the material rather than interpreted from a single average composition. Microscopy shows regional structure, spectroscopy probes composition and bonding, and chemical mapping connects those signals to particular sites. Their combined evidence can separate a surface-associated species from one incorporated into the material.
Location changes the chemical meaning of an impurity. A species at the surface may reflect contamination acquired during processing, whereas one in the bulk can indicate incorporation during synthesis or crystallization. Separating these possibilities helps chemists choose an appropriate purification strategy and interpret whether altered behavior originates at an exposed region or throughout the material.
Grain boundaries and interfaces should be treated as distinct regions, not folded into a bulk measurement. Their composition or bonding may differ from neighboring phases, so localized chemical evidence can reveal concentration in these boundaries. This regional distinction is important when relating impurities to changes in reactivity, conductivity, stability, or catalytic performance.
These stages provide different opportunities for unintended species to become localized. Synthesis may place an impurity within the developing material, processing may introduce surface contamination, and crystallization may produce incorporation or concentration in particular regions. Comparing localization with the material’s history helps chemists connect observed spatial patterns to the stage most likely responsible.
Begin by identifying the regions that could differ, such as the surface, bulk phase, grain boundaries, and interfaces. Then combine microscopy, spectroscopy, and chemical mapping so that structural, compositional, and bonding information can be compared spatially. Finally, interpret the regional signals against the synthesis, processing, or crystallization history to distinguish origin from later contamination.
Localization is especially useful when an impurity may explain a change in material behavior but its overall amount does not identify the cause. Regional analysis can show whether the species is associated with a surface, internal phase, boundary, or interface. That information supports purification decisions and helps explain altered reactivity, conductivity, stability, or catalytic performance.