Topic overview

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In electrophoresis, an analyte’s charge and size influence its mobility; buffer conditions, temperature, and electroosmotic flow also affect migration. Formats include capillary electrophoresis, slab gels, SDS-PAGE, isoelectric focusing, two-dimensional electrophoresis, and pulsed-field methods. Detection can use UV, fluorescence, conductivity, or mass-spectrometry coupling. Applications include assessing purity, protein charge heterogeneity, glycoforms, nucleic-acid size, and peptide maps. X-ray crystallography derives a three-dimensional structure from diffraction by a crystal lattice. Its workflow proceeds through crystallization, data collection, phase determination, electron-density mapping, and model refinement. The method can reveal crystal forms and molecular interactions, but depends on suitable crystals and has limitations such as radiation damage and providing a static structural view. Together, the techniques answer distinct analytical questions.