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Laboratory Techniques β€” Principles

This section focuses on the scientific principles underlying common laboratory techniques used in peptide research. For operational procedures and protocols, refer to our Research Methods section. For COA interpretation guides, see our COA Guide.

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Principles of Peptide Chromatography

Fundamental theory of chromatographic separation β€” partition coefficients, band broadening, van Deemter equation, and selectivity in peptide chromatography.

β†’ Partition and adsorption mechanisms
β†’ van Deemter equation parameters
β†’ Selectivity (Ξ±) and resolution (Rs) theory
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Electrophoresis for Peptide Analysis

Principles of gel electrophoresis, capillary electrophoresis, and isoelectric focusing β€” the physics of peptide migration under electric fields.

β†’ SDS-PAGE principles for peptides
β†’ Capillary electrophoresis theory
β†’ Electroosmotic flow fundamentals
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Spectrophotometric Peptide Quantification

Beer-Lambert law, extinction coefficient calculation, aromatic amino acid absorption, and colorimetric peptide assays β€” principles and limitations.

β†’ A280 method and extinction coefficients
β†’ BCA and Bradford assay chemistry
β†’ Interference and accuracy considerations
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Peptide Labeling Techniques

Chemical principles of fluorescent labeling, radioisotope incorporation, biotinylation, and stable isotope labeling for peptide detection and tracking.

β†’ FITC, rhodamine, and Cy dye chemistry
β†’ SILAC and TMT labeling principles
β†’ Site-specific vs random labeling
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Peptide Digestion and Mapping

Enzymatic digestion principles, protease specificity, peptide mass fingerprinting, and sequence coverage analysis for peptide characterization.

β†’ Trypsin, chymotrypsin, and Lys-C specificity
β†’ Peptide mass fingerprinting (PMF)
β†’ Sequence coverage and missed cleavages