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Thermo Scientific™ Fluoraldehyde™ o-Phthaldialdehyde Reagent Solution (OPA)

Ready-to-use solution of o-phthalaldehyde, a fluorescent, amine-reactive, HPLC pre- or post-column labeling reagent to measure peptides or amino acids (Ex 340nm, Em 455nm).

Supplier:  Thermo Scientific™ 26025

Catalog No. PI26025

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Thermo Scientific™ Pierce Fluoraldehyde (OPA) Reagent is a ready-to-use solution of o-phthalaldehyde, a fluorescent pre- or post-column derivatization reagent for peptide or amino acid detection and quantitation in HPLC.

Fluoraldehyde Reagent contains OPA (o-phthalaldehyde), which reacts with primary amines of amino acids, peptide and proteins to enable fluorescent detection and quantitation. The reagent that can be used as a protein or peptide assay reagent or as a pre- or post-column detection reagent for amino acid analysis (HPLC). Reaction of OPA with proteins and peptides yields linear results over a wide range of concentrations. The Fluoraldehyde Reagent Solution is supplied ready to use and enables fast quantitation of proteins or peptides in solution.


  • For pre- or post-column amino acid derivatization for fluorescent detection and quantitation

  • Reacts with all primary amine-containing analytes to yield fluorescent isoindole derivatives

  • Provides an accurate measure of both composition and absolute protein-peptide content

  • Ideal for work with recombinant proteins and synthetic peptides

  • Can be used for fluorescent protein or peptide assay

  • Pre-column derivatization mixtures can be injected into LC without any processing

Reagent Properties:

  • Formulation: 0.8mg/mL o-phthalaldehyde (OPA) in proprietary buffer, pH 10

  • Form: Clear, colorless to slightly yellow liquid

  • Reactive toward: Primary amines (–NH2)

  • Detection: Fluorescence (excitation/emission = 340nm/455nm)

  • Application: Pre- or post-column derivatization for detection by HPLC



OPA (o-phthaldialdehyde)
945 mL
Store under nitrogen at 4°C away from oxidizing reagents and direct sunlight.


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