--- type: "WebPage" title: "Protein analysis using the Bradford method" description: "Your need: analyze proteins using the Bradford method The Bradford method is a technique for colorimetric protein determination (by absorbance/spectrophotometry), it is based on a series of chemical reactions which result in the formation of a colored complex. Quantify your..." resource: "https://filab.fr/en/sectors-of-activity/biopharmaceutical/protein-analysis-bradford-method/" tags: ["EN", "pll_690c6fafa44ec", "Anaïs DECAUX"] timestamp: "2026-03-12T08:24:56Z" published: "2025-11-06T14:47:14Z" language: "en" author: "Laure Durieux" --- # Protein analysis using the Bradford method ## Your need: analyze proteins using the Bradford method The Bradford method is a technique for **colorimetric protein determination (by absorbance/spectrophotometry)**, it is based on a series of chemical reactions which result in the formation of a colored complex. ### Quantify your proteins with the Bradford method In the [pharmaceutical](https://filab.fr/en/sectors-of-activity/analysis-industry-pharmaceuticals.md), [cosmetic](https://filab.fr/en/sectors-of-activity/laboratory-analysis-cosmetics.md), [chemical](https://filab.fr/en/our-services/our-analysis-services/chemical-analysis-laboratory.md) and [natural ingredients](https://filab.fr/en/our-services/our-analysis-services/chemical-analysis-laboratory/analysis-natural-ingredients.md) industries, **protein quantification** is an essential step in controlling the quality, compliance and performance of finished products. The **Bradford method** offers a quick and simple approach to protein determination, based on a **colorimetric reaction** to precisely measure the protein concentration in your samples, particularly those lightly contaminated by interferents. ### Our services on proteins The FILAB laboratory offers a wide range of analytical services related to proteins. These specialized services are aimed at manufacturers wishing to characterize their proteins of interest in detail. [Proteomic analysis](https://filab.fr/en/sectors-of-activity/biopharmaceutical/laboratory-proteomic-analysis.md) [Analysis of protein purity](https://filab.fr/en/our-services/our-expertise-services/laboratory-analysis-deposit-contamination/purity-analysis-laboratory.md), [stability](https://filab.fr/en/sectors-of-activity/health-pharmaceutical-cosmetics/stability-testing-medications-and-active-ingredients.md) or [degradation](https://filab.fr/en/sectors-of-activity/health-pharmaceutical-cosmetics/forced-degradation-study.md) [Method development](https://filab.fr/en/our-services/our-expertise-services/analytical-development.md) and [transfer](https://filab.fr/en/our-services/our-expertise-services/life-cycle-of-an-analytical-method-in-the-laboratory/analytical-method-transfer-laboratory-for-the-pharmaceutical-industry.md) [Recombinant protein analysis](https://filab.fr/en/sectors-of-activity/biopharmaceutical/biotherapeutic-recombinant-protein-characterization.md) [Protein analysis using the BCA method](https://filab.fr/en/sectors-of-activity/biopharmaceutical/protein-analysis-bca-method.md) [Protein analysis using the BCA method](https://filab.fr/en/sectors-of-activity/biopharmaceutical/protein-analysis-bca-method.md) [Protein analysis using the Lowry method](https://filab.fr/en/sectors-of-activity/biopharmaceutical/protein-analysis-lowry-method.md) [Protein identification or characterisation](https://filab.fr/en/sectors-of-activity/biopharmaceutical/biotherapeutic-recombinant-protein-characterization/protein-analysis.md) [Validation of analytical method according to ICH Q2 (R2)](https://filab.fr/en/our-services/our-expertise-services/life-cycle-of-an-analytical-method-in-the-laboratory/laboratory-analytical-method-validation/validation-of-laboratory-analysis-methods-according-to-the-ich-q2-standard/) [Training in LC technique](https://filab.fr/en/our-services/rd/laboratory-analytical-chemistry-training/lc-training-for-laboratories.md) [Glycoprotein analysis](https://filab.fr/en/sectors-of-activity/biopharmaceutical/biotherapeutic-recombinant-protein-characterization/analysis-characterization-glycoproteins.md) [Characterization of AAVs by GPC/SEC according to the MAM method](https://filab.fr/en/sectors-of-activity/biopharmaceutical/characterization-aavs-mam.md) [Protein analysis using the CBQCA method](https://filab.fr/en/sectors-of-activity/biopharmaceutical/protein-analysis-cbqca-method.md) [Detection and quantification of HCPs (Host Cell Proteins)](https://filab.fr/en/sectors-of-activity/biopharmaceutical/host-cell-protein-hcp-testing-analysis-laboratory.md) ## FILAB performs protein analysis using the Bradford method ### Why choose FILAB for protein analysis using the Bradford method? At the FILAB laboratory, we provide pharmaceutical, cosmetics and chemical manufacturers with **comprehensive analytical expertise** for **protein quantification and characterisation**. FILAB offers tailor-made solutions for protein analysis: dosage, contaminant identification and structural characterisation, supported by [cutting-edge technologies](https://filab.fr/en/our-technical-resources.md) ([LC-MSMS](https://filab.fr/en/our-technical-resources/altis-lc-msms-analysis.md), [HPLC](https://filab.fr/en/our-technical-resources/laboratory-analysis-uplc.md), [UPLC-UV](https://filab.fr/en/our-technical-resources/high-pressure-liquid-chromatography-uplc-laboratory.md), etc.). ### What is the Bradford method? The Bradford method is a technique for **measuring proteins by colorimetry (by absorbance/spectrophotometry)**. It is based on the binding of Coomassie**blue dye G-250** to proteins in an acidic environment. In the presence of proteins, the dye changes from its cationic form (red-brown, maximum absorption at 465 nm) to its anionic form (blue, maximum absorption at **595 nm**). This blue color is stable and proportional to the quantity of proteins. It makes it possible to determine the protein concentration of a sample from a protein standard (often BSA), with **good sensitivity** (µg/mL) and appreciated **speed** of execution. ### What are the main advantages of the Bradford method? Speed ​​and simplicity This is one of the fastest and easiest dosing methods to implement, requiring no heating. High sensitivity It is very sensitive, allowing the quantification of proteins at concentrations on the order of µg/mL. Low interference with certain compounds Unlike the Lowry method, it is generally little affected by reducing agents, chelating agents and certain sugars. ## FAQ How does the Bradford dosage work? The Bradford assay relies on the Coomassie blue dye. In acidic media, this dye exists primarily in two forms: - The **cationic form** (reddish-brown) in the absence of protein (absorption at 465 nm). - The **anionic form** (blue) in the presence of protein. The binding of the dye to basic and aromatic amino acids (such as arginine) stabilizes this blue form, whose maximum absorption is measured at**595 nm**. The intensity of the blue color is directly proportional to the protein concentration in the sample. At what wavelength is absorbance measured? The absorbance of the protein-dye complex (the blue form) is measured by spectrophotometer at 595 nanometers (nm). What does the term "protein variability" mean in the Bradford context? Protein variability means that the amount of blue color produced is not only proportional to the total protein mass, but also to the protein's amino acid composition. Proteins rich in basic amino acids (arginine, lysine, histidine) and aromatic amino acids (tyrosine, tryptophan) induce a more intense color response than others. Consequently, equal amounts of two different proteins can yield two different absorbances, necessitating the use of a reference standard (such as BSA) to calibrate the results.