---
type: "WebPage"
title: "Protein analysis according to the Lowry method"
description: "Your need: to analyze proteins using the Lowry method The Lowry method is a colorimetric protein assay technique (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-lowry-method/"
tags: ["EN", "pll_690b76f634452", "Anaïs DECAUX"]
timestamp: "2026-03-12T08:19:36Z"
published: "2025-11-06T08:25:26Z"
language: "en"
author: "Laure Durieux"
---

# Protein analysis according to the Lowry method

## Your need: to analyze proteins using the Lowry method

The Lowry method is a **colorimetric protein assay technique (by absorbance/spectrophotometry)**, it is based on a series of chemical reactions which result in the formation of a colored complex.

### Quantify your protein levels with the Lowry 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 Lowry method enables **sensitive and** **specific quantification** of proteins, even at very low concentrations, through **colorimetric detection**.

### What is the Lowry method?

The Lowry method relies on the reduction of Cu²⁺ ions by peptide bonds (and aromatic amino acids) in an alkaline medium, followed by the reaction of the reduction products with the Folin-Ciocalteu reagent, yielding a colored complex that measures absorbance.

It allows the determination of the protein concentration of a sample from a protein standard, with good sensitivity (µg/mL) and broad applicability.

### 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 CBQCA method](https://filab.fr/en/sectors-of-activity/biopharmaceutical/protein-analysis-cbqca-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 Bradford method](https://filab.fr/secteur-activite/laboratoire-analyse-biopharmaceutique/analyse-proteines-methode-bradford.md)

## Our technical resources for protein analysis

 [### HPLC-MS/MS](https://filab.fr/en/our-technical-resources/laboratory-analysis-uplc/laboratory-analysis-hplc-lcms.md) [### HRMS](https://filab.fr/en/our-technical-resources/high-resolution-mass-spectrometry-hrms-analysis.md) [### LC-QTOF](https://filab.fr/en/our-technical-resources/laboratory-for-lc-qtof-analysis.md) [### Nanopore](https://filab.fr/en/our-technical-resources/nanopore-sequencing.md) [### Fluorometer](https://filab.fr/en/our-technical-resources/laboratory-fluorometer-analysis.md)
## FILAB performs protein analysis using the Lowry method

### Why choose FILAB for protein analysis using the Lowry 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 are the main advantages of the Lowry method?

 Very high sensitivity
The Lowry method allows the quantification of proteins at intermediate concentrations, making it useful for many production processes or formulations.

 Extensive compatibility with complex formulations
The Lowry method is distinguished by its wide range of applications. It can be used on a broad spectrum of matrices encountered in industrial or research environments:

- Buffer solutions: the method easily adapts to aqueous or slightly saline media used during purification or formulation steps.
- Finished formulations: whether creams, gels, injectable solutions, or supplements, the method can be adjusted to neutralize matrix interferences (surfactants, preservatives, additives, etc.).

Thanks to this broad compatibility, the Lowry method integrates seamlessly into your development, quality control, or process monitoring protocols, while ensuring reliable protein quantification regardless of your product's constraints.

  Signal reproducibility and stability
The fluorescent complex formed by the CBQCA-protein reaction is **stable over time**, ensuring **good reproducibility** of measurements and increased reliability when comparing samples.

 Complementarity with other methods
The Lowry method integrates easily into a multi-technique analytical strategy:

- Used in conjunction with BCA for different concentration ranges,
- In support of HPLC or LC-MS/MS for precise quantification prior to characterization,
- In the context of method development and validation according to ICH Q2 (R2).

## FAQ

 What is the basic principle of Lowry's method?
The**Lowry method** **is a colorimetric assay technique** for proteins in solution. It is based on a two-step reaction:

- **The Biuret reaction**, where peptide bonds reduce ions in an alkaline medium.
- **The reduction of Folin-Ciocalteu** reagents (primarily molybdic and tungstic ions) by Cu+ ions and the phenolic groups (tyrosine and tryptophan amino acids) of the proteins.

This reduction produces an intense blue color, the absorbance of which is measured by spectrophotometry.

 What is the typical sensitivity range of the Lowry method?
The Lowry method is considered very sensitive compared to the simple Biuret method. Its quantification range is generally between 0.005 and 1 mg/mL (i.e., 5 to 1000 µg/mL).

 In which biopharmaceutical contexts is the Lowry method preferred?
It is often used in Research and Development (R&D) or process control where sensitivity is required and where interfering factors can be controlled or eliminated, particularly for:

- **Monitoring protein purification** after certain chromatography steps.
- **Determining the concentration of pure protein stocks**.
- **Quantifying proteins in subcellular fractions** after lysis.

 Is Lowry's method suitable for method validation according to ICH Q2(R2)?
Yes, the Lowry method can be submitted to full method validation according to ICH Q2(R2) guidelines (specificity, accuracy, precision, limits of detection and quantification, linearity, etc.), provided that interferences are controlled and analytical performance (including precision and accuracy) meets the regulatory requirements of the target product.

 Why use the Lowry method for protein quantification?
This method is recognized for its high sensitivity, reproducibility, and adaptability to a variety of matrices.

It allows for the measurement of protein content in samples where other methods (such as Bradford or UV 280 nm) would be less suitable, particularly when high precision is required.

 What are the limitations of the Lowry method?
Certain substances can interfere with the colorimetric reaction, including:

- reducing agents,
- detergents or surfactants,
- high concentrations of salts or alkaline buffers.

However, these effects can be corrected by appropriate preparation or by developing a method specific to the matrix being studied.