Purpurine assay

Purpurine (CAS 81-54-9) is a natural plant-based dye belonging to the anthraquinone family. It is primarily extracted from madder ( Rubia tinctorum ) , a plant historically used for dyeing textiles, but now also studied for its antioxidant and biological properties .
Purpurine analysis allows for the madder extracts purity of plant-based dyes , and the quality control of nutraceutical or cosmetic formulations incorporating natural pigments. This analysis is part of a process of traceability and promotion of naturally derived dyes, in the face of synthetic alternatives.

Analytical methods used

Purpurin analysis relies on high-performance chromatographic methods adapted for the detection of anthraquinone compounds:

• HPLC-DAD (High-Performance Liquid Chromatography with Diode Detector) : the reference technique for the separation and quantification of natural pigments. It allows for obtaining a complete chromatographic profile and identifying purpurine among other anthraquinones such as alizarin.
• LC-MS (Liquid Chromatography coupled with Mass Spectrometry) : used for specific and sensitive detection , particularly in complex or low-concentration matrices.

reliable, reproducible, and traceable results ISO 17025 analyses .
To learn more, see also the High-Performance Liquid Chromatography (HPLC) , commonly used for the analysis of pigments and secondary metabolites.

Matrices involved

Purpurin levels can be measured on various types of natural or industrial matrices:

• Raw extracts of madder roots ( Rubia tinctorum , Rubia cordifolia ).
• Natural dyes and colorants used in cosmetics, textiles or food processing.
• Nutraceutical formulations and antioxidant products based on madder.
• Quality control samples intended for the identification of dyes of natural origin.
• This analysis makes it possible to evaluate the purpurin content , to ensure the consistency of batches and to detect any adulteration by synthetic dyes .

Industrial and scientific applications

Purpurin analysis has multiple applications in different fields:

• Authentication of natural colorants : verification of plant origin and compliance with purity specifications.
• Quality control of botanical extracts : standardization of raw materials for the nutraceutical and cosmetic industries.
• Research and innovation : study of the antioxidant, photoprotective and colorimetric properties of anthraquinones.
• Textiles and agri-food : validation of extraction processes and formulations containing natural dyes.

In the field of research, the measurement of purpurin is often associated with complementary analyses such as the measurement of alizarin (another anthraquinone in madder) or the measurement of total polyphenols to evaluate the overall antioxidant capacities of an extract.

Regulatory issues and quality

European and international regulations mandate precise labeling and complete traceability of natural colorants used in food, cosmetics, and nutraceutical products.
Purpurin analysis falls within this framework for:

• Demonstrate regulatory compliance and the absence of contamination by synthetic dyes.
• Ensure analytical consistency between production batches.
• organic certification or “clean label” initiatives .

Adherence to purity thresholds and accurate quantification of purpurin contribute to the safety of formulations and the promotion of natural products on the market.

YesWeLab's expertise

YesWeLab relies on a network of ISO 17025 and COFRAC accredited laboratories specializing in chromatographic and spectrometric analysis of natural compounds.
Each service is tailored to your needs: matrix type, analytical method, detection limit, or specific regulatory compliance.
Our experts support manufacturers, formulators, and distributors in interpreting results and implementing quality controls adapted to their natural products.

Thanks to its digital platform , YesWeLab simplifies the management of analyses: request for quotes, tracking of samples, consultation of technical reports online.

To complement your analysis, also check out:

• The dosage of chrysophanol , another anthraquinone present in certain medicinal plants.
• The dosage of rutoside (rutin) , used to evaluate the antioxidant potential of plant extracts.

For any specific request or analytical project, contact our scientific team for tailored support.