Conductivity assay

Conductivity analysis is a fundamental physicochemical technique used to assess a solution's ability to conduct electricity. This property depends directly on the nature and concentration of dissolved ions: mineral salts, acids, bases, ionic surfactants, and contaminants. This analysis is widely used in the cosmetics, food and beverage, environmental, and pharmaceutical industries, as well as in industrial processes requiring strict control of solution purity.

Conductivity is a key indicator for verifying the quality of raw materials, controlling aqueous formulations, or monitoring processes involving ion exchange. It also helps identify defects, contamination, or batch variations that could compromise a product's stability or safety.

The importance of dosage in cosmetics and aqueous formulations

In cosmetics, conductivity is a key parameter for:

• to control the purity of the water used in the formulations
• monitor the ionic stability of lotions, gels, micellar solutions or serums
• detect ionic contamination (corrosion, migration from packaging, raw material residues)
• to evaluate the interaction between ionic excipients and water-soluble active ingredients
• characterize electrolytic formulations or products intended for specific devices

Changes in conductivity can reveal physicochemical destabilization, pH changes, or microbiological degradation. This makes it an indispensable tool for quality, R&D, and regulatory compliance departments.

Analytical method

The analysis is performed by conductimetry, a simple, rapid, and extremely sensitive technique. A conductimeter measures the electrical resistance of the solution to the passage of an alternating current between two electrodes. The value obtained is converted into conductivity, generally expressed in µS/cm or mS/cm.

The analysis can be performed:

• at 20°C or 25°C
• in a thermostatic cell
• with calibration to certified standards (KCl)
• according to current standards in the physico-chemistry of water

Temperature compensation is often applied because conductivity increases by about 2% per degree.

Analyzed matrices

• cosmetic waters and process waters
• ionic solutions and micellar solutions
• hydroglycolic or water-soluble plant extracts
• products for cosmetic medical devices
• complex aqueous preparations
• liquid raw materials or technical ingredients
• ultrapure production or cleaning water

Additional applications and related analyses

Depending on the nature of the product, conductivity can be supplemented by various relevant physico-chemical analyses.

pH determination (direct or in solution)
Often correlated with conductivity, pH strongly influences the dissociation of ions.

P2 type water assay
Competent for verifying the purity of technical waters used in cosmetics.

Water dosage type D1
Additional analysis for industrial processes requiring strict control.

Liquid density analysis
Often associated with quality monitoring and characterization of aqueous formulations.

Electrochemical potential determination
https://yeswelab.fr/catalogue-analyses/dosage-potentiel-electrochimique/
A useful complement for sensitive ionic systems or technical formulations.

Importance for quality control

Conductivity measurement addresses several industrial challenges:

verification of raw material conformity,
control of repeatability between batches,
monitoring of production lines requiring purified water,
rapid detection of pollution, corrosion or rinsing defects,
optimization of ionic or micellar formulations

Because of its speed and low cost, analysis is commonly integrated into regular control plans.

Why have this analysis done via YesWeLab?

YesWeLab enables cosmetics and technical formulation manufacturers to access specialized physicochemical laboratories, guaranteeing standardized methods, calibrated equipment, and support tailored to regulatory requirements. Our platform simplifies analysis management, sample submission, and results tracking, while guiding you toward the best technique for your specific matrix.