Surface Charge Determination-Particle

What Is the Surface Charge?

Surface charge refers to the total sum of free electric charges on the surface of particles, and it is measured in Coulombs per square meter (C/m2). It is defined as the quantity of charge per unit area.

Why Measure Surface Charge?

Surface charge is a vital parameter among particle properties, closely linked to the stability, solubility, adsorption characteristics of solid powders, aggregation behavior in solutions, and interactions between drugs and biomolecules.

Testing the surface charge of drug molecules aids in understanding their behavior, such as release and delivery, for optimization.

Additionally, proteins also carry surface charges, and understanding the surface charge of specific target proteins is crucial for targeted drug delivery and therapeutic efficacy.

How to Measure the Surface Charge of Particles?

We employ three primary techniques to measure the surface charge of particles:

  1. Potentiometric Titrations
    This method is based on the electrostatic interactions between ions in a solution. Using a charged titration solution (typically positive or negative ions), the surface charge of the sample is titrated to measure the isoelectric point (charge is zero), thus determining the surface charge of the sample.
  2. Zeta Potential Analysis
    Zeta potential analyzers calculate particle or molecular surface charge density and potential by measuring the electrophoretic movement of particles under an electric field.
  3. Atomic Force Microscopy (AFM)
    AFM examines surface properties by measuring weak atomic interactions between the test sample's surface and a tiny force-sensitive component. This enables the measurement of the surface charge.

Surface Charge Determination-Particle

Services Process

Project Initiation & Planning

We start with a comprehensive consultation with clients to understand their unique analysis requirements. During this step, we create a well-structured project plan, considering the analytical techniques and project timeline.

Sample Preparation & Analysis

Our professional analysts employ a diverse array of methods for the vital pretreatment of samples, which is essential for ensuring accurate analysis across a wide range of sample types. Following the pretreatment process, we proceed with the analysis.


Following analysis, we deliver a comprehensive report. This report includes detailed information on measurements, testing conditions, and the steps taken during the analysis process.

Follow-up Support

We maintain an open channel for communication with our clients, ensuring that any questions or concerns are addressed promptly.

Protheragen-ING is fully dedicated to meeting the demands of global clients for analysis. Please feel free to contact us if you have questions or need more information. We will respond within 2-4 working days.


Daily: 9.30 AM–6.00 PM
Sunday : 9.30 AM–1.00 PM
Holidays: Closed

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