Particulate SystemsNano Particle Size, Molecular Weight and Zeta Potential DLS Analyzer

Outstanding performance, sensitivity, compact bench-top footprint, and intuitive software make the NanoPlus series of products the preferred choice in determining particle size and zeta potential on a wide variety of materials.

Highly Accurate Zeta Potential Measurements of Concentrated Solutions
Patented FST technology utilizes a transparent electrode to minimize path length and reduce multiple scattering effects. This technology permits accurate zeta potential measurement in a wide concentration range of 0.00001 to 40% (w/v) unique to the NanoPlus, eliminating the need to dilute samples.
True Determination of Electrophoretic Mobility
The NanoPlus negates the effects of electroosmosis by measuring zeta potential at five different locations within the cell. As a result, the instrument can calculate and accurately measure true electrophoretic mobility, resulting in a highly accurate determination of zeta potential. This also provides the ability to determine multi-modal distributions of zeta potential mixtures.
Broad Particle Sizing Range with Increased Sensitivity
The Nanoplus has a dynamic sizing range of 0.1 nm to 12.30 µm in a concentration range of up to 40% w/v, and a sensitivity for molecular weight to as low as 250 Da. Dual correlators, log-scale for larger particles prone to time decay and linear scale for small particles, provide high sensitivity measurements in multicomponent samples.
Wide Range of Measuring Cells
The NanoPlus features a wide range of measuring cells available for both zeta and nano particle size measurements. Included is a unique solid sample cell for zeta potential measurement of coated surfaces, films or treated glass slides.

There are three models available:

  • NanoPlus-1 – nano particle sizing instrument
  • NanoPlus-2 – zeta potential instrument
  • NanoPlus-3 – combination nano particle sizing and zeta potential instrument.

For more information take a look at the attached documents.

  1. NanoPlus Sample Cell

    NanoPlus Sample Cells

    The NanoPlus has an array of compatible sample cells for both zeta potential and nano particle size measurements. Each sample cell provides additional measurement capabilities of samples in liquid suspensions

    Particle Size
    – For use with the NanoPlus-1 and NanoPlus-3

    • Standard nano particle sizing cell (0.09) mL) – one included with NanoPlus-1 and NanoPlus-3
    • Disposable nano particle sizing cell (0.90 mL)
    • Micro volume nano particle sizing cell (20 μL)
    • Flow cell assembly for nano particle sizing
    Zeta Potential
    – For use with the NanoPlus-2 and NanoPlus-3

    • Standard sample flow cell assembly (0.70 mL) one included with NanoPlus-2 and NanoPlus-3
    • Micro volume cell assembly (130 μL)
    • Disposable cell for zeta potential measurement
    • High concentration sample cell for zeta potential measurement
    • Low conductivity sample cell for zeta potential measurement
    • Solid sample cell for zeta potential measurement


  1. Principle of Particle Sizing

    Priciples of Particle Sizing

     Particulates dispersed in a solution are normally subject to Brownian motion. The motion is slower with larger particles and faster with smaller particles. When laser light illuminates particles under the influence of Brownian motion, scattered light from the particles shows fluctuation corresponding to individual particles.The fluctuation is observed according to the pinhole type photon detection method, so that particle size and particle size distributions are calculated.



  1. Zeta Potential

    Principle of Zeta Potential Measurement


    In most cases, colloidal particles possess a positive or negative electrostatic charge. As electrical fields are applied to the particle dispersion, the particles migrate in oppositely charged directions. As particles are irradiated in migration, scattering light causes Doppler shift depending on electrophoresis mobility. NanoPlus software calculates the amount of Doppler shift followed by electrophoretic mobility and zeta potential by combining a heterodyne system and photon correlation method to perform Fourier transform (FFT) Slipping level Major part of medium of obtained correlation function.




    Zeta Potential Measurement Features of the NanoPlus-2 and NanoPlus-3

    • Measures zeta-potential of a sample suspension in the range of -500 mV to +500 mV with concentrations from 0.001% to 40%
    • Reliable measurements based on electrophoretic light scattering technology conforms to ISO 13099-2
    • Accurately measures both dilute and concentrated suspensions
    • Capable of evaluating the surface charge on solid surfaces, film, etc. based on electroosmotic probing
    • Variety of sample cells available


    The NanoPlus is capable of obtaining high resolution zeta potential analyses even with multi-component samples. In the examle on the right, a mixture of five polystyrene latexes of different particle sizes was measured. Five spectrums corresponding to each lotex component was detected. The seta potential of these components were in the range of -45mV to -107 mV


    Evaluation of Dispersion Stability by Zeta Potential/Particle Size

    As the absolute value of zeta potential is larger, many colloidal particles show good dispersability as the electrostatic repulsion becomes stronger. However, as the zeta potential registers close to zero, the particles become unstable and are likely to aggregate


  1. FST Method

    Concept of FST Method

    FST – Electrophoretic mobility measurement of concentrated suspension using Forward Scattering through Transparent electrode.

    By conventional methods, scattered light from a concentrated suspension can not be measured correctly due to multiple scattering (A). The FST method detects the scattered light from particles through a transparent electrode. The optical path length is minimized to reduce the effects of multiple scattering. Thus, the NanoPlus can perform a zeta potential measurement of a concentrated suspension with a high degree of accuracy (B).

    Courtesy of Micromeritics

    Courtesy of Micromeritics

  1. True Electrophoretic Mobility
    Determination of True Electrophoretic Mobility

    When the measurement of electrophoresis is actually taken, an electroosmotic current is generated in the cell due to an electric charge on the cell wall. With a negatively charged cell wall, the electroosmotic flow phenomenon causes the positively charged ions and particles to gather together by the cell walls. The solution located by the cell walls migrates toward the negative electrode during electrophoresis. The solution located in the cell center moves in the opposite direction (toward the positive electrode) to compensate for the flow by the cell walls. Therefore, an electroosmotic flow is created during electrophoresis. The NanoPlus is designed to measure electrophoretic mobility at several points in the cell to obtain a position (i.e. static) not influenced by electroosmotic flow. As a result, the instrument can calculate and accurately measure electrophoretic mobility, even if the electroosmotic profile of the system is asymmetrical due to adsorption or sedimentation of the sample.


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