Going beyond the single nano region and into the
sub-nano region, the IG-1000 uses the induced grating (IG) method, which is based on a new principle for measuring the size of nanoparticles using the phenomenon of dielectrophoresis and diffracted light, to provide excellent reproducibility and the acquisition of stable data, particularly for sub-10 nm particles. The IG method does not use scattered light, is free from physical restrictions and does not require the input of the refractive index as a measurement condition. As a result, the IG-1000 can measure the size of nanoparticles simply and with high sensitivity, and is particularly effective for the analysis of single nanoparticles.

Features

High-Sensitivity Analysis of Single Nanoparticles
Stable measurement with good reproducibility is possible because the IG-1000 utilizes optical signals emitted by the diffraction grating formed by the particles, and not scattered light emitted by the particles. Even in the single nano region, a good S/N ratio can be obtained.

Resistance to Contamination
This new measurement principle is resistant to contamination and, even if the sample is mixed with small amounts of foreign particles, information about the particles to be analyzed is captured reliably. The filtering of samples in order to remove coarse particles is not required.

High Reproducibility
The IG method ensures high reproducibility and the acquisition of stable data. In particular,
high reproducibility for particle sizes of less than 10 nm removes the uncertainty of particle analysis in the single nano region. The viewing of the raw data of diffracted light is also possible, enabling a simple approximate validation of measurement results.

Simple, Three-step Workflow
With the IG-1000, analysis is easy: inject the sample, insert the electrode and begin analysis. Using the IG method, it can measure particles in the 0.5 to 200 nm range in about 30 seconds, from measurement start to displayed results.

What Is the "Induced Grating” Method?
Particle size is measured using the diffusion rate of a grating which is composed of particles in the liquid. The diffusion rate of large particles is slow and that of small particles, especially nanometers particles, is fast. The diffusion behavior of particles can be monitored by detecting the change of primary diffracted light, and the concentration of nanoparticles expresses itself as a change in the
refractive index.

In the IG-1000 a grating electrode concentrates the particles in a grid, and when the electrodes are turned off the diffraction grating disappears. The decay process of this particle density diffraction grating is measured via the change in intensity of the diffracted light, and a diffusion coefficient is obtained.
Diffraction Grating Consisting of Microscopic Particles Formed by Dielectrophoresis.

An alternating voltage is applied to cyclically arranged electrodes, and a cyclic concentration distribution of microscopic particles is formed in the liquid by dielectrophoresis. Although the cyclic concentration distribution of microscopic particles acts as a diffraction grating (a particle concentration diffraction grating), if the alternating voltage is stopped, the grating diffuses and disappears (patent pending).
Precision Measurement Achieved with Modification of Electrode Configuration.

The cyclically arranged electrodes also function as a diffraction grating, although the light created is weaker than the diffracted light created by the particle concentration diffraction grating. The electrode configuration has been modified as shown in the figure so that the pitch of the electrode diffraction grating is half that of the particle concentration diffraction grating (patent pending). In this way there is a more precise measurement.

Specifications

*1: Do not use the kind of solvents that may damage Pyrex glass.
* : Measurement is possible as long as the conductivity of the sample liquid does not exceed 400 μS/cm (microsiemens per centimeter). (For example, saline and seawater cannot be used for measurement unless they are greatly diluted.)