Measuring a Wide Range of Concentrations

Overview

The resistive pulse sensing technology that is at the core of Spectradyne's nanoparticle analyzer technology counts individual particles while measuring their size and their velocity. This means that the instrument evaluates not just the distribution of nanoparticles in the analyte, but also yields absolute concentrations of these particles. This distinguishes our technology from dynamic light scattering (DLS), where no concentration information can be extracted.

Concentration Spectral Density (CSD)^TM

The concentration spectral density (CSD^TM) is a measurement-independent means of characterizing the concentration of particles of a given diameter in a sample.

• The CSD has units of particles per milliliter per nanometer (particles · mL^-1 · nm^-1), which represents the number of particles per unit sample volume (measured in mL) per unit particle diameter (measured in nm).


• A CSD of 5 × 10⁹ particles · mL^-1 · nm^-1 at a diameter of 100 nm means that there are 5 × 10⁹ particles per mL of sample with diameters between 99.5 nm and 100.5 nm.


• The CSD can be used to generate a histogram of particle density (particles · mL^-1) by integrating the CSD over the histogram bin width (measured in nm).


• A CSD displaying a Gaussian-like distribution of particle diameters centered on a certain diameter can be integrated over the range of the distribution to give the concentration of particles in that size range, in particles · mL^-1.

Raw data acquired by Spectradyne's instruments is converted to CSD units, enabling the easy quantitative conversion of measurements of different samples to absolute density units.

For more information, send an email to info@spectradynellc.com.