Liposome concentration fraction measurements (over the size range of 80 -180 nm) using TRPS.

TRPS Redefining Concentration Measurements

TRPS has redefined concentration measurements to determine particle concentrations within a clearly defined particle size range. Other concentration measurement techniques only measure the ‘total’ particle concentration, which will crucially depend on the dynamic size range of the technique used and hence be very subjective. Standardisation will be critical, if particle concentrations are to be compared between different samples and research groups in a sensible and reproducible way.

Determining Particle Concentration

Fluid flows through the nanopore as a function of applied pressure. Particle concentration is determined by measuring particle count rate, the higher the concentration the higher the rate of particles for the same fluid flow.  

The relationship between an applied pressure and the measured frequency of blockade events is linear for a given particle. Measurement of a reference standard provides a calibration of the nanopores against which any other sample can be compared to obtain an accurate absolute concentration value. Measuring the sample at 3 different pressures removes the effects electrophoresis, and electroosomosis have on fluid flow.

Comprehensive information on determining particle concentration can be found in our white paper on TRPS technology.