Patent ID: 9664643
Date: 2017-05-30
CPC Classifications: G01N

Claim:
1. A method of determining the charge of at least one test particle, comprising: applying one of an electric current or a voltage across an aperture connecting two chambers, whereby the chambers are at least partially filled with electrolyte and whereby the at least one test particle is suspended in the electrolyte of at least one of the chambers; measuring the other of the electric current or voltage across the aperture; varying a pressure differential between the two chambers, wherein the pressure differential is a non-zero pressure differential; determining the charge based on the measurements of the electric current or voltage; determining a balance pressure differential at which the force on the at least one test particle due to the pressure differential is equal and opposite to the force due to the voltage across the aperture; and wherein the balance pressure differential is determined by extrapolating the linear relationship between pressure differential and a transport rate of the at least one test particle to determine the pressure differential where the transport rate is zero.