Method of electrically measuring the electrical properties of individual particles flowing in a liquid

• Main Authors: Morgan, Hywel, Spencer, Daniel Christopher
• Format: Patent
• Language: English
• Published: 23.07.2019
• Subjects: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; MEASURING; PHYSICS; TESTING

A method of electrically measuring the electrical properties of individual particles flowing in a liquid, which method comprises: (i) providing apparatus (3) which is for electrically measuring the individual particles and which has: (a) a fluidic channel (5) for receiving a liquid (6) having the individual particles (4) in suspension in the liquid (6); (b) a first electrode arrangement (8) having at least one measurement electrode (16) and at least one signal electrode (11); and (c) at least one other electrode arrangement (9) having at least one measurement electrode (18) and at least one signal electrode (13); (ii) providing a flow of the liquid (6) through the fluidic channel (5); (iii) applying a first electrical signal through the liquid (6) and along a first conduction path between the measurement electrode (16) and the signal electrode (11) of the first electrode arrangement (8); (iv) applying an electrical signal through the liquid (6) and along at least one other conduction path; (v) comparing the electrical signal between the first and the other conduction paths to generate a comparison signal; (vi) detecting an individual particle passing through the apparatus (3) by detecting a feature of the comparison signal of the individual particle, and obtaining at least one output waveform; (vii) measuring a height-related feature of the output waveform of the individual particle, and generating a first order assessment of the electrical properties of the individual particle; and (viii) assessing the shape of the output waveform to perform a second order adjustment to the first order assessment of the electrical properties of the individual particle, with the second order adjustment utilising data on a perceived degree of error in the first order assessment based on information on a known relationship between the waveform shape and the error in the first order assessment.