University of Southampton

Daniel Christopher Spencer

Hywel Morgan

A method of electrically measuring the electrical properties of individual particles flowing in a liquid, which method comprises: (i) providing apparatus () which is for electrically measuring the individual particles and which has: (a) a fluidic channel () for receiving a liquid () having the individual particles () in suspension in the liquid (); (b) a first electrode arrangement () having at least one measurement electrode () and at least one signal electrode (); and (c) at least one other electrode arrangement () having at least one measurement electrode () and at least one signal electrode (); (ii) providing a flow of the liquid () through the fluidic channel (); (iii) applying a first electrical signal through the liquid () and along a first conduction path between the measurement electrode () and the signal electrode () of the first electrode arrangement (); (iv) applying an electrical signal through the liquid () 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 () 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.

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

Apparatus () for electrically measuring individual particles () flowing in a liquid (), which apparatus () comprises: (i) a fluidic channel () for receiving a liquid () having the individual particles () in suspension in the liquid (); (ii) a first electrode arrangement () having at least one measurement electrode () and at least one signal electrode (); (iii) at least one other electrode arrangement () having at least one measurement electrode and at least one signal electrode (); (iv) at least one signal conditioning electrode () positioned adjacent to at least one of the measurement electrodes () or at least one of the signal electrode (); and (v) measuring means () for measuring electrical signal changes; and the apparatus () being such that: (vi) the first and the other electrode arrangements () are connected to the measuring means () whereby individual particles passing between the first and other electrode arrangements () cause a change in electrical signal which is measured; and (vii) the electrical potential of the signal conditioning electrode () is controlled to substantially prevent current flow between the first electrode arrangement () and the other electrode arrangement ().

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Southampton, United Kingdom

Daniel Christopher Spencer