Conductance detection system and method

A conductance detector for detecting conductivity and/or dielectric constant of one or more chemical and/or biological species dispersed in a phase and separated by an integrated substantially planar gel electrophoresis apparatus, comprising:

• a first rigid architecture having a top surface a portion of which is electrically conductive forming a first conductive component, the first component being insulated from the phase;
• a second conductive component, the second component being insulated from the phase;
• a gel component through which displacement current generated by the first or second conductive components flows;
• flow pathways through the gel component for the chemical and/or biological species to flow;
• a power supply for generating a time dependent electrical signal for inducing a time dependent response, the power supply being coupled to at least one of said first and second conductive components;
• a signal detector coupled to at least one of said first and second conductive components for measuring the time dependent response;
• and
• a processor connected to said signal detector configured to determine changes in conductance caused by a presence of said chemical and/or biological species.

A method for detecting conductivity and/or dielectric constant of one or more chemical and/or biological species in a phase, comprising:

• flowing a phase being tested for the one or more chemical and/or biological species through a cell structure, the cell structure including
• a rigid architecture having a first electrically conductive component separated from a second conductive component by an insulating component,
• one or more flow pathways between the first conductive component and the second conductive component for the chemical and/or biological species to flow,
• the first conductive component, the second conductive component and the insulating component having an architecture selected to give
• a cross sectional area over which a displacement current and/or external current flows that is on an order of about 1 cm2;
• and
• a distance over which the displacement current and/or external current flows that is in a range from ˜nanometer to hundreds of microns and even higher;
• applying a time dependent electrical signal to at least one of said first and second conductive components for inducing a time dependent response;
• and
• measuring the time dependent response and determining from said time dependent response any changes in conductance caused by a presence of said chemical and/or biological species in said phase.

A method for detecting conductivity and/or dielectric constant of one or more chemical and/or biological species dispersed in a phase and separated by an integrated substantially planar gel electrophoresis apparatus, comprising:

• flowing said phase containing the one or more chemical and/or biological species through a substantially planar electrophoresis gel component which is located between
• a first electrically conductive component, the first electrically component being insulated from the phase and a second electrically conductive component, the second electrically component being insulated from the phase;
• a gel component through which displacement current generated by the first or second conductive components flows;
• flow pathways through the gel component for the chemical and/or biological species to flow;
• applying a time dependent electrical signal for inducing a time dependent response at least one of said first and second conductive components wherein a displacement current is generated by the first or second conductive components flows;
• measuring the time dependent response and processing the measured time dependent response for determining changes in conductance caused by a presence of said chemical and/or biological species in said phase.