A sampling plate comprising: a sample zone for receiving an aqueous liquid sample; wherein said sample zone is surrounded by an air-porous body which is in fluid communication with the sample zone and which is substantially impermeable to the aqueous liquid sample, said air porous body being external to the sample zone and defining at least part of the perimeter of the sample zone such that the sample zone is accessible via an entry port; and, the sample zone further comprises a floor which is free of said air porous body and a roof which is free of said air porous body whereby the air porous body is arranged to receive air displaced from the sample zone as the aqueous liquid sample is received into the sample zone; wherein the floor of the sample zone comprises; two drive electrodes (3, 4) with separate respective electrode terminals spaced by a spacing for receiving a said aqueous liquid sample within the sample zone for use in driving an electrical signal through the aqueous liquid sample; two sensing electrodes (5, 6) with separate respective electrode terminals spaced between the electrode terminals of the two drive electrodes for use in sensing an electrical signal generated by the drive electrodes within a said aqueous liquid sample; wherein the two sensing electrode terminals present to each other opposing sides which define between them an elongate sensing gap extending along the sample zone for receiving said aqueous liquid sample therein; and, wherein a said drive electrode terminal and an adjacent sensing electrode terminal present to each other opposing sides which define between them an elongated partitioning gap extending along the sample zone to define a partition between the adjacent terminals within the sample zone. a sample zone for receiving an aqueous liquid sample; wherein said sample zone is surrounded by an air-porous body which is in fluid communication with the sample zone and which is substantially impermeable to the aqueous liquid sample, said air porous body being external to the sample zone and defining at least part of the perimeter of the sample zone such that the sample zone is accessible via an entry port; and, the sample zone further comprises a floor which is free of said air porous body and a roof which is free of said air porous body whereby the air porous body is arranged to receive air displaced from the sample zone as the aqueous liquid sample is received into the sample zone; wherein the floor of the sample zone comprises; two drive electrodes (3, 4) with separate respective electrode terminals spaced by a spacing for receiving a said aqueous liquid sample within the sample zone for use in driving an electrical signal through the aqueous liquid sample; two sensing electrodes (5, 6) with separate respective electrode terminals spaced between the electrode terminals of the two drive electrodes for use in sensing an electrical signal generated by the drive electrodes within a said aqueous liquid sample; wherein the two sensing electrode terminals present to each other opposing sides which define between them an elongate sensing gap extending along the sample zone for receiving said aqueous liquid sample therein; and, wherein a said drive electrode terminal and an adjacent sensing electrode terminal present to each other opposing sides which define between them an elongated partitioning gap extending along the sample zone to define a partition between the adjacent terminals within the sample zone.