Abstract: A reference electrode of an electrochemical sensor includes a substrate having internal walls defining a well and a channel. The reference electrode includes a conductive element disposed in the substrate. The well extends from a first surface of a substrate towards a second surface of the substrate. The channel is within the substrate. The channel has a first end connected to the well and a second end that is in contact with the conductive element. The reference electrode may include an additional well that extends from the first surface towards the second surface. The additional well may be connected to the second end of the channel and may be in contact with the conductive element. The channel and the wells form a flow path of a conductive medium. The flow path may be coupled to an agitating element or heating element that promotes flow of the conductive medium.