Boron-doped diamond (BDD) electrodes have been recognized for their outstanding electrochemical properties in recent years, but their high cost and limited availability have hindered their widespread use. To address this issue, researchers have developed a lowcost electrochemical sensor by combining a BDD paste electrode (BDDPE) with microfluidic paper-based analytical devices (μPADs). The BDDPEs are made by mixing BDD powder with mineral oil and can be stencil-printed into various electrode geometries.