The use of metallic nanoparticles in consumer products is growing, posing health threatening issues as they are being released into the environment. As such, there is an urgent need for a facile method to be used for the detection and quantification of metallic nanoparticles present in a sample. In this work, the electrochemical behavior of copper oxide nanoparticles in alkaline media has been exploited to develop a sensitive electrochemical method for their determination achieving a quantification limit of 50ng. This technique may be also applied for quantification of other metallic nanoparticles in the future.