Ractopamine is one kind of β-agonists which are widely used in livestock and poultryfeed as grow promoters. it can inhibit fat deposition and promote growth and proteingeneration, as well as clenbuterol. COD (Chemical oxygen demand) is widely used as oneof the most common detectable parameters for water quality. It will be very important forwater evaluation and wastewater prevention to master and control COD in time. In thispaper, an electrochemical sensor based on multi-wall carbon nanotubes (MWNT) and ane...