A drastic increase in the consumption of pharmaceuticals has resulted in a high load of pharmaceuticals in wastewater. Many pharmaceuticals are non-biodegradable and are resistant to conventional wastewater treatments. For this reason there is an obvious need to first detect these substances and, second, to detoxify them. Metamizole is a typical representative of an analgesic non-steroidal. In this first part, a rapid, sensitive, and inexpensive detection method with different commercial screen-printed electrodes (SPEs) were used to quantitatively detect metamizole. (Spectro-)Electrochemical methods such as cyclic voltammetry (CV), electrogenerated chemiluminescence (ECL), and amperometry (AM) are discussed in detail and the sensitivities of the electrochemical methods are compared to the sensitivity of conventional gas chromatography-mass spectrometry detection (GC-MSD). The limit of detection (LOD) is 1 mol/L for GCMS and 5 to 50 mol/L for electrochemical detection depending on the method used.