Ultra-fast determination of caffeine, dipyrone, and acetylsalicylic acid by capillary electrophoresis with capacitively coupled contactless conductivity detection and identification of degradation products.

•The proposed system (CE-C4D) allows fast and simultaneous determination of dipyrone, caffeine, acetylsalicylic acid, and its degradation products.•It is the first time that methylamine was identified (CE–ESI–MS) as a hydrolysis product derived from dipyrone (metamizole).•Fast stoichiometry determination of dipyrone sodium salt in raw material and in pharmaceutical samples without sodium as excipient.•All information has been obtained with a single electropherogram (in less than 1min).