The determination of selected nitroaromatic compounds in liquid chromatography-mass spectrometry with electron capture (EC) ionisation using a commercial atmospheric pressure chemical ionisation (APCI) interface in the negative mode is described. The electron capture effect is observed for nitroaromatics which do not easily undergo deprotonation under these conditions. Depending on the structure of the analytes, either dissociative or, for the first time in LC-MS, non-dissociative electron capture is observed. Limits of detection and linear range for the determination of the analytes match those obtained for nitroaromatics which undergo deprotonation. The investigated substances comprise numerous substituted nitrobenzenes and nitrobenzooxadiazoles.