A ceramic electrochemical reactor (CEM) devoted to electrosyntheses was developed. The CEM was constituted by the assembly of five structured ceramic layers. On one layer, platinum interdigitated band electrodes with a submillimetre interelectrode gap were screen-printed. The microreactor chamber was constituted by seven channels and its volume was less than 100 µL. After a sintering step at 850 °C for 1 h, the CEM appeared as a solid and compact unit. The CEM was directly connected to the six port valve of a mass spectrometer allowing an on-line sampling and analysis of the reaction mixture. The methoxylation of the methyl-2-furoate was carried out and the effect of the residence time in the CEM was investigated thanks to mass spectrometry analyses.