pH- and penicillin-sensitive electrolyte-insulator-semiconductor (EIS) sensors (At/Si/SiO2/Ta2O5 and penicillinase) have been successfully integrated into a commercial flow-injection analysis (FIA) system. For the FIA set-up, a miniaturised home-made flow-through cell of plexiglass with a variable internal volume from 12 to 48 mu l has been developed. As a second platform, an SU-8 based miniaturised flow-through cell, also combined with a pH-sensitive EIS structure, has been fabricated at wafer level. The application of SU-8 as a photoresist with good qualities (distinct chemical resistance, high aspect ratio, good mechanical and dielectric behaviour) is favoured. Different channel/sensor layouts have been realised with sensitive areas of the EIS sensors of 1.7-8.2 mm(2) and sample volumes of 0.3-4 mu l, respectively. FIA parameters (sample volume, flow rate, distance between injection valve and sensor) have been optimised in terms of high throughput, minimum dispersion, fluid consumption, sensitivity and reproducibility. (C) 2005 Elsevier Ltd. All rights reserved.