A new optoelectronic nose has recently been developed using, for the first time, Surface Plasmon Resonance Imaging. Initial studies indicate that the instrument is very promising, and can detect and recognise a large variety of volatile organic compounds (VOCs) even with very limited sampling time. In this paper, we investigate its use as a continuous monitoring system under real-life conditions, recognising VOCs over several months. To this end, we present a robot-based platform which allows fast, realistic and repeatable measurements of several VOCs. We have generated a substantial data set over several months and under different environmental conditions. Results show that the device can be used to recognise VOCs with high reliability, even when training and testing sessions are months apart. The results are quite encouraging for further studies.