The flow cell is integrated into the LOV module adjacent to port #2. It can be configured for UV-VIS spectroscopy with a short light path (1 or 2 mm) A with a standard light path length (up to 10 mm) B or long light path length up to 50 cm. The optical fibers can be also mounted at right angles for fluorescence measurement C. By combining B with C, design simultaneous absorbance and fluorescence monitoring was used for the first time to investigate cellular events (Lähdesmäki 2009).
These flow cell reconfigurations are achieved by repositioning the optical fibers. The fibers are precision made, O.D.30 microns smaller than the I.D. of the LOV channels. This allows a liquid to pass AROUND the optical fibers, unless the channel is blocked by a ferrule (shown as the white rectangle).
The length of the light path is selected by selecting the width of the gap between the fibers or, for absorbance and fluorescence configurations, by changing the position of the fibers within the channel.
When assembling the LOV module for the first time, it is recommended to remove air from the gaps between the channel walls and the optical cables, by releasing the ferrules and by pumping water to flood and fill all individual gaps in turn.