A mid-infrared sensor for monitoring of chlorinated hydrocarbons in the marine environment

As part of the European research project SOFlE - "Spectroscopy using Optica l Fibres in the Marine Environment", a portable sensor system for chlorinat ed hydrocarbons in seawater is being developed. This novel analytical tool for real-time in-situ monitoring of a particularly important class of seawa ter pollutants consists of a robust, miniaturised FT-IR spectrometer in a s ealed aluminium pressure vessel and a fibre optic sensor head. In a laborat ory set-up using an ATR-crystal as a simplified sensor head, the effect of potentially interfering substances, both of natural and anthropogenic origi n, on the sensor response was tested. It was found that the sensor readings for a specific analyte are not susceptible to aliphatic and aromatic compo nents as well as other chlorinated hydrocarbons up to concentrations well a bove the average levels to be encountered in the oceans. The same applies f or the parameters salinity and turbidity. Consequently, the proposed sensor system should be well suited for real-world sub-sea applications.