How can you tell that water has been contaminated by oil?

One way is to use a spectrometer, an instrument used to analyze light transmitted through or reflected from a sample. The spectrometer breakes down light into its specific wavelengths and detects the relative intensities of each wavelength, thus allowing to identify even very small amounts of oil.

In this application the water sample is illuminated and the reflected light is analysed in a spectrometer. Spectrometers are also used for the quality control of food or the environment.

SCHOTT Lighting and Imaging fiber optic light guides allow an easy light transport, also within the spectrometer.