Raman Spectroscopy
Raman Spectroscopy chemical "fingerprinting" of dissolved water contaminants.
Raman spectroscopy is a standard chemistry technique capable of detecting chemicals dissolved in water samples. Our goal is to miniaturize the system and make it at considerable lower cost, applied to aqua cultural systems. In an analytical chemistry lab, this type instrument can exhibit high sensitivity but comes at a prohibitively high cost to the average aqua culture grower. We tailor our sensitivity requirements to those actually needed and can thus can use simpler designs.
Our general path is to take a water sample (few cc's) from the fish tank, automated or by hand. Then we shine diode lasers (red, green, blue) onto this sample and with additional optics collect the scattered light. We use various visible light detectors (photo diode, avalanche photo diode, silicon photo multipliers) for various light intensities, combined with a folded monochromator whose wavelength dispersive grating is rotated by a small stepper motor. The electronics are being developed in-house. The overall instrument will then be the size of toaster oven, will weigh a few kg. The measurement is processed in a few minutes.
A typical use for such a detection system would be to quantify organics, ammonia, nitrates or nitrites in the water.