LAUSR

Contaminants in water were studied using ultraviolet absorption with light emitting diode and deuterium lamp sources, and a thresholding detector. The absorption spectra of potassium hydrogen pthalate, clothianidin, tryptophan, thiamethoxam, uric acid and metaldehyde were obtained in the range 200–360 nm. Only metaldehyde was not suitable for detection in this range. For the other contaminants, and mixtures of pairs of compounds, the transmitted signal could be approximately described with a simple spectral model of the source–absorption–detector system. Combined measurements at two wavelengths could allow relative concentrations in certain mixtures to be determined, and real-time absorption measurements were demonstrated in a flume.