A flow-injection manifold based on reagent injection into the sample stream is described for the determination of phosphate in natural waters. A double-beam photometric detector incorporating light-emitting diodes and photodiodes in enclosed in a 20-cm3 box. The response is linear over the range 0-2000 μg l-1 phosphate-phosphorus (r = 0.9992) and the limit of detection (2σ) is 12 μg l-1 phosphorus. The reagents are stable for at least 30 days and there is no interference from 10 mg l-1 silicate-silicon. © 1987.
Worsfold, P. J., Richard Clinch, J., & Casey, H. (1987). Spectrophotometric field monitor for water quality parameters. The Determination of Phosphate. Analytica Chimica Acta, 197(C), 43–50. https://doi.org/10.1016/S0003-2670(00)84711-X