Simultaneous spectrophotometric flow injection determination of phosphate and silicate

• Simultaneous flow injection determination of phosphate and silicate ions is proposed.
• Molybdophosphoric and molybdosilicic acids are formed in the system.
• After injection of oxalic acid molybdophosphoric acid is decomposed.
• Area of a registered peak corresponds to phosphate concentration.
• Absorbance measured at the peak minimum corresponds to silicate concentration.

A method for the simultaneous determination of phosphate and silicate based on spectrophotometric measurement at 385 nm of a single peak using a flow injection system with two component calibration is described. In the system, a stream of sample containing both analytes is merged with a stream of ammonium molybdate to form (at 1

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