2.4. FI amperometric determination procedure
A KCl electrolyte solution and an acidic molybdate solution were pumped at 1.0 mL min−1 each. A standard/sample solution (75 μL) was injected into the stream of 0.1 M KCl and then merged with the stream of the acidic molydate solution which then flowed through a mixing coil (50 cm in length) to the amperometric flow cell. The 12-molybdophosphate complex produced on-line was then electrochemically reduced at the glassy carbon working electrode producing an electrical current, that was directly proportional to the concentration of phosphate (PO4-P). The current was converted to voltage and continuously recorded as a FI peak. A calibration graph was a plot of peak height obtained vs. P concentration. Concentration of P in sample was then evaluated from the calibration graph.