Selective electrochemical sensor for phosphate determination toward a silicate interference free method in freshwater

This paper proposes an electrochemical method for phosphate determination without silicate interference in freshwater. An electrochemical three-electrode-system was embedded in a sensor, and the water samples containing phosphate could be determined accurately without silicate interference by adding oxalic acid. The compatibility between linear sweep voltammetry and theoretical value is good by using oxalic acid to measure phosphate. The current intensity of the reaction cell has dynamic linear relationship of the phosphate concentration in the range of 0 and 1.0 mg /L (R2=0.99) with a detection limit down to 5.69 μg /L (S/N = 3). The deviation between spectrometry and LSV methods is less than 10% in freshwaters. The electrochemical sensor shows the potential application in flow injection analysis.