We report a novel amperometric sensor for aqueous phosphate ions in freshwater systems based on the reductive square wave voltammetry of molybdate(VI) anions immobilized within a chitosan matrix deposited on a glassy carbon electrode. A sensitivity of 4.4 ± 0.1 μA/μM was realized together with a LOD of 0.15 μM. The sensor was insensitive to chloride and nitrate ions below a threshold concentration of 1.0 mM. Analytical measurements were successfully made in authentic samples of tap and pond water.
Keywords: chitosan; detection in fresh water; molybdate(VI) reduction; phosphate; square wave voltammetry.