Determination of phosphate by carbon paste electrode modified with SMZ by potentiometric method

The utility of carbon paste electrode modified with SMZ (Na-Y zeolite modified with HDTMA surfactant) for the potentiometric determination of phosphate in aqueous solution is demonstrated. The electrode exhibits linear response to phosphate over a wide concentration range (1.58 × 10-5 – 1.00 × 10-2 M) with Nernstian slope of 30 ± 2 mV per decade in temperature range 25 to 50 oC . It has a response time of about 15 s and can be used for a period of two months with good reproducibility and repeatability. The detection limit of this electrode was 1.5 × 10-5 M. The electrode response for phosphate determination in pH range 6-12, was constant and independent from pH. This chemically modified carbon paste electrode was successfully used for the determination of phosphate in ammonium phosphate chemically fertilizer sample.