CHEMetrics Phosphate Test Kits

Phosphate is key analyte for certain wastewater treatment plants. Municipal wastewater facilities that employ biological nutrient removal (BNR) and enhanced nutrient removal (ENR) systems must measure phosphate as a requirement for their discharge permits.

In environmental monitoring, phosphate levels are monitored to gauge the health of aquatic ecosystems. High levels of phosphate can spur algae blooms and eutrophication. Regular phosphate testing can help identify these conditions and pinpoint potential pollution sources, such as fertilizer run-off.

In industrial water treatment, phosphate is used as a conditioner and corrosion inhibitor in boiler and cooling systems. Phosphate testing ensures systems are protected against corrosion and the chemical is not being wasted.

CHEMetrics Phosphate Test Kits measure ortho (reactive) phosphate using two different methods: Stannous Chloride and Vanadomolybdophosphoric Acid. Visual and instrumental phosphate test kit formats that span low and high measurement ranges are offered.

The Stannous Chloride Method

References: APHA Standard Methods, 23rd ed., Method 4500-P D-2005. Phosphate test kits employing this chemistry utilize a stannous chloride reduction. Phosphate reacts with ammonium molybdate and is then reduced by stannous chloride to form a blue complex. Results are expressed as ppm (mg/L) PO₄.

The Vanadomolybdophosphoric Acid Method

References: ASTM D 515-82, Phosphorous in Water, Test Method C. APHA Standard Methods, 23rd ed., Method 4500-P C-2005. In phosphate water test kits employing the vanadomolybdophosphoric acid method, phosphate reacts with ammonium molybdate under acid conditions and in the presence of vanadium to form a yellow-colored product. Results are expressed as ppm (mg/L) PO₄.

Test results for visual test kits use color comparators for analysis while instrumental kits rely on CHEMetrics direct-readout photometers or spectrophotometers capable of accepting a 13-mm diameter round cell.