2767345 Phosphate, Ortho Cuvette Test, 1.0-100 mg/L PO₄

16 mm Test 'N Tube Cuvette test measures 1.0-100 mg/L PO₄ in water and wastewater. The product uses molybdovanadate method (8114). Article 2767345 can be used for 25-50 tests. The product may be evaluated on DR900 only. It is required to use High Range Reactive Phosphorus TNT Vials, light shield or adapter, pipet, test tube rack and deionized water to perform sample analysis.

Before starting analysis:

• It is recommended to measure the collected sample as soon as possible for accurate results.
• The prepared blank-value vial may be used several times.

Procedure for PO₄ determination

Start program 540 P React (HR TNT). Prepare the blank by pipetting 5.0mL of deionized water to Reactive High Range Phosphorus Test 'N Tube Vial. Prepare the sample by adding 5.0mL of water or wastewater sample to another vial. After that close each vial and invert vial content. The temperature of the water and wastewater sample affects the reaction time. If the sample temperature is 23 °C (73 °F), wait 7 minutes. If the sample temperature is 13 °C (55 °F), the reaction time is 15 minutes. If the sample temperature is 33 °C (91 °F), wait 2 minutes.  Put the blank vial in the cell holder of the instrument. Finally, remove the blank-value vial and insert sample vial. It is required to evaluate testing results at 420nm.

Summary of method

Orthophosphate enters into reaction with molybdate in acid medium producing mixed phosphate/molybdate complex. Yellow molybdovanadophosphoric acid forms in the presence of vanadium. The intensity of the yellow color is proportional to the phosphate concentration and should be measured photometrically.

Sample preparation

If immediate analysis is not possible, filter and store the sample at or below 6 °C (43 °F) for up to 48 hours.