microtest® Test Kit Specifications

microtest Phosphate MB

Colorimetric Test for


0.2 – 7 mg/L PO43-

Product Code652000
ContentsReagent A, 15 mL
Reagent B, 7 mL
Cuvette, 4 mL
Colour Comparator
Instructions for Use
Analytical MethodMolybdenum Blue: At a pH of ca. 1, ammonium molybdate reacts with phosphate forming colourless molybdophosphoric acid. Upon reduction with tin(II) chloride it turns into the blue compound phosphoromolybdenum blue. The intensity of the colour is related to the phosphate concentration.
Number of Tests70
InterferencesWater constituents at concentrations commonly found in natural waters will not cause interferences. Various heavy metals (e.g. Nb, Ta, Sn, W, Ti, Zr, Bi) can cause serious interferences.
Seawater: Seawater and waters high in salinity will cause low results. In order to compensate for that, multiply reading by 1.3.
Measuring RangeThe standard measuring range is 0.2 – 7 mg/L. The colour comparator has 6 colour fields: 0.2–0.5–1–2–4–7 mg/L. For higher phosphate concentrations, the sample has to be diluted. A 1:4 sample dilution can be carried out easily, thus extending the measuring range to 28 mg/L.
Shelf Life2 years
ApplicationsDetermination and monitoring of phosphate levels in natural waters (environmental monitoring), waste water.