Merck, 1144490001, Phosphate Test

Phosphate Test is designed for semiquantitative determination of orthophosphate in water and prepared environmental samples by visual color comparison. This MQuant® test uses a color-card comparator rather than a photometer or test-strip endpoint. Orthophosphate reacts with ammonium vanadate and ammonium heptamolybdate in sulfuric solution, forming an orange-yellow complex. Match the treated sample visually against the comparator card to read the phosphate concentration. The color scale spans 1.0–40 mg/L expressed as phosphate-phosphorus or 3.1–123 mg/L expressed as phosphate ion, with seven graduation points. The package supports 190 determinations and includes reagent, graduated syringes, two screw-cap comparison tubes, a comparator block and a color card. Intended sample types include drinking and mineral water, groundwater, surface water, seawater, aquaculture water, boiler and industrial process water, wastewater and prepared soil extracts. The measurement targets orthophosphate rather than total phosphorus. The test reagent is stored closed at 15–25 °C. Its visual comparator format enables routine field-adjacent and laboratory phosphate checks without requiring a spectrophotometer.