Determination of orthophosphate ions using spectrophotometry
Equipment and reagents
- Standard laboratory equipment, in particular: glassware, pipette filler.
- A spectrophotometer
- A water bath
- A test tube rack
- Test tubes (about 25 ml)
- Ascorbic acid solution (1%)
- Sulfomolybdic reagent
- Phosphate stock standard at 10 mg phosphorus.L-1
Precautions for use: The sulfomolybdic reagent is toxic, it is therefore preferable to use a bottle with manual dispensing and to adjust it to the appropriate volume to be delivered (i.e. 2.5 mL). In practice, it will initially be appropriate to purge the dispenser and ensure that there are no air bubbles in it so that the volume of reagent delivered is correct.