Page 499 - Applied Pharmacognosy

• The colour of ferric thiocyanate complex is stable and
proportional to the original chloride ion concentration
present in the sample.

• The intensity of colour is measured in a
spectrophotometer at 460 nm.

Determination of phosphates
• The phosphomolybdate method is based on the reaction

of phosphate ions with ammonium molybdate to form
molybdophosphate complex,

• which form a strongly blue - colored molybdenum
complex