Phosphates are often used in foods and in water treatment. The pH of such formulations is generally adjusted by mixtures of various sodium phosphates, such as this salt.[1] The sodium chloride equivalent value, or E-Value, is 0.49.[clarification needed] It is soluble in 4.5 parts water.[clarification needed] Food additive It is added in animal feed, toothpaste, and evaporated milk. It is used as a thickening agent and emulsifier. Detection of magnesium Monosodium phosphate is used to detect the presence of magnesium ions in salts. Formation of a white precipitate on the addition of ammonium chloride, ammonium hydroxide and monosodium phosphate to an aqueous or dilute HCl solution of the salt indicates presence of magnesium ions.