STUDY ON THE ESTIMATION OF PANS Ⅰ.ESTIMATION OF PANS BY DIAZOTIZATION METHOD

A method for the estimation of PANS is proposed as follows: Weigh accurately 0.4 to 0.5 gm of sample into a 200 ml beaker and dissolve in 30 ml water by the addition of 20 ml of 20 per cent sodium hydroxide solution.Heat the solution with a small flame and boil gently for one hour,cool and neutralise with hydrochloric acid under cooling with ice water.Add 3 gm of potassium bromide and an excess of M/10 sodium nitrite solution.After agitating for several minutes 15 ml of hydrochloric acid are added with thorough agitation cooling.Stir the solution continuously for fifteen minutes and back titrate the excess of sodium nitrite with a standard solution of para-aminobenzenesulfonic acid,using starch-iodide as indicator.Each ml of M/10 sodium nitrite solution is equivalent to 44.66 mg PANS.