Gravimetric Determination of either Phosphorusor Magnesium by the Low Temperature Ignition of Magnesium Ammonium Phosphate

Abstract

New procedure for the gravimetric determination of either phophorus or magnesium was proposed. In this procedure, the magnesium ammonium phosphate (MAP) is filtered on glass filter, and then in this state it is ignited to the magnesium pyrophosphate (MPP) at 570-590°C.
In order to compare the new procedure with the ordinary gravimetric procedure, 10 samples of the MAP precipitated from a certain ammonium phosphate solution were adopted for each procedure, and the operation was examined from the beginning of the filtration of the MAP to the ending of the weighing of the MPP. Results were as follows.
(1) Estimated value of the new procedure agrees with that of the ordinary.
(2) Hours required for the two procedure are nearly equal, but actual working hours for the new procedure is 1/3 of that of the ordinary.
(3) The standard deviations of the estimated value in the new procedure and the ordinary are 1.34 ppt and 1.68 ppt to the arithmetic mean, respectively.
The new procedure offers much saving in time and tedium over the ordinary gravimetric procedure, and is more precise.