Photometric determination of small amount of phosphorus in pure iron with molybdenum bluemethyl-isobutyl ketone extraction method
1968 Volume 17 Issue 5 Pages 597-602
Details
1968 Volume 17 Issue 5 Pages 597-602
A photometric method for the determination of 0.00001 to about 0.005% of phosphorus in pure iron with molybdenum blue-methyl-isobutyl ketone (MIBK) extraction has been studied. This method is highly sensitive, rapid and simple. Beer's law is obeyed up to 10 μg of phosphorus in 10.0 ml of MIBK. The established procedure is as follows.
The sample (0.21.0 g) is decomposed with hydrochloric acid and hydrogen peroxide (30 v/v%), and interfering elements are removed by extraction with MIBK from 7 N hydrochloric acid solution. Three milliliters of perchloric acid is added to the aqueous layer, and it is evaporated strong fumes of perchloric acid expel off hydrochloric acid. The residue is diluted to approximately 20 ml with water. Two milliliters of 10% sodium bisulfite solution and 10 ml of ammonium molybdatehydrazine sulfate composite solution in 1 N sulphuric acid are added, and the solution is heated for 7 to 8 min. on a hot plate. After being cooled, the solution is shaken for 30 sec. with 10.0 ml of MIBK to extract molybdenum blue.
Transfer an aliquot to an absorption cell, and the absorbance is measured at 740 mμ against MIBK.
The time required for an analysis is about 50 min.
