A Modified Procedure for the Determination of Phosphorus in Detergents

The procedure described by the American Society for Testing and Materials for the determination of phosphorus in detergents has been studied. It is concluded that, at 5% phosphorus as P₂O₅, the method as written does not give a true measure of the phosphorus level. A modified titrimetric procedure has been developed which overcomes the difficulties experienced in the ASTM procedure at low phosphorus levels.