Abstract
A very simple, easy and sensitive spectrophotometric manual determination method of phosphorus for the P-PO4
3- ion in
natural waters, based on formation of the blue bismuth-phosphomolybdate complex (BiPMo), was developed. Ascorbic acid
is used for the reduction of bismuth-phosphomolybdic acid to bismuth-phosphomolybdate complex. Beer’s law is obeyed for
the concentration range to 0.6 mg·ℓ-1 (aqueous solution) and to 1.2 mg·ℓ-1 P (IBMK). The effect of foreign ions on absorbance
was examined. Ions do not affect the spectrophotometric determination of phosphorus using the BiPMo complex at concentrations
usually found in natural waters.
The limit of detection (blank + 3 S.D.) was 0.0059 mg·ℓ-1 (aqueous solution) and 0.0050 mg·ℓ-1 (IBMK) using the bismuthphosphomolybdate
complex (BiPMo). The P-PO4
3- in river water, mineral water and spring water was determined by this
method. The results obtained by the proposed method are compared with those of the phosphoantimonylmolybdenum blue
method. The method of standard addition was also applied to the determination of phosphorus in natural waters.