Abstract
Colorimetric determination of phosphorus in ultra micro amounts of serum by molybdenum blue method has been investigated.
An analytical procedure is as follows : 0.02 ml of serum sample is taken, proteins are precipitated with 2ml of about 10% perchloric acid and, after centrifuging, the supernatant liquid is poured into a 10ml test tube. 0.5ml of 5% ammonium molybdate solution and 2ml of n-butyl acetate are added to it and shaked vigorously for 30 seconds. After extracting complex phosphomolybdic acid with n-butyl acetate, 1 ml of extract is transfered into a 3ml measuring tube, 0.2 ml of stannous chloride solution is added and the whole is diluted exactly to the mark with ethyl alcohol. The absorbance is measured at 725 mμ. Recoveries of phosphorus in serum were 97102%.
