In a typical analysis, a set of standard solutions containing known amounts of
phosphorus was prepared by placing appropriate volumes of a 4.00-ppm solution
of P2O5
in a 50-mL volumetric flask, adding 2 mL of the ascorbic acid reducing
solution, and diluting to volume with distilled water. The calibration curve
reported by the authors yields a regression line of
A = - 0.02 + 0.72 CP2O5
(ppm)
Cola beverages were prepared for analysis by pouring a sample into a beaker and
allowing it to stand for 24 h to expel the dissolved gases (CO2
). A 2.50-mL sample
of the degassed sample was transferred to a 50-mL volumetric flask and diluted to
volume. A 2.50-mL aliquot of the diluted sample was then transferred to a 10-mL
volumetric flask, treated with 2 mL of the ascorbic acid reducing solution, and
diluted to volume with distilled water.
A sample of Crystal Pepsi, analyzed as described here, yields an absorbance of
0.565. What is the concentration of phosphorus, reported as parts per million of P,
in the original sample of Crystal Pepsi?