Appendix XV E. Phenol in Immunosera (Antisera) and Vaccines

Homogenise the preparation to be examined. Dilute an appropriate volume with water R so as to obtain a solution presumed to contain 15 µg of phenol per millilitre. Prepare a series of reference solutions with phenol R containing 5 µg, 10 µg, 15 µg, 20 µg and 30 µg of phenol per millilitre respectively. To 5 mL of the solution to be examined and to 5 mL of each of the reference solutions respectively, add 5 mL of buffer solution pH 9.0 R, 5 mL of aminopyrazolone solution R and 5 mL of potassium ferricyanide solution R. Allow to stand for 10 min and measure the intensity of colour at 546 nm.

Plot the calibration curve and calculate the phenol content of the preparation to be examined.