i need to know how to calculate POD values. i had used the following procedure:

2.7 ml of phosphate buffer (pH 7.8), 0.1 ml of enzyme extract, 0.1 ml of H2O2 and 0.1 ml of guaicol was taken and mixed gentely.The time span of 30-60 seconds  was set at spectrophotometer at 470nm wavelength and values were noted.