According to the results, tube C had the best concentration. Three tubes were labeled AC. Tube A contained 1 ml of enzyme solution which was added to tube B containing 4 ml of buffer (pH 5 was used). 1 ml of the solution from tube B was then added to tube C which also contained 4 ml of buffer (pH 5). Tube C was used as the enzyme in all reactions. Nine tubes were taken from them, one was used as a blank, labeled as tube 9. The blank contained 5 ml of buffer (pH 5), 2 ml of hydrogen peroxide, 1 ml of guaiacol and no enzyme. Then, 3 ml of buffer (pH 3) and 2 ml of enzyme were added to tube 1. Tube 2 contained 2 ml of hydrogen peroxide and 1 ml of guaiacol. Tubes 1 and 2 were mixed. For tube 3 the same procedure as for tube 1 was used, but this time the buffer was at pH 5. Tube 4 was prepared in the same way as tube 2. Then, tubes 3 and 4 were mixed. Tube 5 was prepared like tube 1 but with pH 7 buffer and tube 6 was prepared like tube 2. Next, tubes 5 and 6 were mixed. Last but not least, tube 7 was prepared as tube 1 but with pH 9 buffer and tube 8 was prepared as tube 2. Then, tubes 7 and 8 were mixed. The spectrophotometer was set to 470 nm and using blank it was set to zero. The four test tubes were read with different pH (pH 3, pH 5, pH 7, pH 9)