2.2.1. Acetate Buffer

To prepare the acetate buffer, acetic acid was dissolved in double distilled water (DDW) to a final concentration of 0.1 M, while a powder of sodium acetate was dissolved in DDW to the same final concentration of 0.1 M. To obtain a buffer solution with a pH value of 4, 847 mL of the acetic acid solution was mixed with 153 mL of the sodium acetate solution, and the pH value was measured and adjusted to 4 using 1 M NaOH solution. To obtain a pH value of 5.6, 95 mL of the acetic acid solution was mixed with 905 mL of the sodium acetate solution. The pH value was measured and adjusted to 5.6.