If necessary, dilute the sample to 300 ml and neutralize to pH 7.
b. Ammonia removal: Add 10 ml phosphate buffer solution to a sample of drinking water quality and 25 ml to wastewater samples. Add a few glass beads or boiling chips and boil off 300 ml. If desired, distill this fraction and determine the ammonia nitrogen. Alternatively. if ammonia has been determined by the distillation method, use the residue in the distilling flask for the organic nitrogen determination.