Weigh the required sample mass into the combustion boat and cover it with 1,5 g of lead borate, 2 PbB2〇3. Preheat the furnace to a temperature of (1 050 ± 25) °C and place the boat in the centre of the heating zone.
Adjust the oxygen flow rate so as to prevent the risk of air being sucked in from the outside.
For the total carbon in the case of coulometric and conductometric methods, the volume of the combustion gas shall generally be reduced to one-tenth.
NOTE Combustion is usually complete after 5 min.