Determination of oxygen in selenium, tellurium and their compounds

Selenium, tellurium and their compounds were analysed for oxygen by a modification of the Schütze-Unter-zaucher method. When the determination of oxygen in selenium compounds was repeated about twenty to thirty times by the method using platinized carbon heated at 900°C, the activity of the platinized carbon was deteriorated. The use of platinized carbon at 1000 °C gave good results without the deterioration of it. When the determination of oxygen in tellurium com-pounds was repeated a few times by use of platinized carbon heated at 900°C, the activity of the platinized carbon was deteriorated. When carbon at 1030°C was used in place of the platinized carbon, the oxygen content in tellurium (IV) oxide was (113)% higher than the calculated value. The section of a pyrolysis tube (quartz) packed with carbon was found to be corroded by the tellurium produced by pyrolysis and be cracked. In order to prevent this, the inside wall of the pyrolysis tube was coated with carbon which had been produced by the pyrolysis of naphthalene. When the carbon coated tube and carbon heated at 1030°C in place of platinized carbon were used in determining oxygen in tellurium and its compounds, quite favorable results could be obtained. One analysis took about 40 min by a gravimetric method and about 20 min by a coulometric method.