Gas-Chromatographic Determination of Ultramicro Amounts of Selenium in Pure Tellurium Metal

Abstract Selenium (IV) reacts with 4-nitro-o-phenylenediamine to form 5-nitropiaselenol, which is detected by means of a gas chromatograph equipped with an electron-capture detector. By this highly sensitive method, the selenium in pure tellurium metal (99.9–99.999%) can easily be determined. Aqua regia oxidizes both selenium and tellurium to the quadrivalent state, and no loss of selenium is found upon this treatment. This method requires only 10–30 mg of a tellurium sample, and the presence of foreign ions does not interfere. It was found that pure tellurium, commercially available, always contains 10−3–10−4% selenium.