An investigation of the electronic structure of silver azide by the photoemission method

The energy structure of silver azide was investigated by the photoemission method. The photoelectric work function for photons in the energy range 6.7–11.2 eV was determined from the electron energy distribution curves and the Einstein equation. The position of the Fermi level was determined from the difference in stopping potentials for silver metal and silver azide. The position of the acceptor levels is estimated and the structure of the valence band is discussed. A band scheme for silver azide is proposed.     

Synthesis and photochromic properties of spiroanthrooxazine

1,3,3-Trimethylspiro[indoline-2,3-3H-anthraceno[2,1-b][1,4]oxazine] was synthesized. The compound has photochromic properties in solutions and in polymeric matrices. It was found from the spectral data that the colored form of the spiroanthrooxazine exists in a quinoid form and is characterized by a positive solvatochromic effect.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1521–1525, July, 1990.     

Rapid and Selective Electrochemical Determination of Nitrite in Cured Meat in the Presence of Ascorbic Acid

A simple, fast and selective amperometric procedure for nitrite determination in cured meat based on the use of a carbon paste electrode is presented. Direct interference of ascorbic acid, which interferes with electrochemical detection, was eliminated by applying a cellulose acetate membrane of 100Da molecular weight cut-off on the electrode. Indirect interference of ascorbic acid due to its auto-oxidation reaction and its reaction with nitrite is discussed. In order to stabilise the ascorbic acid, metaphosphoric acid and EDTA were added.In contrast to the standard spectrophotometric method, which requires careful control of pH and the use of carcinogenic reagents, amperometric determination of nitrite is simple, rapid, and works without reagents. Also, sample preparation is simpler because it requires neither heating to 80°C nor the centrifugation steps of the official spectrophotometric method. The detection limit achieved was 14ppb (0.2µM) nitrite in the solution, which corresponds to a detection of 2.8ppm in meat samples. The method was compared with the standard spectrophotometric procedure and applied to the detection of nitrites in cured meat samples with satisfactory results.