Atomization Characteristic of Chromium on a Molybdenum Tube Atomizer by Electrothermal Atomic Absorption Spectrometry and Determination of Chromium in Biological Materials

✍ Scribed by Kiyohisa Ohta; Hiroya Uegomori; Syn-ichi Itoh; Takayuki Mizuno

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 110 KB
• Volume: 56
• Category: Article
• ISSN: 0026-265X
• DOI: 10.1006/mchj.1997.1448

✦ Synopsis

Atomization characteristics of chromium have been studied by electrothermal atomic absorption spectrometry with a molybdenum tube atomizer. The appearance temperature (T app ) of chromium nitrate was 1300ЊC. The T app was independent of the heating rate of atomizer, but the temperature at the peak of the Cr AA signal increased with the heating rate. A sensitive absorption chromium signal was obtained in pure argon purge gas. The chromium signal decreased as the ratio of hydrogen in the purge gas increased. The optimal gas flow rate was Ar 480 ml min 01 / H 2 20 ml min 01 because of the avoidance of oxidation of the atomizer. The absolute characteristic mass (the mass of element giving 0.0044 abs.) of chromium by the atomizer was 0.35 pg and the detection limit was 23 pg ml 01 (3S/N). The interferences caused by large amounts of interferents were evaluated. The addition of thiourea served to eliminate the severe interferences. The accuracies of the recommended method were considered almost satisfactory for the determination of chromium in biological materials, compared with the certified values of NIST materials. The recovery of spiked chromium in biological materials was in the range from 93.5 to 102%.