Determination of selenium in soils by HPLC with fluorescence detection

• Published in: Bunseki kagaku Vol. 36; no. 9; pp. 542 - 546
• Main Authors: YAMADA, Hidekazu, HATTORI, Tomoo, MATUDA, Satoshi, KANG, Yumei
• Format: Journal Article
• Language: English
• Published: Tokyo Japan Science and Technology Agency 1987
• ISSN: 0525-1931
• DOI: 10.2116/bunsekikagaku.36.9_542

A method for the determination of selenium in soils was developed by use of HPLC with fluorescence detection. The fine-powdered soil sample of 50 mg was decomposed with a mixture of hydrofluoric, nitric and perchloric acids, and evaporated to strong fumes of perchloric acid. To the resultant solution, 2 ml of 6 M hydrochloric acid was added, and the solution was heated in boiling water bath (97 °C) for 15 min to reduce the selenium in the solution to the quadrivalent state. One ml of 0.1 M EDTA-sodium fluoride solution and 2 ml of 20% acetic acid were added to the solution, and the pH of the solution was adjusted to 1.0 with hydrochloric acid or ammonia. Then, 5 ml of 0.1% 2, 3-diaminonaphathalene (DAN) dissolved in 0.1 M hydrochloric acid solution was added, and the solution was warmed at 50 °C for 30 min. After being cooled to room temperature, the solution was extracted with 4 ml of cyclohexane by shaking for 5 min. A 100μl aliquot of the cyclohexane was analyzed by HPLC on a silica gel column (Cosmosil 5SL, 100 mm × 4.6 mm i.d.) using a mixture of cyclohexane and ethyl acetate (95: 5, v/v%) as mobile phase (flow rate: 1 ml/min). The 4, 5-benzopiazselenol formed on reaction with DAN and selenium was fluorometrically detected with excitation and emission wavelengths of 380 nm and 525 nm, respectively. The method was applied to the determination of selenium in standard soil samples SO-1, SO-2, SO-3 and SO-4 from CCRMP. The results were in good agreement with the reported values.