Selenium determination

The possibility of preconcentration of selenium in form of SeO by evaporation of low alkali water solution (for 20-1000 J.g/L) has been investigated. Considerable losses of selenium have been observed during evaporation of acidic and neutral solutions owing to volatility of selenium compounds. During evaporation of low alkali solutions at ph 9-10 there are no losses of selenium. Relative error of selenium determination is 1-2% for 1000 P-g/L solution and 3-5% for 20-100 p.g/L. Concentration factor is 10. 

It is known that Selenium catalyzes reaction of some dye reduction by Sulphide. On this basis spectrophotometric and test-techniques for Selenium determination are developed. Inefficient reproducibility and low sensitivity are their deficiencies. In the present work, solid-phase reagent on silica gel modified first with quaternary ammonium salt and then by Indigocarmine was proposed for Selenium(IV) test-determination. Optimal conditions for the Selenium determination by method of fixed concentration were found. The detection limit of Se(IV) is 10 ftg/L = 2 ng/sample). Calibration curve is linear in the range 50-400 ftg/L of Se(IV). The proposed method is successfully applied to the Selenium determination in multivitamins and bioadditions. 

Selenium, determination by x-ray emission spectrography, 329 enhancement of germanium radiation by, 189-191... 

Boreua P, Bargellini A, Caselgrandi E, Menditto A, Patriarca M, Taylor A, Vivoli G (1998) Selenium determination in biological matrices. Microchem J 58 325-336. 

Table 15.20 Examples of selenium determination in various materials by gas-liquid chromatography...

V. E. Negretti de Bratter, P. Bratter, A. Tomiak, An automated microtechnique for selenium determination in human body fluids by flow injection hydride atomic absorption spectrometry (FI-HAAS), J. Trace Elem. Electrolytes Health Dis., 4 (1990), 41-48. 

E. Vassileva, H. Docekalova, H. Baelen, S. Vanhentenrijk, M. Hoenios, Revisitation of mineralisation modes for arsenic and selenium determination in environmental samples, Talanta, 54 (2001), 187-196. 

Selenium Determine as directed in Method II under Selenium Limit Test, Appendix IIIB, using a 200-mg sample. 

Loss on Drying Determine as directed under Loss on Drying, Appendix IIC, drying a sample to constant weight at 250°. Selenium Determine as directed in Method II under Selenium Limit Test, Appendix IIIB, using a 200-mg sample. 

Selenium Determine as directed in Method II under Selenium Limit Test, Appendix IIIB, using a 1.2-g sample. Water-Insoluble Substances Dissolve 50 g of sample in 300 mL of hot water contained in a 600-mL beaker allow the insoluble matter to settle and filter by decanting through a tared, sintered-glass filter cmcible, washing the insoluble matter into the crucible with additional hot water. Dry at 100° to 110° for 1 h, cool in a desiccator, and weigh. 

Sanz-Medel and co-workers reported on selenium determination in biological samples by isotope dilution analysis in ICP-QMS with an octopole collision cell." The argon based isobaric interference arising during measurements of °Se was eliminated by using a hydrogen flow of 4 ml min in the octopole cell, so that it is possible to determine Se with a detection limit of 14pgg. ... 

Montes-Bayon, M. et al. Evaluation of different sample extraction strategies for selenium determination in selenium-emiched plants (Allium sativum and Brassica juncea) and Se speciation by HPLC-ICP-MS. Talanta 2006, 68, 1287-1293. 

Chajduk, E., Polkowska-Motrenko, H., Dybczynski, R.S. A definitive RNAA method for selenium determination in biological samples. Uncertainty evaluation and assessment of degree of accuracy. Accred. Qual. Assur. 13, 443 51 (2008)... 

Vassileva, E., Docekalova, H., Baeten, H., Vanhentenrijk, S., Hoenig, M. Revisitation of mineralization modes for arsenic and selenium determinations in environmental samples. Talanta 54, 187-196 (2001)... 

There has been an increasing interest in the determination of selenium at trace levels in a wide variety of matrices. Selenium determinations of environmental samples have become quite important. Large-scale poisoning of water fowl has occurred in several watershed areas of central California. Selenium is washed or leached into these areas, helped through the widespread irrigation of selenium-containing farm soil. 

---