Selenium in body

Few simple direct procedures exist for the measurement of selenium in body tissues and fluids using ETA—AAS. Severe matrix and molecular absorption interferences usually require some form of separation procedure to be used. Saeed et al. [70] recently reported an excellent method for measuring Se in 20 pi volumes of serum. The samples were diluted with 20 pi volumes of 0.1% Ag or Ni nitrate solutions, which effected some degree of matrix modification prior to direct analysis by ETA—AAS. The Ag or Ni... 

Medinsky and coworkers (1985) developed a model to evaluate the potential uptake of selenium in body tissues through chronic inhalation of selenium at the workplace or by ingestion of selenium in food, and to predict resulting equilibrium organ concentrations. Most of the body selenium in humans arises from the diet, only a very small part arises from the trace amounts present in the urban atmosphere. 

Aiaejos ms and Romero DD (1995) Analysis of selenium in body fluids a review. Chem Rev 95, 1 227-257. 

A similar procedure, evaluated for the determination of selenium in body fluids by hydride / S, has been successfully used for arsenic as well. The flasks are the same as already described above with a long neck and 40 mL volume. However, flasks of similar design (e.g. Kjeldahl flasks) may be used as well. The procedure is as follows. 0.5 mL serum, whole blood or urine is placed into the digestion flasks. If necessary a sample volume of 1.0 ml may be also used. After this 1 mL of nitric acid (65% w/v) is added, the digestion flask placed into the aluminium heating block, and the block slowly heated to 140 °C. This temperature is maintained for 25 min and then cooled to room temperature. 0.5 mL (96% w/v) sulphuric and 0.2 mL (70% w/v) perchloric acid is added to the cool solution. The subsequent programme consists of slowly heating (approx. 15 min) to... 

Using pyrolytic graphite tubes, platform atomization and integrated absorbance readings a Zeeman-based instrument provides an acceptable situation for selenium determinations and permits most analyses to be performed against matrix matched calibration graphs. In Table 1 recommended procedures for the direct GF-AAS determination of selenium in body fluids are listed. 

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See also in sourсe #XX -- [ ]

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