Selenium reference values

Institute of Medicine (2000) Dietary Reference Values for Vitamin C, Vitamin E, Selenium and Carotenoids. Washington, DC National Academy Press. 

The reference interval for selenium in whole blood, plasma or serum, hair, and nails should be established locally, since these indices are affected by dietary selenium intake. Plasma selenium adult values lie in the interval 63 to 160pg/L (0.8 to 2.0pmol/L). Values of less than 40 pg Se per L (0.5pmoI/L) indicate probable selenium depletion. 

Riikgauer M, Klein J, Kruse-Jarres JD. 1997. Reference values for the trace elements copper, manganese, selenium, and zinc in the serum/plasma of children, adolescents, and adults. J Trace Elements Med Biol 11 92-98. 

The U. S. Department of Agriculture maintains the USDA National Nutrient Database for Standard Reference, which contains over 7000 food items with data on the energy content, minerals, vitamins, and other properties of nutritional interest. The table here includes about 600 common foods extracted from that database. The properties listed are the energy content (in effect, the enthalpy of combustion) the content of carbohydrates, proteins, and lipids (fats) the cholesterol content and the amount of sodium, potassium, calcium, magnesium, iron, copper, zinc, manganese, phosphorus, and selenium. AU values are given for a 100 gram sample of the food. 

Table 8.3 Reference values for total inorganic selenite and selenate in RM 602 selenium,...

Selenium Distribution, Status Assays, and Dietary Reference Values... 

More recently, selenium recommendations or reference values have been slightly lower. The US committee that set Dietary Reference Intakes in 2000 interpreted the Chinese estimate of 41 pg/day needed to saturate GPx in adult men, and data from New Zealand indicating selenium intake adequacy at 38 pg/day, as supporting an Estimated Average... 

LRNI, Lower Reference Nutrient Intake RNI, Reference Nutrient Intake Al, Adequate Intake RDA, Recommended Dietary Allowance. Sources UK Department of Health (1991) Dietary Reference Values for Food Energy and Nutrients for the United Kingdom, Report on Health and Social Subjects No. 41. London HMSO. USA Food and Nutrition Board, Institute of Medicine (2000) Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium and Carotenoids. Washington, DC National Academy Press. WHO/FAO WHO/FAO (2002) Human Vitamin and Mineral Requirements. Report of a Joint FAO/WHO Expert Consultation, Bangkok, Thailand. Rome WHO/ FAO. 

Chromium, iron and selenium in foodstuffs from animal sources have been analyzed after closed vessel microwave digestion by collision cell ICP-MS.29 The limits of quantification (LOQ) of the analytical procedure were estimated under optimized experimental conditions with 0.025, 0.086 and 0.041 mg kg for Cr, Fe and Se, respectively. The results obtained for the three elements in nine different certified reference materials were, in all cases, in good agreement with the certified values.29... 

Selenium dioxide is an exothermic compound, the heat of formation being 57-2 Calories per gram-molecule, referred to vitreous selenium, whilst the value is somewhat less for the monoclinic element and less still for metallic selenium.1... 

In November 1971, NBS issued Standard Reference Material (SRM) 1630, Mercury in Coal, with a provisionally certified mercury content of 0.13 ppm. Later the provisional value of 2.1 ppm selenium in SRM 1630 was issued. 

Detection limits range from 0.02ng/ml for arsenic to 0.80ng/ml for selenium, and precision values at lOng/ml are less than 6% relative standard deviation. Results of analyses of NBS standard reference materials (wheat flour, rice flour, spinach and orchard leaves) demonstrate the application of the method to the matrices. The layout of the apparatus is illustrated in Fig. 7.6. 

The selenium data are presented in Chapter 111 and Appendix E. Unless otherwise indicated, they refer to standard conditions cf. Section 11.3) and 298.15K (25°C) and are provided with an uncertainty which should correspond to the 95% confidence level (see Appendix C). Thermodynamic parameters (formation data and entropies) that could be evaluated from reaction data with selected TDB auxiliary data in Chapter IV are denoted as selected and presented in Chapter III. When use of non-TDB auxiliary data had to be resorted to in the evaluation, the result is denoted as adopted and presented in Appendix E. The difference in the status between a selected and an adopted value thus depends entirely on the background of the auxiliary data used in the assessment. 

Table 111-1 Selected thermodynamic data for selenium compounds and complexes. All ionic species listed in this table are aqueous species. Unless noted otherwise, all data refer to the reference temperature of 298.15 K and to the standard state, i.e., a pressure of 0.1 MPa and, for aqueous species, infinite dilution (/ = 0). The uncertainties listed below each value represent total uncertainties and correspond in principle to the statistically defined 95% confidence interval. Values obtained from internal calculation, cf. footnotes (a) and (b), are rounded at the third digit after the decimal point and may therefore not be exactly identical to those given in Part V. Systematically, all the values are presented with three digits after the decimal point, regardless of the significance of these digits. The data presented in this table are available on computer media from the OECD Nuclear Energy Agency.

Table V-2 Re-evaluated second and third law enthalpy of formation of Se2(g) at 298.15 K as obtained from mass spectrometric investigations and determinations of the magnetic susceptibility of selenium gas. The last column contains the values evaluated by Gronvold, Drowart, and Westrum [84GRO/DRO] from the cited references. The value attributed to [84GRO/DRO] in the first column was evaluated from the measurements of Tobisawa [60TOB] who did not originally evaluate partial pressures or thermodynamic properties.

The enthalpy of formation of Se02(cr) is obtained from the three accepted measurements of the heat of combustion of Se(trigonal) listed in Table V-22 (references to earlier experimental results or selected values in compilations can be found in [62GAT]). Selenium reacts only partly with oxygen in the bomb calorimeter unless mixed with a combustion aid. Benzoic acid was used for this purpose and the heat evolved by the combustion aid was about 50% in the static bomb and about 90% in the rotating bomb experiments. 

Welz and Schubert-Jacobs [7] determined selenium in standard reference whole blood samples (Seronorm 904, 905, 906) by FI-HGAAS using the prototype of a commercialized FI system, FlAS-200, and obtained good agreement with certified values. The performance of the FI procedure was compared to a standard lUPAC batch procedure to show the advantages of the former. 

The gaseous fission product releases were calculated for the two reference isotopes Kr-85m and Xe-138. Nominal values for the material properties were used in the calculation. The releases for other isotopes can be obtained by assuming that the release-rate-to-birth rate ratio (R/B) varies as the square root of Isotope half-life. Moreover, it is conservatively assumed that bromine and selenium isotopes have the same release characteristics as krypton, and that iodine and tellurivun isotopes have the same release characteristics as xenon. 

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