Considerations in the determination of boron at low concentrations.
Experimental evidence now supports the nutritional essentiality of boron (B) in some biological systems, and accordingly, the need for reliable analytical B data is increasing. However, the accurate determination of B in biological materials is a formidable challenge at low concentrations (<1 mg B/kg). Recent studies still show significant analytical discrepancies in the analysis of animal tissues and fluids, despite the development of instrumental techniques such as TIMS, ICP-MS, ICP-ES, ICAP, SIMS, NA-MS, PGAA, NRA, and so forth, which have demonstrated detection limits approaching or exceeding (microg B/kg concentrations. Since boric acid is both volatile and ubiquitous in nature, the chemical and physical pathways for B contamination and its loss are manifold, especially during sample preparation. An added obstacle is the inadequacy of biological reference materials certified for B below mg B/kg. With an emphasis toward sample preparation and ICP-MS analysis, examples are provided in this article to help the analyst avoid common problems associated with the analysis of B from biological sources. Topics that are discussed include contamination from Teflon vessels during microwave digestion, losses owing to freeze-drying, B isotopic variations, standards preparation, reagent backgrounds, and instrumental interferences.
Downing
R G
RG
R.G.D. Research, Inc., Niskayuna, NY 12309, USA.
Strong
P L
PL
Hovanec
B M
BM
Northington
J
J
D000818:Animals; D001895:Boron / Q000032:analysis* / Q000592:standards; D002623:Chemistry Techniques, Analytical / Q000379:methods / Q000592:standards; D006801:Humans; D012015:Reference Standards; D012680:Sensitivity and Specificity
D001895:Boron