Application of enriched stable isotopes as tracers in biological systems: a critical review

Abstract

The application of enriched stable isotopes of minerals and trace elements as tracers in biological systems is a rapidly growing research field that benefits from the many new developments in inorganic mass spectrometric instrumentation, primarily within inductively coupled plasma mass spectrometry (ICP-MS) instrumentation, such as reaction/collision cell ICP-MS and multicollector ICP-MS with improved isotope ratio measurement and interference removal capabilities. Adaptation and refinement of radioisotope tracer experiment methodologies for enriched stable isotope experiments, and the development of new methodologies coupled with more advanced compartmental and mathematical models for the distribution of elements in living organisms has enabled a broader use of enriched stable isotope experiments in the biological sciences. This review discusses the current and future uses of enriched stable isotope experiments in biological systems.

Inductively coupled plasma- and glow discharge plasma-sector field mass spectrometry : Part II. Applications

“…156 Evans et al quantified Pu, Am and Np in food samples, ranging from cabbage to milk and meat by a combination of ion chromatography, ultrasonic nebulisation and ICP-SFMS. Because of the high sensitivity of sector field instrumentation, detection limits as low as 0.02 pg g À1 (4.6 Â 10 À2 Bq kg À1 ) for 239 Pu, 0.011 pg g À1 (3 Â 10 À4 Bq kg À1 ) for 237 Np and 0.033 pg g À1 (2.45 Â 10 À1 Bq kg À1 ) for 243 Am were obtained. The method described can provide data on plutonium contamination in food within three hours of sample receipt without compromising detection limits or accuracy relative to traditional counting methods.…”

“…Lariviere et al used an ICP-SFMS-based method with a separation from alkaline earth elements and obtained a method detection limit of 0.19 pgL À1 for Ra, equivalent to 7 mBq L À1 . 204 ICP-SFMS was used to quantify 239 Pu in faeces 205 207 Fission products in nuclear samples were determined by Pitois et al 208 using capillary electrophoresis coupled to ICP-SFMS. A comparison between ICP-SFMS and quadrupole ICP-MS resulted again in lower limits of detection for sector field instrumentation (4 pg mL À1 for Cs and 7 pg mL À1 for lanthanides) compared to quadrupole ICP-MS (6 ng mL À1 for Cs and 8 ng mL À1 for lanthanides).…”

“…A sensitive analytical method for determining the artificial radionuclides 90 Sr, 239 Pu and 240 Pu at ultra-trace levels in groundwater samples from the Semipalatinsk Test Site area in Kazakhstan by ICP-SFMS was developed by Zory et al 209 The measurements were performed at medium mass resolution under cold plasma conditions in order to avoid possible spectral interferences at m/z 90 for 90 Sr determination (e.g., 90 Zr + , 40 Ar 50 Cr + , 36 Ar 54 Fe + , 58 Ni 16 O 2+ , 180 Hf 2+ , etc.). Analysis at medium mass resolution displayed interfering peaks in the mass-region of Pu, which points most likely in the direction of lanthanide-containing polyatomic ions.…”

“…In one of their experiments, human serum was saturated with 57 Fe and its subsequent speciation analysis provided information on the original level of Fe and the level of Fe uptake for each individual sialoform of transferrine. St€ urup published two review papers on tracer experiments with stable isotopes-one on human studies 239 and another, broader one, on biological application in general. 240 Natural variations in the isotopic composition of selected elements can be deployed for solving problems in a biological context, as well.…”

“…In both cases, the Pu was demonstrated to be of global fallout origin. Sanders et al demonstrated that this potential of 239 Pu and 240 Pu determination using ICP-SFMS also provides a means of determination of sediment accumulation rates using the example of the coastal mangrove mudflats located in Brazil. 298 The results obtained agreed well with those based on measuring the 210 Pb activity.…”