How isotope dilution analysis works?
isotope dilution, radiochemical method of analysis for measuring the mass and quantity of an element in a substance. By measuring the amount of radioactive isotope and the amount of stable isotope present and determining the ratio of these amounts, both the quantity and mass of the element can be ascertained.
Why isotopic dilution is important?
Isotope dilution is employed chiefly in analytical chemistry in situations in which precise quantitative analysis by conventional means is difficult. Certain kinds of geophysical investigations also require its use, as in determining the occurrence and distribution of trace elements in rock samples and meteorites.
How is isotope dilution used in mass spectrometry?
Isotope dilution mass spectrometry (IDMS)[24] is based on addition of a known. amount of enriched isotope (called the „spike‟) to a sample. After equilibration of the. spike isotope with the natural isotope of the element in the sample, mass. spectrometry (MS) is used to measure the altered isotopic ratio(s).
What are the disadvantages of isotope dilution?
Another disadvantage is its destructive nature: It requires dissolution of the sample for homogenization with the spike, often preventing analysis of other elements on the same sample aliquot.
How are isotopes added in the IDMS technique?
The IDMS technique involves the addition of a known amount of an enriched isotope of the element of interest to the sample. This addition is made prior to sample preparation during which the spiked addition of the enhanced isotope is ‘equilibrated’ with the sample.
How is the ratio of stable isotopes measured?
A known amount of a stable isotope is added to a sample and the ratio between the isotopes can then be measured by MS. The change in ratio of 50 Cr/ 52 Cr after addition of a 50 Cr spike gives an accurate estimate of the original concentration in the sample [7].