Uranium calibration curve

Figure 6.24 Calibration curves for uranium (a) and thorium (b) determination in brain samples via the standard addition mode using micronebulization in LA-ICP-MS. (/. S. Becker et ai, Anal. Chem. 77, 3208 (2005). Reproduced by permission of American Chemical Society.)...

Step 8. Calibrate the instrument for analyte concentration response with uranium standards. If the response is near linear over the range of interest, use at least four uranium standard concentrations per sample concentration range, with one each at the upper and lower extreme. Repeat for the two other uranium isotopes in their own concentration ranges. Record the concentration calibration data in Data Table 19.2. Plot and examine calibration curves to assure their linearity. 

The polarogram was then recorded and the concentration of uranium found from suitable calibration curves. 

Figure 8-9 shows how the calibration for niobium varies with the background counting rate at a single Nb2Os concentration. Similar curves have been proved useful in a large number of uranium determinations on shipping pulp and ores. 

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