Without the addition of cesium, the upward curvature for the atomic lines of Na, K and Ca exceeded the limits and the calibration failed for these lines.
With the addition of cesium, the effect of ionization interference was reduced and all elements calibrated successfully.
Even though the calibrations for the atomic lines of Ca, K and Na failed when cesium was not added, the maximum upward curvature limit was increased post-run so that the calibrations would pass. By so doing, a comparison of the results with and without the addition of cesium could be made.
Note that figures 3-10 show the effect of Cs on the linearity of the calibration and not the effect on the intensity of the analyte peak .
The effect of ionization interference, particularly on the EIE such as K, Na and Ca, is clearly visible from the results displayed in Table 3. Without the addition of Cs, variations in the measured results were found for the atomic lines of Ca (317.933 nm), Na (330.237 nm) and K (766.940 nm and 769.896 nm). The results for the 100-fold dilution blood serum solution were lower than those measured in the 20- fold dilution blood serum solution because of the higher level of EIE in the latter, particularly Na.
The effect of ionization interference on different line types was observed for the Ca atomic line (422.673 nm) and Ca ionic line (317.933 nm). From Figures 6 and 7, it can be seen that ionization interference had considerable effect on the calibration of the Ca (422.673 nm) line while the Ca (317.933 nm) line remained unaffected. This is refl