How does lithium serve as an ionization suppressant in flame photometry?

Answer 1

Berry, Chappell & Barnes (1946) showed that, in estimating sodium and potassium by flame photometry, there were definite improvements in precision and accuracy when lithium was added to the samples as an internal standard (compare Spencer, 1950; Bernstein, 1952). The lithium internal standard signal reduces fluctuation in flame conditions, drift, and dilution errors—ensures reproducible results and precise measurements. The fully automatic ignition and flame optimization sequences reduce set up and calibration time. An automatic gas shutoff mechanism activates if the flame is accidentally extinguished. The monitoring and control software make operation simple and allow measurements only after blanking and calibration.

Answer 2

Lithium serves as an ionization suppressant in flame photometry by effectively suppressing the ionization of other elements present in the flame. When lithium is introduced into the flame, it readily forms Li+ cations, which compete with the cations of other elements for the available electrons. This results in reduced ionization of other elements and enhances the sensitivity of the flame photometry technique.