Answer to Question #65332 in Organic Chemistry for Harleen

Question

Why is Lanthanum and Cesium or Lithium added to solutions to be analysed for Calcium and Sodium respectively?

Answer 1

Answer:
The most widespread chemical interferences are in the atomic absorption analysis of . In the case where the analyte is not completely turned into an atomic state under the influence of flame, then number of atoms capable of absorbing light lowered. This effect is called chemical interference. Getting rid of it is possible, if improve atomization of the temperature or to bring additional energy to break ties by entering exempting additives. When you add such reagents chemical reaction occurs and interfering element can be analyzed correctly.
The most striking example is the analysis of chemical interference calcium. When analyzing the flame method (air-acetylene flame) and the presence of phosphate ions, calcium ions signal weakens considerably due to the effect of calcium. In the presence of excess lanthanum possible to separate calcium ions from the phosphate ions, even if they are in great amount. Also it allows you to overcome the interference increase flame temperature (that is, use acetylene flame -nitrous oxide).
Cs for Na as La for Ca