Dear scientist, In flame atomic absorption method, the addition of potassium nitrate (5000 mg L-1 as potassium) as an ionization inhibitor improved the sensitivity because the ionization of cesium may comes under controlled.

Find fault finding guide for AAS below https://www.agilent.com/cs/library/applications/AA012.pdf

Hi,

Here are a few simple tips that may come in handy:

First, make sure the flame is in the correct position in front of the passing light. It is directly enhanced the sensitivity and your results.

Make sure the air pressure is sufficient. As you know a certain stoichiometry ratio of gas and air is required for the flame production and proper temperature for atomization. It also determines flame stability.

Besides, based on the literature, cesium is significantly ionized in air/acetylene flame. So it needs to add another easily ionized element like potassium in excess.

Please look at the following below link which may help you in your issue:

https://www.agilent.com/cs/library/applications/AA012.pdf

Thanks

Hi there

There are two absorption lines of 852.1 and 455.5 nm for the determination of cesium in concentration ranges of 0.1-5 and 5-1000 ppm, respectively. The use of 852.1 nm along with the introduction of a suitable ionization buffer into standard solutions can improve the signal intensity. At the concentrations higher than 5 ppm for cesium (Absorbances> 0.05), you can analyze real samples under these conditions without any changes

Explanations for Cs and many other tips in the attachment.

Could be spectral interference plus what cuvettes are you using?