Sodium extract is not used for the detection of elements. Instead, flame emission spectroscopy is commonly employed for the qualitative and semi-quantitative dtection of elements.

In flame emission spectroscopy, a sample containing elements of interests is introduced into a flame, causing the atoms to be exited to higher energy levels. As these exited atoms return to their ground state, they emit light of characteristic wavelength. The emitted light is separated using a spectrometer, and the presence and concentration of elements in the sample can be determined by identifying and measuring the intensity of specific emission lines.