Question

Why is source modulation used in atomic absorption spectroscopy?

Short answer

In the case of Atomic Absorption spectroscopy, source modulation is used to remove interferences.

Step-by-step solution

Step1. Given information

Explain why source modulation is used in atomic absorption spectroscopy.

Step2.Reason for the use of source modulation

The radiation emitted by the flame causes numerous interferences. Source modulation is used in Atomic Absorption spectroscopy to eliminate these interferences. In general, a monochromator aids in the removal of the majority of the radiations emitted by the flame. However, radiations with wavelengths inside the monochromator's range cannot be eliminated.

Step3. Removal of interference

To remove these, the source output is modulated so that the detector receives two signal types — a continuous signal type and an alternating signal. These signals are converted into electrical responses, which are then separated using an RC filter, which separates the modulated AC signal from the unmodulated DC signal. In atomic absorption spectroscopy, source modulation is employed to reduce interferences.