In atomic absorption spectrophotometry, which radiation source provides the light that is absorbed by the analyte in the flame?

In atomic absorption spectrophotometry, which radiation source provides the light that is absorbed by the analyte in the flame?

• A. The hollow-cathode lamp
• B. The flame
• C. An external laser
• D. Sunlight

Answer: (A)

In atomic absorption spectrophotometry, the light that is absorbed by the atoms in the flame must come from a source that emits at the exact wavelengths of the element being measured. A hollow-cathode lamp is tailored for the specific element and emits sharp, element-specific wavelengths needed for absorption. As this light passes through the flame, atoms of the analyte absorb photons at those wavelengths, reducing the transmitted light detected downstream. The amount of absorption relates to concentration via Beer-Lambert law, allowing quantification. The flame itself provides the atoms but does not supply the necessary absorption wavelengths; an external laser isn’t used in standard AAS, and sunlight is neither stable nor element-specific for this purpose.

In atomic absorption spectrophotometry, the light that is absorbed by the atoms in the flame must come from a source that emits at the exact wavelengths of the element being measured. A hollow-cathode lamp is tailored for the specific element and emits sharp, element-specific wavelengths needed for absorption. As this light passes through the flame, atoms of the analyte absorb photons at those wavelengths, reducing the transmitted light detected downstream. The amount of absorption relates to concentration via Beer-Lambert law, allowing quantification. The flame itself provides the atoms but does not supply the necessary absorption wavelengths; an external laser isn’t used in standard AAS, and sunlight is neither stable nor element-specific for this purpose.