In flame photometry, which statement is true?

• A. The flame serves as both the sample holder and the light source
• B. The internal standard is the only correction used
• C. The sample is introduced with a dry pellet method
• D. The detector is a mass spectrometer

Answer: (A)

In flame photometry the flame itself is doing the work: it serves as both the container where the sample is held (as it is aspirated into and atomized in the flame) and the light source that provides the emission. The sample, usually introduced as a solution, is carried into the flame where it is vaporized and atoms are formed. These excited atoms emit light at characteristic wavelengths, and the intensity of that emission is measured by a photodetector after spectral isolation. Since the light comes from the flame’s excited atoms, there isn’t a separate illumination source involved. While internal standards can be used to correct for some fluctuations, they aren’t the sole correction method—the technique also relies on background corrections and calibration. The dry pellet method isn’t the standard way samples are introduced in flame photometry, and the detector is not a mass spectrometer but an optical detector such as a photomultiplier. So the statement that the flame acts as both the sample holder and the light source captured the essential mechanism of flame photometry.