Atomic Spectrophotometry: Selectivity vs Sensitivity

For gas-phase atoms, the absorbance ($\epsilon$) is nearly zero for most wavelengths ($\lambda$) incident on the sample.

For solution-phase atoms, the absorbance ($\epsilon$) remains at its maximum value ($\epsilon_{max}$) for all wavelengths ($\lambda$) incident on the sample.

As the concentration (C) approaches infinity, the transmitted power ($P_{trans}$) approaches zero for gas-phase atoms.

For solution-phase atoms, as the concentration (C) nears infinity, the transmitted power ($P_{trans}$) approaches a non-zero value because of stray light.

If sensitivity equals $\epsilon b$, then 'high sensitivity' is achieved with solution-phase atoms.

In gas-phase atomic absorption, a notable decline in sensitivity arises because the average absorbance ($\epsilon$) across all wavelengths becomes unusually small.

If $P_{\phi}$ is the power transmitted by a reference sample, then P is approximately equal to $P_{\phi}$ indicating high sensitivity.

There exists a trade-off between selectivity and sensitivity in atomic absorption measurements, necessitating the consideration of different light sources.

A broader bandwidth signifies a more accurate specification of the wavelengths of light that interact with the sample in the monochromator.

The bandwidth measurement of 1 nm describes a means by which a slit in the monochromator specifies a precise reading of absorbance intensity ($P_{source}$).