Whilst flame atomic absorption spectroscopy (FAAS) is a robust technique used widely in the analytical chemistry world, the accuracy widely depends heavily on how effectively you convert your sample into a stable population of ground-state atoms. There are a few ways we can do this, so let’s focus on two of the most important ways in FAAS we can increase the sensitivity and optimise our analysis.
1. Optimise burner alignment
The light beam from the hollow cathode lamp (HCL), Figure 1, is an important part of AAS sensitivity, the light they produce needs to be passing through the correct part of the flame to achieve the best sensitivity and enhance analysis, therefore perform a “burner head alignment”!
The burner should first be aligned vertically, to ensure the beam of light from the HCL passes through the most atom-dense part of the flame (usually 5-10 mm) above the burner slot. Once aligned vertically, a horizontal alignment can be performed, this rotates and centres the burner head, so the slot runs parallel to the optical path. This maximises path length and increases absorbance.
2. Burner maintenance for stable baselines and good signal
A flickering flame can be caused by carbon build-up or salt deposits on the burner, Figure 2. Cleaning and conditioning are great ways to remove any source of potential contamination, allowing the flame to burn cleaner improving baseline stability and analyte signal.
Overall, optimising burner alignment and maintaining a clean burner are fundamental steps for maximising AAS sensitivity. Together, these practices improve light throughput through the atom-rich region of the flame, resulting in enhanced absorbance, better baseline stability and more reliable results.
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