Seeing Sodium (or Something More?) in the Flame

Ever wonder what metals look like when they burn? In our metallurgical lab, we use Inductively Coupled Plasma (ICP) spectroscopy to analyze metal concentrations in solution. One key indicator that something unusual is in the mix? The color of the plasma flame!

👀 Check out these two images—one shows the normal blue flame, while the other is bright orange. That orange glow? It’s a telltale sign of high sodium content, which emits a strong orange-yellow light at 589 nm. But sodium isn’t the only element that can change the color of the flame.

Other metals that can contribute to an orange flame include:
🟠 Calcium (Ca) – Can give off an orange-red hue.
🟠 Iron (Fe) – At high concentrations, iron can add an orange glow to the flame.
🟠 Strontium (Sr) – Primarily red, but can have some orange tones in its emission.
🟠 Potassium (K) – Usually violet, but at high concentrations, it can cause a faint orange-pink tint.
🟠 Lithium (Li) – Mostly red, but can mix with sodium or calcium to give an orange-red appearance.

While ICP analysis gives us precise metal concentrations, quick visual cues like this can provide immediate insight into sample composition. If an orange flame appears unexpectedly, we might need to adjust dilution factors or use internal standards to maintain accuracy in our results.