Haem iron
Definition
The iron atom at the centre of the porphyrin ring in haemoglobin. It catalyses the luminol reaction by cycling between oxidation states during the decomposition of hydrogen peroxide, generating the excited intermediate that emits light.
Related terms
- Barrier filter
- An optical long-pass filter placed over the camera lens and worn as goggles by the examiner during ALS examination; blocks the excitation...
- Chemiluminescence
- Light emission produced directly by a chemical reaction, without requiring an external light source. Luminol's reaction with haemoglobin in alkaline peroxide is...
- Excitation light
- The external light source used to excite a fluorescent molecule. For fluorescein the optimum excitation is around 490-510 nm (blue-green). The light...
- Fluorescence
- Light emission following absorption of light at a shorter (higher-energy) wavelength. Fluorescein absorbs blue-green excitation light and emits yellow-green light. The emitted...
- Latent bloodstain
- A bloodstain that is no longer visible to the naked eye under normal lighting conditions, either because it has been diluted, cleaned,...
Explained in
- Luminol and FluoresceinThe iron atom at the centre of the porphyrin ring in haemoglobin. It catalyses the luminol reaction by cycling between oxidation states during the decompositio...