Is anyone here familiar with luminol? (radical reactions)

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In summary, the conversation discusses the use of luminol in visualizing cavitation through sonochemiluminescence. The mechanism involves the oxidation of •OH by luminol, resulting in the formation of diazaquinone radical anion, which then reacts with •O to produce hydroproxide addition product and ultimately emits blue light. The person also raises the question of whether the same reaction could occur with •H radicals and seeks advice on how to investigate this further. The conversation concludes with the mention of a paper that is currently being worked on.
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rwooduk
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I am currently using luminol to visualise cavitation via sonochemiluminescence. When bubbles in solution are exposed to ultrasound they cavitate and draw vapour inside them. The bubbles crush the vapour breaking bonds and radicals are produced.

These radicals then do the following (from my own work)...

The mechanism can be described as follows; luminol (I) exists predominantly as the monoanion species (II) oxidising the •OH and producing the diazaquinone radical anion (III) [17]. This species react with •O to form a hydroproxide addition product (IV) which through decomposition and relaxation forms the aminophthalate monoanion (V), this deactivates via florescence and emits characteristic blue light at 430 nm [13, 17-20].

My question is, what if there were •H radicals in solution instead of •O radicals, could the same reaction happen?

I have the idea that I could look how luminol reacts with oxidents, or if it is used as a radical detector, but I am unsure of where to start.

Also what would the main differences be between H and O radicals in a physical sense?

Thanks in advance for any thoughts / ideas on this.
 
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Yes, all sorted now, the problem was the environment in which the reactions were taking place that could produce radicals in different numbers. Paper on the way (hopefully!)
 

FAQ: Is anyone here familiar with luminol? (radical reactions)

1. What is luminol and why is it used?

Luminol is a chemical compound that is commonly used in forensic investigations to detect the presence of blood. It is a luminescent substance that reacts with the iron in hemoglobin, causing it to glow and become visible under certain conditions.

2. How does luminol work in detecting blood?

When luminol is sprayed onto a surface, it reacts with the iron in hemoglobin to produce a blue glow. This reaction occurs because the iron in hemoglobin acts as a catalyst, breaking down the luminol molecule and releasing energy in the form of light.

3. Can luminol detect blood that has been cleaned or washed away?

Yes, luminol is able to detect blood that has been cleaned or washed away, as long as there is still some residual iron from the hemoglobin present on the surface. However, the glow may be fainter compared to fresh blood.

4. Are there any limitations to using luminol in forensic investigations?

Yes, there are some limitations to using luminol. It can produce false positives if there are other substances present that contain iron, such as rust or certain cleaning products. Additionally, the reaction is not specific to human blood and can also detect animal blood or other substances with iron.

5. Is luminol still used in modern forensic investigations?

Yes, luminol is still commonly used in modern forensic investigations, although it is often used in combination with other techniques and methods for more accurate results. It is a useful tool for detecting blood that is not visible to the naked eye and can provide valuable evidence in criminal cases.

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