Luminol Lab Report

Luminol is a white, sometimes pale yellow, crystalline solid that can create a chemiluminescence when mixed with certain oxidizing agents. In order to create luminol, there needs to be a diamindation of 3-Nitrophthalic Acid by Hydrazine, which produces 3-Nitrophthalihydrazine and is then reduced with Sodium Dithionite. The product on its own is not soluble in water but is soluble in most organic solvents. Other than emitting a blue light, luminol is also used in forensic studies. A forensic investigator can use luminol to detect traces of blood by spraying it on an area since it traces an activation oxidant in order to make it emit light. In order to create effective results, investigators must spray even amounts of the solution. The intensity

Then add 20 mL of 3% Hydrogen Peroxide. In a darkened area, add roughly 0.5 g of Potassium Hexacyanoferrate to the mixture and swirl. Do not strongly acidify the solution, since it could produce Hydrogen Cyanide gas. You could also, instead, add a layer of Potassium Hydroxide pellets to the bottom of the Erlenmeyer flask and add in enough Dimethylsulfoxide to cover the pellets. In a darkened area, add 0.20-0.3 g of luminol to the flask, stopper the flask, and shake it vigorously.

The reaction of luminol involves a base removing the nitrogen protons, creating a negative charge. This negative charge then moves onto carbonyl oxygen to form an enolate. An enolate occurs when an anionic charge is delocalized over oxygen and carbon. The oxygen will then perform a cyclic addition to the two previous carbonyl carbons. The Nitrogen will then leave the group and the oxygen will come back to form carboxylate anions, leaving 3-APA. In terms of using luminol with sodium hydroxide, the equation is as follows:

C8H7N3O2 + 2NaOH + O2N2 + Na2APA +

The usage of luminol is important because it helps us collect and examine suspect material faster, it reacts better with the dried up blood often left at scenes, and the luminescence can be reproduced by applying fresh luminol-hydrogen peroxide solutions. There are issues with using luminol since it can react with more than just blood, but the reasoning behind the usage of luminol in crime investigation results from the iron in blood catalyzing the luminescence. Even the smallest amount of iron can cause a larger amount of the luminol to react, which makes it easy to detect small amounts of