![CSI Chemistry Luminol](https://i0.wp.com/www.compoundchem.com/wp-content/uploads/2014/10/CSI-Chemistry-Luminol-2016.png?resize=700%2C495&ssl=1)
Anyone who’s watched CSI or similar shows knows that, whenever the investigating team are on the scene of a gruesome and bloody murder, luminol solution gets sprayed liberally over absolutely everything. The result is a pale blue luminescence whenever the solution meets blood, which itself is a consequence of a chemical reaction that the blood gives a helping hand to. Here, we look at this reaction – and what horseradish has to do with it.