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Being a fan of forensic investigation stuff, I've always been intrigued by luminol, that stuff they spray on a crime scene to make trace amounts of blood glow in the dark. Glowing blood! How cool is that? Well, I figured I should see if I can make some of my own. (Quick note: The photos on this page are from a second attempt to make luminol. I changed a few things the second time around, so if the photos don't match exactly don't fret too much.) The first step was to learn a little about the substance. I figured a cruise through the Sigma-Aldrich chemical supply website might give me an idea of what I was in for. The price wasn't cheap, about $25 for "5g". Gallons or grams? I thought it was something you spray, so why are they measuring in grams? I was surprised to learn that the stuff is not a liquid, but a powder. Oh. Well, you can't spray powder, so clearly it needed to be mixed with a liquid. Next, I had to research how you actually mix the solution. It took some effort, but I finally found a scientific research paper, something about comparing luminol to some competing substance. "We stained identical shirts with blood and tested the leading brand and new Lemon-Fresh Super Luminol™ and found that Luminol makes your reds glow brighter than the competition!" Not sure if that's exactly what it said, but in their "methods" section they gave a detailed account of how the luminol was prepared. Fortunately, the steps looked pretty simple.
OK, I knew what a couple of those things were. Hey, I'm not a chemist. I think I got a C in the one and only chemistry class I ever took, and that was with effort. So still more research was necessary to figure out what that stuff was in layman's terms. Apparently, luminol works by reacting with the iron in hemoglobin. The truth is, luminol has no special affinity for blood, just any sort of iron. I guess forensics experts don't actually use the stuff much because of the large potential for false positives. To facilitate the hemoglobin and luminol mixing you have to destroy the blood cell walls, which is another reason the forensic folks don't use luminol much—destroying cell walls tends to destroy DNA evidence, too. Anyway, this is where the Na2CO3 comes in, a.k.a. washing soda or just soda. Arm & Hammer makes some, and it's available in the laundry detergent aisle. Distilled water is easy. Even I know what that is. I assume there's some difference between distilled and drinking water, but heck if I know what that difference is. I made sure to get the distilled stuff. H2O2 is hydrogen peroxide, the bubbly stuff you put on wounds. The stuff they sell in the pharmacy works just fine. This acts as an oxidizer. An oxidizer is simply a chemical that adds oxygen into the equation, because it seems any reaction worth it's salt needs some oxygen breathed into it to make things happen. Now the only thing left to get was the luminol.
Ordering from a chemical supply house is a somewhat tricky task. You can't just order up a gallon of sulfuric acid and hit "Check Out". No, they wanna know why you want to order such-and-such chemical to make sure you're not making explosives or something. And this was even before September 11th, so it's probably impossible to order anything now. Fortunately, luminol is not a real dangerous substance, so explaining that I wanted it for educational reasons seemed to be good enough. Although, since then I've been trying to think of what nefarious purposes you could put luminol to work for, but I'm having difficulty. All I can figure is someone might use it to check how well they cleaned up the scene of a murder they commited, kind of like those red tablets you got as a kid where you chew them after you brush and it turns any plaque you missed pink.
OK, so I finally got everything I needed. I also invested in a spray bottle, some rubbing alcohol, and razor blades. I needed a sample of blood, after all. More on that in a bit. I had to figure out how I was going to measure these quantities. I own no scale, and have no access to one, either. Crap! So I had to improvise one. I figured if I could find some objects that weigh approximately the same as the two quantities I needed (0.2 and 10.0 grams) I could make an impromptu balance and compare the weight of the chemical to the standard weighted object. So I made one using a ruler for a beam, a paperclip taped to my stove hood as a balance axis, and some aluminum foil baskets to hold the weights. That worked well. Now I needed some small objects of a known weight to compare them to. More research! Coins were the first possibility. I found out a penny weighs about 3.11 grams, and a dime 2.25 grams. After a little algebra I figured 3 dimes and a penny would add up to 9.86 grams. Pretty close! The 0.2 gram weight would be harder. I knew my plastic airsoft BBs were a pretty consistent weight, and I figured out about 18 of them equal the weight of a dime, giving them an individual weight of 0.125 grams each. Ehh, with a little fudging that's about two BBs worth.
So I put all the measured chemicals into the spray bottle and mixed them up. Now the hard part. I had to get some blood. I've never drawn blood intentionally before, and it's nice to know my self-preservation instincts are in good order. I cleaned an area on the back of my hand that I figured wouldn't stretch too much (scabs in flexible areas are painful), and I "autoclaved" the razor blade (read: held over Zippo flame for a few seconds). I prepared to make a quick, small, shallow slice across the skin. I wasn't looking to do surgery here, just to draw a little blood. The first pass did nothing. The self preservation thing said, "What on earth are you doing? I'm not letting you run a razor blade into your skin!" The second time, I shoved self preservation aside and just jerked the blade across the skin real fast. It stung a little, and it bled a lot more than I expected. Good, the more the merrier.
Luminol has a warning that it's an irritant, so I wasn't about to spray the stuff into my wound. I wiped some of the blood on a paper towel and sprayed that instead. And it worked! It's a beautiful color, too. Reminds me of the color of an Indiglo watch.
Excitedly, I started spraying all kinds of stuff. I was disappointed to find that my apartment had not been the site of any grisly murders. Man, nothing interesting ever happens to me. I did discover, however, that those tacky gold flecks in old counter tops seem to contain some iron in them, because they glowed. Screws on lightswitch plates also glowed, and other metallic objects, but there were no splatters of organic material to be found. The glowing is rather faint, and it only lasts a few minutes. It's most intense in the first minute or so after spraying, and respraying will boost the brightness for a little while. Soon after, some friends came over to check it out. After a short demo, I set the spray bottle down on the table next to my printer, and we all headed out to go do something. When I came home, I learned that luminol solution has a short shelf life. It oxidizes over time and releases a gas (hopefully nothing deadly). But it was in a sealed sprayer bottle, and the only way out of that bottle was through the nozzle. So for several hours while I was out, a goodly portion of the bottle's contents oozed out the nozzle and all over my table! Fortunately, my printer had little feet on it that kept it above the rather shallow water level, so it didn't get wet, but I did realize that luminol is something you mix up only when you're ready to use it! An interesting fact. The bottle glows ever so slightly. I think blood acts as a catylist, making the glowing more intense, but the stuff glows just fine on its own. On my second experimentation with luminol it glowed in the bottle much brighter, or else I just noticed it more. I was able to light my way in the dark by using the bottle as a lantern. That's pretty bright! I think I undermeasured the amount of luminol the first time around, and this time it may have been slightly overmeasured, which would explain why it was brighter. I read that luminol also reacts with certain metals and chlorine bleach, so I just dipped a cotton swab into some bleach, then into the luminol bottle. The neat thing about absorbent materials is they seem to lengthen the reaction time. What was really cool was that the cotton glowed unevenly and actively, almost like blue television static. Very pretty! When I was through I poured the remainder of the luminol into my bathroom sink and poured a bit of bleach in. Wow! It reacts really intensely! But it only lasts for a fraction of a second, and it leaves behind a nasty yellow liquid. I turned on the bathroom fan and tried not to breath much, because I know any reaction with bleach tends to release chlorine gas, so I didn't wanna wind up dead or something. When I was mopping up the spilled liquids afterwards I could feel the paper towel getting warmer when the bleach and luminol were reacting. The reaction was so bright I could see little blue flashes with the lights on! Anyway, that's the end of my tale. Don't take any chemistry advice from me, because no doubt I did something you're not supposed to. But hopefully I helped give you a layman's perspective on how the stuff is used. Here are some good links about luminol (including photos and movies):
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