Thanks for the video Mike. I am teaching Forensic Science at the high school level. I used you video to help me prepare for my lab on luminol. The lab went great. Thanks.
Dear Mike, this is the best video i have seen so far on this subject. My theory is that bluestar is a modified version of luminol but it is essentially the same molecule. Clearly, bluestar works better in the sense that it produces a stronger and longer reaction. This is perhaps because the manufacturers add some chemical to the formulation that helps exposing iron in the sample. I´m not pretending to have the final truth, it is just my modest opinion. Luminol is in the best case scenario a presumtptive test. It DOES NOT have any particular afinity for blood but for any substance containing iron. Cross reactions with other substances like bleach, some fruits, copper etc have been well documented. Another issue that in my view has a lot to do with the strength of the reaction is the concentration of luminol in the formula. Generally technnicians add 0.2g of luminol to 10g of sodium carbonate. The solvent is a mixture of 3% H2O2 and distilled water. Ohter formulations use sodium peborate and two different solutions which are mixed at the crime scene but I find that this is somehow difficult to do. My theory is that if you increase the amount of luminol in your mixture you will obtain a stronger reaction; nobody wants to do that since luminol is a expensive chemical. Obviously, the concentration of the blood and other factors like porosity of the surface will influence the amount of energy produced. Another reagent for this purpose is fluorescein, have you used it? God bless you and keep doing these amazing videos. I hope to have the chance to take one of your classes.
If I go to a pharmacy, what should I ask for in order to buy some small pieces of paper that turn green, just as you used in the video in order to take a preliminary test of presumed blood surfaces.
I'm curious how using a porous substance with the bluestar affects the outcome? You said in the video that the bluestar is a training sample so it will destroy DNA and that tests show that luminol does destroy DNA... Were you inferring that non-training grade bluestar doesn't destroy DNA? Thank you!
Those are good questions. The bluestar will work on porous items as well. For example, if you sprayed it on a t-shirt, the shirt would absorb the bluestar, but it will still react to the protein in the blood. I would suggest that you use a very fine mister when using it on clothing. Your second question about the DNA is a good one. Yes, the real bluestar will not destroy the DNA. The training packages are a little cheaper, so I use them for teaching, not for crime scenes. Thanks for watching.
Thanks for the video. Do you know if Bluestar reacts and shows false positives with body fluids other than blood? If it does, how common is that? Any resources or suggestions you might know of on this subject is appreciated. Thanks!
Deborah Abraham the short answer is yes. Blue star, like luminol, is a preliminary blood test that is interacting with the protein in the blood. You would need to use an OBTI test to determine if it is human blood.
Very good presentations Mike. I am curious to know if you would do a video on sound analysis of gunfire. Given the ubiquity of cameras these days it seems there would be a great deal of evidence to be gleaned from the sound recordings as to distance, rate and direction of fire, caliber used etc. I'm not law enforcement just a person interested in how forensic evidence tells stories. Thanks again.
I'm telling the truth. I needed to learn about luminol as I believe I am living in a house where someone was murdered. There appears to be blood cleaned uo from the floor boards.
David Cook Good question. While setting up and preparing for the shoot, some of the blood scrapings were probably on the table. I do a practice run before I shoot the video.
Hey is there any way to contact you personally. I have a local pd that is doing an awful job on my fathers death.... they say its a suicide because they don't want to do The work... but yet there is blood splatter all in the house. Chunks of it. He was found in the yard with a gun. I guess he shot himself in the head and then walked outside.... it's b.s.. any help or ideas how to get it taken care of would be great. Thanks..
it is perhaps because luminol does not have any particular afinity for blood but for any substance containing iron. Other chemicals like common bleach cause similar reactions.
Mike, in a training class I attended, scraping dried blood for collection was advised against, as this could cause micron-sized particles of the blood to become airborne potentially risking the health of the crime scene tech/investigator. I can see this video is dated but I’m just wondering if there is any circumstance you could think of in which scraping the blood evidence would benefit over moistening a swab to collect the sample? Is this something still practiced?
Ylina Isabel Excellent comment! You are 100% correct. I would not recommend scraping blood anymore. I suppose there could be a situation where it would be appropriate, but it would be very uncommon. Thanks for watching.
Yes you can, but not with Luminol or Bluestar. You need to use a hemeglobin test. I use Hexagon OBTI tests from Lynn Peavey Corp. It is simple to use with results in less than three minutes. This screening test rapidly verifies if a bloodstain is human blood. Hexagon OBTI contains a two-part test: a collection tube for the blood sample and a test bar.
Yes we do, different tests determines that, i.e. Hemastix (presumptive test) to determine any kind of blood, then Hexagon Obti (confirmatory test) to determine human blood. There is more facts, but one would rather not go too deep as the wrong elements can get too clever as use it for the wrong reasons
Mike McCutcheon Okay, thanks... I's a junior in high school and I am doing a demonstration for my final project in AP Chemistry course & I'm doing my project on the chemistry of luminol. Thanks for the help!
