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How can you test if something is blood?
- Thread starter Kitty L
- Start date
Good question !!.
The another way to detect the blood spots through chemical reagents.
There are several forms of reagent tests that can be udse to develop blood that are not visible to the naked eye.
The following is a list and description of the various reagent tests available for fingerprints.
Ø Amido Black - dye that stains the protein found in blood and causes a blue-black reaction and should only be utilized to enhance blood-contaminated prints. This test should only be performed on non-porous materials. All blood samples should be obtained prior to utilizing Amido Black as it can destroy body fluid evidence.
The reagent tests will produce either a color reaction or will glow depending on the test performed. The tests are based upon the properties of hemoglobin in the blood .
There are color tests that provide a rapid change in color if the substance is positive for blood. There are five different color tests that can be performed: benzidine, phenolphthalein, o-tolidine, tetramethylbenzidine (TMB), and leucomalachite green (LMG).
Benzidine will have a blue color if the substance is likely to be blood. This chemical is carcinogenic and is no longer in use by most scientists. Phenolphthalein is a chemical that is still utilized today and is usually referred to as the Kastle-Meyer test. When phenolphthalein reacts with the hemoglobin, it produces a pink color, but other substances may react with phenolphthalein producing a false positive. O-Tolidine is very similar in make as benzidine and produces a blue positive reaction. This reagent test has been gradually replaced by the use of tetramethylbenzidine because of its carcinogenic properties. Tetramethylbenzidine will produce a green to blue-green color when blood is the likely substance. The most common way to use this test is through Hemastix, which contains a plastic strip with a filter paper on the tip containing TMB and peroxidase. Luecomalachite Green will produce a positive result with a green color. This test is not nearly as accurate or sensitive as TMB and phenolphthalein.
The other reagent tests that are available for testing blood would be chemiluminescence, fluorescence, luminol, and fluorescein. These four reagent tests have a better accuracy rate and are more sensitive than the color tests. The downside of utilizing these reagent tests is that they may destroy valuable blood and DNA evidence. When these tests are utilized they produce a glowing color that identifies blood and can detect blood that is old and has been cleaned. These products should be used minimally such as spraying each corner and the middle of the room. This method of spraying will prevent too much damage being caused to DNA and blood evidence that may be present.
For your feed back please mail me to [email protected]
The another way to detect the blood spots through chemical reagents.
There are several forms of reagent tests that can be udse to develop blood that are not visible to the naked eye.
The following is a list and description of the various reagent tests available for fingerprints.
Ø Amido Black - dye that stains the protein found in blood and causes a blue-black reaction and should only be utilized to enhance blood-contaminated prints. This test should only be performed on non-porous materials. All blood samples should be obtained prior to utilizing Amido Black as it can destroy body fluid evidence.
The reagent tests will produce either a color reaction or will glow depending on the test performed. The tests are based upon the properties of hemoglobin in the blood .
There are color tests that provide a rapid change in color if the substance is positive for blood. There are five different color tests that can be performed: benzidine, phenolphthalein, o-tolidine, tetramethylbenzidine (TMB), and leucomalachite green (LMG).
Benzidine will have a blue color if the substance is likely to be blood. This chemical is carcinogenic and is no longer in use by most scientists. Phenolphthalein is a chemical that is still utilized today and is usually referred to as the Kastle-Meyer test. When phenolphthalein reacts with the hemoglobin, it produces a pink color, but other substances may react with phenolphthalein producing a false positive. O-Tolidine is very similar in make as benzidine and produces a blue positive reaction. This reagent test has been gradually replaced by the use of tetramethylbenzidine because of its carcinogenic properties. Tetramethylbenzidine will produce a green to blue-green color when blood is the likely substance. The most common way to use this test is through Hemastix, which contains a plastic strip with a filter paper on the tip containing TMB and peroxidase. Luecomalachite Green will produce a positive result with a green color. This test is not nearly as accurate or sensitive as TMB and phenolphthalein.
The other reagent tests that are available for testing blood would be chemiluminescence, fluorescence, luminol, and fluorescein. These four reagent tests have a better accuracy rate and are more sensitive than the color tests. The downside of utilizing these reagent tests is that they may destroy valuable blood and DNA evidence. When these tests are utilized they produce a glowing color that identifies blood and can detect blood that is old and has been cleaned. These products should be used minimally such as spraying each corner and the middle of the room. This method of spraying will prevent too much damage being caused to DNA and blood evidence that may be present.
For your feed back please mail me to [email protected]
D
dutchbob1
Guest
consult a mosquito