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The Kastle–Meyer test is a presumptive blood test, first described in 1903, in which the chemical indicator phenolphthalein is used to detect the possible presence of hemoglobin. It relies on the peroxidase -like activity of hemoglobin in blood to catalyze the oxidation of phenolphthalin (the colorless reduced form of phenolphthalein) into ...
Phenolphthalein is slightly soluble in water and usually is dissolved in alcohols in experiments. It is a weak acid, which can lose H + ions in solution. The nonionized phenolphthalein molecule is colorless and the double deprotonated phenolphthalein ion is fuchsia. Further proton loss in higher pH occurs slowly and leads to a colorless form.
Duquenois-Levine reagent for cannabis; Kastle-Meyer test for blood; Malachite green test for blood; Marquis reagent for narcotics and alkaloids; Benzidine test for blood which changes from clear to blue in color with the presence of blood; Luminol, phenolphthalein, Hemastix, Hemident, and Bluestar are all also used for blood testing [citation ...
As with all presumptive tests, this technique can produce false positive results due to metals and strong chemicals, such as bleach, that will also react. Another common presumptive test is the Kastle-Meyer or Phenolphthalein test. This is a catalytic test that detects the heme group in blood that transports oxygen and carbon dioxide. [5]
If the test solution is of a dark colour, it is preferable to use a paper universal indicator, such as Hydrion paper. Solution: The main components of a universal indicator, in the form of a solution, are thymol blue, methyl red, bromothymol blue, and phenolphthalein.
Phenol red was used by Leonard Rowntree and John Geraghty in the phenolsulfonphthalein test to estimate the overall blood flow through the kidney in 1911. [9] It was the first test of kidney function and was used for almost a century but is now obsolete. The test is based on the fact that phenol red is excreted almost entirely in the urine.
The BBC’s iconic 1995 TV adaptation of Jane Austen’s Pride and Prejudice reportedly cost roughly £1 million per episode (about $9.6 million) to make. And it shows. The attention to period ...
Ferroxyl indicator, or rust indicator, is a solution containing potassium hexacyanoferrate(III), phenolphthalein and sodium chloride. It turns blue in the presence of Fe 2+ ions, and pink in the presence of hydroxide (OH −) ions. It can be used to detect metal oxidation, and is often used to detect rusting in various situations.