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Starch is a substance common to most plant cells and so a weak iodine solution will stain starch present in the cells. Iodine is one component in the staining technique known as Gram staining, used in microbiology. Used as a mordant in Gram's staining, iodine enhances the entrance of the dye through the pores present in the cell wall/membrane.
The cut surface of an apple stained with iodine, indicating a starch level of 4–5. The iodine–starch test is a chemical reaction that is used to test for the presence of starch or for iodine. The combination of starch and iodine is intensely blue-black. [1] [2] The interaction between starch and the triiodide anion (I − 3) is the basis ...
The compound was first produced by the reaction of mercury(II) nitrate and iodine in ether. [1] Other nitrate salts and solvents can also be used. [1] As a gas it is slightly unstable, decaying with a rate constant of −3.2×10 −2 s −1. [2] The possible formation of this chemical in the atmosphere and its ability to destroy ozone have been ...
The solution remaining yellow (pH = 6.2 or above) indicates a negative test, meaning the butanediol fermentation is used. The VP test uses alpha-naphthol and potassium hydroxide to test for the presence of acetylmethylcarbinol (acetoin), an intermediate of the 2,3-butanediol fermentation pathway. After adding both reagents, the tube is shaken ...
Gram stains yield results much more quickly than culturing, and are especially important when infection would make an important difference in the patient's treatment and prognosis; examples are cerebrospinal fluid for meningitis and synovial fluid for septic arthritis.
Nitrate reduction. Mycobacteria containing nitroreductase catalyze the reduction from nitrate to nitrite. The presence of nitrite in the test medium is detected by addition of sulfanilamide and n-naphthylethylendiamine. If nitrate is present, red diazonium dye is formed. [1] Photoreactivity of mycobacteria;
This is an accepted version of this page This is the latest accepted revision, reviewed on 22 December 2024. This article is about the chemical element. For other uses, see Iodine (disambiguation). Chemical element with atomic number 53 (I) Iodine, 53 I Iodine Pronunciation / ˈ aɪ ə d aɪ n, - d ɪ n, - d iː n / (EYE -ə-dyne, -din, -deen) Appearance lustrous metallic gray solid ...
Nitrate Test by using Brown Ring Test. A common nitrate test, known as the brown ring test [2] can be performed by adding iron(II) sulfate to a solution of a nitrate, then slowly adding concentrated sulfuric acid such that the acid forms a layer below the aqueous solution. A brown ring will form at the junction of the two layers, indicating the ...