Search results
Results from the WOW.Com Content Network
It is advised to check the references for photos of reaction results. [1] Reagent testers might show the colour of the desired substance while not showing a different colour for a more dangerous additive. [2] For this reason it is essential to use multiple different tests to show all adulterants.
Dilute solutions containing iodine–starch complex. Using starch as an indicator can help create a sharper color change at the endpoint (dark blue to colorless). The color above can be seen just before the endpoint is reached. To a known volume of sample, an excess but known amount of I − is added, which the oxidizing agent then oxidizes to I 2.
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 Minor test (also known as Minor's test, the starch–iodine test, and the iodine–starch test), described by Victor Minor in 1928, [1] is a qualitative medical test that is used to evaluate sudomotor function (perspiration or sweating).
Melzer's is used by exposing fungal tissue or cells to the reagent, typically in a microscope slide preparation, and looking for any of three color reactions: Amyloid or Melzer's-positive reaction, in which the material reacts blue to black. Pseudoamyloid or dextrinoid reaction, in which the material reacts brown to reddish brown.
Most modern injected radiographic positive contrast media are iodine-based. Iodinated contrast comes in two forms - ionic and nonionic compounds. Nonionic contrast is significantly more expensive than ionic (about three to five times the cost), but nonionic contrast tends to be safer for the patient, causing fewer allergic reactions and ...
Counterstain, which is usually positively charged safranin or basic fuchsine, is applied last to give decolorized gram-negative bacteria a pink or red color. [3] [20] Both gram-positive bacteria and gram-negative bacteria pick up the counterstain. The counterstain, however, is unseen on gram-positive bacteria because of the darker crystal ...
Melzer's reagent is an aqueous solution of chloral hydrate, potassium iodide, and iodine.Depending on the formulation, it consists of approximately 2.50-3.75% potassium iodide and 0.75–1.25% iodine, with the remainder of the solution being 50% water and 50% chloral hydrate.