In the nine-year compulsory education biology class, we have initially studied the basic experiments of related dyeing: in the experiment, the chromatin (body) is dyed, and alkaline dyes such as gentian violet solution or acetic acid magenta solution must be used. The gentian violet or magenta is prepared by dissolving in an acetic acid solution, and the pH of the prepared gentian violet solution is less than about 7 (acidic). Chromatin (body) is easily stained dark by basic dyes. Then why is the gentian violet solution called alkaline dyeing agent? To enhance the dyeing effect, it is necessary to strengthen the principle and purpose of learning acid dyeing.
As a coloring agent, two conditions must be met: one is to have color; the other is to have affinity with the dyed tissue.
The color of the dye and its affinity to the tissue are determined by the molecular structure of the dye itself, and the color-forming chromophore and the color-promoting group that produces affinity with the tissue determine the dyeing properties of the dye. As a dye substance, in addition to a chromophoric group, a color-improving group for ionizing a compound is required.
For example, a dye compound often forms a chromophore group from a nitro group (-NO2), an azo group (-N=N-), a vinyl group, or the like, and an acidic group such as -OH, -SO3H, or -COOH, and A basic group such as NH2, -NHCH3, or -N(CH3)2 constitutes a color-donating group. Their presence ionizes the dye material, enhances polarity, promotes the interaction between the dye and the tissue, and produces a dyeing effect. We refer to dyes having an acidic or basic group in the color-promoting group as acidic or basic dyes, respectively.
The principle of acid dyeing: The day of dyeing is to make the tissue and the intracellular structure differently dyed by means of one or more dyes, so that the internal structure of the cells can be clearly observed under the microscope and the correct judgment can be made.
Chromophore group: A derivative of benzene has an absorption band in the visible region. The apparent absorption bands of these derivatives are related to the instability of their valence bonds. For example, hydroquinone is colorless, and when it oxidizes, it loses two hydrogen atoms, and its molecules become yellowish. The enamel ring that produces the color is called a chromophoric group.
If a compound contains several rings, as long as one of the oxime rings emits a color, the chromophore is called a chromogen. A chromophore: a substance that enables the compound to ionize. Auxiliary atomic group (acid-base group). It further deepens the color of the dye and gives it an affinity for the tissue being dyed. The nature of the coercive group determines that the dye is acidic and basic.
The basic dye has an alkaline color-promoting group, and the colored portion produced in the solvent is a positively charged cation, and the kiss is combined with a negatively charged substance in the tissue cells to develop color. For example, the main chemical component in the nucleus, deoxyribonucleic acid, is easily stained with hematoxylin blue, which is called basophilic. The acid dye has an acidic chromophore group, and the colored portion in the lysozyme is an anion, which is easy to bind to the positively charged portion of the tissue cell to develop color. This property is called eosinophilic, such as a protein in the cytoplasm. It is easily red or orange in combination with eosin or orange.
The principle of tissue cell staining has not been satisfactorily explained, and may be a physical effect, a chemical action, or a combination of both.
The physical function of dyeing is to use capillary phenomenon, permeation, absorption and adsorption to make the pigment particles of the dye firmly enter the tissue cells and make them color.
The chemical action of staining is that the dye that penetrates into the tissue cells chemically reacts with its corresponding substance to produce a colored compound.
Each dye has two properties, namely the production of color; the collection is organized to form affinity. These two properties are mainly produced by chromogenic genes and helper genes.
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Label: Strengthening the dyeing effect It is necessary to strengthen the principle and purpose of learning acid dyeing
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